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Concurrent measurement of strain and chemical reaction rates in a calcite grain pack undergoing pressure solution: Evidence for surface-reaction controlled dissolution

Pressure solution is inferred to be a significant contributor to sediment compaction and lithification, especially in carbonate sediments. For a sediment deforming primarily by pressure solution, the compaction rate should be directly related to the rate of calcite dissolution, transport along grain contacts, and calcite reprecipitation. Previous experimental work has shown that there is evidence that deformation in wet calcite grain packs is consistent with control by pressure solution, but considerable ambiguity remains regarding the rate limiting mechanism. We present the results of laboratory compaction experiments designed to directly measure calcite dissolution and precipitation rates (recrystallization rates) concurrently with strain rate to test whether measured rates are consistent with predicted rates both in absolute magnitude and time evolution. Recrystallization rates are measured using trace element chemistry (Sr/Ca, Mg/Ca) and isotopes (87Sr/86Sr) of fluids flowing slowly through a compacting grain pack as it is being triaxially compressed. Imaging techniques are used to characterize the grain contacts and strain effects in the post-experiment grain pack. Our data show that calcite recrystallization rates calculated from all three geochemical parameters are in approximate agreement and that the rates closely track strain rate. The geochemically inferred rates are close to predicted rates in absolute magnitude. Uncertainty in grain contact dimensions makes distinguishing between surface reaction control and diffusion control difficult. Measured reaction rates decrease faster than predicted from standard pressure solution creep flow laws. This inconsistency may indicate that calcite dissolution rates at grain contacts are more complex, and more time-dependent, than suggested by geometric models designed to predict grain contact stresses.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

RTOG 0211: A Phase 1/2 Study of Radiation Therapy With Concurrent Gefitinib for Newly Diagnosed Glioblastoma Patients

Purpose: To determine the safety and efficacy of gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, in combination with radiation for newly diagnosed glioblastoma (GBM) patients. Methods and Materials: Between March 21, 2002, and May 3, 2004, Radiation Therapy Oncology Group (RTOG) 0211 enrolled 31 and 147 GBM patients in the phase 1 and 2 arms, respectively. Treatment consisted of daily oral gefinitnib started at the time of conventional cranial radiation therapy (RT) and continued post RT for 18 months or until progression. Tissue microarrays from 68 cases were analyzed for EGFR expression. Results: The maximum tolerated dose (MTD) of gefitinib was determined to be 500 mg in patients on non-enzyme-inducing anticonvulsant drugs (non-EIAEDs). All patients in the phase 2 component were treated at a gefitinib dose of 500 mg; patients receiving EIADSs could be escalated to 750 mg. The most common side effects of gefitinib in combination with radiation were dermatologic and gastrointestinal. Median survival was 11.5 months for patients treated per protocol. There was no overall survival benefit for patients treated with gefitinib + RT when compared with a historical cohort of patients treated with RT alone, matched by RTOG recursive partitioning analysis (RPA) class distribution. Younger age was significantly associated with better outcome. Per protocol stratification, EGFR expression was not found to be of prognostic value for gefitinib + RT-treated patients. Conclusions: The addition of gefitinib to RT is well tolerated. Median survival of RTOG 0211 patients treated with RT with concurrent and adjuvant gefitinib was similar to that in a historical control cohort treated with radiation alone.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Epidermal Growth Factor Receptor Expression As Prognostic Marker in Patients With Anal Carcinoma Treated With Concurrent Chemoradiation Therapy

Purpose: To investigate the prognostic value of epidermal growth factor receptor (EGFR) expression in pretreatment tumor biopsy specimens of patients with anal cancer treated with concurrent 5-fluorouracil and mitomycin C-based chemoradiation therapy (CRT). Methods and Materials: Immunohistochemical staining for EGFR was performed in pretreatment biopsy specimens of 103 patients with anal carcinoma. EGFR expression was correlated with clinical and histopathologic characteristics and with clinical endpoints, including local failure-free survival (LFFS), colostomy-free survival (CFS), distant metastases-free survival (DMFS), cancer-specific survival (CSS), and overall survival (OS). Results: EGFR staining intensity was absent in 3%, weak in 23%, intermediate in 36% and intense in 38% of the patients. In univariate analysis, the level of EGFR staining was significantly correlated with CSS (absent/weak vs intermediate/intense expression: 5-year CSS, 70% vs 86%, P=.03). As a trend, this was also observed for DMFS (70% vs 86%, P=.06) and LFFS (70% vs 87%, P=.16). In multivariate analysis, N stage, tumor differentiation, and patients’ sex were independent prognostic factors for CSS, whereas EGFR expression only reached borderline significance (hazard ratio 2.75; P=.08). Conclusion: Our results suggest that elevated levels of pretreatment EGFR expression could be correlated with favorable clinical outcome in anal cancer patients treated with CRT. Further studies are warranted to elucidate how EGFR is involved in the response to CRT.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Long-term Follow-up Results of a Multi-institutional Phase 2 Study of Concurrent Chemoradiation Therapy for Locally Advanced Cervical Cancer in East and Southeast Asia

