AIDS 2014: Preliminary results of SPANC study reveal anal lesions may spontaneously resolve
Andrew Grulich from the Kirby Institute has revealed the preliminary results from the Institute’s Study of the Prevention of Anal Cancer (SPANC) which measured the prevalence of anal lesions and cancers in gay men who have HIV.
While the study has shown that anal lesions and high grade anal dysplasia is common among gay men and men who have sex with men (MSM) who are living with HIV, Grulich’s findings have revealed the lesions often resolve spontaneously and routine treatment may be unnecessary.
Anal cancer and its precursors, anal dysplasia and neoplasia (abnormal cell growth and tissue changes), are more common among people living with HIV – especially men who have sex with men – than in the general population.
Grulich’s ‘natural history’ study was designed to learn more about the role anal human papillomavirus (HPV) infection and anal cancer precursors in HIV-positive and HIV-negative gay men plays in incident, risk factors and occurrence.
Some high risk types of HPV can lead to anal and cervical cancer, often first manifesting as intraepithelial lesions (LSIL), which can progress to high-grade lesions (HSIL).
However HPV does not always cause abnormal changes and Grulich’s study has shown that HSIL is quite common in gay men living with HIV but does not necessarily go on to manifest as a carcinoma.
To date, 450 men have taken part in the SPANC study with a median age of 49. About 30 per cent of the subjects were living with HIV.
The study will take place over three years. Participants make five visits to the clinic during that time, where they receive anal swabs and an anoscopy. Men with abnormalities undergo a biopsy to check for tissue changes.
Unlike treatment trials, this natural history study allowed researchers to observe spontaneous clearance or resolution of anal lesions without therapy. Among 112 men with HSIL, 61 experienced spontaneous clearance, with similar rates for HIV-positive and HIV-negative men. Nor did HSIL clearance differ according to age.
Those least likely to experience a sponatneous clearnce were subjects with persistent HPV-16 infection, but those who started out HPV-16 negative and became infected during the study had a high clearance rate.