ESTRO 2022 - Abstract Book

S1115

Abstract book

ESTRO 2022

interrupted because of acute toxicity in four patients (25%), one of which had a scheduled gap. All patients received concurrent MMC and fluoropyrimidine, but only 4 patients (25%) received the whole scheduled dose of chemotherapy. Regarding CRT tolerance, 13/15 of the patients (87%) had at least one grade 1-2 acute toxicity, and 11/15 of the patients (73%) had at least one grade 3-4 toxicity. There was no treatment-related death. The most frequent grade 3-4 adverse effects were neutropenia (36%), dermatitis (40%), and anitis (47%). Eleven patients (73%) had at least one chronic grade 1 or 2 toxicity such as rectitis, fibrosis or incontinence. One patient had a grade 4 chronic rectitis (7%). The complete local response rate was 81% at first evaluation and 62.5% at the end of the follow-up. The 1-year local PFS rate was 73% (95%CI 61.9-84.6) and the 3-year local PFS rate was 67% (95%CI 54.5-78.8). The median PFS was 14.9 months (2.1-54.6), the 1-year PFS rate was 62.5% (95%CI 50.4-74.6) and the 3-year PFS rate was 33% (95%CI 19.5-46.1). The median OS was not reached. The 1-year OS rate was 87.5% (95%CI 79.2-95.8) and the 3-year OS rate was 75 % (95%CI 64.2-85.8). Conclusion In patients with metastatic SCCA who had a significant objective response after upfront DCF, local CRT was feasible with high complete local response rate. The compliance with concurrent chemotherapy was low. The good local control rate despite interruptions due to toxicities and low CT compliance, underline the role of pelvic RT. The high rate of toxicity prompt the need to adapt the CRT regimen in the metastatic setting. 1 The University of Leeds, Leeds Institute of Medical Research at St James's, Leeds, United Kingdom; 2 Leeds Cancer Centre, St James's University Hospitals, Department of Medical Physics, Leeds, United Kingdom Purpose or Objective Anal cancer is a rare cancer, primarily treated using concurrent chemoradiotherapy (CRT), with IMRT and VMAT being the current standard conformal techniques. However, due to the rarity of anal cancer, there is still very limited consensus on prognostic factors for outcome following conformal CRT. This systematic review aims to evaluate the existing literature to identify prognostic factors for oncological outcomes in anal cancer, focusing on patients treated with curative intent using contemporary conformal radiotherapy techniques. Materials and Methods A literature search was conducted using Medline and Embase to identify studies reporting on prognostic factors for survival and cancer-related outcomes after conformal CRT for anal cancer. Studies were considered if they included ≥ 70% patients treated with conformal radiotherapy techniques (3D-defined targets on computed tomography (CT), beams conformed to targets), reported survival or disease-related outcomes, and examined prognostic factors for outcomes using univariate (UVA) or multivariate (MVA) analysis. Studies were excluded if patients were treated with 2D radiotherapy techniques and/or fields based solely on bony landmarks, if cohorts included less than 100 patients or were derived from population- level databases, or if treated with palliative intent. All meta-analysis studies, reviews, animal model studies, conference abstracts/letters and studies without English translation were excluded. Studies published after 1 st January 2000 and up to 1 st July 2020 were considered. Prognostic factors which were identified as significant in UVA and MVA by each study were extracted. The factors were grouped into three broader categories: clinical factors, biomarkers and imaging factors. Only factors reported as prognostic in more than one study were included in the final results. Results The results from 19 studies were analysed (Figure 1). In both UVA and MVA analysis, higher T stage, higher N stage, and male sex were the most prevalent and reliable clinical prognostic factors for inferior outcomes. This was the case for the majority of outcomes explored (Table 1). Only a few biomarkers have been identified as prognostic by more than one study – pre-treatment biopsy HPV load, as well as the presence of leukocytosis, neutrophilia and anaemia at baseline measurement. The results also highlight the lack of studies with large cohorts exploring the prognostic significance of imaging factors. No imaging factors were identified as prognostic by more than one study. PO-1321 Prognostic factors for anal cancer treated with conformal radiotherapy – a systematic review S. Theophanous 1 , R. Samuel 1 , J. Lilley 2 , A. Henry 1 , D. Sebag-Montefiore 1 , A. Gilbert 1 , A. Appelt 1