Purpose: To report the long-term survival and toxicity of a multi-institutional phase 2 study of concurrent chemoradiation therapy (CCRT) for locally advanced cervical cancer in east and southeast Asia. Methods and Materials: Ten institutions from 8 Asian countries participated in the study. Between April 2003 and March 2006, 120 patients (60 with bulky stage IIB and 60 with stage IIIB) were treated with CCRT. Radiation therapy consisted of pelvic external beam radiation therapy and either high-dose-rate or low-dose-rate intracavitary brachytherapy. Five cycles of weekly cisplatin (40 mg/m{sup 2}) were administered during the course of radiation therapy. Treatment results were evaluated by the rates of local control, overall survival, and late toxicities. Results: Median follow-up was 63.7 months, and the follow-up rate at 5 years was 98%. The 5-year local control and overall survival rates for all patients were 76.8% and 55.1%, respectively. The 5-year rates of major late toxicities of the rectum and bladder were 7.9% and 0%, respectively. Conclusions: The long-term results have suggested that CCRT is safe and effective for patients with locally advanced cervical cancer in east and southeast Asia. However, further efforts are needed to improve overall survival.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Prognostic Significance of Tumor Response as Assessed by Sequential {sup 18}F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography During Concurrent Chemoradiation Therapy for Cervical Cancer

Purpose: To investigate the prognostic role of metabolic response by the use of serial sets of positron emission tomography/computed tomography (PET/CT) in patients with cervical cancer who were treated with concurrent chemoradiation therapy (CCRT). Methods and Materials: A total of 60 patients who were treated with CCRT between February 2009 and December 2010 were analyzed. Three sequential PET/CT images were acquired for each patient: pre-CCRT, during-CCRT at 4 weeks of CCRT, and 1 month post-CCRT PET/CT. Metabolic responses were assessed qualitatively. The percentage changes in the maximum values of standardized uptake value (ΔSUV{sub max}%) from the PET/CT images acquired pre-CCRT and during-CCRT were calculated. Receiver operating characteristic (ROC) curve analysis was performed to evaluate whether ΔSUV{sub max}% could predict complete response (CR) on the post-CCRT PET/CT and to identify the best cutoff value. Prognostic factors of progression-free survival (PFS) were analyzed. Results: During-CCRT PET/CT showed that 8 patients (13%) had CR, and the other 52 patients (87%) had partial response (PR). On the post-CCRT PET/CT, 43 patients (73%) had CR, 12 patients (20%) had PR, and 4 patients (7%) had progressive disease. The average SUV{sub max} in primary tumors was 16.3 (range, 6.4-53.0) on the pre-CCRT PET/CT images and 5.3 (range, 0-19.4) on the during-CCRT PET/CT images. According to ROC curve analysis, ΔSUV{sub max}% could predict CR response on post-CCRT PET/CT (P<.001, cutoff value of 59.7%). In all patients, the PFS rate was 71.9% at 2 years. Multivariate analysis showed that ΔSUV{sub max}% ≥60% (P=.045) and CR response on the post-CCRT PET/CT (P=.012) were statistically significant predictors of PFS. Conclusion: Metabolic responses on the during-CCRT images at 4 weeks of treatment and 1-month post-CCRT PET/CT images may predict treatment outcomes in patients with cervical cancer. ΔSUV{sub max}% ≥60% at 4 weeks of CCRT may predict CR response on 1-month post-CCRT PET/CT and also PFS.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Prospective Evaluation of Acute Toxicity and Quality of Life After IMRT and Concurrent Chemotherapy for Anal Canal and Perianal Cancer

