Background
Phase III RCT using a 2×2 factorial design (ESPAC-1). 289 patients with resected pancreatic ductal adenocarcinoma at 61 European centers. Patients randomly assigned to: chemoradiotherapy alone (20 Gy + 5-FU), chemotherapy alone (5-FU/leucovorin), both CRT and chemotherapy, or observation.
Interventions and follow up
Arm A: Chemoradiotherapy: 20 Gy in 10 fractions + 5-FU 500 mg/m² bolus × 3 days per course; two courses with a 2-week gap
Arm B: Chemotherapy: 5-FU 425 mg/m² + leucovorin 20 mg/m² days 1–5 every 28 days × 6 cycles
Primary endpoint: Overall survival
Median follow-up: 47 months
Arm B: Chemotherapy: 5-FU 425 mg/m² + leucovorin 20 mg/m² days 1–5 every 28 days × 6 cycles
Primary endpoint: Overall survival
Median follow-up: 47 months
Results
5-yr OS (CRT vs no CRT): 10% vs 20%, P=.05 — CRT was detrimental
5-yr OS (chemo vs no chemo): 21% vs 8%, P=.009 — chemo was beneficial
mOS (chemo vs no chemo): 19.7 vs 14.0 months
5-yr OS (chemo vs no chemo): 21% vs 8%, P=.009 — chemo was beneficial
mOS (chemo vs no chemo): 19.7 vs 14.0 months
Adverse events
Chemoradiotherapy arms: Significantly more toxicity, including myelosuppression and gastrointestinal side effects, with reduced quality of life.
Treatment-related deaths: Several chemotherapy-related deaths occurred during the study.
Treatment-related deaths: Several chemotherapy-related deaths occurred during the study.
Conclusions
Adjuvant chemotherapy (5-FU/LV) significantly improved survival in resected pancreatic cancer, while adjuvant chemoradiotherapy had a statistically significant detrimental effect on survival. ESPAC-1 fundamentally changed European practice away from adjuvant CRT toward systemic chemotherapy alone.
Key Limitations
Key Limitations: Factorial design complexity and some protocol deviations (some patients received both CRT and chemo outside factorial assignment). Confounded by the split-course RT technique delivering only 40 Gy — lower than standard US doses. 5-FU/LV was the chemotherapy — not modern gemcitabine-based regimens. Margin status and lymph node data were imprecisely captured. The study has been criticized for its design complexity and limited per-arm sample sizes.
Clinical Context
ESPAC-1 established the primacy of systemic chemotherapy over CRT in the adjuvant setting. Subsequent ESPAC-3 and ESPAC-4 refined chemotherapy choices (gemcitabine, then gemcitabine + capecitabine). PRODIGE-24 further established mFOLFIRINOX as the preferred adjuvant regimen for fit patients per ASCO and ESMO guidance. Adjuvant CRT is now reserved for margin-positive resections at select centers.
References