Long-term follow-up experience in anal canal cancer treated with Intensity-Modulated Radiation Therapy: Clinical outcomes, patterns of relapse and predictors of failure

Maïlys de Meric de Bellefon (1, 2) , Claire Lemanski (1, 2) , Florence Castan (1, 2) , Emmanuelle Samalin (3, 1) , Thibault Mazard (3, 1) , Alexis Lenglet (1, 2) , Sylvain Demontoy (1, 2) , Olivier Riou (1, 2) , Carmen Llacer-Moscardo (1, 2) , Pascal Fenoglietto (1, 2) , Norbert Aillères (1, 2) , Simon Thezenas (1, 2) , Charles Debrigode (4, 2) , Sabine Vieillot (5) , Sophie Gourgou (1, 2) , David Azria (1, 2)

1 ICM - Institut régional de Cancérologie de Montpellier
2 UM - Université de Montpellier
3 IRCM - U1194 Inserm - UM - Institut de Recherche en Cancérologie de Montpellier
4 CHU Nîmes - Centre Hospitalier Universitaire de Nîmes
5 Catalan Institute of Oncology [Perpignan]

Background and purpose: To assess the long-term outcomes of patients with squamous cell carcinoma of the anal canal (SCCAC) treated with Intensity-Modulated Radiation Therapy (IMRT).Material and methods: From 2007 to 2015, 193 patients were treated by IMRT for SCCAC. Radiotherapy delivered 45 Gy in 1.8 Gy daily-fractions to the primary tumor and elective nodal areas, immediately followed by a boost of 14.4-20 Gy to the primary tumor and involved nodes. Concurrent chemotherapy with 5-FU-mitomycin (MMC) or cisplatin was added for locally advanced tumors. Survivals were estimated by Kaplan-Meier method. Locoregional (LR) relapses were precisely assessed. Prognostic factors were evaluated by uni- and multivariate analyses. Late toxicity was scored according to the Common Toxicity Criteria for Adverse Events v4.0.Results: Median follow-up was 70 months (range, 1-131). Forty-nine men (25%) and 144 women (75%) were analyzed. Median age was 62 years. Tumor stages were I, II, III and IV in 7%, 24%, 63% and 6% of cases, respectively. Chemotherapy was delivered in 167 patients (87%), mainly MMC (80%). Five-year OS, DFS, CFS and LR control rates were 74%, 68%, 66% and 85%, respectively. Forty-one patients (21%) had a relapse: 22 were LR, mostly in-field (68%). Predictors for LR failure were exclusive radiotherapy, chemotherapy lacking MMC and treatment breaks >3 days. Overall late toxicity ≥grade 2 occurred in 43% of patients, with 24% grade 3 and one case of grade 4 (hematuria).Conclusion: CRT with IMRT assures excellent local control in locally advanced SCCAC with manageable long-term toxicity. Multicentric prospective trials are required to reinforce those results.

Mots clés: Anal canal carcinoma; IMRT; Long-term follow-up; Patterns of relapse; Prognostic factors; Survival

Domaines: Sciences du Vivant [q-bio]

Maïlys de Meric de Bellefon, Claire Lemanski, Florence Castan, Emmanuelle Samalin, Thibault Mazard, et al.. Long-term follow-up experience in anal canal cancer treated with Intensity-Modulated Radiation Therapy: Clinical outcomes, patterns of relapse and predictors of failure. Radiotherapy & Oncology, 2020, 144, pp.141 - 147. ⟨10.1016/j.radonc.2019.11.016⟩. ⟨hal-03488620⟩