Topotecan in a Real-World Small-Cell Lung Cancer Cohort: Prognostic Biomarkers Improve Selection of Patients for Second-Line Treatment.

BACKGROUND

Small-cell lung cancer (SCLC) is a highly aggressive tumor, and overall survival (OS) remains poor despite intensive efforts to develop new treatment strategies. In second line, topotecan is the only approved drug, with a median OS of 5.9 months. However, real-world SCLC patients are often in worse condition and harbor more comorbidities than study populations. Therefore, the real-world performance of topotecan may differ from that seen in studies. Here, we analyzed outcomes of SCLC patients receiving topotecan and identified predictive and prognostic markers.

PATIENTS AND METHODS

We retrospectively analyzed 44 consecutive SCLC patients receiving topotecan between 2015 and 2022. We analyzed baseline characteristics (age, ECOG-PS, topotecan cycles, and dosage) and pre-treatment blood values (LDH, CRP, sodium) as well as prognostic scores (neutrophil/lymphocyte ratio (NLR), thrombocyte/lymphocyte ratio (TLR), Glasgow Prognostic Score, prognostic nutritional score, systemic inflammation index (SII), and the prognostic index) extracted from electronic patients' charts to identify predictive and prognostic markers.

RESULTS

In our cohort, mPFS and mOS were only 1.9 and 5.6 months, respectively. Gender, ECOG-PS, active brain metastases, NLR, GPS, PNI, and SII significantly influenced PFS and OS in univariate analysis. ECOG-PS ( > 0.001), active brain metastases ( = 0.001), and SII ( = 0.008) were significant independent prognostic variables in a multivariate COX regression model. Selecting patients by these three markers achieved an mPFS of 5.7 months and thus increased the mPFS three-fold. Patients not meeting all criteria had an mPFS of 1.8 months ( = 0.006). Patients identified by prognostic markers had an mOS of 9.1 months ( = 0.002).

CONCLUSIONS

The efficacy of topotecan in SCLC real-world patients is poor, indicating that many patients were treated without any benefit. Easy-to-obtain markers can predict response and treatment efficacy and should therefore be validated in larger cohorts to identify patients who are more likely to benefit from topotecan.