Clinical characteristics of long-term survivors of small cell lung cancer

Small cell lung cancer (SCLC) is an aggressive disease with poor prognosis. Long-term survivors (LTS) are rare, and factors associated with LTS remain unclear. This study investigated the characteristics and treatment outcomes of LTS with SCLC.

Patients diagnosed with SCLC who received systemic therapy between 2007 and 2025 were retrospectively reviewed. LTS were defined as those surviving ≥18 months. Baseline clinical features, laboratory data, and treatment outcomes were compared between LTS and non-LTS.

Among 217 patients, 60 were LTS. LTS were younger and had better performance status, recurrence after surgery or chemoradiotherapy, fewer liver and bone metastases, fewer metastatic organs, lower tumor burden, and lower neutrophil-to-lymphocyte ratios (NLR). In the multivariate analysis, younger age, lower tumor burden, and lower NLR were independently associated with LTS. The proportion of LTS did not differ between patients treated with or without immune checkpoint inhibitors (ICIs). LTS showed significantly longer progression-free survival (PFS) after first-line therapy and also maintained longer PFS across second- to fourth-line treatments, indicating sustained chemosensitivity. ICI-containing regimens tended to improve PFS and overall survival in both groups, though the degree of benefit varied.

LTS with SCLC were characterized by favorable baseline features, particularly younger age, lower tumor burden, and lower NLR, as well as sustained responsiveness to later-line chemotherapy.