Purpose: A prospective cohort study was conducted to evaluate toxicity, quality of life (QOL), and clinical outcomes in patients treated with intensity modulated radiation therapy (IMRT) and concurrent chemotherapy for anal and perianal cancer. Methods and Materials: From June 2008 to November 2010, patients with anal or perianal cancer treated with IMRT were eligible. Radiation dose was 27 Gy in 15 fractions to 36 Gy in 20 fractions for elective targets and 45 Gy in 25 fractions to 63 Gy in 35 fractions for gross targets using standardized, institutional guidelines, with no planned treatment breaks. The chemotherapy regimen was 5-fluorouracil and mitomycin C. Toxicity was graded with the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3. QOL was assessed with the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 and CR29 questionnaires. Correlations between dosimetric parameters and both physician-graded toxicities and patient-reported outcomes were evaluated by polyserial correlation. Results: Fifty-eight patients were enrolled. The median follow-up time was 34 months; the median age was 56 years; 52% of patients were female; and 19% were human immunodeficiency virus—positive. Stage I, II, III, and IV disease was found in 9%, 57%, 26%, and 9% of patients, respectively. Twenty-six patients (45%) required a treatment break because of acute toxicity, mainly dermatitis (23/26). Acute grade 3 + toxicities included skin 46%, hematologic 38%, gastrointestinal 9%, and genitourinary 0. The 2-year overall survival (OS), disease-free survival (DFS), colostomy-free survival (CFS), and cumulative locoregional failure (LRF) rates were 90%, 77%, 84%, and 16%, respectively. The global QOL/health status, skin, defecation, and pain scores were significantly worse at the end of treatment than at baseline, but they returned to baseline 3 months after treatment. Social functioning and appetite scores were significantly better at 12 months than at baseline. Multiple dose-volume parameters correlated moderately with diarrhea, skin, and hematologic toxicity scores. Conclusion: IMRT reduces acute grade 3 + hematologic and gastrointestinal toxicities compared with reports from non-IMRT series, without compromising locoregional control. The reported QOL scores most relevant to acute toxicities returned to baseline by 3 months after treatment.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Neoadjuvant Sandwich Treatment With Oxaliplatin and Capecitabine Administered Prior to, Concurrently With, and Following Radiation Therapy in Locally Advanced Rectal Cancer: A Prospective Phase 2 Trial

Purpose: Systemic failure remains the major challenge in management of locally advanced rectal cancer (LARC). To optimize the timing of neoadjuvant treatment and enhance systemic control, we initiated a phase 2 trial to evaluate a new strategy of neoadjuvant sandwich treatment, integrating induction chemotherapy, concurrent chemoradiation therapy, and consolidation chemotherapy. Here, we present preliminary results of this trial, reporting the tumor response, toxicities, and surgical complications. Methods and Materials: Fifty-one patients with LARC were enrolled, among which were two patients who were ineligible because of distant metastases before treatment. Patients were treated first with one cycle of induction chemotherapy consisting of oxaliplatin, 130 mg/m² on day 1, with capecitabine, 1000 mg/m² twice daily for 14 days every 3 weeks (the XELOX regimen), followed by chemoradiation therapy, 50 Gy over 5 weeks, with the modified XELOX regimen (oxaliplatin 100 mg/m²), and then with another cycle of consolidation chemotherapy with the XELOX regimen. Surgery was performed 6 to 8 weeks after completion of radiation therapy. Tumor responses, toxicities, and surgical complications were recorded. Results: All but one patent completed the planned schedule of neoadjuvant sandwich treatment. Neither life-threatening blood count decrease nor febrile neutropenia were observed. Forty-five patents underwent optimal surgery with total mesorectal excision (TME). Four patients refused surgery because of clinically complete response. There was no perioperative mortality in this cohort. Five patients (11.1%) developed postoperative complications. Among the 45 patients who underwent TME, pathologic complete response (pCR), pCR or major regression, and at least moderate regression were achieved in 19 (42.2%), 37 (82.2%), and 44 patients (97.8%), respectively. Conclusions: Preliminary results suggest that the strategy of neoadjuvant sandwich treatment using XELOX regimen as induction, concomitant, and consolidation chemotherapy to the conventional radiation is well tolerated. The strategy is highly effective in terms of pCR and major regression, which warrants further investigation.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Efficacy Endpoints of Radiation Therapy Group Protocol 0247: A Randomized, Phase 2 Study of Neoadjuvant Radiation Therapy Plus Concurrent Capecitabine and Irinotecan or Capecitabine and Oxaliplatin for Patients With Locally Advanced Rectal Cancer

