Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “DIGESTIVE SYSTEM”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Dosimetric Impact of Interfraction Catheter Movement in High-Dose Rate Prostate Brachytherapy

Purpose: To evaluate the impact of interfraction catheter movement on dosimetry in prostate high-dose-rate (HDR) brachytherapy. Methods and Materials: Fifteen patients were treated with fractionated HDR brachytherapy. Implants were performed on day 1 under transrectal ultrasound guidance. A computed tomography (CT) scan was performed. Inverse planning simulated annealing was used for treatment planning. The first fraction was delivered on day 1. A cone beam CT (CBCT) was performed on day 2 before the second fraction was given. A fusion of the CBCT and CT was performed using intraprostatic gold markers as landmarks. Initial prostate and urethra contours were transferred to the CBCT images. Bladder and rectum contours were drawn, and catheters were digitized on the CBCT. The planned treatment was applied to the CBCT dataset, and dosimetry was analyzed and compared to the initial dose distribution. This process was repeated after a reoptimization was performed, using the same constraints used on day 1. Results: Mean interfraction catheter displacement was 5.1 mm. When we used the initial plan on day 2, the mean prostate V100 (volume receiving 100 Gy or more) decreased from 93.8% to 76.2% (p < 0.01). Rectal V75 went from 0.75 cm{sup 3} to 1.49 cm{sup 3} (p < 0.01). A reoptimization resulted in a mean prostate V100 of 88.1%, closer to the initial plan (p = 0.05). Mean rectal V75 was also improved with a value of 0.59 cm{sup 3}. There was no significant change in bladder and urethra dose on day 2. Conclusions: A mean interfraction catheter displacement of 5.1 mm results in a significant decrease in prostate V100 and an increase in rectum dose. A reoptimization before the second treatment improves dose distribution.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Prediction of Response to Neoadjuvant Radiotherapy in Patients With Locally Advanced Rectal Cancer by Means of Sequential 18FDG-PET

Purpose: Morphologic imaging techniques perform poorly in assessing the response to preoperative radiotherapy (RT), mainly because of desmoplastic reactions. The aim of this study was to investigate the potential of sequential 18-fluoro-2-deoxy-D-glucose (18FDG-PET) in assessing the response of rectal cancer to neoadjuvant RT and to determine which parameters can be used as surrogate markers for histopathologic response. Methods and Materials: 18FDG-PET scans were acquired before and during the 5th week after the end of RT. Tracer uptake was assessed semiquantitatively using standardized uptake values (SUV). The percentage differences (%{Delta}) between pre- and post-RT scans in SUV{sub max}, SUV{sub mean}, metabolic volume (MV), and total glycolytic volume (tGV) were calculated. Results: Forty-five consecutive patients with histologically confirmed rectal adenocarcinoma were enrolled. After neoadjuvant RT, 20 of the 45 patients were classified as histopathologic responders and 25 as non-responders. Intense 18F-FDG uptake was seen in all tumors before neoadjuvant RT (average SUV{sub max} 12.9 {+-} 6.0). When patients were classified as histologic responders and nonresponders, significant differences in %{Delta}SUV{sub max} (55.8% vs. 37.4%, p = 0.023) and %{Delta}SUV{sub mean} (40.1% vs. 21.0%, p = 0.001) were observed between the two groups. For %{Delta}MV and %{Delta}tGV, decreases were more prominent in responders but were not significantly different from those in nonresponders. As demonstrated by receiver operating characteristic analysis, %{Delta}SUV{sub mean} was a more powerful discriminator than was %{Delta}SUV{sub max}. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for optimal threshold of %{Delta}SUV{sub mean} (24.5%) were 80%, 72%, 76%, 70%, and 82% respectively. Conclusion: Sequential 18FDG-PET allows assessment of the response to preoperative RT. Both %{Delta}SUV{sub mean} and %{Delta}SUV{sub max} correlate with histopathologic response and can be used to evaluate and compare the effectiveness of different neoadjuvant treatment strategies. The maximum accuracy figures and the positive predictive value figures for both {Delta}%SUV{sub mean} and {Delta}%SUV{sub max} are, however, too low to justify modification of the standard treatment protocol of an individual patient.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Hypofractionated Dose-Painting Intensity Modulated Radiation Therapy With Chemotherapy for Nasopharyngeal Carcinoma: A Prospective Trial

