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EP-1269: Comparison of 2 and 3 arc VMAT versus fixed field IMRT and proton beam therapy in anal cancer
S682 ESTRO 36 _______________________________________________________________________________________________
Conclusion The system appears to be able to compensate the disomogenities due to the presence of magnetic field through the use of optimizer. EP-1268 Tumor response according to NK cell change during preoperative chemoradiotherapy in rectal cancer J. Heo1, Y.T. Oh1, O.K. Noh1, M. Chun1, J.E. Park2, S.R. Cho3 1 Ajou University School of Medicine, Radiation Oncology, Suwon, Korea Republic of 2 Ajou University School of Medicine, Pediatrics, Suwon, Korea Republic of 3 Ajou University School of Medicine, Laboratory Medicine, Suwon, Korea Republic of Purpose or Objective The objective of this prospective study was to evaluate the relationship between the circulating lymphocyte subpopulation counts during preoperative chemoradiotherapy (CRT) and tumor response in locally advanced rectal cancer. Material and Methods In this prospective study, from August 2015 to June 2016, 10 patients treated with preoperative CRT followed by surgery were enrolled. Patients received conventional fractionated radiotherapy (50.4 Gy) with fluorouracilbased chemotherapy. Surgical resection was performed at 4 to 8 weeks after the completion of preoperative CRT. The absolute blood lymphocyte subpopulation was obtained prior to and after 4 weeks of CRT. We analyzed the association between a tumor response and change in the lymphocyte subpopulation during CRT. Results Among 10 patients, 2 (20%) had evidence of pathologic complete response. In 8 patients with clinically node positive, 4 (50%) had nodal tumor response. All lymphocyte subpopulation counts at 4 weeks after CRT were significantly lower than those observed during pretreatment (p < 0.01). A high decrease in NK cell count during CRT (baseline cell count − cell count at 4 weeks) was associated with node down staging (p = 0.034). Conclusion Our results suggest that the change of lymphocyte subset to preoperative CRT may be a predictive factor for tumor response in rectal cancer. EP-1269 Comparison of 2 and 3 arc VMAT versus fixed field IMRT and proton beam therapy in anal cancer C. Kronborg1, E.E. Wilken2, J. Hansen1, L. Nyvang1, J.B. Petersen1, E. Serup-Hansen2, K.L.G. Spindler1 1 Aarhus University Hospital, Oncology, Aarhus C, Denmark 2 Herlev and Gentofte Hospital, Oncology, Herlev, Denmark Purpose or Objective Chemoradiotherapy is the standard treatment for squamous cell carcinoma of the anus (SCCA) and is the source of both acute and late toxicity. Advanced radiotherapy treatment techniques aim at reducing dose to organs at risk (OAR) while maintaining target coverage and dose homogeneity. Further, VMAT techniques shorten delivery time considerably. We compared dosimetric advantages of fixed field IMRT, 2 and 3 arc VMAT and additional 3- and 4-field pencil beam scanning proton therapy. Material and Methods Twenty patients with SCCA treated at two different centres were included. Standard treatment was 64-51,2 Gy/32 F or 60-49,5/30 Gy/F delivered with 2 or 3 arc VMAT technique and concurrent chemotherapy according to
local practice. Alternative treatment plans were generated for all patients using 5- or 6- fixed field IMRT and 3 arc VMAT (All Varian Eclipse planning system). Four patients with doses above normal constraints (ex high V40 Gy to the bowel) were selected for additional proton therapy planning; both 3- and 4- field plans were generated (Eclipse ver. 10 Multi Field Optimization (IMPT)). Bowel was delineated as potential bowel cavity and bladder as total circumference. Results Target volume coverage and homogeneity were comparable between the different planning techniques. We compared multiple dose volume parameters to OAR including V40 Gy and V50 Gy to the bowel cavity, V45 Gy to the bladder, mean dose to femoral heads using IMRT, 2 arc VMAT and 3 arc VMAT techniques and found no significant differences in any parameter. Both 3- and 4field proton treatment plans demonstrated significant sparing on V40 Gy to the bowel cavity: median volume using 2 Arc VMAT was 667 cc, 3- and 4-field proton therapy 522 cc and 535 cc respectively. V45 Gy to the bladder was also considerably lower using protons: 2 arc VMAT 49,3% vs. 23,4% and 28,5% using 3- and 4-field proton therapy. Mean