Purpose: To report secondary efficacy endpoints of Radiation Therapy Oncology Group protocol 0247, primary endpoint analysis of which demonstrated that preoperative radiation therapy (RT) with capecitabine plus oxaliplatin achieved a pathologic complete remission prespecified threshold (21%) to merit further study, whereas RT with capecitabine plus irinotecan did not (10%). Methods and Materials: A randomized, phase 2 trial evaluated preoperative RT (50.4 Gy in 1.8-Gy fractions) with 2 concurrent chemotherapy regimens: (1) capecitabine (1200 mg/m{sup 2}/d Monday-Friday) plus irinotecan (50 mg/m{sup 2}/wk × 4); and (2) capecitabine (1650 mg/m{sup 2}/d Monday-Friday) plus oxaliplatin (50 mg/m{sup 2}/wk × 5) for clinical T3 or T4 rectal cancer. Surgery was performed 4 to 8 weeks after chemoradiation, then 4 to 6 weeks later, adjuvant chemotherapy (oxaliplatin 85 mg/m{sup 2}; leucovorin 400 mg/m{sup 2}; 5-fluorouracil 400 mg/m{sup 2}; 5-fluorouracil 2400 mg/m{sup 2}) every 2 weeks × 9. Disease-free survival (DFS) and overall survival (OS) were estimated univariately by the Kaplan-Meier method. Local–regional failure (LRF), distant failure (DF), and second primary failure (SP) were estimated by the cumulative incidence method. No statistical comparisons were made between arms because each was evaluated individually. Results: A total of 104 patients (median age, 57 years) were treated; characteristics were similar for both arms. Median follow-up for RT with capecitabine/irinotecan arm was 3.77 years and for RT with capecitabine/oxaliplatin arm was 3.97 years. Four-year DFS, OS, LRF, DF, and SP estimates for capecitabine/irinotecan arm were 68%, 85%, 16%, 24%, and 2%, respectively. The 4-year DFS, OS, LRF, DF, and SP failure estimates for capecitabine/oxaliplatin arm were 62%, 75%, 18%, 30%, and 6%, respectively. Conclusions: Efficacy results for both arms are similar to other reported studies but suggest that pathologic complete remission is an unsuitable surrogate for traditional survival metrics of clinical outcome. Although it remains uncertain whether the addition of a second cytotoxic agent enhances the effectiveness of fluorouracil plus RT, these results suggest that further study of irinotecan may be warranted.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Is Intermediate Radiation Dose Escalation With Concurrent Chemotherapy for Stage III Non–Small-Cell Lung Cancer Beneficial? A Multi-Institutional Propensity Score Matched Analysis

Purpose: The clinical benefits and risks of dose escalation (DE) for stage III non–small-cell lung cancer (NSCLC) remain uncertain despite the results from Radiation Therapy Oncology Group (RTOG) protocol 0617. There is significant heterogeneity of practice, with many clinicians prescribing intermediate dose levels between the 0617 study arms of 60 and 74 Gy. This study investigated whether this strategy is associated with any survival benefits/risks by analyzing a large multi-institutional database. Methods and Materials: An individual patient database of stage III NSCLC patients treated with radical intent concurrent chemoradiation therapy was created (13 institutions, n=1274 patients). Patients were divided into 2 groups based on tumor Biological Effective Dose at 10 Gy (BED 10): those receiving standard dose (SD; n=552), consisting of 72Gy ≤ BED 10 ≤ 76.8 Gy (eg 60-64 Gy/30-32 fractions [fr]), and those receiving intermediate dose (ID; n=497), consisting of 76.8Gy < BED 10 < 100.8 Gy (eg >64 Gy/32 fr and <74 Gy/37 fr), with lower-dose patients (n=225) excluded from consideration. Patients were then matched using propensity scores, leading to 2 matched groups of 196 patients. Outcomes were compared using various statistics including interquartile range (IQR), Kaplan-Meier curves, and adjusted Cox regression analysis. Results: Matched groups were found to be balanced except for N stage (more N3 disease in SD), median treatment year (SD in 2003; ID in 2007), platinum and taxane chemotherapy (SD in 28%; ID in 39%), and median follow-up (SD were 89 months; ID were 40 months). Median dose fractionation was 60 Gy/30 fr in SD (BED 10 IQR: 72.0-75.5 Gy) and 66 Gy/33 fr (BED 10 IQR: 78.6-79.2 Gy) in ID. Survival curves for SD and ID matched cohorts were statistically similar (P=.27); however, a nonstatistically significant trend toward better survival for ID was observed after 15 months (median survival SD: 19.3 months; ID: 21.0 months). There was an increase in grades III to V lung toxicity associated with ID (13.0% vs 4.9%, respectively). Conclusions: No significant overall survival benefits were found with intermediate DE; however, more grade III or greater lung toxicity was observed. The separation of survival curves after 15 months of follow-up suggests that a small overall survival improvement associated with intermediate DE cannot be excluded.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Phase 1 Trial of Bevacizumab With Concurrent Chemoradiation Therapy for Squamous Cell Carcinoma of the Head and Neck With Exploratory Functional Imaging of Tumor Hypoxia, Proliferation, and Perfusion