Purpose: To evaluate the feasibility of dose-painting intensity-modulated radiation therapy (DP-IMRT) with a hypofractionated regimen to treat nasopharyngeal carcinoma (NPC) with concomitant toxicity reduction. Methods and Materials: From October 2002 through April 2007, 25 newly diagnosed NPC patients were enrolled in a prospective trial. DP-IMRT was prescribed to deliver 70.2 Gy using 2.34-Gy fractions to the gross tumor volume for the primary and nodal sites while simultaneously delivering 54 Gy in 1.8-Gy fractions to regions at risk of microscopic disease. Patients received concurrent and adjuvant platin-based chemotherapy similar to the Intergroup 0099 trial. Results: Patient and disease characteristics are as follows: median age, 46; 44% Asian; 68% male; 76% World Health Organization III; 20% T1, 52% T2, 16% T3, 12% T4; 20% N0, 36% N1, 36% N2, 8% N3. With median follow-up of 33 months, 3-year local control was 91%, regional control was 91%, freedom from distant metastases was 91%, and overall survival was 89%. The average mean dose to each cochlea was 43 Gy. With median audiogram follow-up of 14 months, only one patient had clinically significant (Grade 3) hearing loss. Twelve percent of patients developed temporal lobe necrosis; one patient required surgical resection. Conclusions: Preliminary findings using a hypofractionated DP-IMRT regimen demonstrated that local control, freedom from distant metastases, and overall survival compared favorably with other series of IMRT and chemotherapy. The highly conformal boost to the tumor bed resulted low rates of severe ototoxicity (Grade 3-4). However, the incidence of in-field brain radiation necrosis indicates that 2.34 Gy per fraction is not safe in this setting.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Phase II Study of Oral S-1 and Concurrent Radiotherapy in Patients With Unresectable Locally Advanced Pancreatic Cancer

Purpose: S-1 is an oral fluoropyrimidine derivative that has demonstrated favorable antitumor activity in patients with metastatic pancreatic cancer. The aim of this study was to evaluate safety and efficacy of S-1 and concurrent radiotherapy in patients with unresectable locally advanced pancreatic cancer. Methods and Materials: Patients with histopathologically proven, unresectable, locally advanced pancreatic cancer were eligible. Radiotherapy was delivered in 1.8 Gy daily fractions to a total dose of 50.4 Gy over 5.5 weeks. S-1 was administered orally twice a day at a dose of 80 mg/m{sup 2}/day from day 1 to 14 and 22 to 35. Two weeks after the completion of chemoradiotherapy, maintenance chemotherapy with S-1 was administered for 28 days every 6 weeks until progression. Results: Thirty-four patients were enrolled in this study. The most common Grade 3 toxicities during chemoradiotherapy were anorexia (24%) and nausea (12%). The overall response rate was 41% (95% confidence interval, 25%-58%) and overall disease control rate (partial response plus stable disease) was 97%. More than 50% decrease in serum CA 19-9 was seen in 27 of 29 evaluable patients (93%). The median progression-free survival was 8.7 months. The median overall survival and 1-year survival rate were 16.8 months and 70.6%, respectively. Conclusions: Oral S-1 and concurrent radiotherapy exerted a promising antitumor activity with acceptable toxicity in patients with locally advanced pancreatic cancer. This combination therapy seems to be an attractive alternative to conventional chemoradiotherapy using 5-fluorouracil infusion.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Matched Survival Analysis in Patients With Locoregionally Advanced Resectable Oropharyngeal Carcinoma: Platinum-Based Induction and Concurrent Chemoradiotherapy Versus Primary Surgical Resection

