Comorbidity in patients with cancer of the head and neck: Prevalence and impact on treatment and prognosis

At the time of diagnosis, many patients with head and neck cancer have other medical conditions, referred to as comorbidity. These other medical conditions may affect treatment and prognosis. Several valid instruments are available to capture the individual comorbid ailments and their prognostic impact. Inclusion of comorbidity information will assist in the analysis of treatment effectiveness, quality of care assessment, and outcomes studies based on observational studies.