Outcomes and Trends of Anal Squamous Cell Carcinoma in Queensland: A 26-Year Review

Anal cancer is rare, with anal squamous cell carcinoma (ASCC) being the most common histological type. ASCC incidence has rapidly increased in western populations over recent decades; however, outcomes for patients in Queensland, Australia, have not been previously described. The aim of this study was to report on local ASCC incidence and survival over time and identify predictive factors for survival.

A prospectively maintained database was searched to identify anal cancer cases in Queensland between January 1991 and December 2016. Kaplan-Meier analysis was used to calculate overall survival (OS) of all anal cancer patients. Further analysis was performed for ASCC patients specifically relating to age (< 60 years old, > 60 years old), era of diagnosis (1991-2010, 2011-2016), geographical remoteness (urban and remote) and whether they required salvage surgery.

A total of 1106 patients were included. Eighty two percent (899 patients) were diagnosed with ASCC. ASCC incidence increased by 54.4% over the study period. Five-year OS of ASCC, adenocarcinoma and melanoma was 67%, 46.6% and 25.5%, respectively. Five-year OS of ASCC patients who underwent salvage surgery was 56%. Though age significantly predicted survival (p < 0.001), era of diagnosis and geographical remoteness were not significant prognostic factors (p = 0.11 and p = 0.8).

This study is the first state-wide assessment of ASCC outcomes in Queensland across 26 years. A rapidly increasing incidence and mortality rate was observed. Though younger ASCC patients have better outcomes, there is no survival disadvantage to geographic remoteness. Survival outcomes have not changed significantly throughout the study period.