Purpose: The outcome of a prospective case series of 47 patients with newly diagnosed resectable locoregionally advanced oropharyngeal squamous cell carcinoma treated with platinum-based induction-concurrent chemoradiotherapy (IC/CCRT) was compared with the outcome of 47 matched historical control patients treated with surgery and postoperative RT. Methods and Materials: A total of 47 control patients with locoregionally advanced oropharyngeal squamous cell carcinoma were identified from review of a prospectively compiled comprehensive computerized head-and-neck cancer database and were matched with a prospective case series of patients undergoing IC/CCRT by disease stage, nodal status, gender, and age ({+-}5 years). The IC/CCRT regimen consisted of one cycle of induction chemotherapy followed by conventionally fractionated RT to a total dose of 66-70 Gy concomitantly with two cycles of chemotherapy. Each cycle of chemotherapy consisted of cisplatinum, 100 mg/m{sup 2}, and a continuous infusion of 5-fluorouracil, 1,000 mg/m{sup 2}/d for 5 days. The survival analysis was performed using Kaplan-Meier estimates. Matched-pair survival was compared using the Cox proportional hazards model. Results: No significant difference was found in the overall survival or progression-free survival rates between the two groups. The matched analysis of survival did not show a statistically significant greater hazard ratio for overall death (hazard ratio, 1.35; 95% confidence interval, 0.65-2.80; p = .415) or progression (hazard ratio, 1.44; 95% confidence interval, 0.72-2.87; p = .301) for patients undergoing IC/CCRT. Conclusion: Although the sample size was small and not randomized, this matched-pair comparison between a prospective case series and a historical cohort treated at the same institution showed that the efficacy of IC/CCRT with salvage surgery is as good as primary surgical resection and postoperative RT.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Longitudinal Study of Intestinal Symptoms and Fecal Continence in Patients With Conformal Radiotherapy for Prostate Cancer

Purpose: To prospectively assess the intestinal symptoms and fecal continence in patients who had undergone conformal radiotherapy (CRT) for prostate cancer. Methods and Materials: A total of 78 men who had undergone definitive CRT for prostate cancer were evaluated. The patients were assessed before, during (treatment Weeks 4 and 6), and 2, 12, and 24 months after CRT completion. The intestinal symptoms and fecal continence were evaluated with comprehensive standardized questionnaires. Results: The intestinal symptoms were mostly intermittent, with only a small minority of patients affected daily. Defecation pain, fecal urge, and rectal mucous discharge increased significantly during therapy. Defecation pain and rectal mucous discharge had returned to baseline levels within 8 weeks and 1 year after CRT, respectively. However, fecal urge remained significantly elevated for {<=}1 year and then returned toward the pretreatment values. The prevalence of rectal bleeding was significantly elevated 2 years after CRT. Fecal continence deteriorated during CRT and remained impaired at 1 year after treatment. Incontinence was mostly minor, occurring less than once per week and predominantly affecting incontinence for gas. Conclusion: Intestinal symptoms and fecal incontinence increased during prostate CRT. Except for rectal bleeding, the intestinal symptoms, including fecal incontinence, returned to baseline levels within 1-2 years after CRT. Thus, the rate of long-term late radiation-related intestinal toxicity was low.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Rectal Motion in Patients Receiving Preoperative Radiotherapy for Carcinoma of the Rectum

Purpose: To assess the movement of rectum, mesorectum, and rectal primary during a course of preoperative chemoradiotherapy. Methods and Materials: Seventeen patients with Stage II or III rectal cancer had a planning CT scan with rectal contrast before commencement of preoperative chemoradiation. The scan was repeated during Weeks 1, 3, and 5 of chemoradiation. The rectal primary (gross tumor volume), rectum, mesorectum, and bladder were contoured on all four scans. An in-house biomechanical model-based deformable image registration technique, Morfeus, was used to measure the three-dimensional spatial change in these structures after bony alignment. The required planning target volume margin for this spatial change, after bone alignment, was also calculated. Results: Rectal contrast was found to introduce a systematic error in the position of all organs compared with the noncontrast state. The largest change in structures during radiotherapy was in the anterior and posterior directions for the mesorectum and rectum and in the superior and inferior directions for the gross tumor volume. The planning target volume margins required for internal movement for the mesorectum based on the three scans acquired during treatment are 4 mm right, 5 mm left, 7 mm anterior, and 6 mm posterior. For the rectum, values were 8 mm right, 8 mm left, 8 mm anterior, and 9 mm posterior. The greatest movement of the rectum occurred in the upper third. Conclusions: Contrast is no longer used in CT simulation. Assuming bony alignment, a nonuniform margin of 8 mm anteriorly, 9 mm posteriorly, and 8 mm left and right is recommended.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Three-Dimensional Analysis of Recurrence Patterns in Rectal Cancer: The Cranial Border in Hypofractionated Preoperative Radiotherapy Can Be Lowered

