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

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

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).

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.

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