Clinical course of multiple primary oral cancer: three of 13 cases with second primary tumor.

Of 124 patients with oral squamous cell carcinomas treated during the past 14 years, 13 developed second primary cancers with clinical symptoms in the same tissues or in organs different from those of the initial lesions during follow-up. The second primary tumors also appeared in the oral cavity in 3 of the patients, the hypopharynx in 1, the esophagus in 2, the stomach in 2, the colon in 1, the thyroid gland in 2 and the lung in 2. Of the 3 patients with second tumors in the oral cavity, 1 underwent surgery after chemo- and radiotherapy and 2 underwent laser surgery or chemo- and radiotherapy only. The second primary cancers appeared on the contralateral or ipsilateral side, completely separate from the sites of the primary lesions during a period of 1 to 3 years. One patient with triple cancers involving the oral cavity, esophagus and hypopharynx is still alive after 15 years. The other two patients died of cervical or lung metastases after 3 years.