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At least 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Dose-Volume Analysis of Predictors for Gastrointestinal Toxicity After Concurrent Full-Dose Gemcitabine and Radiotherapy for Locally Advanced Pancreatic Adenocarcinoma

Purpose: To identify dosimetric predictors for the development of gastrointestinal (GI) toxicity in patients with locally advanced pancreatic adenocarcinoma (LAPC) treated with concurrent full-dose gemcitabine and radiotherapy (GemRT). Methods and Materials: From June 2002 to June 2009, 46 LAPC patients treated with definitive GemRT were retrospectively analyzed. The stomach and duodenum were retrospectively contoured separately to determine their dose-volume histogram (DVH) parameters. GI toxicity was defined as Grade 3 or higher GI toxicity. The follow-up time was calculated from the start of RT to the date of death or last contact. Univariate analysis (UVA) and multivariate analysis (MVA) using Kaplan-Meier and Cox regression models were performed to identify risk factors associated with GI toxicity. The receiver operating characteristic curve and the area under the receiver operating characteristic curve (AUC) were used to determine the best DVH parameter to predict for GI toxicity. Results: Of the patients, 28 (61%) received concurrent gemcitabine alone, and 18 (39%) had concurrent gemcitabine with daily erlotinib. On UVA, only the V{sub 20Gy} to V{sub 35Gy} of duodenum were significantly associated with GI toxicity (all p {<=} 0.05). On MVA, the V{sub 25Gy} of duodenum and the use of erlotinib were independent risk factors for GI toxicity (p = 0.006 and 0.02, respectively). For the entire cohort, the V{sub 25Gy} of duodenum is the best predictor for GI toxicity (AUC = 0.717), and the 12-month GI toxicity rate was 8% vs. 48% for V{sub 25Gy} {<=} 45% and V{sub 25Gy} > 45%, respectively (p = 0.03). However, excluding the erlotinib group, the V{sub 35Gy} is the best predictor (AUC = 0.725), and the 12-month GI toxicity rate was 0% vs. 41% for V{sub 35Gy} {<=} 20% and V{sub 35Gy} > 20%, respectively (p = 0.04). Conclusions: DVH parameters of duodenum may predict Grade 3 GI toxicity after GemRT for LAPC. Concurrent use of erlotinib during GemRT may increase GI toxicity.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Intensity-Modulated Radiotherapy for Pancreatic Adenocarcinoma

Purpose: To report the outcomes and toxicities in patients treated with intensity-modulated radiotherapy (IMRT) for pancreatic adenocarcinoma. Methods and Materials: Forty-seven patients with pancreatic adenocarcinoma were treated with IMRT between 2003 and 2008. Of these 47 patients, 29 were treated adjuvantly and 18 definitively. All received concurrent 5-fluorouracil chemotherapy. The treatment plans were optimized such that 95% of the planning target volume received the prescription dose. The median delivered dose for the adjuvant and definitive patients was 50.4 and 54.0 Gy, respectively. Results: The median age at diagnosis was 63.9 years. For adjuvant patients, the 1- and 2-year overall survival rate was 79% and 40%, respectively. The 1- and 2-year recurrence-free survival rate was 58% and 17%, respectively. The local-regional control rate at 1 and 2 years was 92% and 80%, respectively. For definitive patients, the 1-year overall survival, recurrence-free survival, and local-regional control rate was 24%, 16%, and 64%, respectively. Four patients developed Grade 3 or greater acute toxicity (9%) and four developed Grade 3 late toxicity (9%). Conclusions: Survival for patients with pancreatic cancer remains poor. A small percentage of adjuvant patients have durable disease control, and with improved therapies, this proportion will increase. Systemic therapy offers the greatest opportunity. The present results have demonstrated that IMRT is well tolerated. Compared with those who received three-dimensional conformal radiotherapy in previously reported prospective clinical trials, patients with pancreatic adenocarcinoma treated with IMRT in our series had improved acute toxicity.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Resected Pancreatic Neuroendocrine Tumors: Patterns of Failure and Disease-Related Outcomes With or Without Radiotherapy

