Development of a new head and neck cancer-specific comorbidity index

Background: Most patients with head and neck squamous cell carcinoma are older and may have coexistent or comorbid diseases. Objectives: To determine the prognostic impact of individual comorbid conditions in patients with head and neck cancer, to combine the individual comorbid conditions to form a new a head and neck-specific comorbidity instrument, and to compare it with the Modified Kaplan-Feinstein Index to determine if the new disease-specific instrument offers any improvement in survival prediction over a general comorbidity index. Design: Retrospective review of medical records. Population: The study population comprised 1153 patients with biopsy-proven, newly diagnosed squamous cell carcinoma of the oral cavity, oropharynx, or larynx. Results: Seven comorbid conditions (congestive heart disease, cardiac arrhythmia, peripheral vascular disease, pulmonary disease, renal disease, cancer controlled, and cancer uncontrolled) were significantly related to survival. These comorbid conditions were assigned integer weights to reflect their relative prognostic importance and combined to create the new Washington University Head and Neck Comorbidity Index (WUHNCI). Survival was significantly related to levels of comorbidity severity as defined by the WUHNCI. The WUHNCI predicted survival better than the Modified Kaplan-Feinstein Index despite containing far fewer ailments. Conclusions: Comorbidity is an important feature of the patient with head and neck cancer. The WUHNCI can be used for retrospective review or prospective outcomes research.