“We weren’t looking for gender differences, so the results were really surprising. 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,” said senior study author Jed A. Katzel, MD, a medical oncologist at Kaiser Permanente in Santa Clara, CA. “With this mathematical model, we have a tool that can help us identify patients likely to benefit from more intensive treatment, as well as those more likely to die from other non-cancer-related causes. The hope is that by integrating this model into our care, we can improve the care of all patients with head and neck cancer.”

Head and neck cancers account for approximately 4% of all cancers in the United States and are more than twice as common among men as they are among women.¹

When considering treatment, oncologists take into account a patient’s activity level and other medical problems. Patients with head and neck cancer who have good performance status (a measure of overall well-being) may be offered more intense treatments, including platinum-based chemotherapy with radiation therapy. Patients who cannot tolerate intensive chemotherapy may be offered less intensive treatments, such as targeted therapy cetuximab (Erbitux) with radiation, radiation alone, or even no cancer treatment at all.

Another factor influencing head and neck cancer treatment and outcomes is whether the cancer is caused by the human papillomavirus (HPV). HPV-related head and neck tumors are more responsive to treatment, and people with such cancers generally have a better prognosis. HPV-related head and neck cancer is more common in men than in women. In the authors’ prior analysis of patients in Northern California, for example, they found that only about 22.6% of HPV-related cancers occurred in women, compared with 77.4% in men.² 

About the Study
Researchers evaluated health outcomes for 223 female and 661 male patients with stage II-IVB head and neck cancer treated at Kaiser Permanente Northern California. The odds of receiving intensive cancer treatment were estimated using logistic regression models and adjusting for factors such as age, gender, tumor stage, Charlson Comorbidity Index, and history of smoking and alcohol use. A mathematical tool called the generalized competing event (GCE) model was used to compare the risk of dying from cancer to the risk of dying from other causes. The GCE model controls for differences in age, gender, tumor site, and Charlson score. In this analysis, the researchers did not control for differences in tumor type with respect to HPV status.

Key Findings
Overall, the study identified several differences by gender:

• Treatment: The odds of receiving intensive chemotherapy were 35% for women versus 46% for men, and the odds of receiving radiation were 60% for women and 70% for men.
• Mortality: At a median follow-up of 2.9 years, 271 patients died of cancer and 93 from other causes. While both men and women were more likely to die of cancer than of other causes, the ratio of cancer deaths versus non-cancer deaths was 1.92 times higher for women than for men.
• HPV-related cancers: Fewer women than men had oropharyngeal cancers (38% vs. 55%). While further analysis is ongoing, this may also be a factor driving higher cancer-related mortality rates in women, as HPV-related cancers occur most frequently in the oropharynx.

Next Steps
Researchers plan to conduct a more detailed review of treatments that women in the study received. They’re also interested in determining causes for the gender differences in survival, such as if the findings reflect the difference in the rate of HPV-related head and neck cancers between women and men.

Additionally, “the GCE model will be further evaluated in the NRG-HN004 trial that is currently enrolling patients,” said Dr. Katzel. “It is a trial that we will be participating in.”

This study received funding from Kaiser Permanente Northern California Graduate Medical Education Department.

Study at a Glance

View the full abstract.

For your readers:

• Guide to Head and Neck Cancer

ATTRIBUTION TO THE AMERICAN SOCIETY OF CLINICAL ONCOLOGY ANNUAL MEETING IS REQUESTED IN ALL COVERAGE.

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¹Siegel RL, Miller KD, Jemal A. Cancer Statistics, 2017. CA: A Cancer Journal for Clinicians 2017; 67(1):7-30
²Katzel JA, Merchant M, Chaturvedi AK Silverberg MJ, Contribution of demographic and behavioral factors on the changing incidence rates of oropharyngeal and oral cavity cancers in Northern California. Cancer Epidemiol Biomarkers Prev; 24(6):978-984)