Efficacy of Prophylactic Cranial Irradiation in Early to Mid-stage Small Cell Lung Cancer Patients in the Era of Magnetic Resonance Imaging.

BACKGROUND

Recent advancements in magnetic resonance imaging (MRI) for staging have highlighted the critical question of the need for prophylactic cranial irradiation (PCI) in managing early to mid-stage small cell lung cancer (SCLC). This study assesses the impact of PCI on overall survival (OS) and intracranial control among patients with stage I-IIB SCLC.

METHODS

Data from 148 stage I-IIB SCLC patients treated with thoracic radiation therapy (TRT) at two centers were examined. Patients were categorized based on PCI administration: 63 received PCI, while 85 did not. All underwent pretreatment MRI, achieving at least a partial response to therapy. A 1:1 propensity score matching analysis corrected for potential biases.

RESULTS

Propensity scores were generated to 116 patients, considering patient demographics, disease progression, and treatment methods. Death was included as a competing risk. The 3-year brain metastases (BM) occurrence rate was significantly higher in patients who did not receive PCI (30.0%) compared to those who did (14.8%), however, the difference was not statistically significant (No PCI vs. PCI, hazard ratio [HR]: 2.08, 95% CI [0.93-4.55], P = .07). No significant effect of PCI on OS was observed [PCI vs. No PCI, HR: 0.80, 95% CI (0.45-1.43), P = .45]. A subgroup analysis of stage IIB patients showed a significant increase in BM risk and mortality for those not receiving PCI (No PCI vs. PCI, BM risk HR: 5.85, 95% CI: 1.83-18.87, P = .003; mortality HR: 2.78, 95% CI: 1.14-6.67, P = .02), with less pronounced effects in stages I-IIA.

CONCLUSION

With modern MRI-based screening, PCI may markedly benefit stage IIB SCLC patients by reducing BM and improving OS after initial sensitive treatment. This benefit does not appear to extend to stage I-IIA patients.