Evaluation of surgical outcomes and prognostic factors of second primary lung cancer based on a systematic review and meta-analysis

BACKGROUND: Although surgery has been widely applied for SPLC therapy, there is still no uniform treatment approach. Whether SPLC and primary lung cancer have similar prognostic characteristics remains controversial. Herein, based on a systematic review and meta-analysis, we aimed to enucleate the influences of diverse surgical strategies and underlying prognostic factors on the prognosis of patients with both the first primary lung cancer and SPLC underwent surgical resection. METHODS: A comprehensive and systematic literature search was implemented in three databases (MEDLINE, EMBASE, and Cochrane), and eligible studies were screened following inclusion and exclusion criteria. Meanwhile, we extracted the hazard ratios (HR) together with 95% confidence intervals (CI) for each prognostic factor, either directly or indirectly, from the enrolled literature. RESULTS: Eleven studies (published between 2000 and 2022) were included in this study, including 1,131 SPLC patients. The overall survival (OS) exhibited no difference between patients with lobectomy and sublobar resection after SPLC (HR: 0.87, 95%CI: 0.62–1.21, P = 0.41). The patients after completion pneumonectomy had a poor prognosis (HR: 1.85, 95% CI: 1.34–2.55, P < 0.01). Poor prognostic factors after SPLC surgery included synchronous SPLC (HR: 3.38, 95%CI: 1.53–7.46, P < 0.01), tumor diameter > 2 cm (HR: 2.44, 95%CI: 1.73–3.44, P < 0.01), solid predominant in CT morphology (HR: 3.08, 95% CI: 1.14–8.33, P = 0.03), lymph node metastasis (HR: 2.79, 95%CI: 1.40–5.56), and smoking (HR: 2.37, 95%CI: 1.08–26.82, P < 0.01). Tumor disease-free interval (DFI), tumor histological type, and gender had no impact on the prognosis of patients received SPLC surgery. CONCLUSIONS: Patients with SPLC, especially those with poor cardiopulmonary function reserve, should be prioritized for sublobar resection for treatment. These patients should also try to avoid completion pneumonectomy. Patients with synchronous SPLC, tumor diameter > 2 cm, solid predominant in CT morphology, lymph node metastasis, and smoking had a poor prognosis. Meanwhile, SPLC has similar prognostic characteristics with single primary lung cancer. However, the study has some limitations and more evidence is warranted to verify the findings.