Outcomes of Salvage Surgery for Anal Squamous Cell Carcinoma: Results from a Tertiary Centre

Introduction: Squamous cell carcinoma of the anus (SCCA) is a rare cancer with a lifetime incidence of 0.2%, however the incidence is increasing. First line treatment is chemoradiotherapy (CRT), however approximately 20% of patients will have ‘recurrent’ or ‘persistent’ disease. These patients then undergo ‘salvage surgery’ consisting of an abdominoperineal excision and reconstruction, which is associated with serious morbidity. Five-year survival rates range from 23-69%. The aim of this study is to examine the post operative and oncological outcomes from our tertiary care regional anal neoplasia centre. Methods: Retrospective case series including all consecutive patients undergoing salvage surgery for SCCA from 2017 to 2023 were included. Demographical data, pre-operative parameters including TNM staging, resection margin status (R0 vs R1), post operative complications particularly wound complications were collected. Patient survival and time to recurrence were measured over this 6-year period and information regarding surveillance following completion of CRT and salvage surgery gathered. Results: Twenty-five patients were included. Our overall survival and disease-free survival rates were 51% and 57% over a six-year period. No patients died within 30 days of their operation. Seven patients (28%) died during follow -up period with median survival of these patients was 12.7 months (IQR: 8.3 - 18.2). Eight patients (32%) developed recurrent disease. Median time to recurrence was 5.3 months (IQR: 3.3 - 12.5). R1 resection showed a trend towards higher chance of recurrence and lower survival rate compared to R0 resections but was not statistically significant. Of note, two patients with R1 resections had re-recurrence picked up on early CT and MRI at 2 and 3 months respectively. Two thirds of patient with recurrent SCCA had T3/T4 tumours. Only three patients were screened for HIV. Conclusions: Our survival and recurrence rates are in keeping with reported literature. There are limited data regarding the follow up and imaging of the post salvage surgery for SCCA. We propose close follow up of SCCA following CRT with consideration of High Resolution Anoscopy and early imaging in R1 resections may aid decision making for systemic cancer treatment.