Purpose: The aim of this study was to determine whether and where the radiotherapy (RT) clinical target volume (CTV) could be reduced in short-course preoperative treatment of rectal cancer patients. Methods and Materials: Patients treated in the Dutch total mesorectal excision trial, with a local recurrence were analyzed. For 94 (25 who underwent radiation therapy 69 who did not) of 114 patients with a local recurrence, the location of the recurrence was placed in a three-dimensionalthree (3D) model. The data in the 3D model were correlated to the clinical trial data to distinguish a group of patients eligible for CTV reduction. Effects of CTV reduction on dose to the small bowel was tested retrospectively in a dataset of 8 patients with three-field conformal plans and intensity-modulated RT (IMRT). Results: The use of preoperative RT mainly reduces anastomotic, lateral, and perineal recurrences. In patients without primary nodal involvement, no recurrences were found cranially of the S2-S3 interspace, irrespective of the delivery of RT. In patients without primary nodal involvement and a negative circumferential resection margin (CRM), only one recurrence was found cranial to the S2-S3 interspace. With a cranially reduced CTV to the S2-S3 interspace, over 60% reduction in absolute small bowel exposure at dose levels from 15 to 35 Gy could be achieved with three-field conventional RT, increasing to 80% when IMRT is also added. Conclusions: The cranial border of the CTV can safely be lowered for patients without expected nodal or CRM involvement, yielding a significant reduction of dose to the small bowel. Therefore, a significant reduction of acute and late toxicity can be expected.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Digital Tomosynthesis for Respiratory Gated Liver Treatment: Clinical Feasibility for Daily Image Guidance

Purpose: Breath-hold (BH) treatment minimizes internal target volumes (ITV) when treating sites prone to motion. Digital tomosynthesis (DTS) imaging has advantages over cone-beam CT (CBCT) for BH imaging: BH-DTS scan can be completed during a single breath-hold, whereas BH-CBCT is usually acquired by parsing the gantry rotation into multiple BH segments. This study evaluates the localization accuracy of DTS for BH treatment of liver tumors. Methods: Both planning CT and on-board DTS/CBCT images were acquired under BH, using the planning CT BH window as reference. Onboard imaging data sets included two independent DTS orientations (coronal and sagittal), and CBCT images. Soft tissue target positioning was measured by each imaging modality and translated into couch shifts. Performance of the two DTS orientations was evaluated by comparing target positioning with the CBCT benchmark, determined by two observers. Results: Image data sets were collected from thirty-eight treatment fractions (14 patients). Mean differences between the two DTS methods and the CBCT method were <1 mm in all directions (except the lateral direction with sagittal-DTS: 1.2 mm); the standard deviation was in the range of 2.1-3.5 mm for all techniques. The Pearson correlation showed good interobserver agreement for the coronal-DTS (0.72-0.78). The interobserver agreement for the sagittal-DTS was good for the in-plane directions (0.70-0.82), but poor in the out-of-plane direction (lateral, 0.26). Conclusions: BH-DTS may be a simpler alternative to BH-CBCT for onboard soft tissue localization of the liver, although the precision of DTS localization appears to be somewhat lower because of the presence of subtle out-of-plane blur.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Intraoperative Radiotherapy for Unresectable Pancreatic Cancer: A Multi-Institutional Retrospective Analysis of 144 Patients

