CHICAGO – Sex disparities in the treatment of head and neck cancer may be leading to poorer outcomes for women, according to a retrospective registry-based cohort study of 884 patients reported at annual meeting of the American Society of Clinical Oncology.

“The treatment of head and neck cancer often requires intensive treatment that can have lasting side effects,” senior study author Jed A. Katzel, MD, a medical oncologist at Kaiser Permanente in Santa Clara, Calif., said in a press briefing. “Our goal was to review data from a large group of patients in Northern California to determine which patients are most likely to benefit from aggressive therapy, while minimizing toxicity for those likely to die from competing events.”

Study results showed that women had rates of receipt of intensive chemotherapy and radiation therapy that were lower by an absolute 10%-11%. And in a generalized competing event (GCE) analysis that controlled for potential confounders, the ratio of deaths from cancer to deaths from other causes was almost twice as high for women.

The reasons for the observed sex disparities are not known, according to Dr. Katzel. However, they may include patient preferences, physician practices, and the higher proportion among men of oropharynx tumors, as those tumors are more commonly associated with human papillomavirus (HPV), which carries a more favorable prognosis.

“Further investigation is needed to determine if there is an actual difference in treatment and outcomes for women, compared with men,” he said. “To this end, we have planned a chart-by-chart review, as well as a prospective analysis that will be performed in the currently enrolling NRG HN004 clinical trial.”

“The outcome of this study was very surprising to us, the idea that there are disparities in both the treatment that women receive relative to men, but also in the rate of death from head and neck cancer for women compared to men,” commented ASCO Expert Joshua Jones, MD, MA, who is also a radiation oncologist at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia.

“We don’t know why those differences exist, but it’s really important that we continue this research, that we continue to figure out what those differences are and why they are happening so that we can make sure as we’re talking to patients with head and neck cancer, that we are providing the right treatment for the right patient at the right time, and that everybody has the appropriate access to outstanding clinical care for head and neck cancer,” Dr. Jones said.

Dr. Katzel and his colleagues used the Kaiser Permanente Northern California registry to identify patients with stage II to IVB head and neck cancer diagnosed during 2000-2015.

Analyses were based on 223 women and 661 men, relative numbers that are not surprising given the known demographics of this cancer. Oropharyngeal tumors accounted for 38% of the cancers in the former, but 55% in the latter. (HPV status was not directly ascertained.)

The rate of receipt of intensive chemotherapy was 35% for women and 46% for men (adjusted odds ratio, 0.68; 95% CI, 0.48-0.98; P = .006). Similarly, the rate of receipt of radiation therapy was 60% for women and 70% for men (AOR, 0.79; 95% CI, 0.56-1.11; P = .008). Receipt of surgery was similar for the sexes.

The investigators analyzed deaths according to type using a GCE model that controlled for age, sex, tumor site, and Charlson Comorbidity Index. “The GCE model essentially describes the degree to which cancer is the patient’s problem,” Dr. Katzel explained.

Results showed that both women and men were more likely to die from cancer than from other causes; however, the ratio was 7 for women, compared with just 3.8 for men, a difference translating to a relative hazard ratio of 1.92 (95% CI, 1.07-3.43).

In terms of potential confounding, there were only 19 noncancer deaths among the women studied, suggesting that they may have been more healthy than the men, which could have influenced the calculations, according to Dr. Katzel.

“This GCE model has been validated in head and neck cancer, but also in breast cancer, prostate cancer, and endometrial cancer, so we are using a validated model to do this evaluation,” he noted. “So I would say we are confident in our findings.”

Dr. Katzel disclosed that he had no relevant conflicts of interest. The study received funding from Kaiser Permanente Northern California Graduate Medical Education Department.

SOURCE: Park A et al. ASCO 2018 Abstract LBA6002.

H&N cancer may be undertreated in women