Smoking and the risk of anal cancer recurrence: The Addenbrookes Hospital experience.

Abstract

439 Background: Anal cancer, a tumour induced by the human papilloma virus (HPV) is highly responsive to chemoradiation. Smoking appears to be an important cofactor in its development, possibly through immunomodulatory mechanism and has been reported to have a negative effect on prognosis. Objective is to evaluate the relation between smoking and the outcome in patients receiving radical chemoradiotherapy (50.4 Gy/ 28f with concomitant 5FU/Mitomycin) for squamous carcinoma of the anus. Methods: 109 patients treated with radical intent from January 2009- Feb 2013 were retrospectively analysed. Details of staging, smoking history, HIV status, response to treatment, follow up time and recording of persistent or recurrence were collected. High risk disease (HR) was defined as any T3/T4 disease or TxN2+, standard risk (SR) as T1/2 N0-1. Results: 68 females and 41 males with an age range 38-83 (median 61).Data about smoking status was available in 74 patients: 28 smokers, 8 ex-smokers, and 38 non-smokers. 54/109 (49%) had high risk disease (HR), and the distribution was balanced across the groups. 4 patients were HIV positive. Median follow up time was 23 months. Complete clinical response was achieved in 101/109 (93%), 1 patient died (cause unknown), and 7 had persistent disease. Of these 6 were smokers (2 SR, 3HR, 1 HR and HIV+) 1 was a non-smoker (1 HR). 9 patients developed recurrent disease: 5 smokers (2 SR, 3 HR), 1 ex-smoker (HR), 3 unknown (2HR, 1SR). 11/16 patients who had a local failure were persistent smokers. Using ordinal logistic regression, smoking increases the risk of recurrence with an Odds ratio of 17.4 (p=0.008). Conclusions: This retrospective series suggest that smoking is associated with a higher risk of local recurrence following chemoradiotherapy. One of the hypothesis is that tissue hypoxia may impact on the oxygen dependent effect of chemoradiation. Patients should be encouraged to stop smoking and smoking may need to be considered as a factor defining a higher risk category which may benefit from dose escalation.