Purpose: A phase 1 trial was completed to examine the safety and feasibility of combining bevacizumab with radiation and cisplatin in patients with locoregionally advanced squamous cell carcinoma of the head and neck (HNSCC) treated with curative intent. Additionally, we assessed the capacity of bevacizumab to induce an early tumor response as measured by a series of biological imaging studies. Methods and Materials: All patients received a single induction dose of bevacizumab (15 mg/kg) delivered 3 weeks (±3 days) before the initiation of chemoradiation therapy. After the initial dose of bevacizumab, comprehensive head and neck chemoradiation therapy was delivered with curative intent to 70 Gy in 33 fractions with concurrent weekly cisplatin at 30 mg/m{sup 2} and bevacizumab every 3 weeks (weeks 1, 4, 7) with dose escalation from 5 to 10 to 15 mg/kg. All patients underwent experimental imaging with [{sup 18}F]fluorothymidine positron emission tomography (FLT-PET) (proliferation), [{sup 61}Cu]Cu-diacetyl-bis(N4-methylthiosemicarbazone) PET (Cu-ATSM-PET) (hypoxia), and dynamic contrast-enhanced computed tomography (DCE-CT) (perfusion) at 3 time points: before bevacizumab monotherapy, after bevacizumab monotherapy, and during the combined therapy course. Results: Ten patients were enrolled. All had stage IV HNSCC, all achieved a complete response to treatment, and 9 of 10 remain alive, with a mean survival time of 61.3 months. All patients experienced grade 3 toxicity, but no dose-limiting toxicities or significant bleeding episodes were observed. Significant reductions were noted in tumor proliferation (FLT-PET), tumor hypoxia (Cu-ATSM-PET), and DCE-CT contrast enhancement after bevacizumab monotherapy, with further decreases in FLT-PET and Cu-ATSM-PET during the combined therapy course. Conclusions: The incorporation of bevacizumab into comprehensive chemoradiation therapy regimens for patients with HNSCC appears safe and feasible. Experimental imaging demonstrates measureable changes in tumor proliferation, hypoxia, and perfusion after bevacizumab monotherapy and during chemoradiation therapy. These findings suggest opportunities to preview the clinical outcomes for individual patients and thereby design personalized therapy approaches in future trials.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Hyperfractionated Accelerated Radiation Therapy (HART) of 70.6 Gy With Concurrent 5-FU/Mitomycin C Is Superior to HART of 77.6 Gy Alone in Locally Advanced Head and Neck Cancer: Long-term Results of the ARO 95-06 Randomized Phase III Trial

Purpose: To report the long-term results of the ARO 95-06 randomized trial comparing hyperfractionated accelerated chemoradiation with mitomycin C/5-fluorouracil (C-HART) with hyperfractionated accelerated radiation therapy (HART) alone in locally advanced head and neck cancer. Patients and Methods: The primary endpoint was locoregional control (LRC). Three hundred eighty-four patients with stage III (6%) and IV (94%) oropharyngeal (59.4%), hypopharyngeal (32.3%), and oral cavity (8.3%) cancer were randomly assigned to 30 Gy/2 Gy daily followed by twice-daily 1.4 Gy to a total of 70.6 Gy concurrently with mitomycin C/5-FU (C-HART) or 16 Gy/2 Gy daily followed by twice-daily 1.4 Gy to a total dose of 77.6 Gy alone (HART). Statistical analyses were done with the log-rank test and univariate and multivariate Cox regression analyses. Results: The median follow-up time was 8.7 years (95% confidence interval [CI]: 7.8-9.7 years). At 10 years, the LRC rates were 38.0% (C-HART) versus 26.0% (HART, P=.002). The cancer-specific survival and overall survival rates were 39% and 10% (C-HART) versus 30.0% and 9% (HART, P=.042 and P=.049), respectively. According to multivariate Cox regression analysis, the combined treatment was associated with improved LRC (hazard ratio [HR]: 0.6 [95% CI: 0.5-0.8; P=.002]). The association between combined treatment arm and increased LRC appeared to be limited to oropharyngeal cancer (P=.003) as compared with hypopharyngeal or oral cavity cancer (P=.264). Conclusions: C-HART remains superior to HART in terms of LRC. However, this effect may be limited to oropharyngeal cancer patients.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

A Contralateral Esophagus-Sparing Technique to Limit Severe Esophagitis Associated With Concurrent High-Dose Radiation and Chemotherapy in Patients With Thoracic Malignancies

