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Five‐year cumulative incidence of invasive anal cancer among HIV ‐infected patients according to baseline anal cytology results: an inception cohort analysis
Author(s) -
Cachay E,
Agmas W,
Mathews C
Publication year - 2015
Publication title -
hiv medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.53
H-Index - 79
eISSN - 1468-1293
pISSN - 1464-2662
DOI - 10.1111/hiv.12190
Subject(s) - medicine , anal cancer , cumulative incidence , incidence (geometry) , cohort , proportional hazards model , cytology , population , cancer , gynecology , pathology , physics , optics , environmental health
Objectives The aim of the study was to estimate the cumulative incidence of, and rates of progression to, invasive anal cancer ( IAC ) according to baseline anal cytology screening category in an unselected HIV clinical care cohort in the antiretroviral era. Methods A retrospective cohort analysis of HIV ‐infected patients under care at the U niversity of C alifornia at S an D iego O wen C linic was carried out. Patients were eligible for this analysis if they had at least two anal cytohistological results available for longitudinal analysis. K aplan− M eier analysis was used to estimate the cumulative incidence of IAC over time according to baseline cytology category [less than high‐grade intraepithelial lesion ( HSIL ) versus HSIL ]. Cox regression analysis was used to adjust for the following covariates: antiretroviral use, level of HIV viraemia, smoking status and infrared photocoagulation ( IRC ) ablation therapy. Results Between 2000 and 2012, we followed 2804 HIV ‐infected patients for a median of 4 years under a clinic protocol requiring baseline anal cytology screening. Incident IAC was diagnosed in 23 patients. Patients with a baseline HSIL anal cytology had an estimated 5‐year probability of progression to IAC of 1.7% and an estimated annual progression risk of 1 in 263. None of the examined covariates was significantly associated with IAC incidence when examined in separate unadjusted Cox models. Conclusions HIV ‐infected patients with a baseline HSIL anal cytology had a 5‐year cumulative incidence of IAC of 1.65%, with an upper 95% confidence bound of 4.5%. This population‐based study provides quantitative risk estimates that may be used for counselling patients regarding management options for abnormal cytology results.