Purpose: Pancreatic neuroendocrine tumors (NET) are rare and have better disease-related outcomes compared with pancreatic adenocarcinoma. Surgical resection remains the standard of care, although many patients present with locally advanced or metastatic disease. Little is known regarding the use of radiotherapy in the prevention of local recurrence after resection. To better define the role of radiotherapy, we performed an analysis of resected patients at our institution. Methods: Between 1994 and 2009, 33 patients with NET of the pancreatic head and neck underwent treatment with curative intent at Duke University Medical Center. Sixteen patients were treated with surgical resection alone while an additional 17 underwent resection with adjuvant or neoadjuvant radiation therapy, usually with concurrent fluoropyrimidine-based chemotherapy (CMT). Median radiation dose was 50.4 Gy and median follow-up 28 months. Results: Thirteen patients (39%) experienced treatment failure. Eleven of the initial failures were distant, one was local only and one was local and distant. Two-year overall survival was 77% for all patients. Two-year local control for all patients was 87%: 85% for the CMT group and 90% for the surgery alone group (p = 0.38). Two-year distant metastasis-free survival was 56% for all patients: 46% and 69% for the CMT and surgery patients, respectively (p = 0.10). Conclusions: The primary mode of failure is distant which often results in mortality, with local failure occurring much less commonly. The role of radiotherapy in the adjuvant management of NET remains unclear.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

High-dose Helical Tomotherapy With Concurrent Full-dose Chemotherapy for Locally Advanced Pancreatic Cancer

Purpose: To improve poor therapeutic outcome of current practice of chemoradiotherapy (CRT), high-dose helical tomotherapy (HT) with concurrent full-dose chemotherapy has been performed on patients with locally advanced pancreatic cancer (LAPC), and the results were analyzed. Methods and Materials: We retrospectively reviewed 39 patients with LAPC treated with radiotherapy using HT (median, 58.4 Gy; range, 50.8-59.9 Gy) and concomitant chemotherapy between 2006 and 2009. Radiotherapy was directed to the primary tumor with a 0.5-cm margin without prophylactic nodal coverage. Twenty-nine patients (79%) received full-dose (1000 mg/m{sup 2}) gemcitabine-based chemotherapy during HT. After completion of CRT, maintenance chemotherapy was administered to 37 patients (95%). Results: The median follow-up was 15.5 months (range, 3.4-43.9) for the entire cohort, and 22.5 months (range, 12.0-43.9) for the surviving patients. The 1- and 2-year local progression-free survival rates were 82.1% and 77.3%, respectively. Eight patients (21%) were converted to resectable status, including 1 with a pathological complete response. The median overall survival and progression-free survival were 21.2 and 14.0 months, respectively. Acute toxicities were acceptable with no gastrointestinal (GI) toxicity higher than Grade 3. Severe late GI toxicity ({>=}Grade 3) occurred in 10 patients (26%); 1 treatment-related death from GI bleeding was observed. Conclusion: High-dose helical tomotherapy with concurrent full-dose chemotherapy resulted in improved local control and long-term survival in patients with LAPC. Future studies are needed to widen the therapeutic window by minimizing late GI toxicity.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Radiotherapy Technical Considerations in the Management of Locally Advanced Pancreatic Cancer: American-French Consensus Recommendations

Summary: Pancreatic carcinoma is a leading cause of cancer-related mortality. Approximately 30% of pancreatic cancer patients present with locally advanced, unresectable nonmetastatic disease. For these patients, two therapeutic options exist: systemic chemotherapy or chemoradiotherapy. Within this context, the optimal technique for pancreatic irradiation is not clearly defined. A search to identify relevant studies was undertaken using the Medline database. All Phase III randomized trials evaluating the modalities of radiotherapy in locally advanced pancreatic cancer were included, as were some noncontrolled Phase II and retrospective studies. An expert panel convened with members of the Radiation Therapy Oncology Group and GERCOR cooperative groups to review identified studies and prepare the guidelines. Each member of the working group independently evaluated five endpoints: total dose, target volume definition, radiotherapy planning technique, dose constraints to organs at risk, and quality assurance. Based on this analysis of the literature, we recommend either three-dimensional conformal radiation therapy or intensity-modulated radiation therapy to a total dose of 50 to 54 Gy at 1.8 to 2 Gy per fraction. We propose gross tumor volume identification to be followed by an expansion of 1.5 to 2 cm anteriorly, posteriorly, and laterally, and 2 to 3 cm craniocaudally to generate the planning target volume. The craniocaudal margins can be reduced with the use of respiratory gating. Organs at risk are liver, kidneys, spinal cord, stomach, and small bowel. Stereotactic body radiation therapy should not be used for pancreatic cancer outside of clinical trials. Radiotherapy quality assurance is mandatory in clinical trials. These consensus recommendations are proposed for use in the development of future trials testing new chemotherapy combinations with radiotherapy. Not all of these recommendations will be appropriate for trials testing radiotherapy dose or dose intensity concepts.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Analysis of Dosimetric Parameters Associated With Acute Gastrointestinal Toxicity and Upper Gastrointestinal Bleeding in Locally Advanced Pancreatic Cancer Patients Treated With Gemcitabine-Based Concurrent Chemoradiotherapy

