Long-term survival in multiple primary lung cancer with immune-based combination therapy: a case report

With the increasing prevalence of multiple lung nodules detected through low-dose computed tomography (CT) screening, the proportion of multiple primary lung cancer (MPLC) among all lung cancers is rising. The diagnosis and treatment of MPLC continue to present obstacles and problems. It is frequently misidentified as intrapulmonary metastasis (IPM). Although surgery is considered the optimal therapeutic approach, many patients present with distant metastases at the time of diagnosis, thereby losing the opportunity for surgical intervention. We present a case of a 69-year-old man who had small-cell carcinoma in his left upper lobe and adenocarcinoma in his left lower lobe. Following his initial diagnosis, he received a comprehensive treatment regimen including immunotherapy, chemotherapy, and localized radiation therapy over one year, achieving remission lasting four and a half years.