CHICAGO, IL (May 29, 2013)—Patients with metastatic or recurrent forms of head and neck cancer respond better to systemic treatments if their tumors arise in association with the human papillomavirus (HPV), according to new findings to be presented by Fox Chase Cancer Center researchers at the 49th Annual Meeting of the American Society of Clinical Oncology on Sunday, June 2.
Specifically, 55% of the people whose tumor samples tested positive for HPV responded to subsequent treatment in two clinical trials of chemotherapy combinations, compared to only 19% of those without signs of HPV. Furthermore, HPV-positive patients were more likely live longer while on therapy.
Although only 11 of the more than 60 tested tumors had HPV, the significant difference in response rates suggests HPV status could have a significant impact on the results of clinical trials, says study author Ranee Mehra, MD, associate professor at Fox Chase. In other words, disproportionate numbers of people with or without HPV could skew a trials' results, suggesting future clinical trials should stratify metastatic head and neck cancer patients according to whether or not they carry the virus, she says.
"There's always interest in studying new regimens for metastatic head and neck cancer, but we don't currently stratify these patients for HPV," says Mehra. "But if you know the different impact it has on survival, it may be reasonable, when studying new drugs, to know the patients' HPV status."
Researchers have long known that some head and neck tumors show signs of infection by HPV, the virus frequently associated with cervical cancer.
Although it may seem counterintuitive that cancer patients with HPV fare better with treatment, previous studies have shown the same trend in patients who are newly diagnosed with head and neck cancer, says Mehra. She notes—it's possible that people who develop cancer as a result of HPV never smoked, so their tumors don't carry a host of mutations related to that exposure. In addition, many tobacco-related cancers contain a mutation in the tumor suppressor gene p53, while cancers that stem from HPV appear to often simply reduce the expression of p53, rather than mutating it, so the mechanism that suppresses tumors remains intact.
To study whether the same pattern appears in patients with metastatic and recurrent forms of the disease, Mehra and her colleagues examined tumor samples collected from more than 60 patients undergoing clinical trials. They reported their findings at the ASCO Annual Meeting 2013.
The researchers also tested samples for the presence of the enzyme excision repair cross-complementation group 1 (ERCC1), which is involved in DNA repair. Many cancer treatments work by damaging DNA, and one school of thought is that this enzyme may help tumors evade the effects of treatment. The researchers could only detect the high or low levels of ERCC1 in a smaller group of tumors, so caution that these results may be limited given the small numbers of patients studied.
Currently, more clinicians are routinely checking head and neck cancer patients to determine if they have HPV, says Mehra, and Fox Chase will test patients with tumors in the oropharynx, which is particularly associated with the virus. "The incidence of HPV-related oropharanx cancer is increasing, so it's reasonable to ask your doctor to test your tumor if you have been diagnosed," says Mehra. "Knowing this may not always change treatment, but it can help guide prognosis."
Co-authors on the study include Ann Marie Egloff, Shuli Li, Dong-hua Yang, Fang Zhu, Arlene Forastiere, Barbara Burtness, and Athanassios Argiris.