Objective: Synchronous multiple primary lung cancer (SMPLC) has a reported occurrence from 0.5% to 2% in lung cancer, and the surgical treatment and prognosis were quite diverse. With the discovery of driver mutations in lung adenocarcinoma (ADC), next-generation sequencing (NGS) would provide an explicit answer to the key question, whether individual tumors represent intrapulmonary metastases or independent tumors. Here, we reported a 64-year-old female diagnosed with a synchronous trilateral early-stage ADC with distinct driver alterations.
Materials and Methods: NGS test targeting 31 cancer-relevant genes and amplification RNA sequencing (if gene fusion was found on DNA level) were performed on the surgical tumor tissue.
Results: A 64-year-old Chinese female never smoker was found with one nodule in the right upper lobe and two nodules in the right middle lobe through chest computed tomography. The lesions were resected through video-assisted thoracic surgery and diagnosed with stage IA ADC, T1N0M0, in the postoperative pathology. NGS detected three independent driver mutations in three primary sites, respectively, EGFR  19del, EGFR  20ins and ROS1  fusion.
Conclusion: This is the first report of a synchronous trilateral early-stage ADC with distinct driver alterations. All individual tumors were independent identified by NGS methodology, which had provided a clear answer to the key question of SMPLC in this case and should be used as a routine genetic test to explore fully pathological diagnosis and more comprehensive oncogenesis information in the early-stage ADC clinical prevention.
Keywords: synchronous multiple primary lung cancer, lung adenocarcinoma, NGS, EGFR  mutation, ROS1  fusion