KEY POINTS
- This randomized phase II study included 97 patients with esophageal squamous cell carcinoma requiring definitive chemoradiotherapy because of unresectable disease, medical inoperability, treatment refusal, or recurrence.
- Radiotherapy used involved-field treatment delivering 50.4 Gy in 28 fractions or 60 Gy in 30 fractions. Both arms received two concurrent courses of nedaplatin 80 mg/m² plus S-1 80 mg/m², repeated every four weeks.
- Three-year progression-free survival was 45% with 50.4 Gy versus 26% with 60 Gy (p = 0.017).
- Three-year cumulative local control was 65% versus 46% (p = 0.047), while three-year overall survival was 73% versus 42% (p = 0.018).
- The apparent progression-free and overall survival advantages with 50.4 Gy were no longer statistically significant after adjustment for important covariates, arguing against interpretation of 50.4 Gy as biologically superior.
- Grade 3–4 toxicity was similar at 53% with 50.4 Gy versus 51% with 60 Gy, and radiotherapy was completed by 98% of participants.
- Taken together with previous randomized dose-escalation studies, the trial provides no evidence that increasing definitive esophageal chemoradiotherapy from approximately 50 Gy to 60 Gy improves outcomes.
CLINICAL TAKEAWAY
For definitive chemoradiotherapy of esophageal squamous cell carcinoma, these data reinforce 50–50.4 Gy as the appropriate standard rather than routine escalation to 60 Gy. The surprisingly large unadjusted survival difference should be interpreted cautiously because it did not persist after covariate adjustment.
SOURCE
International Journal of Radiation Oncology, Biology, Physics