Abstract
Multiple primary cancers are increasing according to the improvement and development of cancer diagnosis and treatment. Criteria of multiple cancers and the method for evaluation whether or not the frequency of occurrence of second cancer is high compared to that by chance were briefly reviewed.
To know the risk factors for the second primary cancer, lung cancer patients with multicentric origin and laryngeal cancer patients with second malignancy were selected for case-control study. A risk of cigarette smoking was highly suggested histology-matched case-control study on multicentric lung cancer. Heavy smoking and hazardous occupation were recognized in MPC cases with lung cancer. In laryngeal cancer, the effect of smoking and drinking was suggested, but the statistical significance was not present, probably because of the overmatching between cases and controls.
Importance of education to avoid or prolong the occurrence of second cancer for the patients with high risk was discussed.
