The characteristics and prognoses of 72 postoperative synchronous multiple primary lung cancer patients.

Purpose: Synchronous multiple primary lung cancer (SMPLC) is a special type. Currently, there are few reports on the clinical characteristics, genetic status, treatment strategies, and prognosis of SMPLC after radical surgery.

Methods: We retrospectively reviewed cases of SMPLC patients from January 2018 to October 2023. All patients underwent radical surgery and had genetic results using Next-generation sequencing (NGS) or Amplification refractory mutation system polymerase chain reaction (ARMS-PCR) for at least one lesion. Analysis was conducted on the clinical information, pathological types, genetic status, treatment strategies, and prognoses.

Results: We analyzed 72 patients with SMPLC in stage I-IIIA, and 64 of them were in stage IA. Epidermal growth factor receptor (EGFR) mutation was the most common gene, followed by Tumor protein 53(TP53) and Kirsten Rat sarcoma viral oncogene homolog (KRAS). Among the population with EGFR mutations, EGFR L858R, EGFR 19DEL, and EGFR G719X are common, accounting for 47.6%, 33.3%, and 7.2%, respectively. Among the 72 patients, 66 were lung cancer-free with a median follow-up time of 32 months and six patients experienced disease recurrence with a median Disease-free survival (DFS) of 24 months. For stage IA patients, DFS was correlated with the presence of pathological high-risk factors (combined small cell lung cancer, solid/micropapillae subtype) (P<0.001) and PD-L1 expression (P = 0.008), but was not correlated with the number of primary lesions, pathological stage (IA1, IA2, IA3), TP53/KRAS mutation, or status of EGFR sensitive mutation.

Conclusion: EGFR is a high-frequency mutation in early stage SMPLC. Radical surgery is a suitable treatment strategy for stage IA SMPLC patients, including those with EGFR sensitive mutations. Pathological high-risk factors and PDL-1 positive expression correlate with poorer prognoses in stage IA patients.