[Clinical analysis of 26 cases of multiple primary cancer]

Of 412 head and neck cancers in the Department of oral Surgery, Sapporo Medical College from 1976 to 1987, 26 cases (6.3%) were multiple primary cancers. One of these cases was triple cancer. The ages of these 26 cases ranged from 42 to 81 (average 61 year-old) with 20 males and 6 females (3.3:1). As to the interval between the first and second cancer, five cases (20%) were synchronous and twenty cases (80%) were metachronous in our series. Of the five synchronous, three were found by careful examination at the time of admission to our department. The stomach and head and neck cancers were frequently observed as the first cancer of metachronous cases. Second primary cancers occurred in the head and neck region were 64% and those in other regions were 36%. On the other hand, digestive cancer was predominant in the additional cancer to the index cancer (66.7%). These numbers emphasize that patients with head and neck cancers are in a cancer-prone group that develops digestive cancers. These findings have important implications in follow up policy.