[Two operated cases of synchronous double cancer of the lung and digestive tract in patients over 80 years old and genetical diagnosis].

Synchronous double cancer of the lung and gastrointestinal organ was successfully resected by an one-step approach in two aged patients over 80 years. An 81-year-old man was clinically diagnosed as having a right lung cancer (S3) along with a sigmoid colon cancer. The pathological cell types of these cancers were squamous cell carcinoma and adenocarcinoma respectively. Right upper lobectomy and sigmoidectomy were performed at the same time because he had no risks for the operation. An-80-year-old woman was diagnosed as having a left lung cancer (S8-9) along with a stomach cancer. The cell types of these cancers were both highly differentiated adenocarcinoma. Left lower lobectomy and subtotal gastrectomy were performed at the same time, too. We limited lymph nodes dissection to shorten the operation time and no postoperative complications occurred in both patients. It is suggested that simultaneous operation for double cancer in aged patients can be safely performed in selected cases. In the latter patient, pathological cell type of the lung cancer was similar to that of stomach cancer. So we applied polymerase chain reaction (PCR) for making a diagnosis of double cancer postoperatively, and it was proved that the lung and gastric cancers were different from each other in genetical natures. Application of the genetical technique to clinical field which greatly contribute to making a diagnosis of double cancer is expected.