Purpose: To retrospectively analyze the results of intraoperative radiotherapy (IORT) + external beam radiotherapy (EBRT) for unresectable pancreatic cancer. Methods and Materials: The records of 144 patients treated with IORT, with or without, EBRT were reviewed. One hundred and thirteen patients (78.5%) were treated with IORT + EBRT and 114 patients (79.2%) were treated in conjunction with chemotherapy. The median doses of IORT and EBRT were 25 Gy and 45 Gy, respectively. The median follow-up of all 144 patients was 9.6 months (range, 0.5-69.7 months). Results: At the time of this analysis, 131 of 144 patients (91.0%) had disease recurrences. Local progression was observed in 60 patients (41.7%), and the 2-year local control (LC) rate in all patients was 44.6%. Patients treated with IORT, with or without, EBRT had significantly more favorable LC (2-year LC, 50.9%) than those treated with IORT without EBRT (p = 0.0004). The 2-year overall survival (OS) rate and the median survival time in all 144 patients were 14.7% and 10.5 months, respectively. Patients treated with chemotherapy had a significantly favorable OS than those treated without chemotherapy (p < 0.0001). On univariate analysis, chemotherapy use alone had a significant impact on OS and on multivariate analysis; chemotherapy use was a significant prognostic factor. Late gastrointestinal morbidity of National Cancer Institute-Common Terminology Criteria Grade 3 was observed in 2 patients (1.4%). Conclusion: IORT + EBRT yields a relatively favorable LC rate for unresectable pancreatic cancer with low frequency of severe late toxicity, and IORT combined with chemotherapy conferred a survival benefit compared with IORT without chemotherapy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Volumetric Change of Selected Organs at Risk During IMRT for Oropharyngeal Cancer

Purpose: To assess volumetric changes of selected organs at risk (OAR) during intensity-modulated radiotherapy (IMRT) for oropharyngeal carcinoma. Materials and Methods: Twenty-six consecutive patients that were treated with definitive IMRT {+-} chemotherapy between November 2007 and November 2008 were selected for the present study. As part of an internal quality assurances program, a repeat kilovolt (KV) computed tomography was planned weekly during the 7-week treatment course. On each available scan, a single observer contoured the parotid submandibular, and thyroid glands (PG/SMG/TG), larynx (L), and constrictor, masticatory, and sternocleidomastoid muscles (CM/MM/SCM) as appropriate. The volume at each scan was compared with the one at planning CT in a pair-wise fashion. p values <0.05 after correction for multiple testing were considered significant. Results: A total of 159 scans was obtained during treatment for a total of 185 scans, including the baseline imaging. All OARs showed statistically significant changes over baseline by week 5. At week 7, the PG showed the largest absolute change with an average reduction of {approx}10 mL followed by both the SCM and MM ({approx}-5 mL). The largest ({approx}-30%) relative change was observed for the salivary glands. L and CM showed a {approx}15% increase in volume during treatment. Conclusion: All selected OAR undergo significant volumetric changes during a course of IMRT for oropharyngeal squamous cell carcinoma.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Position Verification for the Prostate: Effect on Rectal Wall Dose

Purpose: To evaluate the effect of gold marker (GM)-based position correction on the cumulative dose in the anorectal wall compared with traditional bony anatomy (BA)-based correction, taking into account changes in anorectal shape and position. Methods and Materials: A total of 20 consecutive prostate cancer patients, treated with curative external beam radiotherapy, were included. Four fiducial GMs were implanted in the prostate. Positioning was verified according to the shift in BA and GMs on daily electronic portal images. Position corrections were determined using on- and off-line position verification protocols according to the position of the GMs (GM-on and GM-off) and BA (BA-off). For all patients, intensity-modulated radiotherapy plans were made for the GM (8-mm planning target volume margin) and BA (10-mm planning target volume margin) protocols. The dose distribution was recomputed on 11 repeat computed tomography scans to estimate the accumulated dose to the prostate and anorectal wall while considering internal organ motion. Results: The dose that is at least received by 99% of the prostate was, on average, acceptable for all protocols. The individual patient data showed the best coverage for both GM protocols, with >95% of the prescribed dose for all patients. The anorectal wall dose was significantly lower for the GM protocols. The dose that is at least received by 30% of the rectal wall was, on average, 54.6 Gy for GM-on, 54.1 Gy for GM-off, and 58.9 Gy for BA-off (p <.001). Conclusion: Position verification with GM and reduced planning target volume margins yielded adequate treatment of the prostate and a lower rectal wall dose, even when accounting for independent movement of the prostate and anorectal wall.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Predictive Factors of Tumor Response After Neoadjuvant Chemoradiation for Locally Advanced Rectal Cancer