Purpose: To identify the dosimetric parameters associated with gastrointestinal (GI) toxicity in patients with locally advanced pancreatic cancer (LAPC) treated with gemcitabine-based chemoradiotherapy. Methods and Materials: The data from 40 patients were analyzed retrospectively. Chemoradiotherapy consisted of conventional fractionated three-dimensional radiotherapy and weekly gemcitabine. Treatment-related acute GI toxicity and upper GI bleeding (UGB) were graded according to the Common Toxicity Criteria Adverse Events, version 4.0. The dosimetric parameters (mean dose, maximal absolute dose which covers 2 cm{sup 3} of the organ, and absolute volume receiving 10-50 Gy [V{sub 10-50}]) of the stomach, duodenum, small intestine, and a composite structure of the stomach and duodenum (StoDuo) were obtained. The planning target volume was also obtained. Univariate analyses were performed to identify the predictive factors for the risk of grade 2 or greater acute GI toxicity and grade 3 or greater UGB, respectively. Results: The median follow-up period was 15.7 months (range, 4-37). The actual incidence of acute GI toxicity was 33%. The estimated incidence of UGB at 1 year was 20%. Regarding acute GI toxicity, a V{sub 50} of {>=}16 cm{sup 3} of the stomach was the best predictor, and the actual incidence in patients with V{sub 50} <16 cm{sup 3} of the stomach vs. those with V{sub 50} of {>=}16 cm{sup 3} was 9% vs. 61%, respectively (p = 0.001). Regarding UGB, V{sub 50} of {>=}33 cm{sup 3} of the StoDuo was the best predictor, and the estimated incidence at 1 year in patients with V{sub 50} <33 cm{sup 3} of the StoDuo vs. those with V{sub 50} {>=}33 cm{sup 3} was 0% vs. 44%, respectively (p = 0.002). The dosimetric parameters correlated highly with one another. Conclusion: The irradiated absolute volume of the stomach and duodenum are important for the risk of acute GI toxicity and UGB. These results could be helpful in escalating the radiation doses using novel techniques, such as intensity-modulated radiotherapy, for the treatment of pancreatic cancer.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Pancreatic Neuroendocrine Tumors With Involved Surgical Margins: Prognostic Factors and the Role of Adjuvant Radiotherapy

Purpose: Pancreatic neuroendocrine tumors (pNET) are rare neoplasms associated with poor outcomes without resection, and involved surgical margins are associated with a worse prognosis. The role of adjuvant radiotherapy (RT) in these patients has not been characterized. Methods and Materials: We retrospectively evaluated 46 consecutive patients with positive or close (<1 mm) margins after pNET resection, treated from 1983 to 2010, 16 of whom received adjuvant RT. Median RT dose was 50.4 Gy in 1.8-Gy fractions; half the patients received concurrent chemotherapy with 5-fluorouracil or capecitabine. No patients received adjuvant chemotherapy. Cox multivariate analysis (MVA) was used to analyze factors associated with overall survival (OS). Results: Median age at diagnosis was 56 years, and 52% of patients were female. Median tumor size was 38 mm, 57% of patients were node-positive, and 11% had a resected solitary liver metastasis. Patients who received RT were more likely to have larger tumors (median, 54 mm vs. 30 mm, respectively, p = 0.002) and node positivity (81% vs. 33%, respectively, p = 0.002) than those not receiving RT. Median follow-up was 39 months. Actuarial 5-year OS was 62% (95% confidence interval [CI], 41%-77%). In the group that did not receive RT, 3 patients (10%) experienced local recurrence (LR) and 5 patients (18%) developed new distant metastases, while in the RT group, 1 patient (6%) experienced LR and 5 patients (38%) developed distant metastases. Of all recurrences, 29% were LR. On MVA, male gender (adjusted hazard ratio [AHR] = 3.81; 95% CI, 1.21-11.92; p = 0.02) and increasing tumor size (AHR = 1.02; 95% CI, 1.01-1.04; p = 0.007) were associated with decreased OS. Conclusions: Long-term survival is common among patients with involved-margin pNET. Despite significantly worse pathologic features among patients receiving adjuvant RT, rates of LR between groups were similar, suggesting that RT might aid local control, and merits further evaluation.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Survival After Chemoradiation in Resected Pancreatic Cancer: The Impact of Adjuvant Gemcitabine

