Demographics, pattern of practice and clinical outcomes in rectal squamous cell carcinoma

Aim: The aim of this study was to describe the baseline clinical features, treatment patterns and outcomes in rectal squamous cell carcinoma (SCC).

Method: This is a retrospective study of patients with rectal SCC treated at the Princess Margaret Cancer Centre (Toronto, Canada) between 1 January 1995 and 31 December 2020. Clinical factors associated with locoregional failure (LRF), distant metastases (DM), disease-free survival (DFS) and overall survival (OS), such as age, sex, HIV status, T-category, nodal status, grade and primary treatment, were investigated with univariate analysis (UVA).

Results: Twenty nine patients with rectal SCC were analysed with a median follow-up of 7.4 years (range 0.3-20.4 years). The median age at diagnosis was 52 years, with the majority presenting with clinical T3 disease or higher (n = 21, 72%) and positive regional lymph nodes (n = 16, 55%), while more than quarter of patients (28%) had metastatic disease. Definitive chemoradiation was the treatment modality of choice in more than half of all cases (n = 17, 59%) with a response rate of 100%. The 10-year cumulative incidence of LRF and DM was, respectively, 12% (95% CI 1.8%-32.9%) and 31% (95% CI: 12.0%-52.6%). The 5- and 10-year OS was 82% (95% CI 66.1%-100%). UVA revealed a trend towards an association of male gender (hazard ratio = 4.65, 95% CI 0.9%-24.1; p = 0.067) and primary surgical treatment (hazard ratio = 0.76, 95% CI 0.09-6.34; p = 0.061) with DFS.

Conclusion: Definitive chemoradiation is an effective and preferred treatment for rectal SCC allowing for sphincter preservation with complete clinical response observed in all patients.