Carboplatin versus cisplatin in combination with etoposide in the first-line treatment of small cell lung cancer: a pooled analysis

Background: Extensive-stage small cell lung cancer (ES-SCLC) is an aggressive disease with poor survival, and platinum-etoposide chemotherapy is indicated as the mainstay of treatment. In this study, we compared the efficacy and safety between the cisplatin plus etoposide (EP) and carboplatin plus etoposide (EC) regimens.

Methods: A total of 1305 patients with previously untreated ES-SCLC were included in this study. Data from five trials were collected from the public database Project Data Sphere. Survival analysis and adverse events (AEs) analysis were conducted.

Results: Of the 1305 patients, 800 received the EC regimen whereas 505 received the EP regimen as their front-line treatment. Overall, the median progression-free survival (PFS) and the median overall survival (OS) were 172 and 289 days, respectively. The EP and EC treatment groups did not have significantly different PFS or OS. After adjusting for age, sex, body mass index (BMI) and Eastern Cooperative Oncology Group (ECOG) performance status (PS), the EP regimen was independently associated with better PFS (hazard ratio [HR] = 0.76, 95% CI = 0.63-0.92, p = 0.0041) and OS (HR = 0.79, 95% CI = 0.64-0.97, p = 0.0220) among patients who were overweight and obese (BMI ≥ 25 kg/m²). In the safety analysis, patients who received the EC treatment experienced significantly more grade ≥ 3 AEs (n = 599, 74.9%) than those who received the EP treatment (n = 337, 66.7%; p = 0.002). Furthermore, the EC regimen was associated with a higher risk of grade 3-4 neutropaenia (p = 0.001), thrombocytopaenia (p < 0.001) and hyponatraemia (p = 0.036), whereas the EP regimen was associated with a higher risk of grade 3-4 vomiting (p = 0.021).

Conclusions: In summary, this study presented the efficacy and safety of the EC and EP regimens in patients with ES-SCLC in the first-line setting. Patients who are overweight and obese benefit more from the EP regimen than EC regimen. Approaches to define the optimal chemotherapy regimen in different BMI subgroups are needed.