Lobectomy Versus Sublobectomy in Metachronous Second Primary Lung Cancer: A Propensity Score Study

Abstract

The optimal surgical approach for metachronous second primary lung cancer (MSPLC) has not been well established yet. In this study, survival outcome of lobectomy was compared with sublobectomy for MSPLC. A retrospective study was conducted based on the Surveillance, Epidemiology, and End Results database. Propensity score matching was used to reduce the potential bias caused by the variance of the clinicopathologic features of the first and second lung cancer. The effect of lobectomy and sublobectomy for MSPLC was assessed and explored in subgroup analyses. We identified 1,392 MSPLC patients, and 454 pairs of patients were matched. Lobectomy was associated with a significantly better survival (p= 0.023). Subgroup analyses showed that lobectomy achieved a significantly better prognosis if previous lung cancer was stage I, whereas sublobectomy had advantages in patients with initial stage III cancer. Moreover, patients with lobectomy had a significantly better prognosis in N0 disease but not in N1 or N2. Stratified by tumor size, the prognosis of sublobectomy was comparable to lobectomy for tumors sized 1 cm or smaller. Lobectomy was associated with a better survival in tumors sized 1 to 2 cm, although without statistical significance. For tumors sized 2 to 3 cm, lobectomy conferred a significantly better survival. This study indicates that lobectomy is still a valid choice for MSPLC. Sublobectomy has value and shows equivalency in tumors sized 2 cm or smaller. For patients with advanced disease or at high risk, additional studies are needed to explore the value of sublobectomy.