WEAB0102 - Oral Abstract Session
Incidence and clearance of anal high-grade squamous intraepithelial lesions (HSIL) in HIV positive and HIV negative homosexual men
Presented by Andrew E Grulich (Australia).
A.E. Grulich1, F. Jin1, I.M. Poynten1, J. Roberts2, A. Farnsworth2, D.J. Templeton1,3, S.N. Tabrizi4, S.M. Garland4, C.K. Fairley5, R.J. Hillman6,7, the SPANC Study Team
1UNSW, Kirby Institute, Sydney, Australia, 2Douglass Hanly Moir Pathology, Sydney, Australia, 3Royal Prince Alfred Hospital, RPA Sexual Health, Sydney, Australia, 4University of Melbourne, Royal Women's Hospital, Melbourne, Australia, 5Melbourne Sexual Health Centre, Melbourne, Australia, 6University of Sydney, Western Sydney Sexual Health Centre, Sydney, Australia, 7St Vincent's Hospital, Sydney, Australia
Background: Anal cancer is a common non AIDS-defining cancer
in people with HIV, and incidence has not decreased despite the widespread
availability of effective HIV treatment. The cancer precursor, anal HSIL,
occurs in up to 50% of the highest risk population, HIV positive homosexual
men. Ablative therapies of uncertain efficacy are advocated, but some prefer
watchful waiting with therapy targeted only to the highest risk lesions. We
aimed to determine incidence, clearance, and associated risk factors for anal HSIL
in a community-recruited cohort of homosexual men.
Methods: The Study of the Prevention of Anal Cancer
(SPANC) is a three-year prospective study of the natural history of anal HPV
infection and cancer precursors in HIV-negative and -positive homosexual men
aged ≥ 35 years. At each visit all men receive an anal swab for cytology and
HPV genotyping (Roche Linear Array), followed by high resolution anoscopy-directed
biopsy for histological assessment. Anal HSIL is defined as having either anal
intraepithelial neoplasia grade 2/3 on histology and/or HSIL on cytology.
Results: The first 350 men were recruited by July 2013.
Median age was 49 and 29% were HIV-positive. At baseline, the prevalence of anal
HSIL was higher in HIV-positive than in the HIV-negative (45% vs 35%, p=0.059).
Among those without HSIL at baseline, HSIL incidence was nearly twice as high
in HIV-positive men (21.3 vs 12.3 per 100 person-years, p=0.064). Among those with
HSIL at baseline, the clearance rate was similar between the two (34.0 vs 40.2 per
100 person-years, p=0.627). Compared with those who were HPV16 negative at both
baseline and the latest follow-up visit, those who developed incident HPV16 had
the highest HSIL incidence (HR=16.81,
95% CI 5.97-47.36), followed by those who had persistent HPV16 (HR=9.32,
95% CI 3.95-21.96). Conversely, HSIL clearance was lowest in those with persistent
HPV16 (HR=0.22, 95% CI 0.11-0.46).
Conclusions: Prevalent and incident anal HSIL were more
common in HIV-positive homosexual men, but clearance was common regardless of
HIV status. Persistent HPV16 was associated with higher incidence and lower
clearance. The role of HPV biomarkers in identifying those HSIL lesions most
likely to require therapy should be investigated.
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