Oral Cavity Adjuvant Therapy (OCAT) -A Phase III, Randomized Controlled Trial of Surgery followed by Conventional RT (5 fr/wk) vs Concurrent CT-RT vs Accelerated RT (6fr/wk) in Locally Advanced, Resectable, Squamous Cell Carcinoma of Oral Cavity
Mené entre 2005 et 2013 sur 2 519 patients atteints d'un carcinome épidermoïde de la cavité buccale de stade avancé et réséqué (durée médiane de suivi : 95,9 mois), cet essai randomisé de phase III évalue l'intérêt, du point de vue du taux de contrôle locorégional à 5 ans, de l'intensification du traitement adjuvant (chimioradiothérapie concomitante ou radiothérapie accélérée par rapport à radiothérapie standard)
Background: Limited data exists regarding the impact of intensification of adjuvant therapy in resected Oral Cavity Squamous Cell Carcinomas (OCSCC) with adverse prognostic features on histopathology. Patients and Methods: This was a three-arm phase III randomized trial including patients with resected advanced OCSCC. Randomization was in a 1:1:1 ratio: Arm-A- standard Adjuvant Radiation Therapy (RT) 60Gy/30 fractions over six weeks vs. Arm-B-Concurrent chemoradiation vs. Arm-C-Accelerated RT (6 days a week). The trial was powered to detect an absolute difference of 10% in 5-year Locoregional Control (LRC). Results: The trial was conducted between June 2005 and March 2013. Majority of patients were males, had T3-T4 disease, had N2-N3 nodal status, and had ECE in nodes. The median follow-up was 95.9 months. There was no difference between the three arms (A vs. B vs. C) for 10-year LRC:60.2% vs.61.4% vs.65.7%, p=0.57; Disease Free Survival (DFS): 37.4% vs.43.9% vs.39.6%,p=0.40 or Overall Survival (OS): 39.7% vs.46.6% vs.40.4%,p=0.40. There was no benefit of intensification with either modality in patients with any single adverse pathological factor. A benefit of intensification could be seen in patients with a combination of high-risk features: T3-T4 primary tumors with N2-N3 nodes along with ECE for DFS (Arm B Vs Arm A HR =0.53,Arm C Vs Arm A HR =0.63) and OS (Arm B Vs Arm A HR =0.58,Arm C Vs Arm A HR =0.60). Conclusions: All optimally resected OCSCC with adverse features did not benefit from intensification of adjuvant therapy. Only a cohort of patients with a combination of high-risk features are likely candidates for intensification. Clinical trial registration NCT00193843.