Purpose: Neoadjuvant chemoradiation followed by surgery is the standard of care for locally advanced rectal cancer. The aim of this study was to correlate tumor response to survival and to identify predictive factors for tumor response after chemoradiation. Methods and Materials: From 1998 to 2008, 168 patients with histologically proven locally advanced adenocarcinoma treated by preoperative chemoradiation before total mesorectal excision were retrospectively studied. They received a radiation dose of 45 Gy with a concomitant 5-fluorouracil (5-FU)-based chemotherapy. Analysis of tumor response was based on lowering of the T stage between pretreatment endorectal ultrasound and pathologic specimens. Overall and progression-free survival rates were correlated with tumor response. Tumor response was analyzed with predictive factors. Results: The median follow-up was 34 months. Five-year disease-free survival and overall survival rates were, of 44.4% and 74.5% in the whole population, 83.4% and 83.4%, respectively, in patients with pathological complete response, 38.6% and 71.9%, respectively, in patients with tumor downstaging, and 29.1and 58.9% respectively, in patients with absence of response. A pretreatment carcinoembryonic antigen (CEA) level of <5 ng/ml was significantly independently associated with pathologic complete tumor response (p = 0.019). Pretreatment small tumor size (p = 0.04), pretreatment CEA level of <5 ng/ml (p = 0.008), and chemotherapy with capecitabine (vs. 5-FU) (p = 0.04) were significantly associated with tumor downstaging. Conclusions: Downstaging and complete response after CRT improved progression-free survival and overall survival of locally advanced rectal adenocarcinoma. In multivariate analysis, a pretreatment CEA level of <5 ng/ml was associated with complete tumor response. Thus, small tumor size, a pretreatment CEA level of < 5ng/ml, and use of capecitabine were associated with tumor downstaging.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Phase II Trial of Full-Dose Gemcitabine and Bevacizumab in Combination With Attenuated Three-Dimensional Conformal Radiotherapy in Patients With Localized Pancreatic Cancer

Purpose: To evaluate response rate, survival, and toxicity in patients with nonmetastatic pancreatic cancer treated with gemcitabine, bevacizumab, and radiotherapy. Methods and Materials: Patients received three cycles of therapy over 10 weeks. In total, treatment consisted of intravenous (IV) gemcitabine, 1,000 mg/m{sup 2}, every 1 to 2 weeks (7 doses), IV bevacizumab, 10 mg/kg every 2 weeks (5 doses), and 36 Gy of radiotherapy (2.4-Gy fractions during cycle two). Response was assessed by cross-sectional imaging and carbohydrate antigen 19-9 (CA 19-9) levels. Patients with resectable tumors underwent surgery 6 to 8 weeks after the last dose of bevacizumab. Maintenance gemcitabine and bevacizumab doses were delivered to patients who had unresected tumors and no progression. Results: Twenty-eight of the 32 enrolled patients completed all three cycles. The median follow-up was 11.07 months. Most grade 3 or 4 toxicities occurred in the initial treatment phase; the most frequent toxicities were leukopenia (21%), neutropenia (17%), and nausea (17%). At week 10, 1 patient (4%) had a complete response, 2 patients (7%) had partial responses, 21 patients (75%) had stable disease, and 4 patients (14%) had progressive disease. The median pretreatment and posttreatment CA 19-9 levels (25 patients) were 184.3 and 57.9 U/ml, respectively (p = 0.0006). One of 10 patients proceeding to surgery experienced a major complication. Two of 6 patients undergoing resection had complete pathologic responses. The median progression-free and overall survival durations were 9.9 months and 11.8 months, respectively. Conclusions: The combination of full-dose gemcitabine, bevacizumab, and radiotherapy was active and was not associated with a high rate of major surgical complications.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Bevacizumab, Capecitabine, Amifostine, and Preoperative Hypofractionated Accelerated Radiotherapy (HypoArc) for Rectal Cancer: A Phase II Study