Purpose: To evaluate survival in patients with resected pancreatic cancer treated with concurrent chemoradiation with or without adjuvant gemcitabine (Gem). Methods and Materials: From 1998 to 2010, 86 patients with pancreatic adenocarcinoma who underwent resection were treated with adjuvant concurrent chemoradiation. Thirty-four patients received concurrent 5-fluorouracil-based chemoradiation (5-FU/RT) with traditional field radiation (range, 45-61.2 Gy; median, 50.4 Gy) without further adjuvant therapy. Thirty patients received traditional field 5-FU/RT (range, 45-60.4 Gy; median, 50.4 Gy) with Gem (1,000 mg/m{sup 2} weekly) either before and after radiotherapy or only after radiotherapy. Twenty-two patients received concurrent full-dose Gem (1,000 mg/m{sup 2} weekly)-based chemoradiation (Gem/RT), consisting of involved-field radiation (range, 27-38 Gy; median, 36 Gy) followed by further adjuvant Gem. Results: The median age of the cohort was 65 years (range, 40-80 years). Of the patients, 58 had T3 tumors (67%), 22 had T2 tumors (26%), and 6 had T1 tumors (7%). N1 disease was present in 61 patients (71%), whereas 18 patients (21%) had R1 resections. Performance status, lymph node status, and margin status were all similar among the treatment groups. Median follow-up was 19.0 months. Median overall survival (OS) (19.2 months, 19.0 months, and 21.0 months) and 3-year OS rates (26.5%, 27.2%, and 32.1%) were similar among patients with 5-FU/RT with no adjuvant Gem, those with 5-FU/RT with adjuvant Gem, and those with Gem/RT with adjuvant Gem, respectively (p = 0.88). Patients who received adjuvant Gem had a similar median OS (22.1 months) and 3-year OS rate (29%) compared to patients who did not (19.2 months and 26.5%, respectively) (p = 0.62). There was a trend for improved 3-year OS rates in patients with R0 vs. R1 resections (28.1% vs. 14.2%, p = 0.06) and in patients with T1 and T2 vs. T3 tumors (38% vs. 20%, p = 0.09). Node-negative patients had an improved 3-year OS rate (30.1%) when compared with patients with N1 disease (16.2%) (p = 0.02). Conclusion: In our cohort of patients with resected pancreatic cancer, Gem chemotherapy did not improve OS after chemoradiotherapy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Intraoperative Radiotherapy for Pancreatic Cancer: 30-Year Experience in a Single Institution in Japan

Purpose: To analyze retrospectively the results of intraoperative radiotherapy (IORT) with or without external beam radiotherapy ({+-} EBRT) for localized pancreatic cancer in the past three decades and to analyze prognostic factors by multivariate analysis. Methods and Materials: Records for 322 patients with pancreatic cancer treated by IORT {+-} EBRT in Tohoku University Hospital between 1980 and 2009 were reviewed. One hundred ninety-two patients who had no distant organ metastases or dissemination at the time of laparotomy were enrolled in the present study. Results: Eighty-three patients underwent gross total resection (R0: 48 patients, R1: 35 patients), and 109 patients underwent only biopsy or palliative resection. Fifty-five patients underwent adjuvant EBRT, and 124 underwent adjuvant chemotherapy. The median doses of IORT and EBRT were 25 and 40 Gy, respectively. The median follow-up period was 37.5 months. At the time of the analysis, 166 patients had disease recurrence, and 35 patients had local failure. The 2-year local control (LC) and overall survival (OS) rates were 71.0% and 16.9%, respectively. Comparison of the results for each decade showed that OS was significantly improved decade by decade (2-year: 25.0% vs. 18.8% vs. 4.2%, p < 0.001). Multivariate analysis showed that degree of resection (R0-1 vs. R2, hazard ratio = 1.97, p = 0.001) and adjuvant chemotherapy (yes vs. no, hazard ratio = 1.54, p = 0.028) had significant impacts on OS. Late gastrointestinal morbidity of Common Terminology Criteria for Adverse Events version 3.0 grade 4 or 5 was observed in four patients. Conclusion: Excellent local control for pancreatic cancer with few cases of severe late toxicity was achieved by using IORT. OS of patients with pancreatic cancer treated by IORT {+-} EBRT improved significantly decade by decade. Multivariate analysis showed that degree of resection and adjuvant chemotherapy had significant impacts on OS.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

A Phase I/II Trial of Intensity Modulated Radiation (IMRT) Dose Escalation With Concurrent Fixed-dose Rate Gemcitabine (FDR-G) in Patients With Unresectable Pancreatic Cancer

