ESTRO 38 Abstract book

S192 ESTRO 38

3-year visit than patients without neurotoxicity (n=65 vs. n=296; mean 59,0 vs. 69,3; difference of means -10,4; 95% CI [-16,1;-4,6]). Conclusion The addition of oxaliplatin to a 5-FU-based preoperative CRT and postoperative CTx is not associated with worse overall QoL during follow-up. Given the benefit of improved DFS, our findings support the addition of oxaliplatin as a potential treatment option for patients with locally advanced rectal adenocarcinomas. OC-0385 Gender associated differences in outcome after neoadjuvant chemoradiotherapy for rectal cancer S. Meltzer 1 , K.M. Bakke 1 , K.L. Rød 2 , S. Dueland 3 , K. Flatmark 4 , A.T. Kristensen 4 , F.O. Larsen 5 , J.V. Schou 5 , A.J. Fuglestad 6 , C. Kersten 6 , K.R. Redalen 2 , A.H. Ree 7 1 Akershus University Hospital, Department of Oncology, Lørenskog, Norway ; 2 Norwegian University of Science and Technology, Department of Physics, Trondheim, Norway ; 3 Oslo University Hospital, Department of Oncology, Oslo, Norway ; 4 Oslo University Hospital - Norwegian Radium Hospital, Department of Tumor Biology, Oslo, Norway ; 5 Herlev and Gentofte Hospital, Department of Oncology, Herlev, Denmark ; 6 Sørlandet Hospital, Center for Cancer Treatment, Kristiansand, Norway; 7 Institute of Clinical Medicine, University of Oslo, Oslo, Norway Purpose or Objective As combined-modality treatment of rectal cancer has resulted in high local control rates, dissemination to distant organs remains the foremost reason of treatment failure, disease-related morbidity, and impaired survival. While colon cancer primarily metastasizes to the liver, probably due to mesenteric venous drainage into the portal vein, rectal cancer is more prone to primarily spread to the lungs. We hypothesized that this may relate to anatomic and hemodynamic factors in the pelvic cavity. Material and Methods From 705 rectal cancer patients prospectively enrolled onto six clinical studies at four centers in Norway and Denmark between October 2005 and December 2017, 354 patients (216 men, 138 women) with locally advanced rectal cancer (LARC) were included for analysis of gender disparities in metastasis outcome. The selected patients had disease confined to the pelvic cavity at diagnosis and underwent study cohort-specific schedules of neoadjuvant chemoradiotherapy with curative intent. Progression-free survival was recorded as time from study enrolment until the first metastatic event or up to five years after surgery in the case of no event. In one of the study cohorts, dynamic susceptibility contrast-based magnetic resonance and computed tomography imaging at diagnosis enabled measurements of tumor blood perfusion (n=94) and the diameter of the inferior mesenteric vein (IMV; n=137), from patients who either proceeded directly to primary surgery or to standard neoadjuvant chemoradiotherapy. The IMV diameter was measured following the left colic, superior rectal and sigmoid veins to their confluence and then measuring the widest diameter of the IMV just after. Results Significantly more women than men developed lung metastasis (Figure 1), while the opposite was the case for liver metastasis (Figure 2). Women had both higher tumor blood perfusion than men (mean of 122.1 versus 99.83 ml/min/100g, p=0.004 by Student’s t-test, parameters were normally distributed) and smaller IMV diameter (mean of 4.69 versus 5.48 mm, p<0.001 by Student’s t- test). Finally, IMV diameter ≥5 mm was associated with progression to liver metastasis (p=0.016 by log-rank test, cutoff selected by receiver operating characteristics curve).

Oncology, Würzburg, Germany ; 2 University of Frankfurt and German Cancer Consortium DKTK partner site, Department of Radiotherapy and Oncology, Frankfurt, Germany ; 3 University Hospital Erlangen, Department of Radiation Oncology, Erlangen, Germany; 4 University Medical Centre Göttingen, Department of General- Visceral and Paediatric Surgery, Göttingen, Germany; 5 Kliniken Maria Hilf GmbH Mönchengladbach, Department of Haematology/Oncology and Gastroenterology, Mönchengladbach, Germany; 6 University Hospital Erlangen, Department of Surgery, Erlangen, Germany; 7 Tumour Biology Centre Freiburg, Tumour Biology Centre Freiburg, Freiburg, Germany ; 8 University Hospital Mannheim- University of Heidelberg, Interdisciplinary Tumour Centre, Heidelberg, Germany ; 9 University of Oldenburg, Department of General and Visceral Surgery, Oldenburg, Germany ; 10 University Medical Centre Göttingen, Institute of Pathology, Göttingen, Germany; 11 Klinikum Esslingen, Department of Surgery, Esslingen, Germany ; 12 DiaCura & Klinikum Coburg, Department of Radiation Oncology and Radiotherapy, Coburg, Germany ; 13 University Hospital Carl Gustav Carus, Medical Department I- University Cancer Centre, Dresden, Germany ; 14 University Erlangen-Nürnberg, Department of Medical Informatics- Biometry and Epidemiology, Erlangen, Germany Purpose or Objective In a phase 3, open label randomised multicentre trial we previously confirmed that the inclusion of oxaliplatin (OX) into standard fluorouracil-based (5-FU) combined modality treatment for locally advanced rectal cancer (UICC II/III) was well tolerated and led to an improved disease-free survival (DFS) at 3 years. Here, we present 5- year results of patient reported quality of life (QoL). Material and Methods Between July, 2006, and February, 2010, 1236 patients aged 18 years or older with rectal carcinoma (clinically staged T3-4 or any node-positive) were randomly assigned to two groups at 88 participating German centres. Treatment was either standard 5-FU-based chemoradiotherapy (CRT) followed by total mesorectal excision (TME-surgery) and postoperative chemotherapy (CTx) with 5-FU, or preoperative CRT with 5-FU and OX, followed by TME-surgery and postoperative CTx with OX, leucovorin and 5-FU. 613 patients were randomised to the investigational group and 623 patients to the control group. The primary endpoint was DFS. QoL questionnaires (EORTC QLQ-C30, colorectal module CR38) were completed pretherapeutically, at the end of postoperative Ctx and during follow-up (1-, 3-, and 5-year visit). QoL assessment did not comprise specific questions on neurotoxicity. Analysis was done according to intention- to-treat. Recruitment and long-term follow-up are completed. ClinicalTrials.gov identifier: NCT00349076. Results Available questionnaires at baseline were 84,0% (n=515) in the investigational group and 82,5% (514) in the control group, 39,0% (239) vs. 36,8% (229) at 3 years, and 15,2% (93) vs. 16,4% (102) at 5 years (for all patients). General health status (GHS) for disease-free patients was stable in both groups (range 0 to 100): baseline: OX arm mean 63,2 (SD +/- 22; n=503) vs. standard arm 62,0 (+/- 21,6; n=491), 95% CI [-1,5;3,9]; at 5 years: OX arm 65,5 (+/- 22,4; n=83) vs. standard arm 64,9 (+/- 21,1; n=85), 95% CI[ -6;7,2]. At the end of treatment and during follow-up, no moderate or large clinically relevant and statistically significant differences (differences of more than 10 points) between groups were found in QoL domains, including scales for diarrhea, gastrointestinal symptoms, chemotherapy side-effects or fatigue. Adjusting for age and gender, as well as including non-disease-free patients did not induce considerable changes. Regardless of the treatment arm, disease-free patients experiencing neurotoxic side-effects (grade 1-4) showed worse GHS at