CHICAGO, Illinois — Because human papillomavirus (HPV) is transmitted through sexual contact, patients with HPV-related cancer often ask whether their partners are at risk and whether they should they change their sexual practices.
For patients with HPV-related oral cancers, data from the Human Oral Papillomavirus Transmission in Partners Over Time (HOTSPOT) study, presented here at the 2013 Annual Meeting of the American Society of Clinical Oncology (ASCO®), will be reassuring.
In the small pilot study of 166 patients with HPV-related oral cancer and 94 long-term partners, researchers measured HPV DNA in oral rinse samples taken at baseline and at 1-year follow-up. The results show that the partners do not appear to be at increased risk for HPV infection, so they are not at increased risk for HPV-related oral cancer, the researchers conclude.
“This is reassuring for patients and their partners,” said lead author Gypsyamber D’Souza, PhD, MPH, MS, from the John Hopkins Bloomberg School of Public Health in Baltimore, Maryland.
At a press briefing, she explained that patients are often anxious about this issue, and has heard of instances where it has led to divorce.
“Couples who have been together for several years have likely already shared whatever infections they have and no changes in their physical intimacy are needed.” However, “with new partners, caution is always advised,” she added.
Results Not Surprising
The results are not surprising, Otis Brawley, MD, chief medical officer for the American Cancer Society, told Medscape Medical News.
The median age of the patients in this study was 56 years; presumably, the partners were also in this age range. By that time, individuals have built up a natural immunity against HPV, Dr. Brawley said.
The main window for HPV transmission is in the first 5 years after initiation of sexual activity, he explained, which is usually in the teenage and early adult years.
Dr. Brawley cited a study of female college freshmen. At college entry, about 15% had been exposed to HPV; this had risen to 80% by the time of graduation. “Sexual activity in the late teenage years in the United States almost always leads to HPV infection, which is one of the reasons HPV vaccines are directed at girls 9 to 12 years of age,” he explained. “Once they have HPV in their body, the vaccine doesn’t work as well. It may lower certain subtypes, but it usually doesn’t work very well.”
Transmission From Genitals
For the HPV that causes oropharyngeal cancer (mainly HPV type 16), the main route of transmission appears to be from the genitals to mouth, Dr. Brawley noted.
This point was also made by study discussant Quynh-Thu Le, MD, from Stanford University in California. Previous studies have shown that male partners of women who have cervical cancer are at increased risk for tonsil cancer, she noted.
In the HOTSPOT study, 3 of the patients had previous spouses with cervical cancer and 2 of the partners reported a history of cervical precancer, but Dr. D’Souza and colleagues note that “these were self-reported, unconfirmed cases.”
The recent sharp increase in HPV-related oropharyngeal cancers has been linked to an increase in oral sex during the 1960s, as previously reported by Medscape Medical News. However, studies of sexual behavior suggest that oral sex is not the whole answer, Dr. Le said.
More research is needed to determine the time line of progression for HPV-related oral cancers and the way HPV is transmitted and suppressed by the immune system, she explained.
HPV in the Throat for Many Years
Dr. Brawley emphasized that the window for HPV transmission is early on, and said that the study patients in their 50s who had HPV-related oral cancer probably had the HPV infection in their throat for 30 years or more.
This issue recently caused a furor in celebrity news outlets after Oscar-winning actor Michael Douglas said that his throat cancer was the result of HPV contracted after he engaged in oral sex.
The comment, made during an interview with the Guardian, was later released by the newspaper as an audioclip because the actor denied he had said it.
The actor backtracked because of the huge embarrassment to his wife, Catherine Zeta-Jones, and his ex-wife, Diandra Douglas, both of whom then said publicly that they do not have the HPV infection. It also highlighted his past antics as a self-confessed womanizer, which led him to seek treatment for his “sex addiction.”
Later the same day, Michael Douglas appeared at an event hosted by the American Cancer Society, and joked that he had become “a poster boy” for oral cancer. “Just so you all understand, I think we would all love to know where our cancer comes from,” he added.
In the HOTSPOT study, 55% of the patients with HPV-related oral cancer had an oral HPV infection when they were diagnosed, but only 7% still had the infection a year after having undergone cancer treatment.
Among the 94 partners, 6 had oral HPV infections (6.5%) and 2 had infection with HPV 16. No oral cancers were detected in the 60 partners who underwent a visual examination. These infections were “at very low levels,” and were not detectable a year later, the researchers note.
“They had it, and then they cleared the virus,” Dr. D’Souza said. “HPV infection is common and most individuals do not get cancer,” he added.
The study was funded by the Johns Hopkins Innovation Fund and the Richard Gelb Cancer prevention Award. Dr. D’Souza reports receiving research funding from Merck.
2013 Annual Meeting of the American Society of Clinical Oncology: Abstract CRA6031. Presented June 1, 2013.