Predictors of recurrence following local excision for early-stage anal squamous cell carcinoma

Introduction: There is increasing use of local excision (LE) for definitive treatment of early-stage anal squamous cell carcinoma (ASCC) to avoid the morbidity associated with chemoradiotherapy (CRT). However, the importance of different histological variables on risk of recurrence is poorly understood.

Methods: A detailed analysis of patient characteristics, histology results, recurrence patterns and salvage treatment was conducted in consecutive T1/T2N0 ASCC patients treated by LE 2010-2021 across a UK regional cancer network multi-disciplinary team (MDT). Associations between potential predictors of disease recurrence were explored using chi-squared and Kruskal-Wallis tests for categorical and continuous variables respectively.

Results: Of 621 ASCC patients discussed in the network MDT, 164 had early-stage disease (T1/T2 N0). Of these, 36 (22%) were deemed suitable for LE (median age 61 years, female to male ratio 2:1). Twenty-two LE tumours were T1; 14 were T2. There were 12 well-differentiated tumours, 21 moderate and 3 poorly-differentiated. Seven out of 36 LE patients (19.4%) developed recurrence, all of whom went on to have salvage treatment with CRT (n = 4), re-excision (n = 2) or radiotherapy (n = 1). Predictors of disease recurrence following LE were: tumour differentiation (p = 0.024), tumour depth (p = 0.033) and R1 resection margin (p = 0.034). Tumour stage and site (margin/canal) were non-significant.

Conclusion: LE for T1/T2 N0 ASCC of the margin or canal is a viable treatment strategy to avoid the morbidity associated with CRT and salvage treatments are still available for patients that develop recurrence. Tumour differentiation, depth and margin status are all important factors to consider when discussing management of early-stage ASCC.