Six versus twelve months of adjuvant trastuzumab in combination with dose-dense chemotherapy for women with HER2-positive breast cancer: A multicenter randomized study by the Hellenic Oncology Research Group (HORG)
Mené en Grèce sur 481 patientes atteintes d'un cancer du sein HER2+ de stade précoce, cet essai randomisé compare l'efficacité, du point de vue de la survie sans récidive à 3 ans, et la toxicité de deux durées (6 et 12 mois) d'administration du trastuzumab en traitement adjuvant
Background : Adjuvant trastuzumab in combination with chemotherapy improves survival of women with HER2-positive early breast cancer. In this study we compared 12 versus 6 months of adjuvant trastuzumab. Patients and methods : Axillary node-positive or high-risk node-negative women with HER2-positive early breast cancer were randomized to receive 12 or 6 months of adjuvant trastuzumab concurrently with dose-dense, G-CSF-supported docetaxel (75mg/m2 every 14 days for 4 cycles). All patients received upfront dose dense, G-CSF-supported FEC (5-fluorouracil 700mg/m2, epirubicin 75mg/m2, cyclophosphamide 700mg/m2 every 14 days for 4 cycles). Randomization was performed before commence of chemotherapy. The primary endpoint was the 3-year disease-free survival (DFS). Results : 481 patients were randomized to receive 12 months (n=241) or 6 months (n=240) of adjuvant trastuzumab. Chemotherapy was completed in 99% and 98% of patients, while trastuzumab therapy in 100% and 96% of patients in the 12- and 6-month group, respectively. After 47 and 51 months of median follow-up, there were 17 (7.1%) and 28 (11.7%) disease relapses in the 12- and 6-month groups (p=0.08). The 3-year DFS was 95.7% versus 93.3% in favor of the 12-month treatment group (HR=1.57; 95%CI=0.86 to 2.10; p=0.137). There was no difference in terms of overall survival and cardiac toxicity between the two groups. Conclusions : Our study failed to show non-inferiority for the 6-month arm. The results further support the current standard of care that is administration of adjuvant trastuzumab for 12 months.