HIV is associated with a 30-fold increased lifetime risk of anal SCC and a 4-fold increase in 5-year mortality. Men who have sex with men (MSM) with HIV are at increased risk of human papillomavirus (HPV) associated cancers including anal SCC. Diagnosis of AIN presents an opportunity to initiate monitoring before SCC development. The characteristics of patients with AIN are poorly understood, as are the factors associated with progression from AIN to SCC. This project aimed to describe the cases of AIN and anal SCC in a large urban cohort of people living with HIV (n=2400) in the UK.
We identified all cases of AIN and anal SCC in patients attending a single HIV outpatient centre in the UK. We reviewed case notes and histopathology.
23 AIN cases and 28 SCC cases diagnosed 2001-2016: all white MSM. Where documented, 56% were current smokers and 36% ex-smokers. Median age 48 years (range 27-73), nadir CD4 284 cells/mm3 (4-1312), median months since diagnosis 171 (24-361), 100% on antiretroviral therapy (ART). Of the AIN group 16/23 (70%) had previous anorectal sexually transmitted infections (STIs), 15/23 (65%) HPV, 5/23 (22%) gonorrhoea, 4/23 (17%) herpes simplex virus (HSV) and 2/23 (9%) chlamydia. Of the SCC group 24/28 (86%) had documented STI history, 21/24 (88%) with anorectal STIs: 16/21 (76%) HPV, 5/21 (24%) gonorrhoea, 4/21 (19%) chlamydia and 4/21 (19%) HSV. Most AIN patients (83%) presented with an anal lump and the majority (83%) were AIN III. Patients who progressed from AIN to SCC did over 1-9 years, had comparable age (median 52, range 39-72) and nadir CD4 385 cells/mm3( 4-1312) to the broader cohort but were diagnosed with HIV further in the past (210 months,159-226). SCC presenting symptoms were anal lump (75%), pain (21%), and rectal bleeding (17%). 25/28 (89%) had local disease, 3/28 (11%) local nodes with no metastatic disease, 4/28 (14%) had previous AIN. Of those treated at our centre 8/13 (62%) had chemoradiotherapy, 2/13 (15%) had radiotherapy alone, and 3/12 (23%) had surgery. 2/13 (15%) patients needed surgery after unsuccessful chemoradiotherapy. 2/14 (14%) diagnosed with AIN after successful SCC treatment. 5/28 (18%) patients have died, with 2 deaths attributable to SCC.
AIN and SCC are emerging issues for MSM living with HIV on effective ART. We found that a large proportion of patients had anorectal HPV diagnosed before anal SCC but only a minority had previously diagnosed AIN. Further research is needed to clarify which patients are most at risk of developing SCC and to establish the impact of anal cancer screening on the reduction of anal SCC in this population is urgently needed.