Postoperative oligo-recurrence of non-small-cell lung cancer: clinical features and survival

Postoperative recurrences of non-small-cell lung cancer (NSCLC) are usually disseminated and systemic. Recently, the concept of oligo-recurrence, which is theoretically curable by definitive local therapy (DLT), has been proposed in several cancers. The aim of this study was to clarify clinical features and outcomes of patients with postoperative oligo-recurrence of NSCLC. From 3275 patients with resected pathological stage IA-IIIB NSCLC between 1993 and 2011, a total of 768 patients who developed recurrence were included in this study. Oligo-recurrence was defined as 1-3 loco-regional or distant recurrent lesions restricted to a single organ. Other recurrences were classified as poly-recurrence. Second primary lung cancers and suspected lesions were excluded. DLT included surgery, stereotactic radiotherapy and radiotherapy with a 45 Gy or higher dose, performed with curative intent. Oligo-recurrence was identified in 162 (21%) patients, mainly as a solitary recurrence (n = 129, 80%) in regional lymph nodes, brain, lung, bone and adrenal gland, and the proportion of patients with oligo-recurrence increased gradually year by year. The patients with oligo-recurrence had more early-staged disease at initial surgery and a longer time to recurrence than those with poly-recurrence. The entire population of oligo-recurrence patients had better post-recurrence survival (PRS) than those with poly-recurrence (5-year PRS: 32.9 vs 9.9%, P < 0.001). For oligo-recurrence, DLT was totally conducted in 105 (65%) patients as initial treatment. Multivariate analyses revealed that the initial DLT was associated with improved PRS [odds ratio (OR) 0.44; 95% confidence interval (CI) 0.29-0.68]. The recurrence location and initial pathological stage did not affect PRS. The 5-year PRS and postoperative progression-free survival rates after DLT were 38.6 and 22.3%, respectively. Of the 10 long-term (>= 5-year) progression-free survivors, 9 were those with a solitary recurrence. Initial DLT for oligo-recurrence achieved favourable PRS in a selected population. Oligo-recurrence curable by DLT was found in a subset of patients who received DLT, mostly as a solitary recurrence.