[Clinical study of synchronous multiple primary cancer involving the lung]

Ten cases of synchronous multiple primary cancer involving the lung were experienced in our hospital during the period from January 1962 to May 1987. The incidence rate was 1.3% of all hospitalized cases of primary lung cancer. The counterpart organs were thyroid gland (4 cases), stomach (2 cases), colorectum (2 cases) and lung (2 cases). Three of four thyroid cancer cases were resected at the same time of pulmonary resection, whereas the stomach and colorectal cancer cases underwent two stage operation. Lung perfusion scintigraphy was very useful in determining the operative method for synchronous multiple primary lung cancer. The 5-year survival rate of all cases of synchronous multiple primary cancer involving the lung was 26.3%, with no hospital death. Surgical treatment is recommended for such cases when both cancers are expected to be resected completely.