- Category: Cancer/Malignancies
- Published on Tuesday, 03 January 2012 16:33
- Written by Liz Highleyman
Electrocautery ablation to remove abnormal tissue significantly reduced the likelihood of progression to anal cancer for both HIV positive and HIV negative gay men with high-grade anal intraepithelial neoplasia, according to a study described in the November 30, 2011, advance online edition of the Journal of Acquired Immune Deficiency Syndromes.
As antiretroviral therapy (ART) has extended survival and reduced the rate of AIDS-defining illnesses, anal cancer has become a growing concern for people with HIV, especially men who have sex with men.
HIV positive people are more likely than their HIV negative counterparts to carry high-risk or oncogenic (cancer-causing) types of human papillomavirus (HPV), including types 16 and 18. HPV can cause abnormal cell changes in the anal-genital region known as dysplasia, intraepithelial neoplasia, or squamous intraepithelial lesions. Intraepithelial neoplasia is graded as low, moderate, or high (corresponding to stages 1,2, and 3), and can progress to anal or cervical squamous cell carcinoma, a form of cancer.
Women routinely receive Pap tests to screen for cervical cancer and experts increasingly recommend that gay and bisexual men should undergo similar screening for anal cancer. A variety of treatments are used to prevent anal intraepithelial neoplasia (AIN) from progressing to cancer including topical chemotherapy and techniques to remove abnormal tissue.
Douglas Marks and Stephen Goldstone from Mount Sinai School of Medicine conducted a retrospective analysis of electrocautery, or burning with an electrical current, to ablate or remove high-grade anal neoplasia. The procedure was done in the clinician's office and did not require anesthesia or sedation.
The study authors looked at medical records from a New York City surgical practice, identifying patients with high-grade AIN who were treated with electrocautery ablation between 2006 and 2010. They were followed for at least 5 months with high-resolution anoscopy (examination of the anus with a microscope), biopsy, and/or cytology (examination of cells in the laboratory). They determined the likelihood of high-grade AIN recurrence and progression to anal carcinoma after the procedure.
The analysis included 232 men who have sex with men, 132 of them HIV positive and 100 HIV negative. The median ages for the 2 groups were 42 and 49 years, respectively. Median follow-up durations were 19.0 and 17.5 months, respectively.
- The first electrocautery procedure cured high-grade AIN lesions in 75% of HIV positive men and 85% of HIV negative men.
- During follow-up, 61% of HIV positive men and 53% of HIV negative experienced AIN recurrence.
- Mean numbers of recurrent lesions were 1.9 and 1.6, respectively.
- HIV positive men were 1.28 times more likely than HIV negative men to experience AIN recurrence after the first electrocautery procedure, not a significant difference.
- HIV positive men were 2.34 times more likely to experience recurrence after a second electrocautery attempt, which was significant (P = 0.009)
- A majority of recurrences were additional AIN lesions at untreated sites (known as metachronous recurrence), rather than recurrence at the same site.
- HIV positive patients with fewer high-grade AIN lesions at initial presentation had a lower recurrence rate than men with multiple lesions; men with 1 lesion were 55% less likely to experience recurrence than those with 2 lesions, and 73% less likely than those with 3 lesions.
- At the last visit, 69% of HIV positive men and 83% of HIV negative men were free of high-grade AIN.
- 1 HIV positive patient developed anal carcinoma (0.4%).
- The most common side effect was post-treatment pain, which was manageable with over-the-counter medication.
Based on these findings, the researchers concluded, "Electrocautery ablation is an effective treatment for high-grade AIN, with fewer patients progressing to anal squamous cell carcinoma than predicted with expectant management."
In both HIV positive and HIV negative patients, lesions that were not cured with the initial electrocautery procedurewere less likely to be successfully ablated with subsequent treatment, they elaborated in their discussion.
"This observation has both positive and negative implications," they wrote. "[T]here does not appear to be any lasting tissue effect following electrocautery ablationsuch as scarring or destruction of the transformation zone that could diminish recurrence." Development of persistent lesions may be due to inadequate initial ablation, or cancer-causing HPV in adjacent cells could be activated during wound healing and cause new AIN lesions to develop.
"Despite the fact that patients required multiple treatments to ablate high-grade AIN and recurrence remained high, morbidity was minimal," the authors wrote. "The mean time to recurrence in both groups approached a year. Moreover, the mean number of recurrent lesions did not exceed 2 so repeat ablations were localized and not extensive. This could translate into less pain with more rapid healing."
They also noted that cure rates for electrocautery ablationwere similar to those seen for another ablation method, infrared coagulation (72% for HIV positive and 81% for HIV negative patients in 1 study). Topical treatment with imiquimod (Aldara) or tricholoracetic acid also produced cure rates in the 60%-70% range in previous studies, though these were not directly comparable.
The authors acknowledged that some clinicians advocate a more conservative approach of closely monitoring high-grade AIN and only treating if early cancer develops, since many patients with high-grade AIN never progress to cancer and those who do would be caught early, but studies have shown that people with early anal cancer often require radiation or more drastic surgery -- outcomes associated with "significant morbidity and decreased quality of life."
"Treatment of high-grade AIN aims to reduce incidence of anal cancer and requirements for large surgical resection or radiation and chemotherapy," they continued. Treatment resulted in a 0%-1.2% rate of progression to anal cancer -- far lower than retrospective studies which showed 8.5% to 13% progression without intervention.
"Electrocautery ablationof high-grade AIN is a safe and effective office-based procedure comparable to other available treatments," the researchers summarized. "Cure rates of individual lesions are excellent but patients continue to develop metachronous recurrence making continued follow-up important. While we documented a single progression to anal squamous cell carcinoma (0.4%), rates are far lower than series advocating a 'watch and wait' approach."
Investigator affiliations: Department of Surgery, Mount Sinai School of Medicine, New York, NY.
DK Marks and SE Goldstone. Electrocautery Ablation of High-Grade Anal Squamous Intraepithelial Lesions in HIV-Negative and HIV-Positive Men who have sex with Men. Journal of Acquired Immune Deficiency Syndromes. November 30, 2011 (Epub ahead of print).