Abstract 518P
Background
Squamous cell carcinoma of the anus (SCCA) is a rare cancer. Chemoradiotherapy (CRT) is the recommended curative treatment for SCCA stage I-III. The aim of the study was to investigate the 3- and 5-year disease-free survival (DFS) and overall survival (OS), locoregional treatment failure rate, and determine prognostic factors for DFS.
Methods
141 patients were entered in a prospective observational study (ANCARAD; NCT 01937780) at Oslo University Hospital from Oct 2013 to Sept 2017. Main inclusion criteria were histologically proven SCCA, planned radiotherapy, and performance status (ECOG) ≤ 2. CRT was delivered to doses of 54–58 Gy with concomitant mitomycin and 5-fluorouracil or capecitabine, with 5-year follow-up. Disease stage, patient characteristics, treatment, response and survival were prospectively registered. Human papilloma virus (HPV) status was assessed. Disease-free and overall survival were analyzed by the Kaplan-Meier method and Cox’ proportional hazard model.
Results
Of the 141 patients included, 132 were eligible for final analyses. Median age was 63 years (range 39-90), 73% were women, 42% had T3-T4 tumors and 44% had N1-3 disease. Median follow up time was 49.3 months (range 3-71). Eighteen patients (14%) had treatment failure, 9 locoregional, 4 distant and 5 both locoregional and distant failure. Of these, 15 patients underwent surgery, 12 had salvage abdomino-perineal resection and 3 resection of metastases. Eleven of the 18 patients were alive with no evidence of disease at last follow-up. DFS at 3 and 5 years was 85% and 77%, respectively. OS was 93% at 3 years and 85% at 5 years. HPV negative tumors (Hazard Ratio (HR) = 2.9, p <0.01), N3 disease (HR = 2.5, p <0.05), tumor size >4cm (HR = 2.2, p <0.05) and male gender (HR = 2.2, p <0.05) were statistically significant negative prognostic factors in univariate analyses for DFS. HPV negativity, N3 disease, and tumor size >4cm remained significant after adjusting for age and gender in multivariate analyses for DFS.
Conclusions
Chemoradiotherapy for SCCA resulted in excellent clinical outcomes in this prospective study, with less than 15% observed treatment failures and an estimated 3-years DFS of over 80%. Known prognostic factors were confirmed.
Clinical trial identification
NCT 01937780.
Editorial acknowledgement
Legal entity responsible for the study
Oslo University Hospital.
Funding
Oslo University Hospital.
Disclosure
All authors have declared no conflicts of interest.