dose to femoral heads was significantly lower with proton therapy while V40 Gy and V30 Gy to the sacral bone were comparable. Conclusion We found dosimetric equality on the selected parameters for OAR when comparing 2 arc VMAT with fixed field IMRT and 3 arc VMAT, and no differences between 2 and 3 arc VMAT either. VMAT reduces overall treatment time and is a feasible option for standard treatment planning in SCCA. In four patients with high V40 Gy to the bowel proton treatment plans proved superior in V40 Gy to the bowel, V45 Gy to the bladder, and mean dose to femoral heads with the potential to reduce subsequent toxicity. Data on acute toxicity will be presented at the meeting. EP-1270 Clinical outcome of non-metastatic rectal cancer patients with extremely high CEA level S.H. YOUN1, D.Y. KIM1, T.H. KIM1, S.Y. KIM2, J.H. BAEK2, Y.J. CHA2, H.J. CHANG2, M.J. KIM2, S.C. PARK2, J.H. OH2 1 National Cancer Center, Proton Therapy Center, Goyang-si-, Korea Republic of 2 National Cancer Center, Center for Colorectal Cancer, Goyang-si-, Korea Republic of Purpose or Objective To investigate clinical outcome of non-metastatic rectal cancer patients with extremely high pretreatment serum CEA level after radical surgery following preoperative chemoradiotherapy Material and Methods A total of 959 patients with clinical stage II-III rectal cancer who underwent preoperative chemoradiotherapy followed by radical surgery between October 2001 and July 2011 were retrospectively analyzed. There were 332 patients with elevated pretreatment serum CEA level (> 5ng/ml) and among them, we defined 23 patients with CEA level of > 50 ng/ml as an extremely high pretreatment CEA group. Overall survival rate, relapse-free survival rate, locoregional recurrence-free survival rate and distant metastasis-free survival rate were compared between pretreatment CEA levels of 5-50 ng/ml and > 50 ng/ml. Results Median follow-up duration was 69 months (range, 3-165). The five-year survival rate were 80.5% and 73.4%, and the 10-year survival rate were 64.5% and 73.4% in patients with pretreatment serum CEA level of 5-50 ng/ml and > 50 ng/ml, respectively (p = 0.672). The extremely high CEA group (> 50 ng/ml) had significantly lower relapse-free survival rate (RFS) at 5-year and 10-year than patients with CEA level of 5-50 ng/ml (5-year RFS 70.6% versus.
Conclusion The system appears to be able to compensate the disomogenities due to the presence of magnetic field through the use of optimizer. EP-1268 Tumor response according to NK cell change during preoperative chemoradiotherapy in rectal cancer J. Heo1, Y.T. Oh1, O.K. Noh1, M. Chun1, J.E. Park2, S.R. Cho3 1 Ajou University School of Medicine, Radiation Oncology, Suwon, Korea Republic of 2 Ajou University School of Medicine, Pediatrics, Suwon, Korea Republic of 3 Ajou University School of Medicine, Laboratory Medicine, Suwon, Korea Republic of Purpose or Objective The objective of this prospective study was to evaluate the relationship between the circulating lymphocyte subpopulation counts during preoperative chemoradiotherapy (CRT) and tumor response in locally advanced rectal cancer. Material and Methods In this prospective study, from August 2015 to June 2016, 10 patients treated with preoperative CRT followed by surgery were enrolled. Patients received conventional fractionated radiotherapy (50.4 Gy) with fluorouracilbased chemotherapy. Surgical resection was performed at 4 to 8 weeks after the completion of preoperative CRT. The absolute blood lymphocyte subpopulation was obtained prior to and after 4 weeks of CRT. We analyzed the association between a tumor response and change in the lymphocyte subpopulation during CRT. Results Among 10 patients, 2 (20%) had evidence of pathologic complete response. In 8 patients with clinically node positive, 4 (50%) had nodal tumor response. All lymphocyte subpopulation counts at 4 weeks after CRT were significantly lower than those observed during pretreatment (p < 0.01). A high decrease in NK cell count during CRT (baseline cell count − cell count at 4 weeks) was associated with node down staging (p = 0.034). Conclusion Our results suggest that the change of lymphocyte subset to preoperative CRT may be a predictive factor for tumor response in rectal cancer. EP-1269 Comparison of 2 and 3 arc VMAT versus fixed field IMRT and proton beam therapy in anal cancer