Therapeutic Strategies for Metachronous Multiple Primary Lung Cancer

BACKGROUNDS It is not uncommon to encounter metachronous primary lung cancer after surgical treatment along with the increase in the elderly patients. In consideration of increasing number of such patients, it is necessary to take various treatment strategies. METHODS In order to establish a treatment strategy for multiple lung cancer, we retrospectively examined multiple lung cancer cases operated for primary lung cancer in our department from January 2013 to December 2019, and the future treatment strategy was examined. RESULTS Of 821 patients who underwent surgery for primary lung cancer, 61 were multiple lung cancers, 31 were synchronous multiple lung cancers, and 30 were metachronous multiple lung cancers. Among the cases of metachronous multiple lung cancer, 28 cases had undergone lobectomy or more in the first operation, 1 case of segmental resection, and 1 case of partial resection. As for the treatment of secondary lung cancer lesions, 21 lesions were performed surgery( lobectomy;2, segmental resection;2, partial resection;17), 6 lesions of photodynamic therapy (PDT), and 3 lesions of stereotactic body radiation therapy (SBRT). Among the surgical cases, there were three cases on the same side as the first cancer and 18 cases on the opposite side. The three cases underwent partial resection. Among 21 patients, postoperative home oxygen therapy was introduced in 2 patients. Regarding the prognosis, three patients who had surgical resection, died of recurrence of the first lesion. One of the six PDT patients died of recurrence of the first lung cancer and another died of other disease. All three patients who underwent SBRT are alive without recurrence. CONCLUSIONS If early detection and early diagnosis are made as a treatment strategy for metachronous multiple lung cancer, it may be possible to preserve lung function by reducing surgery or SBRT, PDT, and to cure without damaging the quality of life.