Purpose: Local failure in unresectable pancreatic cancer may contribute to death. We hypothesized that intensification of local therapy would improve local control and survival. The objectives were to determine the maximum tolerated radiation dose delivered by intensity modulated radiation with fixed-dose rate gemcitabine (FDR-G), freedom from local progression (FFLP), and overall survival (OS). Methods and Materials: Eligibility included pathologic confirmation of adenocarcinoma, radiographically unresectable, performance status of 0-2, absolute neutrophil count of {>=}1500/mm{sup 3}, platelets {>=}100,000/mm{sup 3}, creatinine <2 mg/dL, bilirubin <3 mg/dL, and alanine aminotransferase/aspartate aminotransferase {<=}2.5 Multiplication-Sign upper limit of normal. FDR-G (1000 mg/m{sup 2}/100 min intravenously) was given on days -22 and -15, 1, 8, 22, and 29. Intensity modulated radiation started on day 1. Dose levels were escalated from 50-60 Gy in 25 fractions. Dose-limiting toxicity was defined as gastrointestinal toxicity grade (G) {>=}3, neutropenic fever, or deterioration in performance status to {>=}3 between day 1 and 126. Dose level was assigned using TITE-CRM (Time-to-Event Continual Reassessment Method) with the target dose-limiting toxicity (DLT) rate set to 0.25. Results: Fifty patients were accrued. DLTs were observed in 11 patients: G3/4 anorexia, nausea, vomiting, and/or dehydration (7); duodenal bleed (3); duodenal perforation (1). The recommended dose is 55 Gy, producing a probability of DLT of 0.24. The 2-year FFLP is 59% (95% confidence interval [CI]: 32-79). Median and 2-year overall survival are 14.8 months (95% CI: 12.6-22.2) and 30% (95% CI 17-45). Twelve patients underwent resection (10 R0, 2 R1) and survived a median of 32 months. Conclusions: High-dose radiation therapy with concurrent FDR-G can be delivered safely. The encouraging efficacy data suggest that outcome may be improved in unresectable patients through intensification of local therapy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Impact of Gemcitabine Chemotherapy and 3-Dimensional Conformal Radiation Therapy/5-Fluorouracil on Quality of Life of Patients Managed for Pancreatic Cancer

Purpose: To report quality of life (QOL) results for patients receiving chemoradiation therapy for pancreatic cancer. Methods and Materials: Eligible patients (n=41 locally advanced, n=22 postsurgery) entered the B9E-AY-S168 study and received 1 cycle of induction gemcitabine (1000 mg/m{sup 2} weekly Multiplication-Sign 3 with 1-week break) followed by 3-dimensional conformal radiation therapy (RT) (54 Gy locally advanced and 45 Gy postsurgery) and concomitant continuous-infusion 5-fluorouracil (5FU) (200 mg/m{sup 2}/d throughout RT). After 4 weeks, patients received an additional 3 cycles of consolidation gemcitabine chemotherapy. Patients completed the European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-PAN26 questionnaires at baseline, before RT/5FU, at end of RT/5FU, before consolidation gemcitabine, and at treatment completion. Results: The patterns of change in global QOL scores differed between groups. In the locally advanced group global QOL scores were +13, +8, +3, and +1 compared with baseline before RT/5FU (P=.008), at end of RT/5FU, before consolidation gemcitabine, and at treatment completion, respectively. In the postsurgery group, global QOL scores were -3, +4, +15, and +17 compared with baseline at the same time points, with a significant improvement in global QOL before consolidation gemcitabine (P=.03). No significant declines in global QOL were reported by either cohort. Conclusions: This study demonstrates that global QOL and associated function and symptom profiles for pancreatic chemoradiation therapy differ between locally advanced and postsurgery patients, likely owing to differences in underlying disease status. For both groups, the treatment protocol was well tolerated and did not have a negative impact on patients' global QOL.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

A Multicenter Phase II Trial of S-1 With Concurrent Radiation Therapy for Locally Advanced Pancreatic Cancer

