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Screening Program Cuts Anal Cancer Precursor Rate in 405 MSM With HIV
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17th European AIDS Conference, November 6-9, 2019, Basel
Mark Mascolini
A screening protocol adopted at a large Spanish hospital clinic significantly lowered rates of high-grade squamous intraepithelial lesions (HSIL), an anal cancer precursor, in HIV-positive men who have sex with men (MSM) [1]. Among men treated for HSIL, none went on to anal squamous cell carcinoma (ASCC) during the 2010-2018 study period.
Researchers at Granada's University Hospital Virgen de las Nieves noted that ASCC remains one of the most frequent non-AIDS cancers in people with HIV, mainly MSM. Research links development of this anal cancer to chronic infection with high-risk human papillomavirus (HPV). These investigators analyzed data from consecutive HIV-positive MSM seen from May 2010 through December 2018 to gauge the impact of an anal cancer screening program.
All men undergo anal cytology and PCR to determine HPV type. Those with normal anal cytology and negative PCR get repeat screening every year. Men with abnormal cytology (low-grade squamous intraepithelial lesion [LSIL], HSIL, or atypical squamous cells) or who test PCR-positive for high-risk HPV undergo high-resolution anoscopy (HRA). If HRA is normal, men resume annual screening with anal cytology and HPV PCR. If HRA indicates LSIL, men have an annual checkup including HRA, anal cytology, and HPV PCR. If HRA shows HSIL or squamous cell carcinoma of the anal canal (SCCA), treatment begins. The Granada center offered two treatment options for HSIL: mucosectomy with electric scalpel from May 2010 onward, or self-administered intra-anal 5% imiquimod 3 times weekly for 16 weeks from November 2013 onward.
The study group averaged 36.2 years in age and had a median of 1 male sex partner in the past 12 months (interquartile range [IQR] 1 to 7). Almost three quarters of men (72.6%) reported regular condom use, and 31.6% had a history of anal or genital warts. Half of these men (52.8%) smoked, averaging 1.5 pack-years. Baseline CD4 count stood at 689.6 and median viral load was undetectable. Sixty-six participants (16.3%) received the quadrivalent HPV vaccine (Gardasil) from May 2012 to May 2014.
Among these 405 men, 353 (87%) had two or more HRAs through a median follow-up of 36 months (IQR 12 to 69). During that time clinicians detected 88 cases of HSIL (21.7% of 405) and 3 cases of ASCC (0.74% of 405). Incidence came to 30.86 per 1000 person-years for HSIL and 81.22 per 100,000 person-years for ASCC. Two of the 3 men with ASCC responded to treatment and 1 died 15 months after diagnosis. Among men with HSIL, 49 underwent mucosectomy and 34 took imiquimod. No treated men had progression to ASCC.
New cases of HSIL fell significantly from 42.9% in 2010 to 4.1% in 2018 (P = 0.034), from 42.9% in 2010 to 13.8% in 2013 (P = 0.003), and from 13.8% in 2013 to 4.8% in 2016 (P = 0.0001). HSIL incidence stabilized at 4.8% in 2016 and 4.1% in 2018.
Multivariate analysis indicated several independent predictors of HSIL: HPV-11, HPV-16, HPV-53, HPV-61, HPV-68, low- plus high-risk HPV, and low CD4 nadir.
The researchers attributed falling rates of HSIL to "the bundle of measures adopted at our center," including yearly screening and HPV vaccination.
Reference
1. Hidalgo Tenorio C, Gil Anguita C, Omar M, et al. COHORT SDT (Granada): decrease of the incidence of HSIL+ in the anal mucosa of HIV+ patients MSM after the performance of a screening, diagnostic and therapeutic program (2010-2018). 17th European AIDS Conference, November 6-9, 2019, Basel. Abstract PE14/6.
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