Purpose: Severe (Radiation Therapy Oncology Group [RTOG] grade 3 or greater) esophagitis generally occurs in 15% to 25% of non–small cell lung cancer (NSCLC) patients undergoing concurrent chemotherapy and radiation therapy (CCRT), which may result in treatment breaks that compromise local tumor control and pose a barrier to dose escalation. Here, we report a novel contralateral esophagus-sparing technique (CEST) that uses intensity modulated radiation therapy (IMRT) to reduce the incidence of severe esophagitis. Methods and Materials: We reviewed consecutive patients with thoracic malignancies undergoing curative CCRT in whom CEST was used. The esophageal wall contralateral (CE) to the tumor was contoured as an avoidance structure, and IMRT was used to guide a rapid dose falloff gradient beyond the target volume in close proximity to the esophagus. Esophagitis was recorded based on the RTOG acute toxicity grading system. Results: We identified 20 consecutive patients treated with CCRT of at least 63 Gy in whom there was gross tumor within 1 cm of the esophagus. The median radiation dose was 70.2 Gy (range, 63-72.15 Gy). In all patients, ≥99% of the planning and internal target volumes was covered by ≥90% and 100% of prescription dose, respectively. Strikingly, no patient experienced grade ≥3 esophagitis (95% confidence limits, 0%-16%) despite the high total doses delivered. The median maximum dose, V45, and V55 of the CE were 60.7 Gy, 2.1 cc, and 0.4 cc, respectively, indicating effective esophagus cross-section sparing by CEST. Conclusion: We report a simple yet effective method to avoid exposing the entire esophagus cross-section to high doses. By using proposed CE dose constraints of V45 <2.5 cc and V55 <0.5 cc, CEST may improve the esophagus toxicity profile in thoracic cancer patients receiving CCRT even at doses above the standard 60- to 63-Gy levels. Prospective testing of CEST is warranted.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Clinical and Dosimetric Predictors of Acute Severe Lymphopenia During Radiation Therapy and Concurrent Temozolomide for High-Grade Glioma

Purpose: Acute severe lymphopenia (ASL) frequently develops during radiation therapy (RT) and concurrent temozolomide (TMZ) for high-grade glioma (HGG) and is associated with decreased survival. The current study was designed to identify potential predictors of ASL, with a focus on actionable RT-specific dosimetric parameters. Methods and Materials: From January 2007 to December 2012, 183 patients with HGG were treated with RT+TMZ and had available data including total lymphocyte count (TLC) and radiation dose-volume histogram parameters. ASL was defined as TLC of <500/μL within the first 3 months from the start of RT. Stepwise logistic regression analysis was used to determine the most important predictors of ASL. Results: Fifty-three patients (29%) developed ASL. Patients with ASL had significantly worse overall survival than those without (median: 12.5 vs 20.2 months, respectively, P<.001). Stepwise logistic regression analysis identified female sex (odds ratio [OR]: 5.30; 95% confidence interval [CI]: 2.46-11.41), older age (OR: 1.05; 95% CI: 1.02-1.09), lower baseline TLC (OR: 0.92; 95% CI: 0.87-0.98), and higher brain volume receiving 25 Gy (V{sub 25Gy}) (OR: 1.03; 95% CI: 1.003-1.05) as the most significant predictors for ASL. Brain V{sub 25Gy} <56% appeared to be the optimal threshold (OR: 2.36; 95% CI: 1.11-5.01), with an ASL rate of 38% versus 20% above and below this threshold, respectively (P=.006). Conclusions: Female sex, older age, lower baseline TLC, and higher brain V{sub 25Gy} are significant predictors of ASL during RT+TMZ therapy for HGG. Maintaining the V{sub 25Gy} of brain below 56% may reduce the risk of ASL.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Concurrent Chemoradiation Therapy Followed by Consolidation Chemotherapy for Localized Extranodal Natural Killer/T-Cell Lymphoma, Nasal Type

Purpose: To evaluate the effectiveness of concurrent chemoradiation therapy (CCRT) with 40 Gy followed by consolidation chemotherapy for localized extranodal natural killer (NK)/T-cell lymphoma (ENKTL), nasal type. Methods and Materials: From August 2004 to August 2012, 62 patients with newly diagnosed stage IE to IIE ENKTL underwent CCRT followed by consolidation chemotherapy. The median RT dose was 40 Gy. Cisplatin, 30 mg/m{sup 2}, was administered weekly during the RT course. Responders to CCRT were encouraged to undergo consolidation chemotherapy. Three different consolidation chemotherapy regimens were used consecutively: VIPD (etoposide, ifosfamide, cisplatin, and dexamethasone); VIDL (etoposide, ifosfamide, and dexamethasone followed by intramuscular injection of L-asparaginase); and MIDLE (methotrexate, etoposide, ifosfamide, mesna, and L-asparaginase). Results: The median follow-up period was 49 months (range 8-112). After completion of CCRT, 56 patients (90.3%) had a complete response, 4 (6.4%) had a partial response, 1 (1.6%) had stable disease, and 1 patient (1.6%) had progressive disease (PD). Consolidation chemotherapy was recommended to 61 patients, after excluding the patient with PD, but was actually delivered to 58. Of these 58 patients, 56 (96.5%) had a complete response and 2 (3.5%) had PD. During the follow-up period, 17 patients (including 3 with PD) experienced progression. The median interval to progression was 11 months (range 1-61). Local failure developed in 6 patients, of whom, 2 had developed progression outside the RT field. For all patients, the 3-year overall survival, progression-free survival, and local control rates were 83.1%, 77.1%, and 92.4%, respectively. Grade ≥3 nonhematologic toxicity developed in only 3 patients (4.8%). Conclusions: Excellent clinical outcomes were achieved using CCRT with 40 Gy followed by consolidation chemotherapy. Additional investigation, however, is warranted to confirm our findings.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Factors Associated With Early Mortality in Patients Treated With Concurrent Chemoradiation Therapy for Locally Advanced Non-Small Cell Lung Cancer

