Multiple primary malignancies in head and neck cancer.

Multiple primary (MP) malignancies were found in 9.7% of 1961 patients with primary head and neck cancer diagnosed at The Johns Hopkins Hospital, Baltimore, during the years 1975 to 1985. The index tumors were divided into six main groups. Out of the 190 MP malignancies, 46.9% were synchronous and 53.1% were metachronous. Seventy-four percent of MP lesions were noted during the first year after diagnosis of the index primary tumor. Patients with an index tumor in the upper aerodigestive tract had a significantly increased risk of developing a second cancer in the head and neck area. This risk was 5.94 for the oral cavity, 6.98 for the pharynx, 3.57 for the larynx, and 7.02 for the esophagus. Patients with an index tumor in the salivary gland or the thyroid gland had, respectively, a 3.59 and a 7.38 higher risk than the general population of developing a second tumor. Efforts aimed at improving the survival of patients with head and neck cancer must incorporate strategies for the prevention, early detection, and treatment of MP neoplasms.