Background
Phase III RCT (UNICANCER ACCORD-III). 307 patients with locally advanced anal canal cancer (T2 >4 cm, T3–T4, or N1–N3). Compared standard 5-FU + MMC + 45 Gy vs dose-intensified regimen with induction 5-FU + cisplatin followed by 5-FU + cisplatin + 60 Gy RT. Standard arm: 5-FU 800 mg/m²/d × 4d days 1–4 and 36–39 + MMC 20 mg/m² day 1 + pelvic RT 45 Gy + boost to 59 Gy total. Intensive arm: 2 induction cycles 5-FU + cisplatin 80 mg/m², then 5-FU + cisplatin + 60 Gy (dose-escalated continuous course with concomitant boost).
Interventions and follow up
Arm A: 5-FU + MMC + 45 Gy (+ boost to 59 Gy total) — standard regime
Arm B: 2 induction cycles 5-FU + cisplatin, then 5-FU + cisplatin + 60 Gy dose-escalated RT
Primary endpoint: 3-year colostomy-free survival
mFollow up: 50 month
Arm B: 2 induction cycles 5-FU + cisplatin, then 5-FU + cisplatin + 60 Gy dose-escalated RT
Primary endpoint: 3-year colostomy-free survival
mFollow up: 50 month
Results
3-year CFS: 76.5% (standard) vs 75.0% (intensive), P=.37 — not significant
3-year OS: 86.0% (standard) vs 79.8% (intensive), P=.09 — not significant
3-year locoregional control: 83.1% vs 81.2%, P=.64 — not significant
pCR rate: Not reported separately; CR rates comparable
3-year OS: 86.0% (standard) vs 79.8% (intensive), P=.09 — not significant
3-year locoregional control: 83.1% vs 81.2%, P=.64 — not significant
pCR rate: Not reported separately; CR rates comparable
Adverse events
Main adverse events: Grade 3–4 early toxicity significantly higher in intensive arm: 90% vs 74%, P<.05. Higher rates of hematologic and mucosal toxicity with cisplatin + dose escalation. Treatment delays more common in intensive arm.
Conclusions
Dose escalation with cisplatin induction followed by cisplatin + 60 Gy RT did not improve colostomy-free survival or OS compared with standard 5-FU + MMC + 45–59 Gy CRT, while adding significant toxicity.
Key Limitations
Key Limitations: The intensive arm combined two changes (cisplatin substitution and dose escalation), making it impossible to attribute any difference to cisplatin vs dose alone. The concomitant boost technique in the intensive arm is not standard at most centers. Tumor staging did not include PET-CT (pre-modern era). Only T2 >4 cm and beyond were enrolled — not applicable to smaller T2 tumors.
Clinical Context
ACCORD-III confirmed that dose escalation beyond ~50–59 Gy with cisplatin substitution does not improve outcomes for locally advanced anal cancer. Standard 5-FU + MMC + RT (~50.4–59 Gy) remains the backbone of care. The failure of dose intensification reinforces the principle that conventional CRT doses should not be exceeded in standard risk patients.
References
References: Peiffert D et al, J Clin Oncol 2012 (ACCORD-III)