Surgery vs. radiotherapy in a population-based cohort of elderly patients with early-stage small-cell lung cancer: an IPTW propensity-score analysis

BACKGROUND: Due to the lack of treatment outcome data comparing surgical and non-surgical treatment modalities in the era of contemporary staging and treatments, the management of elderly patients with early-stage small cell lung cancer (SCLC) continues to be debated. This study sought to compare surgery and radiotherapy in elderly patients (aged ≥70 years) with early-stage SCLC using data from the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: The inverse probability of treatment weighting (IPTW) method was used to address the selection bias between the surgery and radiotherapy groups. The Kaplan-Meier method and multivariate Cox proportional hazards regression were used to compare the overall survival (OS) of the treatment cohorts before and after the IPTW adjustment. The competing risk survival analyses used Fine and Gray’s method to compare the cancer-specific survival between the groups. RESULTS: Between 2004 and 2018, 685 elderly patients received local treatment for early-stage SCLC. Of these patients, 193 patients (26.6%) received surgery and 492 patients (73.4%) received radiotherapy. Surgery was associated with a longer OS time than radiotherapy (median OS time: 32 vs. 20 months; 5-year OS time: 30.6% vs. 17.6%; P=0.002). The survival advantage of surgery was consistent in the IPTW-adjusted cohort (median OS time: 32 vs. 20 months; 5-year OS time: 30.6% vs. 17.6%; P<0.002). In the multivariate analysis, an increased age (P=0.001), stage T2 (P=0.047), radiotherapy (P<0.001), and no chemotherapy (P=0.034) were associated with unfavorable OS. In the IPTW-adjusted cohort, the multivariate analysis showed a decreased age (P<0.001), stage T1 (P=0.038), and surgery (P<0.001) were associated with superior OS. The competing risk analyses demonstrated that surgery produced a consistent decrease in the cancer-specific mortality rate compared to radiotherapy among the patients aged 70–80 years (53.6% vs. 61.0%, P=0.01), but no difference was observed in the 5-year cumulative incidence rate of cancer-related death between the surgery and radiotherapy groups (66.3% vs. 64.9%; P=0.66) in patients aged ≥80 years. CONCLUSIONS: In this population-based study of the optimal local treatment for elderly early-stage SCLC, patients who underwent surgery had superior OS compared to those who underwent radiotherapy.