Real-world comparison of survival outcomes with cisplatin versus carboplatin in patients with limited-stage small-cell lung cancer.

Introduction: Limited-stage small-cell lung cancer (LS-SCLC) is potentially curable with concurrent chemoradiation (CRT). Cisplatin is the preferred platinum for the chemotherapy backbone in national guidelines. Unfortunately, many LS-SCLC patients are elderly, with comorbidities and poor performance status (PS), which preclude the use of cisplatin. Carboplatin may be a suitable alternative. This analysis evaluates the overall survival (OS) and time to next treatment (TTNT) in LS-SCLC patients receiving concurrent CRT by platinum use.

Materials And Methods: The study included LS-SCLC patients in the Flatiron Health nationwide de-identified electronic health record-derived database who received CRT in 2013-2019 with follow-up through May 2020. TTNT and OS were compared using both unadjusted and inverse propensity-weighted Cox proportional hazards models.

Results: This study included patients treated with carboplatin (n = 600) or cisplatin (n = 572) in combination with etoposide and radiation. Cisplatin patients were younger, had a shorter time from diagnosis to radiation, and had less kidney disease. In an unadjusted analysis, median overall survival (mOS) was greater in the cisplatin group than the carboplatin group with mOS of 22.3 months vs. 19.2 months and Hazard Ratio (HR) of 0.83 (p = 0.01). In the inverse propensity-weighted analysis, this difference was no longer significant (HR 0.93, p = 0.37). No differences were seen in TTNT.

Conclusion: When balancing on key clinical factors, we observed no statistical difference in OS or TTNT by platinum choice in real-world LS-SCLC patients treated with CRT.  Although observational, the results from this large data set are consistent with the hypothesis that either cisplatin or carboplatin is an appropriate therapy regardless of health status.