Impact of the initial site of recurrence on prognosis after curative surgery for primary lung cancer.

OBJECTIVES This retrospective study aimed to elucidate the impact of the initial site of recurrence on relapse-free survival and post-recurrence survival (PRS) after the curative resection of primary lung cancer. METHODS We enrolled 325 patients who developed recurrence after curative resection of pathological stage I-IIIA primary lung cancer between January 2006 and December 2018 at the Kanagawa Cancer Center. Cases were classified as follows based on the initial site of recurrence: cervicothoracic lymph node (n = 144), lung (n = 121), pleural dissemination (n = 52), bone (n = 59), brain and meningeal dissemination (n = 50) and abdominal organ (n = 34) cases. The relapse-free survival and PRS of patients with and without recurrence at each site were compared using the log-rank test. The impact of the initial site of recurrence on PRS was analysed using the Cox proportional hazards model. RESULTS Relapse-free survival was significantly poorer in patients with abdominal organ recurrence than in patients without abdominal organ recurrence (11.5 vs 17.6 months, P = 0.024). The PRS of patients with bone and abdominal organ recurrences was worse than that of patients without bone (18.4 vs 31.1 months, P < 0.001) or abdominal organ (13.8 vs 30.6 months, P < 0.001) recurrence. Multiple recurrence sites were observed more frequently in patients with bone and abdominal organ recurrences. Bone [hazard ratio (HR) 2.13; P < 0.001] and abdominal organ metastasis (HR 1.71; P = 0.026) were independent poor prognostic factors for PRS. CONCLUSIONS This study suggests surveillance for abdominal organ recurrence in the early postoperative period. Patients with bone and abdominal organ recurrence should receive multimodality treatment to improve their prognosis.