Infrared treatment for pre-cancerous anal lesions in HIV-positive patients safe and has good outcomes

An infrared treatment provides safe therapy for pre-cancerous anal lesions in HIV-positive individuals, according to a US study published in the January 1^st edition of the Journal of Acquired Immune Deficiency Syndromes. The treatment, which is non-invasive and involved only mild and transient side-effects, led to a resolution of pre-cancerous anal lesions in two-thirds of patients in the study. Importantly, the therapy can be safely delivered by non-surgical specialist staff.

Anal cancer is an increasingly important cause of illness and death in HIV-positive individuals. As with cervical cancer, anal malignancies are preceded by precancerous, intraepithelial lesions caused by cancer-causing strains of human papilloma virus (HPV).

Rates of cervical cancer in the general population have fallen markedly in recent years due to screening programmes and the treatment of any pre-cancerous lesions that are detected. Aspects of these screening programmes, such as anal cytology and high-resolution anoscopy, have been adapted to screen patients for pre-cancerous and cancerous changes in the anus.

A highly effective treatment for pre-cancerous cervical lesions is surgical excision. But this is not an option for the treatment of anal lesions as excision of large sections of the anal canal can have significant adverse effects. Alternative therapies involve laser treatment or cyrotherapy (freezing).

Another potential treatment is the use of an infrared coagulator. This therapy has been approved in the US for the treatment of haemorrhoids, tattoo removal and genital warts. It involves the delivery of short pulses of a narrow beam of visible and infrared light. It results in tissue death. The depth of tissue death can be precisely adjusted.

A retrospective study involving 68 HIV-positive men with pre-cancerous anal lesions has previously shown that the infrared coagulator is a safe and effective treatment (Goldstone, 2005). Almost three-quarters of lesions treated didn’t recur within two years and no complications were reported.

Investigators therefore decided to carry out a multicentre prospective study to further evaluate the safety and tolerability. The investigators also reported on its effectiveness. The study was developed by the HPV Working Group of the AIDS Malignancy Consortium (AMC).

A total of 18 patients (16 men) were included in the study. All were HIV-positive, had biopsy-proven precancerous anal lesions and were taking stable antiretroviral therapy. Median age was 44 years, median HIV viral load was 75 copies/ml and median CD4 cell count was 581 cells/mm³.

Treatment with the infrared coagulator was provided during anoscopy under local anaesthetic. Patients were monitored every three months for one year and repeat treatment was provided for persistent lesions. CD4 cell count and viral load were monitored to see if these markers affected treatment outcome. Tests were also performed to determine HPV genotype to see if this affected the efficacy of treatment.

Of the 16 patients who were followed for one year (two patients were lost to follow-up), ten (63%) had a complete response to treatment and resolution of their precancerous anal lesions. In the remaining six patients, the lesions persisted or recurred.

A total of 44 lesions were treated (average, 2.2 per patient), and 2 (66%) resolved after the first treatment.

Although PAP smears are a standard test used to detect pre-cancerous changes in the cervix, their value to diagnose cell changes in the anus is uncertain. The investigators found that although all their patients had biopsy confirmed high grade precancerous anal cell changes, most PAP smears were only minimally abnormal.

There was no relationship between CD4 cell count or viral load and the outcome of treatment, nor did HPV genotype affect treatment efficacy.

The treatment was generally well tolerated. Twelve patients reported mild to moderate side-effects including anal discomfort, rectal bleeding and short-term incontinence. No serious or long-term side-effects were reported.

“In this study, we confirm the report of Goldstone et al that this treatment of [pre-cancerous lesions] of the anal canal with the infrared coagulator in HIV-infected patients is safe and well tolerated. Reported adverse events were mild or moderate and were described by patients as being of minimal concern”, comment the investigators.

Another advantage of the infrared coagulator is that its use does not require specialist surgical staff. All the personnel using the equipment were assessed and certified by the AMC, but only six were surgeons, four were gynaecologists and eight were non-surgical general clinicians.

“In conclusion”, write the investigators, “the infrared coagulator is a well-tolerated method for treating discrete anal canal high grade pre-cancerous lesions in HIV-infected patients.” They add that a larger study of its efficacy in HIV-positive patients is warranted.