Evaluation of the prognosis in patients with small-cell lung cancer treated by chemotherapy using tumor shrinkage rate-based radiomics.

Background: Small-cell lung cancer (SCLC) is a leading cause of cancer-related death. However, the prognostic value of the tumor shrinkage rate (TSR) after chemotherapy for SCLC is still unknown.

Methods: We performed a retrospective analysis of 235 patients with SCLC. The TSR cutoff was determined based on receiver-operating characteristic curve analysis. The associations of TSR with progression-free survival (PFS) and overall survival (OS) were assessed using univariate and multivariate Cox proportional hazards models. Survival curves were obtained by the Kaplan-Meier method and compared using the log-rank test. Recurrence patterns after first-line treatment were summarized in a pie chart. A nomogram was constructed to validate the predictive role of the TSR in SCLC.

Results: The TSR cutoff was identified to be  - 6.6%. Median PFS and OS were longer in the group with a TSR < -6.6% than in the group with a TSR ≥ - 6.6%. PFS and OS were also longer in patients with extensive SCLC when the TSR was < - 6.6% than when it was > - 6.6%. Brain metastasis-free survival was better in the group with a TSR < - 6.6%. There was a significant positive correlation between TSR and PFS. Furthermore, univariate and multivariate regression analyses showed that the TSR, patient age, and previous radiotherapy were independent prognostic factors for OS while TSR and M stage were independent prognostic factors for PFS.

Conclusions: The TSR may prove to be a good indicator of OS and PFS in patients receiving chemotherapy-based first-line treatment for SCLC.