ESTRO 2024 - Abstract Book

S1503

Clinical - Lower GI

ESTRO 2024

1121

Digital Poster

Examining clinical outcomes and toxicities in definitive chemoradiation for carcinoma of anal canal.

Andrea Romei 1 , Alessandra Galardi 2 , Gabriele Simontacchi 3 , Carlotta Becherini 3 , Daniela Greto 3 , Emanuela Olmetto 3 , pietro Garlatti 3 , Erika Scoccimarro 3 , Luca Visani 3 , Pierluigi Bonomo 3 , Anna Peruzzi 3 , Icro Meattini 3 , Isacco Desideri 3 , Monica Mangoni 3 , Marco Banini 3 , Cinzia Talamonti 4 , Lorenzo Livi 3 1 Radiation Oncology, Azienda Ospedaliero Universitaria Careggi of Biomedical, Experimental, and Clinical Sciences ''M. Serio'', Florence, Italy. 2 Radiation Oncology, Azienda Ospedaliero Universitaria Careggi, FLorence, Italy. 3 Radiation Oncology, Azienda Ospedaliero Universitaria Careggi, Florence, Italy. 4 Medical Physics Unit, AOU Careggi, Florence, Italy

Purpose/Objective:

Current standard treatment for locally advanced squamous cell carcinoma of the anal canal (SCCAC) is definitive chemoradiation (CRT), resulting in excellent oncological outcomes. Nevertheless, this particular treatment approach may be burdened by important side effects. In clinical practice there are many problems in balancing treatment toxicities and oncological outcomes . The purpose of this study was to evaluate the clinical outcomes and adverse events in real-world clinical practice in patients with SCCAC who undergo radiotherapy.

Material/Methods:

We analyzed a cohort of consecutive patients who received definitive radiotherapy with or without concurrent chemotherapy (CT) from 2013 to 2023. All patients underwent moderately hypofractionated radiotherapy (total dose of 55 Gy in 25 daily fractions schedule). We reviewed clinical and treatment related data. We calculated local control (LC), distant metastasis free survival (DMFS), overall survival (OS) and Grade≥ 3 (G≥3) toxicity rate according to CTCAE version 5.1 .

Results:

A total of 104 patients, with a median age of 67 years, were enrolled in the study. All patients completed the prescribed treatment, and 77 received concurrent chemotherapy. Thirtyseven patients were Stage III or more and 47 patients had a node positive disease at diagnosis. After a median follow-up of 34 months, 18 patients experienced disease progression. The 3-year LC, DMFS and OS rates were 82%,88% and 85%, respectively. Stage III disease (p=0.0037) and omission of CT (p=0.0028) had an adverse impact on LC, while positive nodal staging was correlated with DMFS (p=0.042) at multivariate analysis. CT omission was also correlated with impaired OS (p=0.004). G≥3 diarrhea, dermatitis and hematologic toxicity were observed in 6, 15 and 10 patients, respectively.

Conclusion:

Considering the favorable oncological outcomes seen in the analyzed patients and the occurrence of non-cancer specific deaths, it is worth considering an evaluation of a de-escalation of treatment for patients diagnosed with stage II or lower disease. Initial strategies in de-escalation of treatment have been experienced in ACT4 trial