Development and validation of a nomogram for assessing survival in extensive-stage small-cell lung cancer patients with superior vena cava syndrome referred for thoracic radiotherapy: a comparison of upfront vs. consolidative approaches

Abstract

Purpose: This study sought to design and validate a nomogram capable of predicting outcomes in extensive-stage small-cell lung cancer (ES-SCLC) patients with superior vena cava syndrome (SVCS) based upon the timing of their radiotherapy treatment.

Methods: We retrospectively analyzed data from 175 ES-SCLC patients with SCVS, comparing outcomes between those that underwent upfront thoracic radiotherapy (initial radiotherapy with simultaneous chemotherapy) and those that underwent consolidative thoracic radiotherapy (following 4-6 cycles of chemotherapy). Significant predictors of patient outcomes were identified using a Cox proportional hazard model and were used to construct our nomogram. This model was subsequently validated using receiver operating characteristic (ROC) curves, concordance index (C-index) values, and a risk classification system in order to evaluate its discriminative and predictive accuracy.

Results: The overall survival (OS) of ES-SCLC patients with SVCS that underwent chemotherapy (CT), consolidative thoracic radiotherapy (cc-TRT), and upfront thoracic radiotherapy (cu-TRT) was 8.2, 11.7, and 14.9 months, respectively (p < 0.001), with respective progression-free survival (PFS) durations of 3.3, 5.0, and 7.3 months (p < 0.001). A multivariate regression analysis revealed age, gender, ECOG performance status, sites of tumor metastasis, and treatment approach to all be independent predictors of survival outcomes. A nomogram was therefore developed incorporating these factors. C‑index values upon internal and external validation of this nomogram were 0.7625 and 0.7959, respectively, and ROC and calibration curves revealed this model to be accurate and consistent.

Conclusions: We found that upfront thoracic radiotherapy in combination with chemotherapy may be associated with a positive impact on outcomes in ES-SCLC patients with SVCS.

Keywords: Extensive-stage small-cell lung cancer; Superior vena cava syndrome; Thoracic radiotherapy; Treatment outcomes; Up-front strategy.