Purpose: The aim of this trial was to evaluate the efficacy and toxicity of S-1 and concurrent radiation therapy for locally advanced pancreatic cancer (PC). Methods and Materials: Locally advanced PC patients with histologically or cytologically confirmed adenocarcinoma or adenosquamous carcinoma, who had no previous therapy were enrolled. Radiation therapy was delivered through 3 or more fields at a total dose of 50.4 Gy in 28 fractions over 5.5 weeks. S-1 was administered orally at a dose of 80 mg/m{sup 2} twice daily on the day of irradiation during radiation therapy. After a 2- to 8-week break, patients received a maintenance dose of S-1 (80 mg/m{sup 2}/day for 28 consecutive days, followed by a 14-day rest period) was then administered until the appearance of disease progression or unacceptable toxicity. The primary efficacy endpoint was survival, and the secondary efficacy endpoints were progression-free survival, response rate, and serum carbohydrate antigen 19-9 (CA19-9) response; the safety endpoint was toxicity. Results: Of the 60 evaluable patients, 16 patients achieved a partial response (27%; 95% confidence interval [CI], 16%-40%). The median progression-free survival period, overall survival period, and 1-year survival rate of the evaluable patients were 9.7 months (95% CI, 6.9-11.6 months), 16.2 months (95% CI, 13.5-21.3 months), and 72% (95%CI, 59%-82%), respectively. Of the 42 patients with a pretreatment serum CA19-9 level of {>=}100 U/ml, 34 (81%) patients showed a decrease of greater than 50%. Leukopenia (6 patients, 10%) and anorexia (4 patients, 7%) were the major grade 3-4 toxicities with chemoradiation therapy. Conclusions: The effect of S-1 with concurrent radiation therapy in patients with locally advanced PC was found to be very favorable, with only mild toxicity.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Dosimetric Analysis of Organs at Risk During Expiratory Gating in Stereotactic Body Radiation Therapy for Pancreatic Cancer

Purpose: To determine how the respiratory phase impacts dose to normal organs during stereotactic body radiation therapy (SBRT) for pancreatic cancer. Methods and Materials: Eighteen consecutive patients with locally advanced, unresectable pancreatic adenocarcinoma treated with SBRT were included in this study. On the treatment planning 4-dimensional computed tomography (CT) scan, the planning target volume (PTV), defined as the gross tumor volume plus 3-mm margin, the duodenum, and the stomach were contoured on the end-expiration (CT{sub exp}) and end-inspiration (CT{sub insp}) phases for each patient. A separate treatment plan was constructed for both phases with the dose prescription of 33 Gy in 5 fractions with 95% coverage of the PTV by the 100% isodose line. The dose-volume histogram (DVH) endpoints, volume of duodenum that received 20 Gy (V{sub 20}), V{sub 25}, and V{sub 30} and maximum dose to 5 cc of contoured organ (D{sub 5cc}), D{sub 1cc}, and D{sub 0.1cc}, were evaluated. Results: Dosimetric parameters for the duodenum, including V{sub 25}, V{sub 30}, D{sub 1cc}, and D{sub 0.1cc} improved by planning on the CT{sub exp} compared to those on the CT{sub insp}. There was a statistically significant overlap of the PTV with the duodenum but not the stomach during the CT{sub insp} compared to the CT{sub exp} (0.38 ± 0.17 cc vs 0.01 ± 0.01 cc, P=.048). A larger expansion of the PTV, in accordance with a Danish phase 2 trial, showed even more overlapping volume of duodenum on the CT{sub insp} compared to that on the CT{sub exp} (5.5 ± 0.9 cc vs 3.0 ± 0.8 cc, P=.0003) but no statistical difference for any stomach dosimetric DVH parameter. Conclusions: Dose to the duodenum was higher when treating on the inspiratory than on the expiratory phase. These data suggest that expiratory gating may be preferable to inspiratory breath-hold and free breathing strategies for minimizing risk of toxicity.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Duodenal Toxicity After Fractionated Chemoradiation for Unresectable Pancreatic Cancer

Purpose: Improving local control is critical to improving survival and quality of life for patients with locally advanced unresectable pancreatic cancer (LAPC). However, previous attempts at radiation dose escalation have been limited by duodenal toxicity. In order to guide future studies, we analyzed the clinical and dosimetric factors associated with duodenal toxicity in patients undergoing fractionated chemoradiation for LAPC. Methods and Materials: Medical records and treatment plans of 106 patients with LAPC who were treated with chemoradiation between July 2005 and June 2010 at our institution were reviewed. All patients received neoadjuvant and concurrent chemotherapy. Seventy-eight patients were treated with conventional radiation to 50.4 Gy in 28 fractions; 28 patients received dose-escalated radiation therapy (range, 57.5-75.4 Gy in 28-39 fractions). Treatment-related toxicity was graded according to Common Terminology Criteria for Adverse Events, version 4.0. Univariate and multivariate analyses were performed to assess prognostic influence of clinical, pathologic, and treatment-related factors by using Kaplan-Meier and Cox regression methods. Results: Twenty patients had treatment-related duodenal toxicity events, such as duodenal inflammation, ulceration, and bleeding. Four patients had grade 1 events, 8 had grade 2, 6 had grade 3, 1 had grade 4, and 1 had grade 5. On univariate analysis, a toxicity grade ≥2 was associated with tumor location, low platelet count, an absolute volume (cm{sup 3}) receiving a dose of at least 55 Gy (V{sub 55} {sub Gy} > 1 cm{sup 3}), and a maximum point dose >60 Gy. Of these factors, only V{sub 55} {sub Gy} ≥1 cm{sup 3} was associated with duodenal toxicity on multivariate analysis (hazard ratio, 6.7; range, 2.0-18.8; P=.002). Conclusions: This study demonstrates that a duodenal V{sub 55} {sub Gy} >1 cm{sup 3} is an important dosimetric predictor of grade 2 or greater duodenal toxicity and establishes it as a dosimetric constraint when treating patients with unresectable pancreatic cancer with concurrent chemoradiation.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Tumor Size on Abdominal MRI Versus Pathologic Specimen in Resected Pancreatic Adenocarcinoma: Implications for Radiation Treatment Planning

