A Case of Rectal Cancer Successfully Treated with Surgery and Stereotactic Radiotherapy for Metachronous Lung Metastases

A 64-year-old woman underwent polypectomy for a rectal polyp(Isp). Pathological findings were invasion of the submucosa( 3,500 mm diameter), and she underwent anterior resection for rectal cancer(RS, pT1b, pN0, cM0, Stage I )without adjuvant chemotherapy. Lung masses were found in her right(8mm)and left lung(7mm). The tumors enlarged during the 4 month follow-up period. We decided to perform left partial pneumonectomy. The tumor was diagnosed as a lung metastasis from colon cancer by pathology. Because the right tumor was located towards the center, performing right pneumonectomy would have been quite invasive and we feared occult metastases. We decided to apply SRT(50 Gy)to the right tumor. The tumor shrunk and became a scar after treatment. There were no complications such as radiation pneumonitis. The patient was in good health without any recurrence for 12 months after SRT. Surgical resection is an optimal method to control lung metastasis from colon cancer if the lesion is operable. However, in the case of a tumor centrally located, surgical resection may cause deterioration of lung function. There are also cases with contraindications for surgery due to co-morbidities. In addition, there is no consensus on observation periods to exclude occult metastases. SRT can be an effective treatment for lung metastases from colon cancer when there are bilateral lung metastases and no metastases outside the lungs.