Purpose: Bevacizumab has established therapeutic activity in patients with metastatic colorectal cancer, and anti-vascular endothelial growth factor therapy enhances the activity of radiotherapy in experimental models. We assessed the feasibility and efficacy of preoperative radiochemotherapy combined with bevacizumab in patients with rectal cancer. Methods and Materials: Nineteen patients with radiologic T3 and/or N+ rectal carcinoma were treated with preoperative conformal hypofractionated accelerated radiotherapy (3.4 Gy in 10 consecutive fractions) supported with amifostine (500-1,000 mg daily), capecitabine (600 mg/m{sup 2} twice daily, 5 days per week), and bevacizumab (5 mg/kg every 2 weeks for 2 cycles). Surgery followed 6 weeks after the end of radiotherapy. A cohort of 14 sequential patients treated with the same regimen without bevacizumab was available for comparison. Results: Grade 2 or 3 diarrhea was noted in 7 of 19 patients (36.8%), which was statistically worse than patients receiving the same regimen without bevacizumab (p = 0.01). A higher incidence of Grade 2 or 3 proctalgia was also noted (21.1%) (p = 0.03). Bladder and skin toxicity was negligible. All toxicities regressed completely within 2 weeks after the end of therapy. Pathologic complete and partial response was noted in 7 of 19 cases (36.8%) and 8 of 19 cases (42.1%). Within a median follow-up of 21 months, none of the patients has had late complications develop and only 1 of 18 evaluable cases (5.5%) has had locoregional relapse. Conclusions: Bevacizumab can be safely combined with hypofractionated radiotherapy and capecitabine as a preoperative radiochemotherapy regimen for patients with rectal cancer. The high pathologic complete response rates urges the testing of bevacizumab in randomized studies.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Intensity-Modulated Radiotherapy Reduces Gastrointestinal Toxicity in Patients Treated With Androgen Deprivation Therapy for Prostate Cancer

Purpose: Androgen deprivation therapy (AD) has been shown to increase late Grade 2 or greater rectal toxicity when used concurrently with three-dimensional conformal radiotherapy (3D-CRT). Intensity-modulated radiotherapy (IMRT) has the potential to reduce toxicity by limiting the radiation dose received by the bowel and bladder. The present study compared the genitourinary and gastrointestinal (GI) toxicity in men treated with 3D-CRT+AD vs. IMRT+AD. Methods and Materials: Between July 1992 and July 2004, 293 men underwent 3D-CRT (n = 170) or IMRT (n = 123) with concurrent AD (<6 months, n = 123; {>=}6 months, n = 170). The median radiation dose was 76 Gy for 3D-CRT (International Commission on Radiation Units and Measurements) and 76 Gy for IMRT (95% to the planning target volume). Toxicity was assessed by a patient symptom questionnaire that was completed at each visit and recorded using a Fox Chase Modified Late Effects Normal Tissue Task radiation morbidity scale. Results: The mean follow-up was 86 months (standard deviation, 29.3) for the 3D-CRT group and 40 months (standard deviation, 9.7) for the IMRT group. Acute GI toxicity (odds ratio, 4; 95% confidence interval, 1.6-11.7; p = .005) was significantly greater with 3D-CRT than with IMRT and was independent of the AD duration (i.e., <6 vs. {>=}6 months). The interval to the development of late GI toxicity was significantly longer in the IMRT group. The 5-year Kaplan-Meier estimate for Grade 2 or greater GI toxicity was 20% for 3D-CRT and 8% for IMRT (p = .01). On multivariate analysis, Grade 2 or greater late GI toxicity (hazard ratio, 2.1; 95% confidence interval, 1.1-4.3; p = .04) was more prevalent in the 3D-CRT patients. Conclusion: Compared with 3D-CRT, IMRT significantly decreased the acute and late GI toxicity in patients treated with AD.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Patterns of Response After Preoperative Treatment in Gastric Cancer

