Anal cancer survival: a socioeconomic analysis

Squamous cell carcinoma is the most common variant of anal malignancy. Certain disease-related factors have been established in determining survival. These include tumour size, differentiation and nodal involvement. Other factors such as HIV status, human papillomavirus infection, smoking and socioeconomic disparity may have important roles, however few data are available on the UK population. We aim to correlate social deprivation and survival of anal cancer patients at a tertiary centre.

All consecutive cases diagnosed with anal squamous cell carcinoma and treated as per local protocol between July 2010 and April 2017 were included. The pathological and demographical details were collected from a prospectively maintained database. Socioeconomic deprivation was defined for each postcode using the Index of Multiple Deprivation decile compiled by local governments in England. Survival was estimated using Kaplan-Meier analysis and Cox regression was used to investigate the effect of different factors on overall survival.

A total of 129 patients with anal squamous cell carcinoma over a median follow-up of 43 months were included. Overall survival for the entire patient cohort was 87.7% (95% confidence interval, CI, 82.0-93.7%), 75.5% (95% CI 67.5-84.5%) and 68.9% (95% CI 59.7-79.6%) at one year, three years and five years, respectively. On multivariate analysis, Index of Multiple Deprivation and income do not significantly influence overall survival (p = 0.79, hazard ratio, HR, 1.07; 95% CI 0.61-1.63), (p = 0.99, HR=1.00; 95% CI 0.61-1.63), respectively. Increased risk of death was observed for male sex (p = 0.02, HR=2.80; 95% CI 1.02-5.50) and larger tumour size (p = 0.01, HR=1.64; 95% CI 1.12-2.41).

In contrast to US studies, there is little difference in survival between the least deprived and most deprived groups. We attribute this to equal access to intensity-modulated radiation therapy-based chemoradiotherapy. Thus, a highly effective treatment made available to all mitigates any survival difference between socioeconomic groups.