Treating HIV Patients’ Precancerous Growths Reduces Anal Cancer by Half

Progression to anal cancer in HIV patients is 57 percent lower when a patient is involved in HSIL (or precancerous growths) treatment compared to active monitoring, according to a paper published in The New England Journal of Medicine.

Investigators from the University of California, San Francisco School of Medicine randomized 4446 participants living with HIV aged 35 years or older in a phase 3 trial across 25 US cities in order to determine any related effect on treatment for anal high-grade squamous intraepithelial lesions (HSILs), as they noted anal cancer incidence is higher among HIV patients compared to the general population. The study authors said that data gathered from prospective studies based on treatment for anal HSIL to prevent anal cancer have so far been lacking. They also added that HSILs precede cancer, similar to the prognosis of cervical cancer.

The patients were randomized into groups that either received HSIL treatment—which included office-based ablative procedures, ablation, or excision under anesthesia, or topic administration of fluorouracil or imiquimod—or active monitoring without treatment. The patients in the intervention group were treated until HSIL was completely resolved, the study authors said, and all patients underwent high-resolution anoscopy at least every 6 months. The study participants also underwent biopsy; for the intervention group, that was performed for suspected ongoing HSIL. For the control group, biopsy was performed annually or any time there was a cancer concern, the study authors explained.

The investigators found 9 cases in the treatment group after a median follow-up of 25 months, they said, compared to 21 cases in the active-monitoring group. They determined that the rate of progression to anal cancer was lower in the treatment group compared to the active monitoring group by 57 percent.

“We’ve now shown for the first time that treating anal HSIL is effective at reducing the incidence of anal cancer in a very high-risk group of people — people living with HIV,” study leader Joel Palefsky, MD, said in a press release.

The study authors continued by saying they believe these findings could lead to changing the standard of care for other groups who are at a lower, but still increased, risk for anal cancer. This includes HIV-negative men who have sex with men, women who have had human papillomavirus (HPV) -related precancers or cancers, and people who are immunosuppressed after organ transplant or for other reasons.

“Although we did show a statistically significant reduction in anal cancer due to treatment, we did not prevent all the cases of cancer,” Palefsky added, but noted that the data supports treating HSIL as the standard of care for HIV patients aged 35 years or older. “What that points to is a need for ongoing follow-up of everybody who has developed anal HSIL, even if they’ve been treated, as well as for improvements in the treatments that we use.”

One reason the study authors noted their trial was successful was due to the level of training the participating clinicians received for high-resolution anoscopy and in treating HSILs. The results may not be replicated by other teams if the treatments are performed by clinicians with less training and clinical support, they wrote, which further highlights the need for more training for more clinicians.