Long-term results of postoperative unsuspected small cell lung cancer on real-world data

In traditional opinion, solid pulmonary nodule suspected lung cancer should be confirmed by pathology before the operation to exclude small cell lung cancer (SCLC), considering SCLC tends to be aggressive and surgical effect in the management of SCLC remains controversial. The aim of this study was to evaluate the survival result and risk factors of postoperative unsuspected SCLC.

A total of 120 patients with postoperative unsuspected SCLC who were confirmed by pathology and referred to Chinese PLA General Hospital between 2000 and 2021 were retrospectively analyzed (surgery group). Additionally, 120 patients with limited-stage SCLC who underwent chemotherapy and radiotherapy in the same period were enrolled in the chemoradiotherapy group.. Kaplan-Meier method was used to estimate survival; the Log-Rank test was used to compare survival rates between different groups; a COX stepwise regression model was used for multivariate analysis.

Among 120 patients in the surgery group, 28 were with central type and other 92 with peripheral type. The median survival (OS) was 44.85 months, and the 5-year survival rate was 46%. The 5-year survival rates for stage I, II, and III were 52.1%, 45.4%, and 27.8%, respectively. The mean disease-free survival time (DFS) was 30.63 ± 4.38 months, and the 5-year DFS rate was 31.5%. In the chemoradiotherapy group, the mean OS was 21.4 ± 4.26 months, and the 5-year survival rate was 28.3%. The 5-year survival rates for clinical stage I, II, and III were 42.5%, 39.8%, and 20.5%, respectively. The mean progression-free survival (PFS) was 10.63 ± 3.6 months. In the surgery group, one-way ANOVA revealed that the gender, symptoms, smoking history, tumor location, and postoperative radiotherapy were not associated with OS (P ≥ 0.05), while age, surgical approach, surgical method, N stage, TNM stage, and vascular tumor thrombus were related to OS (P < 0.05). Multivariate analysis indicated that the N stage was associated with OS (HR = 1.86 P = 0.042).

Surgery and adjuvant therapy were found to have encouraging outcomes in postoperative unsuspected SCLC. Patients with stage I, stage II and part of stage IIIA SCLC could benefit from surgery and the standard lobectomy, and systematic lymph node dissection, is also recommended for these patients.