A clinic-based intervention offers safe and effective
treatment for high-grade pre-cancerous anal lesions, US investigators report in
the online edition of the Journal of
Acquired Immune Deficiency Syndromes.
Doctors at the Mount Sinai School of Medicine, New York,
used a technique called electrocautery ablation to treat pre-cancerous anal
lesions in 232 gay men, 132 of whom were HIV-positive.
Eighteen months after treatment, 83% of HIV-negative men and
69% of those with HIV were free of high-grade pre-cancerous anal lesions.
“Electrocautery ablation of high-grade anal squamous
intraepithelial lesions is a safe and effective office-based procedure
comparable to other available treatments,” comment the investigators.
Incidence of anal cancer has increased dramatically among
gay men in recent years. HIV-positive gay men appear to be especially
vulnerable to the disease, and its incidence is five-times higher in these
patients compared to HIV-negative men.
Infection with high certain high-risk strains of human papillomavirus can cause cell changes in the anus, resulting in the formation of
lesions. The severity of these changes is graded, and between 9% and 13% of
high-grade lesions progress to anal cancer.
There are a number of treatments for these pre-cancerous
lesions including infrared coagulation and topical creams such as imiquimod.
Another therapy is electrocautery ablation. The
investigators described the procedure thus: “Using a gentle brushing technique
the lesion was ablated [worn down] by moving [a] blade lightly across the
surface like a paint-brush.” The therapy has a number of advantages and can be
performed in clinics without the need for anaesthetic or sedation.
Investigators wished to assess the safety and effectiveness
of this procedure. They therefore retrospectively analysed the notes of gay men
who had the treatment between 2006 and 2010. The patients received an initial
treatment and were then followed at intervals of three to six months and were
provided with additional treatment if necessary.
At the first treatment session, a total of 375 lesions were
treated in HIV-infected men compared to 226 lesions in the HIV-negative
patients, a significant difference (p = 0.006).
Lesions recurred in 53% of HIV-negative men (mean number of
lesions, 1.6) and in 61% of HIV-positive men (mean number of lesions, 1.9).
The number of lesions present at the time of the initial
treatment session was associated with the risk of recurrence. Patients with
only one lesion at this time were 55% and 73% less likely to experience a
recurrence than individuals with two or three lesions (p = 0.008 and p <
0.001 respectively).
The persistence of individual lesions after the initial
session of treatment was also examined by the researchers. They found a cure
rate of 85% in HIV-negative individuals and 75% in HIV-positive patients.
The first treatment session appeared to offer the best
chance of eradicating lesions. In HIV-negative patients the persistence rate
after a second ablation treatment was 3.03 times greater than that observed
after the first session.
Further analysis showed that lesions were a significant 2.34
times more likely to recur in HIV-positive men compared to HIV-negative men
after a second treatment (p = 0.008).
“Extensive dysplastic tissue may indicate either infection
with more oncogenic virus or a more immune compromised host,” suggest the
investigators.
Nevertheless, at the last follow-up visit, 83% of
HIV-negative individuals and 69% of men with HIV were free of high-grade anal
lesions.
Such a level of efficacy is comparable to that achieved with
alternative therapies.
“Given that infrared coagulation and electrocautery ablation
have similar outcomes when treating high-grade anal squamous intraepithelial
lesions, the choice of modality should be based on clinician comfort and
preference,” comment the authors. “In our hands the overall impression was that
electrocautery ablation seemed faster, more hemostatic and allowed more
extensive disease to be treated in office.”
Pain after treatment was the most commonly reported
side-effect. However, this was adequately controlled with mild painkillers. One
HIV-positive patient progressed to anal cancer, despite multiple ablation
treatments.
“While we documented a single progression (0.4%), rates were
far lower tan series advocating a ‘watch and wait’ approach,” conclude the
authors.