A clinical study of multiple primary cancers in patients with oral squamous cell carcinoma

Abstract

Among 479 cases with oral squamous cell carcinoma from 1998 to 2007 in the Department of Maxillofacial Surgery, Tokyo Medical and Dental University Dental Hospital, multiple primary cancers were observed in 60 (12.5%) patients. The incidence of multiple primary cancers was high in males; the male-female ratio was 4 : 1. Thirty-three (48.5%) of 68 lesions were found in the digestive tract. The period between detection of first cancer and development of second cancer was significantly shorter in the group in which oral cancer occurred first than in the group in which other cancers occurred first. The survival rates of patients with multiple primary cancers were significantly lower than those of patients without multiple primary cancers. Significant risk factors in the development of multiple primary cancers included age, sex, lesion and smoking.