Consolidative radiation therapy for extensive-stage small cell lung cancer

Immunotherapy in Extensive-Stage Small Cell Lung Cancer

Small cell lung cancer (SCLC) remains a poorly understood disease with aggressive features, high relapse rates, and significant morbidity as well as mortality, yet persistently limited treatment options. For three decades, the treatment algorithm of SCLC has been stagnant despite multiple attempts to find alternative therapeutic options that could improve responses and increase survival rates. On the other hand, immunotherapy has been a thriving concept that revolutionized treatment options in multiple malignancies, rendering previously untreatable diseases potentially curable. In extensive stage SCLC, immunotherapy significantly altered the course of disease and is now part of the treatment algorithm in the first-line setting. Nevertheless, the important questions that arise are how best to implement immunotherapy, who would benefit the most, and finally, how to enhance responses.

Patient selection for thoracic radiotherapy in extensive-stage small-cell lung cancer

Treatment of extensive-stage small-cell lung cancer remains a challenge with poor local control and overall survival. Chemotherapy is the mainstay of treatment, consisting of a combination of a platinum agent plus etoposide. The role of consolidative chest radiotherapy in extensive-stage small-cell lung cancer remains controversial. Two randomized clinical trials have been published demonstrating improved intrathoracic disease control with a small survival benefit, though interpretation and application of these results to clinical practice has been debated. These two trials examined different radiotherapy techniques and doses, with a third trial treating consolidative chest and oligometastatic disease having closed prematurely due to an interim analysis demonstrating treatment futility plus increased toxicity. Patients with residual intrathoracic disease after chemotherapy appear to benefit the most from consolidative chest radiotherapy, offering a potential tool to help select appropriate patients.

Timing of thoracic radiotherapy in the treatment of extensive-stage small-cell lung cancer: important or not?

Background

This study evaluated the prognosis of patients with extensive-stage small-cell lung cancer (ES-SCLC) that may be associated with timing of thoracic radiotherapy (TRT).

Methods

ES-SCLC patients (n = 232) without progression were retrospectively analyzed after first-line induction chemotherapy. Patients in the TRT group were stratified as early-TRT (ERT; ≤3 cycles of induction chemotherapy received prior to TRT, n = 65) or late-TRT (LRT; >3 cycles, n = 122). To avoid selection bias, we conducted Propensity Score Matching (PSM) for patients. Overall survival (OS), progression-free survival (PFS), and locoregional recurrence-free survival (LRRFS) were assessed and compared.

Results

Overall, the median survival time, PFS, and LRRFS were 13.2, 8.7, and 14.6 months, respectively. After matching by PSM, there were 45 patients total in the TRT/non-TRT groups, and 56 patients total in the ERT/LRT groups. OS, PFS, and LRRFS were significantly longer in the TRT group than the non-TRT group (P < 0.001, all). However, between the ERT and LRT groups these survival parameters were similar (P > 0.05, all).

Conclusion

For ES-SCLC patients without progression, the addition of TRT after first-line chemotherapy benefited survival greatly. Early TRT showed no significant benefit over late TRT.