Adjuvant chemotherapy plus nine weeks or one year of adjuvant trastuzumab for HER2-positive breast cancer: long-term follow-up of the SOLD trial

The standard adjuvant treatment for patients with HER2-positive breast cancer is chemotherapy plus one year of trastuzumab. Shorter duration of trastuzumab administration may improve cardiac safety, but more information is needed about the effect on survival. The randomized SOLD trial, with 2174 patients at 65 centers in 7 European countries, compared adjuvant chemotherapy plus 9 weeks of trastuzumab administration versus adjuvant chemotherapy plus 1 year of trastuzumab administration. Long-term follow-up results of the trial have now been published. At median follow-up of 8.1 years (IQR 8.0-8.9), disease-free survival was significantly longer in the 1-year group than in the 9-weeks group. There were no significant differences between the groups for distant disease-free survival or overall survival. Four patients died of cardiac cause: three in the 9-weeks group and one in the 1-year group. The authors conclude that 1 year versus 9 weeks of adjuvant trastuzumab is associated with improved disease-free survival among patients with early-stage HER2-positive breast cancer.