FC 23-04PREDICTORS OF 12-MONTH PERSISTENT HIGH-GRADE SQUAMOUS INTRAEPITHELIAL LESIONS (HSIL) IN A COHORT OF GAY AND BISEXUAL MEN

02. Epidemiology and natural history
I.M. Poynten 1, F. Jin 1, R. Hillman 2, D. Templeton 3, C. Law 4, J. Roberts 5, A. Farnsworth 5, C. Fairley 6, S. Garland 7, A. Cornall 7, S. Tabrizi 7, A. Grulich 1.
1The Kirby Institute, UNSW Australia, Sydney, NSW, Australia (Australia), 2St Vincent’s Hospital, Sydney, NSW Australia and Western Sydney Sexual Health Centre, University of Sydney, Sydney, NSW, Australia (Australia), 3The Kirby Institute, UNSW Australia, Sydney, NSW, Australia, RPA Sexual Health, Sydney Local Health District, Sydney, NSW, Australia and Central Clinical School, The University of Sydney, Sydney, NSW, Australia (Australia), 4St Vincent’s Hospital, Sydney, NSW Australia (Australia), 5Douglass Hanly Moir Pathology, Sydney, NSW, Australia (Australia), 6Melbourne Sexual Health Centre, Melbourne, VIC, Australia (Australia), 7Royal Women’s Hospital, University of Melbourne, Melbourne, VIC, Australia (Australia)

Background / Objectives

Gay and bisexual men (GBM), particularly HIV positive GBM, are at greatly increased risk of anal cancer. The anal cancer precursor HSIL is so highly prevalent in GBM that it is clear most HSIL do not progress to cancer. We examined predictors for 12- month HSIL persistence and clearance in GBM with HSIL at study baseline, with the aim of identifying clinically-useful predictors of risk of progression to anal cancer.


Methods

Participants were 617 GBM from the ongoing Study of the Prevention of Anal Cancer conducted in Sydney, Australia. They completed detailed demographic and behavioural questionnaires and underwent cytological, histological and HPV assessments of anal canal samples at baseline, 6- and 12-months. Composite HSIL was defined as either cytological and/or histological detection. Among those with HSIL at baseline, clearance and persistence were defined by non-detection (double negative) and persistent (double positive) detection of HSIL at both 6- and 12-month visits, respectively.

 

 


Results

By March 2017, 485 participants had completed their 12-month visits and of these 435 (89.7%) attended all three of the baseline, 6- and 12-month visits. A total of 390 men (63.2%) had both cytological and high resolution anoscopy results available from each visit. Of these, the median age was 49 years and 137 (35.1%) were HIV-positive. Among 159(40.8%) who had composite HSIL at baseline, 44(27.7%) had HSIL detected at baseline only and 89 (56.0%) had HSIL which persisted at all three visits. HSIL in older men was much less likely to clear (p=0.005) than in younger men. HIV status was not associated with HSIL clearance. HSIL-AIN3 lesions were half as likely to clear as HSIL-AIN2 lesions (HR 0.42, 95% CI 0.20-0.85, p=0.016). Larger lesions (more than one octant) were also less likely to clear (HR 0.33, 95% CI 0.009-1.25, p=0.005). HPV16 positivity at baseline was strongly associated with decreased rates of clearance of HSIL (RR=0.15, 95% CI 0.006-0.36).  Clearance was lowest in those who had HPV16 (p<0.001) and type-specific non-HPV16 high risk HPV (p<0.001) at both 6- and 12-month visits.


Conclusion

Among men with HSIL at baseline, HSIL persisted for at least 12 months in over half the participants and one in five had no evidence of HSIL at two subsequent visits. Both baseline and persistent high risk HPV and in particular HPV16, strongly predicted lack of clearance of HSIL. Two HPV tests separated by at least 6 months may identify a subgroup of men with HSIL that is likely to be persistent, and thus at high risk of progression to cancer.  


References