Clinical Trial Shows First Evidence That Anal Cancer Is Preventable
By Jason Bardi | October 27, 2011
A large, international clinical trial led by doctors at the University of California, San Francisco indicates that a vaccine to prevent anal cancer is safe and effective, according to a study reported in the October 27, 2011 issue of New England Journal of Medicine.
Though anal cancer is less common than other forms of the disease in the United States, the number of cases has increased in recent years, and is particularly common among men who have sex with men and HIV-infected individuals.
Anal cancer is caused by infection with human papilloma virus (HPV), the most common sexually-transmitted pathogen in the United States. The virus also causes cervical cancer in women, and the vaccine is already approved and routinely recommended to prevent this condition. The new clinical trial suggests that the same vaccine would also protect men, and likely women, against anal cancer.
In the 1990’s, UCSF established the Anal Neoplasia Clinic at the UCSF Helen Diller Family Comprehensive Cancer Center, the world’s first clinic devoted to promoting research, awareness, screening and prevention of anal cancer. UCSF professor Joel Palefsky, MD, FRCPC, who founded and directs the clinic, led the clinical trial, and has recently founded a new professional society devoted to the study of the disease.
"Almost six thousand people every year in this country are diagnosed with anal cancer, and more than 700 people die from the disease," said Palefsky. "What this trial showed is that those cancers and deaths could be prevented."
The trial involved a group of 602 men who have sex with men from Australia, Brazil, Canada, Croatia, Germany, Spain and the United States all of whom had at least one, but no more than five, sexual encounters and who were between the ages of 16-26 years. All were randomized into groups that either received a placebo or a three-shot injection of the vaccine Gardasil, which protects against HPV 16 and 18, the most common HPV types involved in anal cancer, and HPV 6 and 11, the most common types in anogenital warts. The patients were enrolled in the trial from 2006-2008, and they were followed for three years after their last shot.