C. Kronborg1, E.E. Wilken2, J. Hansen1, L. Nyvang1, J.B. Petersen1, E. Serup-Hansen2, K.L.G. Spindler1 1 Aarhus University Hospital, Oncology, Aarhus C, Denmark 2 Herlev and Gentofte Hospital, Oncology, Herlev, Denmark Purpose or Objective Chemoradiotherapy is the standard treatment for squamous cell carcinoma of the anus (SCCA) and is the source of both acute and late toxicity. Advanced radiotherapy treatment techniques aim at reducing dose to organs at risk (OAR) while maintaining target coverage and dose homogeneity. Further, VMAT techniques shorten delivery time considerably. We compared dosimetric advantages of fixed field IMRT, 2 and 3 arc VMAT and additional 3- and 4-field pencil beam scanning proton therapy. Material and Methods Twenty patients with SCCA treated at two different centres were included. Standard treatment was 64-51,2 Gy/32 F or 60-49,5/30 Gy/F delivered with 2 or 3 arc VMAT technique and concurrent chemotherapy according to
local practice. Alternative treatment plans were generated for all patients using 5- or 6- fixed field IMRT and 3 arc VMAT (All Varian Eclipse planning system). Four patients with doses above normal constraints (ex high V40 Gy to the bowel) were selected for additional proton therapy planning; both 3- and 4- field plans were generated (Eclipse ver. 10 Multi Field Optimization (IMPT)). Bowel was delineated as potential bowel cavity and bladder as total circumference. Results Target volume coverage and homogeneity were comparable between the different planning techniques. We compared multiple dose volume parameters to OAR including V40 Gy and V50 Gy to the bowel cavity, V45 Gy to the bladder, mean dose to femoral heads using IMRT, 2 arc VMAT and 3 arc VMAT techniques and found no significant differences in any parameter. Both 3- and 4field proton treatment plans demonstrated significant sparing on V40 Gy to the bowel cavity: median volume using 2 Arc VMAT was 667 cc, 3- and 4-field proton therapy 522 cc and 535 cc respectively. V45 Gy to the bladder was also considerably lower using protons: 2 arc VMAT 49,3% vs. 23,4% and 28,5% using 3- and 4-field proton therapy. Mean dose to femoral heads was significantly lower with proton therapy while V40 Gy and V30 Gy to the sacral bone were comparable. Conclusion We found dosimetric equality on the selected parameters for OAR when comparing 2 arc VMAT with fixed field IMRT and 3 arc VMAT, and no differences between 2 and 3 arc VMAT either. VMAT reduces overall treatment time and is a feasible option for standard treatment planning in SCCA. In four patients with high V40 Gy to the bowel proton treatment plans proved superior in V40 Gy to the bowel, V45 Gy to the bladder, and mean dose to femoral heads with the potential to reduce subsequent toxicity. Data on acute toxicity will be presented at the meeting. EP-1270 Clinical outcome of non-metastatic rectal cancer patients with extremely high CEA level S.H. YOUN1, D.Y. KIM1, T.H. KIM1, S.Y. KIM2, J.H. BAEK2, Y.J. CHA2, H.J. CHANG2, M.J. KIM2, S.C. PARK2, J.H. OH2 1 National Cancer Center, Proton Therapy Center, Goyang-si-, Korea Republic of 2 National Cancer Center, Center for Colorectal Cancer, Goyang-si-, Korea Republic of Purpose or Objective To investigate clinical outcome of non-metastatic rectal cancer patients with extremely high pretreatment serum CEA level after radical surgery following preoperative chemoradiotherapy Material and Methods A total of 959 patients with clinical stage II-III rectal cancer who underwent preoperative chemoradiotherapy followed by radical surgery between October 2001 and July 2011 were retrospectively analyzed. There were 332 patients with elevated pretreatment serum CEA level (> 5ng/ml) and among them, we defined 23 patients with CEA level of > 50 ng/ml as an extremely high pretreatment CEA group. Overall survival rate, relapse-free survival rate, locoregional recurrence-free survival rate and distant metastasis-free survival rate were compared between pretreatment CEA levels of 5-50 ng/ml and > 50 ng/ml. Results Median follow-up duration was 69 months (range, 3-165). The five-year survival rate were 80.5% and 73.4%, and the 10-year survival rate were 64.5% and 73.4% in patients with pretreatment serum CEA level of 5-50 ng/ml and > 50 ng/ml, respectively (p = 0.672). The extremely high CEA group (> 50 ng/ml) had significantly lower relapse-free survival rate (RFS) at 5-year and 10-year than patients with CEA level of 5-50 ng/ml (5-year RFS 70.6% versus.