Cervical Cancer Vaccine Also Protects Against Vaginal Cancers

MONDAY, June 5, 2006 (HealthDay News) -- The cervical cancer vaccine that is expected to receive approval in the United States this week also appears to protect women against vulvar and vaginal cancers.

According to Finnish research presented Monday at the annual meeting of the American Society of Clinical Oncology (ASCO) in Atlanta, the Gardasil vaccine was 100 percent effective against vulvar and vaginal pre-cancerous lesions caused by HPV types 16 and 18 and 81 percent effective against all HPV types.

HPV, or human papillomavirus, is responsible for virtually all cases of cervical cancers and is present in 80 percent of the 6,000 cases of vaginal and vulvar cancers diagnosed in the United States each year.

"This study shows that the prophylactic vaccine developed to prevent cervical cancer could actually also prevent vulvar and vaginal cancer as well," said Dr. Jorma Paavonen, lead author of the study and chief physician in the department of obstetrics and gynecology at the University of Helsinki in Finland.

"This could be a transforming vaccine for millions of women around the world," added Dr. Robert F. Ozols, senior vice president of the Medical Science Division at Fox Chase Cancer Center in Philadelphia and moderator of a press briefing to announce the findings. "I don't think you can overestimate the benefit these vaccines will have," he said.

Although less common than cervical cancer, vulvar and vaginal cancers are becoming more common in young women. "Management of the disease is extremely challenging," Paavonen said. "Surgery is difficult and could be disfiguring."

The Gardasil vaccine, made by Merck & Co., was developed to target four strains of HPV, two of which (HPV 16 and 18) are linked to cervical cancer and two (HPV 6 and 11) which cause anogenital warts. Last month, an advisory panel of the U.S. Food and Drug Administration recommended that it be approved, which is expected to happen June 8.

The current study looked at combined data from three clinical trials evaluating Gardasil use by more than 18,000 women around the world. The women, none of whom had been exposed to HPV at the start of the trial, were randomly assigned to receive at least one dose and up to three doses of the vaccine or a placebo over a six-month period and were followed for two years.

At the end of the trial, 24 women in the placebo arm and zero in the vaccine arm had developed high-grade pre-cancerous lesions associated with HPV 16 and 18. These lesions are precursors of vulvar and vaginal cancer.

"The vaccine efficacy was 100 percent against this disease caused by HPV types 16 and 18," Paavonen said.

Twenty-seven women in the placebo arm and five women in the vaccine arm developed lesions caused by all HPV types, giving the vaccine 81 percent efficacy against vulvar and vaginal cancers associated with any HPV type.

"These results suggest that this vaccine indeed may prevent vulvar and vaginal cancer," Paavonen said. "This represents additional health benefits that can be gained by the HPV vaccine."

Also Monday, researchers presented Phase III results of a second HPV vaccine, this one made by GlaxoSmithKline. All women in the study group demonstrated antibody response against HPV 16 and 18. The vaccine is very similar to Gardasil but does not target any HPV types other than 16 and 18, said Dr. Michael Bookman, director of medical gynecologic oncology at Fox Chase Cancer Center in Philadelphia.

In other findings reported at the meeting, a new cancer trial showed that removing ovaries and fallopian tubes -- a procedure known as an oophorectomy -- could be effective in preventing breast cancer in women with the BRCA1 and/or BRCA2 mutations, depending on the exact mutation.

Women with mutations in the BRCA1 gene had a greater reduction in their risk of developing ovarian cancer, while women with mutations in the BRCA2 gene had a greater reduction in breast cancer risk.

The study compared 561 women with a BRCA1 or BRCA2 mutation who underwent surgery with 325 women who also had a mutation but did not have the surgery.

Overall, oophorectomy reduced breast cancer risk by 47 percent and ovarian cancer risk by 89 percent. In women with a BRCA2 mutation, surgery reduced breast cancer risk by 72 percent versus 39 percent in women with a BRCA1 mutation.

The surgery reduced ovarian cancer risk in women with a BRCA1 mutation by 87 percent.

"There appear to be differences in magnitude of protection," said Dr. Noah Kauff, lead author of the study and assistant attending physician at Memorial Sloan-Kettering Cancer Center in New York City. "Future studies should stratify for mutation type."

More information

For more on vaginal cancer, visit the National Cancer Institute.