Photodynamic therapy for carcinoma in situ of the anus

Photodynamic therapy (PDT) for carcinoma in situ of the anus is an alternative to surgical excision in patients who are seropositive for human immunodeficiency virus (HIV).

Before-after trial. Settings Tertiary referral center.

Twelve HIV-seropositive patients who were actively being treated for AIDS with high-grade dysplasia on anal Papanicolaou test results had site-directed biopsies of acetowhitening foci immediately after application of dilute acetic acid. Biopsy results showed that 5 patients had anal carcinoma in situ. These patients were given the photosensitizer delta-aminolevulinic acid orally. Four to 4.25 hours later, the entire anal circumference was treated with PDT. All 5 patients, after being treated with PDT, had repeated Papanicolaou tests at monthly intervals. If acetowhitening occurred at the fifth month, site-directed biopsy was done.

Anal cytologic examination by Papanicolaou test and site-directed biopsy if acetowhitening was found at 5 months in order to determine effectiveness of PDT in downstaging cytologic findings.

All patients had a consistent downgrading of cytologic findings during the 5 months of follow-up. Papanicolaou test results showed 2 patients had no dysplasia, 2 had mild dysplasia, and 1 had moderate dysplasia. Moderate dysplasia was confirmed by site-directed biopsy results. No complications of PDT occurred, but all 5 patients developed various abnormalities in liver function test results that returned to baseline values within 2 weeks; this also has been noted in patients ingesting delta-aminolevulinic acid who are presumably HIV seronegative.

In a group of patients who are at high risk for recurrence irrespective of initial treatment, PDT can be used as a successful alternative to surgical excision for anal carcinoma in situ.