KEY TAKEAWAYS
- The phase 3 trial (CALGB 30610/RTOG 0538) assessed the efficacy of higher-dose once-daily radiotherapy versus twice-daily radiotherapy in patients with limited-stage small-cell lung cancer.
- Results showed that overall survival was not improved on the once-daily arm, with a median survival of 28.5 and 30.1 months and 5-year OS of 29% and 32% for twice-daily and once-daily treatment, respectively.
- This study provides essential information to guide radiotherapy decisions for limited-stage small-cell lung cancer.
Although 45 Gy of radiation twice a day is supported by level 1 evidence as the standard for limited-stage small-cell lung cancer, most patients undergo higher-dose once-daily regimens. Whether or not a higher dose of radiation results in better outcomes remains unproven.
CALGB 30610/RTOG 0538 was two stages, phase III clinical investigation. Beginning with the first or second of four total rounds of chemotherapy, individuals with limited-stage illness were randomly assigned to undergo 45-Gy twice daily, 70-Gy once daily, or 61.2-Gy concomitant-boost radiation. After the interim toxicity analysis was completed as scheduled, the 61.2-Gy arm was removed from the study, and the other 2 arms continued. The primary endpoint was overall survival (OS) in the study’s primary analysis population.
Accrual in the trial began on March 15, 2008, and ended on December 1, 2019. All 313 patients who received 45 Gy twice daily and 325 patients who received 70 Gy once daily were included in this study. There was no difference in OS between the once-daily and twice-daily groups after a median follow-up of 4.7 years (hazard ratio for death, 0.94; 95% CI, 0.76 to 1.17; P =.594). The 5-year OS rates are 29% for those who receive treatment twice daily and 32% for those who receive treatment once daily. The median survival time for both treatment schedules is 28.5 months. Tolerability was high, with both groups experiencing an exact rate of severe side events such as esophageal and pulmonary toxicity.
This study offers the most comprehensive evidence available to guide the choice of thoracic radiation regimen for patients with limited-stage small-cell lung cancer, even if 45-Gy twice-daily radiotherapy remains the standard of care.
Clinical Trial: https://clinicaltrials.gov/ct2/show/NCT00632853
Bogart J, Wang X, Masters G, Gao J, Komaki R, Gaspar L, Heymach J, Bonner J, Kuzma C, Waqar S, Petty W, Stinchcombe T, Bradley J, Vokes E. High-Dose Once-Daily Thoracic Radiotherapy in Limited-Stage Small-Cell Lung Cancer: CALGB 30610 (Alliance)/RTOG 0538. J Clin Oncol. 2023 Jan 9:JCO2201359. doi: 10.1200/JCO.22.01359. Epub ahead of print. PMID: 36623230.