Purpose: Concurrent chemoradiation therapy (con-CRT) is recommended for fit patients with locally advanced non-small cell lung cancer (LA-NSCLC) but is associated with toxicity, and observed survival continues to be limited. Identifying factors associated with early mortality could improve patient selection and identify strategies to improve prognosis. Methods and Materials: Analysis of a multi-institutional LA-NSCLC database consisting of 1245 patients treated with con-CRT in 13 institutions was performed to identify factors predictive of 180-day survival. Recursive partitioning analysis (RPA) was performed to identify prognostic groups for 180-day survival. Multivariate logistic regression analysis was used to create a clinical nomogram predicting 180-day survival based on important predictors from RPA. Results: Median follow-up was 43.5 months (95% confidence interval [CI]: 40.3-48.8) and 127 patients (10%) died within 180 days of treatment. Median, 180-day, and 1- to 5-year (by yearly increments) actuarial survival rates were 20.9 months, 90%, 71%, 45%, 32%, 27%, and 22% respectively. Multivariate analysis adjusted by region identified gross tumor volume (GTV) (odds ratio [OR] ≥100 cm{sup 3}: 2.61; 95% CI: 1.10-6.20; P=.029) and pulmonary function (forced expiratory volume in 1 second [FEV{sub 1}], defined as the ratio of FEV{sub 1} to forced vital capacity [FVC]) (OR <80%: 2.53; 95% CI: 1.09-5.88; P=.030) as significant predictors of 180-day survival. RPA resulted in a 2-class risk stratification system: low-risk (GTV <100 cm{sup 3} or GTV ≥100 cm{sup 3} and FEV{sub 1} ≥80%) and high-risk (GTV ≥100 cm{sup 3} and FEV{sub 1} <80%). The 180-day survival rates were 93% for low risk and 79% for high risk, with an OR of 4.43 (95% CI: 2.07-9.51; P<.001), adjusted by region. A clinical nomogram predictive of 180-day survival, incorporating FEV{sub 1}, GTV, N stage, and maximum esophagus dose yielded favorable calibration (R{sup 2} = 0.947). Conclusions: This analysis identified several risk factors associated with early mortality and suggests that future research in the optimization of pretreatment pulmonary function and/or functional lung avoidance treatment may alter the therapeutic ratio in this patient population.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Multicenter Phase 2 Study of Cisplatin and 5-Fluorouracil With Concurrent Radiation Therapy as an Organ Preservation Approach in Patients With Squamous Cell Carcinoma of the Cervical Esophagus

Purpose: To clarify, in a multicenter, single-arm, phase 2 study (UMIN Clinical Trials Registry no. UMIN000001439), the clinical profile of chemoradiotherapy (CRT) for cervical esophageal cancer. Patients and Methods: Patients with operable cervical esophageal cancer, excluding candidates for endoscopic resection, were enrolled. Protocol treatment consisted of CRT and adjuvant chemotherapy (CT). First, patients received concurrent CRT with 5-fluorouracil (5-FU) plus cisplatin (CDDP). Chemotherapy consisted of 5-FU at 700 mg/m{sup 2} intravenous on days 1 to 4 and CDDP at 70 mg/m{sup 2} intravenous on day 1, repeated every 4 weeks for 2 cycles. Radiation therapy consisted of 60 Gy in 30 fractions. After completion of CRT, 2 additional cycles of CT with 5-FU (800 mg/m{sup 2}, days 1-5) and CDDP (80 mg/m{sup 2}, day 1) were repeated at a 4-week interval. The primary endpoint was 3-year overall survival. Results: Thirty patients were enrolled across 8 institutions in Japan, consisting of 26 men and 4 women with a median age of 64.5 years (range, 50-75 years). No grade 4 hematologic toxicity was seen in the CRT phase, and 1 grade 4 thrombocytopenia was seen in the CT phase. Grade 3 nonhematologic acute toxicities in the CRT phase were nausea (10%), mucositis (13.3%), and dysphagia (13.3%). No treatment-related death in either phase occurred. Overall complete response rate was 73%, and 3-year overall and laryngectomy-free survival were 66.5% and 52.5%, respectively. Regarding T4 disease, 3-year overall and laryngectomy-free survival were 58.3% and 38.5%, respectively. Conclusions: This study, the first prospective study for cervical esophageal cancer, showed that CRT has sufficient efficacy and safety for use as an alternative to surgery for these patients.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Effect of Intensity Modulated Radiation Therapy With Concurrent Chemotherapy on Survival for Patients With Cervical Esophageal Carcinoma

