Discussion: genetics of multiple primary tumors: a clinical etiologic approach illustrated by three patients.

Clinicians can shed new light on the genetic and environmental origins of cancer, particularly multiple primary malignancies, by asking additional questions at the bedside. Areas to explore include occupational history, personal habits, residence, and medical and family histories with emphasis on subtle clues of disorders predisposing to cancer, such as birth defects and benign neoplasms. When this bedside approach to cancer etiology was applied to three patients with a total of 19 primary malignancies, the most striking finding was a variety of benign neoplasms in the patients and a similar array of benign and malignant tumors among first-degree relatives, some of whom also had multiple primary tumors. A single gene trait, Cowden (multiple hamartoma) disease, was recognized in one patient. It is suggested that, in future studies of multiple tumors, epidemiologists consider not just malignancies, but all forms of neoplasia, both in the patient and in the family.