The burden of the U.S. oropharynx cancer epidemic is shifting toward older adults, finds a population-based cohort study spanning 23 years. As a result, the disease will likely become one predominantly affecting elderly white men over the next decade. In addition, projections suggest that the annual number of new cases will likely rise exponentially.
Historically, the incidence of oropharynx cancer rose rapidly among white men aged younger than 60 years because of human papillomavirus (HPV) infections (J Clin Oncol. 2011;29:4294-301). But given factors such as aging, possible changes in behavior, and vaccination, the current trajectory is unknown.
Investigators led by Joseph E. Tota, PhD, of the division of cancer epidemiology and genetics at the National Cancer Institute analyzed Surveillance, Epidemiology, and End Results registry data for 1992-2015 to ascertain whether the increases in oropharynx cancer have continued into recent birth cohorts and to forecast future burden across subgroups.
Results published in theshowed that, among white men, oropharynx cancer incidence accelerated among those born during 1927-1939 (by 3.5% per 2-year birth cohort) and during 1939-1955 (by 5.3% per 2-year birth cohort), whereas the pace of increase moderated among those born during 1955-1969 (by 1.7% per 2-year birth cohort).
Given these trends, the investigators forecast that incidence will increase sharply between 2016 and 2029 among older white men aged 65-74 years (from 40.7 to 71.2 per 100,000) and 75-84 years (from 25.7 to 50.1 per 100,000), increase moderately among white men aged 55-64 years (from 40.3 to 52.0 per 100,000), and remain stable among white men aged 45-54 years (at roughly 18 per 100,000).
Taking population growth into account, Dr. Tota and colleagues project a 52% increase in annual number of cases in the United States (from 20,124 to 30,629 between 2016 and 2029), mainly driven by a 127% increase among older adults aged at least 65 years (from 7,976 to 18,072) and a 54% increase among white men (from 14,453 to 22,241). As of 2029, white men older than 65 years will account for approximately 44% of all cases.
“Our results suggest an ebbing of the oropharynx cancer epidemic in younger individuals, exaggeration of the epidemic in older individuals, and a continued exponential increase in the annual number of oropharynx cancers over the next decade,” Dr. Tota and coinvestigators summarized.
The findings have important implications regarding treatment of older patients with oropharynx cancer, they noted. “It is likely that the biology of HPV-positive tumors is similar in younger versus older patients; nonetheless, older patients have poorer survival outcomes because of competing comorbidities, treatment-associated acute and chronic toxicity with chemoradiation, or an inability to receive maximally effective therapies. … Thus, older patients with oropharynx cancer may have different risks and benefits when receiving deintensified regimens than younger patients. The emergence of immunotherapies, whose efficacy may be more age invariant than cytotoxic chemotherapies, could provide a promising treatment avenue for older patients with oropharynx cancer.”
Dr. Tota reported receiving travel, accommodations, and expenses from Merck. The study was supported by the Intramural Research Program of the National Institutes of Health/NCI.
SOURCE: Tota JE et al. J Clin Oncol. 2019 Apr 26. .