Purpose: We evaluated the effect of consecutive protocols on overall survival (OS) for cervical esophageal carcinoma (CEC). Methods and Materials: All CEC cases that received definitive radiation therapy (RT) with or without chemotherapy from 1997 to 2013 in 3 consecutive protocols were reviewed. Protocol 1 (P1) consisted of 2-dimensional RT of 54 Gy in 20 fractions with 5-fluorouracil plus either mitomycin C or cisplatin. Protocol 2 (P2) consisted of 3-dimensional conformal RT (3DRT) of ≥60 Gy in 30 fractions plus elective nodal irradiation plus cisplatin. Protocol 3 (P3) consisted of intensity modulated RT (IMRT) of ≥60 Gy in 30 fractions plus elective nodal irradiation plus cisplatin. Multivariable analyses were used to assess the effect of the treatment protocol, RT technique, and RT dose on OS, separately. Results: Of 81 cases (P1, 21; P2, 23; and P3, 37), 34 local (P1, 11 [52%]; P2, 12 [52%]; and P3, 11 [30%]), 16 regional (P1, 6 [29%]); P2, 3 [13%]; and P3, 7 [19%]), and 34 distant (P1, 10 [48%]; P2, 9 [39%]; and P3, 15 [41%]) failures were identified. After adjusting for age (P=.49) and chemotherapy (any vs none; hazard ratio [HR] 0.5, 95% confidence interval [CI] 0.3-0.9; P=.023), multivariable analysis showed P3 had improved OS compared with P1 (HR 0.4, 95% CI 0.2-0.8; P=.005), with a trend shown for benefit compared with P2 (HR 0.6, 95% CI 0.3-1.0; P=.061). OS between P1 and P2 did not differ (P=.29). Analyzed as a continuous variable, higher RT doses were associated with a borderline improved OS (HR 0.97, 95% CI 0.95-1.0; P=.075). IMRT showed improved OS compared with non-IMRT (HR 0.57, 95% CI 0.3-0.8; P=.008). Conclusions: The present retrospective consecutive cohort study showed improved OS with our current protocol (P3; high-dose IMRT with concurrent high-dose cisplatin) compared with historical protocols. The outcomes for patients with CEC remain poor, and novel approaches to improve the therapeutic ratio are warranted.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Phase 1/2 Trial of 5-Fraction Stereotactic Radiosurgery With 5-mm Margins With Concurrent and Adjuvant Temozolomide in Newly Diagnosed Supratentorial Glioblastoma: Health-Related Quality of Life Results

Purpose: We report a longitudinal assessment of health-related quality of life (HRQOL) in patients with glioblastoma (GBM) treated on a prospective dose escalation trial of 5-fraction stereotactic radiosurgery (25-40 Gy in 5 fractions) with concurrent and adjuvant temozolomide. Methods: HRQOL was assessed using the European Organization for Research and Treatment of Cancer (EORTC) quality of life questionnaire core-30 (QLQ-C30) general, the EORTC quality of life questionnaire-brain cancer specific module (QLQ-BN20), and the M.D. Anderson Symptom Inventory–Brain Tumor (MDASI-BT). Questionnaires were completed at baseline and at every follow-up visit after completion of radiosurgery. Changes from baseline for 9 predefined HRQOL measures (global quality of life, physical functioning, social functioning, emotional functioning, motor dysfunction, communication deficit, fatigue, insomnia, and future uncertainty) were calculated at every time point. Results: With a median follow-up time of 10.4 months (range, 0.4-52 months), 139 total HRQOL questionnaires were completed by the 30 patients on trial. Compliance with HRQOL assessment was 76% at 12 months. Communication deficit significantly worsened over time, with a decline of 1.7 points per month (P=.008). No significant changes over time were detected in the other 8 scales of our primary analysis, including global quality of life. Although 8 patients (27%) experienced adverse radiation effects (ARE) on this dose escalation trial, it was not associated with a statistically significant decline in any of the primary HRQOL scales. Disease progression was associated with communication deficit, with patients experiencing an average worsening of 13.9 points per month after progression compared with 0.7 points per month before progression (P=.01). Conclusion: On this 5-fraction dose escalation protocol for newly diagnosed GBM, overall HRQOL remained stable and appears similar to historical controls of 30 fractions of radiation therapy. Tumor recurrence was associated with worsening communication deficit, and ARE did not correlate with a decline in HRQOL.

62 RADIOLOGY AND NUCLEAR MEDICINE↗