Time-varying survival effects for squamous cell carcinomas at oropharyngeal and nonoropharyngeal head and neck sites in the United States, 1973-2015.

It is generally assumed that the effects of tumor and personal characteristics on the survival of patients with head and neck cancer are fixed over time, but this study shows that many factors are most important only in the first few years after diagnosis. Also, recent improvements in the survival of patients with head and neck cancer appear to benefit only patients with cancers of the oropharynx. The improvements may be due more to an increasing fraction of cancers caused by human papillomavirus (which generally have better outcomes) than to advances in head and neck cancer treatment overall.