Purpose: To analyze the rate of pathologic response in patients with locally advanced gastric cancer treated with preoperative chemotherapy with and without chemoradiation at our institution. Methods and Materials: From 2000 to 2007 patients were retrospectively identified who received preoperative treatment for gastric cancer (cT3-4/ N+) with induction chemotherapy (Ch) or with Ch followed by concurrent chemoradiotherapy (45 Gy in 5 weeks) (ChRT). Surgery was planned 4-6 weeks after the completion of neoadjuvant treatment. Pathologic assessment was used to investigate the patterns of pathologic response after neoadjuvant treatment. Results: Sixty-one patients were analyzed. Of 61 patients, 58 (95%) underwent surgery. The R0 resection rate was 87%. Pathologic complete response was achieved in 12% of the patients. A major pathologic response (<10% of residual tumor) was observed in 53% of patients, and T downstaging was observed in 75%. Median follow-up was 38.7 months. Median disease-free survival (DFS) was 36.5 months. The only patient-, tumor-, and treatment-related factor associated with pathologic response was the use of preoperative ChRT. Patients achieving major pathologic response had a 3-year actuarial DFS rate of 63%. Conclusions: The patterns of pathologic response after preoperative ChRT suggest encouraging intervals of DFS. Such a strategy may be of interest to be explored in gastric cancer.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

High-Dose Split-Course Radiation Therapy for Anal Cancer: Outcome Analysis Regarding the Boost Strategy (CORS-03 Study)

Purpose: To retrospectively assess the clinical outcome in anal cancer patients treated with split-course radiation therapy and boosted through external-beam radiation therapy (EBRT) or brachytherapy (BCT). Methods and Materials: From January 2000 to December 2004, a selected group (162 patients) with invasive nonmetastatic anal squamous cell carcinoma was studied. Tumor staging reported was T1 = 31 patients (19%), T2 = 77 patients (48%), T3 = 42 patients (26%), and T4= 12 patients (7%). Lymph node status was N0-1 (86%) and N2-3 (14%). Patients underwent a first course of EBRT: mean dose 45.1 Gy (range, 39.5-50) followed by a boost: mean dose 17.9 Gy (range, 8-25) using EBRT (76 patients, 47%) or BCT (86 patients, 53%). All characteristics of patients and tumors were well balanced between the BCT and EBRT groups. Results: The mean overall treatment time (OTT) was 82 days (range, 45-143) and 67 days (range, 37-128) for the EBRT and BCT groups, respectively (p < 0.001). The median follow-up was 62 months (range, 2-108). The 5-year cumulative rate of local recurrence (CRLR) was 21%. In the univariate analysis, the prognostic factors for CRLR were as follows: T stage (T1-2 = 15% vs. T3-4 = 36%, p = 0.03), boost technique (BCT = 12% vs. EBRT = 33%, p = 0.002) and OTT (OTT <80 days = 14%, OTT {>=}80 days = 34%, p = 0.005). In the multivariate analysis, BCT boost was the unique prognostic factor (hazard ratio = 0.62 (0.41-0.92). In the subgroup of patients with OTT <80 days, the 5-year CRLR was significantly increased with the BCT boost (BC = 9% vs. EBRT = 28%, p = 0.03). In the case of OTT {>=}80 days, the 5-year CRLR was not affected by the boost technique (BCT = 29% vs. EBRT = 38%, p = 0.21). Conclusion: In anal cancer, when OTT is <80 days, BCT boost is superior to EBRT boost for CRLR. These results suggest investigating the benefit of BCT boost in prospective trials.

62 RADIOLOGY AND NUCLEAR MEDICINE↗