Purpose: We assessed the accuracy of abdominal magnetic resonance imaging (MRI) for determining tumor size by comparing the preoperative contrast-enhanced T1-weighted gradient echo (3-dimensional [3D] volumetric interpolated breath-hold [VIBE]) MRI tumor size with pathologic specimen size. Methods and Materials: The records of 92 patients who had both preoperative contrast-enhanced 3D VIBE MRI images and detailed pathologic specimen measurements were available for review. Primary tumor size from the MRI was independently measured by a single diagnostic radiologist (P.M.) who was blinded to the pathology reports. Pathologic tumor measurements from gross specimens were obtained from the pathology reports. The maximum dimensions of tumor measured in any plane on the MRI and the gross specimen were compared. The median difference between the pathology sample and the MRI measurements was calculated. A paired t test was conducted to test for differences between the MRI and pathology measurements. The Pearson correlation coefficient was used to measure the association of disparity between the MRI and pathology sizes with the pathology size. Disparities relative to pathology size were also examined and tested for significance using a 1-sample t test. Results: The median patient age was 64.5 years. The primary site was pancreatic head in 81 patients, body in 4, and tail in 7. Three patients were American Joint Commission on Cancer stage IA, 7 stage IB, 21 stage IIA, 58 stage IIB, and 3 stage III. The 3D VIBE MRI underestimated tumor size by a median difference of 4 mm (range, −34-22 mm). The median largest tumor dimensions on MRI and pathology specimen were 2.65 cm (range, 1.5-9.5 cm) and 3.2 cm (range, 1.3-10 cm), respectively. Conclusions: Contrast-enhanced 3D VIBE MRI underestimates tumor size by 4 mm when compared with pathologic specimen. Advanced abdominal MRI sequences warrant further investigation for radiation therapy planning in pancreatic adenocarcinoma before routine integration into the treatment planning process.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Prognostic Significance of Carbohydrate Antigen 19-9 in Unresectable Locally Advanced Pancreatic Cancer Treated With Dose-Escalated Intensity Modulated Radiation Therapy and Concurrent Full-Dose Gemcitabine: Analysis of a Prospective Phase 1/2 Dose Escalation Study

Purpose: Although established in the postresection setting, the prognostic value of carbohydrate antigen 19-9 (CA19-9) in unresectable locally advanced pancreatic cancer (LAPC) is less clear. We examined the prognostic utility of CA19-9 in patients with unresectable LAPC treated on a prospective trial of intensity modulated radiation therapy (IMRT) dose escalation with concurrent gemcitabine. Methods and Materials: Forty-six patients with unresectable LAPC were treated at the University of Michigan on a phase 1/2 trial of IMRT dose escalation with concurrent gemcitabine. CA19-9 was obtained at baseline and during routine follow-up. Cox models were used to assess the effect of baseline factors on freedom from local progression (FFLP), distant progression (FFDP), progression-free survival (PFS), and overall survival (OS). Stepwise forward regression was used to build multivariate predictive models for each endpoint. Results: Thirty-eight patients were eligible for the present analysis. On univariate analysis, baseline CA19-9 and age predicted OS, CA19-9 at baseline and 3 months predicted PFS, gross tumor volume (GTV) and black race predicted FFLP, and CA19-9 at 3 months predicted FFDP. On stepwise multivariate regression modeling, baseline CA19-9, age, and female sex predicted OS; baseline CA19-9 and female sex predicted both PFS and FFDP; and GTV predicted FFLP. Patients with baseline CA19-9 ≤90 U/mL had improved OS (median 23.0 vs 11.1 months, HR 2.88, P<.01) and PFS (14.4 vs 7.0 months, HR 3.61, P=.001). CA19-9 progression over 90 U/mL was prognostic for both OS (HR 3.65, P=.001) and PFS (HR 3.04, P=.001), and it was a stronger predictor of death than either local progression (HR 1.46, P=.42) or distant progression (HR 3.31, P=.004). Conclusions: In patients with unresectable LAPC undergoing definitive chemoradiation therapy, baseline CA19-9 was independently prognostic even after established prognostic factors were controlled for, whereas CA19-9 progression strongly predicted disease progression and death. Future trials should stratify by baseline CA19-9 and incorporate CA19-9 progression as a criterion for progressive disease.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Stereotactic Body Radiation Therapy for Locally Advanced and Borderline Resectable Pancreatic Cancer Is Effective and Well Tolerated

