Background With legal acceptance of homosexuality in India, men who have sex with men (MSM) are increasingly being reported. Akin to cervical cancer in sexually active women, MSM are predisposed to anal cancers especially with co-infection of HIV. Further, screening of Papanicolaou stained anal smears in MSM can greatly reduce morbidity and mortality due to anal cancer; similar to cervical Pap screening in sexually active women. P16/ink4, a surrogate marker for oncogenic HPV coinfection, improves diagnostic accuracy for anal dysplasia. However, there are only two studies from Asia and none from India analysing anal dysplasia in MSM. This cross-sectional study endeavoured to assess the prevalence of anal dysplasia using Pap smears and p16 immunostaining amongst MSM in India.

Methods A total of 31 consecutive HIV positive and 34 HIV negative MSM (n = 65) were subjected to anal cytological evaluation with Pap stain and p16 staining. Chi-square test and coefficient of correlation were used for comparison.

Results Twenty four (36.9%) and thirty one (47.6%) patients were transgender and bisexual respectively. Eighteen (27.7%) had abnormal anal cytology which was higher in HIV positive as compared to HIV negative group (35% versus 20%, p = 0.180). Similarly, both low grade (25.8% vs 17.6%, p = 0.549) and high grade lesions (8.3% vs 4.8%, p = 0.341) were comparable in HIV positive and negative groups. A negative correlation of CD4 count at time of recruitment with degree of anal dysplasia was observed (r = –0.073, p = 0.696). A total of 13 (20%) smears were P16 positive with sensitivity, specificity, positive predictive value and negative predictive value of 72.3%, 100%, 100% and 92.3% respectively.

Conclusion Anal cytology should be used to screen for anal dysplasia in MSM irrespective of HIV status. Furthermore, addition of P16, with greater specificity for high grade lesions, will significantly improve diagnostic accuracy.