Women with head and neck cancer were less likely to receive intensive chemotherapy and radiation than men in a large managed care system, according to a study presented this week at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago. The study also showed that women had a higher rate of cancer-related death.

“We don’t know why women are getting less treatment and having worse outcomes, and we need to find out,” said ASCO expert Joshua Jones, MD, MA, of the University of Pennsylvania. “Though these findings are specific to California, the disparities we see are startling and worth considering in treatment discussions in everyday practice.”

Head and neck cancer, which includes cancers of the mouth, oropharynx (upper part of the throat), nasal cavity, sinuses and larynx (voice box), accounts for around 4 percent of cancers in the United States, according to ASCO. Overall, head and neck cancer is about twice as common among men as it is among women. A growing proportion of head and neck cancers—especially among men—are caused by the human papillomavirus (HPV).

When considering treatment for head and neck cancer, doctors take into account a patient’s other medical conditions, activity level and performance status. People in overall good health may receive more intensive treatment including platinum-based chemotherapy plus radiation therapy. Those who cannot tolerate intensive chemotherapy may receive less intensive targeted therapy using Erbitux (cetuximab) plus radiation, radiation alone or no treatment. HPV-related head and neck cancers generally respond better to treatment.

Jed Katzel, MD, of Kaiser Permanente in Santa Clara, California, and colleagues conducted a study to determine which patients were most likely to benefit from aggressive therapy while minimizing side effects for those likely to die of other causes.

This retrospective analysis included 223 women and 661 men diagnosed with Stage II to Stage IV head and neck cancer between 2000 and 2015 at Kaiser Permanente Northern California. Less than a quarter of the women, but more than three-quarters of the men, had HPV-related cancers.

The researchers used mathematical models to compare the risk of dying of cancer versus dying of other causes, after adjusting for sex, age, tumor stage, comorbidities and history of smoking and alcohol use.

The study showed that 35 percent of the women received intensive chemotherapy, compared with 46 percent of the men. Similarly, 60 percent and 70 percent, respectively, received radiation therapy. Fewer women received combined chemotherapy plus radiation, but women and men were about equally likely to undergo surgery, Katzel reported at an ASCO press briefing.

Over the course of the study, both women and men were more likely to die of cancer than to die of other causes, but the ratio of cancer-to-noncancer mortality was about twice as high for women.

“Female patients in our cohort may be undertreated in clinical practice, potentially missing the opportunity to aggressively treat their head and neck cancer,” the researchers concluded.

As a possible explanation for the disparity, Katzel noted that women were less likely to have easier-to-treat HPV-related cancers. Women were also less likely than men (38 percent versus 55 percent) to have cancer of the oropharynx, the most common site of HPV-related cancer.

“We weren’t looking for gender differences, so the results were really surprising,” Katzel said. “Besides undertreatment, there are a number of factors that could contribute to the differences in outcomes between women and men with head and neck cancer, and it’s clear we need further investigation…The hope is that by integrating this model into our care, we can improve the care of all patients with head and neck cancer.”

Click here to read the study abstract.

Click here to read an ASCO press release about the study.