Background
Systematic review and meta-analysis of thoracic RT timing (early vs late) relative to chemotherapy in limited-stage SCLC. Included randomized trials published after 1985 directly addressing RT timing. Analyzed by risk ratio (RR); subgroups by RT fractionation and chemotherapy regimen.
Interventions and follow up
Arm A: Early thoracic RT (initiated with chemotherapy cycle 1-2)
Arm B: Late thoracic RT (delayed relative to chemotherapy)
Primary endpoint: 2- and 3-year overall survival
mFollow up: Variable across included trials
Arm B: Late thoracic RT (delayed relative to chemotherapy)
Primary endpoint: 2- and 3-year overall survival
mFollow up: Variable across included trials
Results
2-yr OS (all studies): RR 1.17 (95% CI 1.02-1.35), P=.03 — early RT significantly superior
3-yr OS (all studies): RR 1.13 (95% CI 0.92-1.39), P=.2 (NS)
2-yr OS (hyperfractionated RT subgroup): RR 1.44 (95% CI 1.17-1.77), P=.001
3-yr OS (hyperfractionated RT subgroup): RR 1.39 (95% CI 1.02-1.90), P=.04
2-yr OS (platinum-based chemo subgroup): RR 1.30 (95% CI 1.10-1.53), P=.002
3-yr OS (all studies): RR 1.13 (95% CI 0.92-1.39), P=.2 (NS)
2-yr OS (hyperfractionated RT subgroup): RR 1.44 (95% CI 1.17-1.77), P=.001
3-yr OS (hyperfractionated RT subgroup): RR 1.39 (95% CI 1.02-1.90), P=.04
2-yr OS (platinum-based chemo subgroup): RR 1.30 (95% CI 1.10-1.53), P=.002
Adverse events
Pooled toxicity: Not the primary focus of the meta-analysis
Esophagitis: Higher with early RT timing, consistent with primary trial data
Esophagitis: Higher with early RT timing, consistent with primary trial data
Conclusions
Early thoracic RT significantly improved 2-yr OS vs late RT in limited SCLC (RR 1.17), with greatest benefit in trials using hyperfractionated RT and platinum-based chemotherapy. Early concurrent CRT (cycle 1-2) is preferred over delayed RT in limited SCLC.
Key Limitations
Meta-analysis of heterogeneous trials with varying definitions of "early" vs "late", differing RT doses/fractionation and chemotherapy regimens; 3-yr OS benefit not significant overall; subgroup findings hypothesis-generating; pooled toxicity not systematically analyzed.
Clinical Context
Supports early concurrent thoracic CRT for limited-stage SCLC, complementing INT-0096 (twice-daily 45 Gy) and CONVERT data. Reinforces platinum-etoposide with early hyperfractionated RT as a standard limited-SCLC approach.