Purpose: Stereotactic body radiation therapy (SBRT) provides high rates of local control (LC) and margin-negative (R0) resections for locally advanced pancreatic cancer (LAPC) and borderline resectable pancreatic cancer (BRPC), respectively, with minimal toxicity. Methods and Materials: A single-institution retrospective review was performed for patients with nonmetastatic pancreatic cancer treated with induction chemotherapy followed by SBRT. SBRT was delivered over 5 consecutive fractions using a dose painting technique including 7-10 Gy/fraction to the region of vessel abutment or encasement and 5-6 Gy/fraction to the remainder of the tumor. Restaging scans were performed at 4 weeks, and resectable patients were considered for resection. The primary endpoints were overall survival (OS) and progression-free survival (PFS). Results: Seventy-three patients were evaluated, with a median follow-up time of 10.5 months. Median doses of 35 Gy and 25 Gy were delivered to the region of vessel involvement and the remainder of the tumor, respectively. Thirty-two BRPC patients (56.1%) underwent surgery, with 31 undergoing an R0 resection (96.9%). The median OS, 1-year OS, median PFS, and 1-year PFS for BRPC versus LAPC patients was 16.4 months versus 15 months, 72.2% versus 68.1%, 9.7 versus 9.8 months, and 42.8% versus 41%, respectively (all P>.10). BRPC patients who underwent R0 resection had improved median OS (19.3 vs 12.3 months; P=.03), 1-year OS (84.2% vs 58.3%; P=.03), and 1-year PFS (56.5% vs 25.0%; P<.0001), respectively, compared with all nonsurgical patients. The 1-year LC in nonsurgical patients was 81%. We did not observe acute grade ≥3 toxicity, and late grade ≥3 toxicity was minimal (5.3%). Conclusions: SBRT safely facilitates margin-negative resection in patients with BRPC pancreatic cancer while maintaining a high rate of LC in unresectable patients. These data support the expanded implementation of SBRT for pancreatic cancer.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Phase 2 Study of Erlotinib Combined With Adjuvant Chemoradiation and Chemotherapy in Patients With Resectable Pancreatic Cancer

Purpose: Long-term survival rates for patients with resected pancreatic ductal adenocarcinoma (PDAC) have stagnated at 20% for more than a decade, demonstrating the need to develop novel adjuvant therapies. Gemcitabine-erlotinib therapy has demonstrated a survival benefit for patients with metastatic PDAC. Here we report the first phase 2 study of erlotinib in combination with adjuvant chemoradiation and chemotherapy for resected PDAC. Methods and Materials: Forty-eight patients with resected PDAC received adjuvant erlotinib (100 mg daily) and capecitabine (800 mg/m{sup 2} twice daily Monday-Friday) concurrently with intensity modulated radiation therapy (IMRT), 50.4 Gy over 28 fractions followed by 4 cycles of gemcitabine (1000 mg/m{sup 2} on days 1, 8, and 15 every 28 days) and erlotinib (100 mg daily). The primary endpoint was recurrence-free survival (RFS). Results: The median follow-up time was 18.2 months (interquartile range, 13.8-27.1). Lymph nodes were positive in 85% of patients, and margins were positive in 17%. The median RFS was 15.6 months (95% confidence interval [CI], 13.4-17.9), and the median overall survival (OS) was 24.4 months (95% CI, 18.9-29.7). Multivariate analysis with adjustment for known prognostic factors showed that tumor diameter >3 cm was predictive for inferior RFS (hazard ratio, 4.01; P=.001) and OS (HR, 4.98; P=.02), and the development of dermatitis was associated with improved RFS (HR, 0.27; P=.009). During CRT and post-CRT chemotherapy, the rates of grade 3/4 toxicity were 31%/2% and 35%/8%, respectively. Conclusion: Erlotinib can be safely administered with adjuvant IMRT-based CRT and chemotherapy. The efficacy of this regimen appears comparable to that of existing adjuvant regimens. Radiation Therapy Oncology Group 0848 will ultimately determine whether erlotinib produces a survival benefit in patients with resected pancreatic cancer.

62 RADIOLOGY AND NUCLEAR MEDICINE↗