ESTRO 2022 - Abstract Book

S804

Abstract book

ESTRO 2022

Results Eighty-four and 76 patients received margin-based and anatomy-based PART, respectively. Median follow-up time was 40.1 months (IQR: 25.5–58.9). The V45 and V30 of small bowel and duodenum were significantly lower in the anatomy-based PART group compared with margin-based PART group (small bowel, V45: 159.6 ± 32.8 vs. 188.7 ± 47.4, p <0.001; V30: 615.3 ± 131.0 vs. 742.6 ± 127.1, p <0.001; duodenum, V45: 8.3 ± 3.9 vs. 16.1 ± 5.9, p <0.001; V30: 19.8 ± 6.2 vs. 26.9 ± 6.4, p <0.001, respectively). The V15 of small bowel and duodenum were not significantly different between groups. Patients who received anatomy-based PART experienced significantly less patient-reported severe toxicity (PRO-CTCAE score ≥ 3) than patients who received margin-based PART in terms of frequency of diarrhea (7.9% vs. 20.2%; p =0.03), severity of abdominal pain (3.9% vs. 14.3%; p =0.03), and interference of abdominal pain (2.6% vs. 11.9%; p =0.03). The patterns of failures were not different between groups (Table 1). The sites of PALN failures of these two patients were above the level of left renal vein. There was no in-field or marginal PALN failure in these two groups. The 3-year overall survival and disease-free survival for margin-based PART vs. anatomy-based PART were 80.9% vs. 84.9% ( p =0.61) and 71.8% vs. 77.4% ( p =0.47), respectively.

Conclusion Anatomy-based PART can reduce the dose-volume to the small bowel and duodenum, and lower the incidence of severe patient-reported GI toxicity. The patterns of failure and survival outcomes were similar between para-aortic delineations.

PD-0909 Outcome of multiple high-risk factors on overall survival in adjuvant cervical cancer chemoradiation

Z. Horne 1 , S. Abel 1 , S. Crafton 2 , E. Miller 2 , C. Morse 2 , J. Nakayama 2 , T. Krivak 2 , S. Glaser 3 , R. Wegner 1 , A. Patel 1 , S. Beriwal 1

1 Allegheny Health Network Cancer Institute, Radiation Oncology, Pittsburgh, USA; 2 Allegheny Health Network Cancer Institute, Gynecologic Oncology, Pittsburgh, USA; 3 City of Hope National Medical Center, Radiation Oncology, Duarte, USA Purpose or Objective Standard adjuvant treatment for cervical cancers involving the lymph nodes, parametria and/or surgical margins consists of concurrent pelvic chemoradiation. The recent OUTBACK study found no benefit to the addition of further chemotherapy