Outcomes for women with operable HER2-positive breast cancer were similar whether they received standard combination chemotherapy with either concurrent or sequential paclitaxel/trastuzumab, long-term results of the phase 3, randomized American College of Surgeons Oncology Group Z1041 trial showed.
Among 280 women with HER-2 positive breast cancer followed for a median of 5.1 years, there were no significant differences in either pathological complete response rates (pCR), disease-free survival (DFS), or overall survival with either concurrent or sequential therapy, wrote Aman U. Buzdar, MD, from the University of Texas MD Anderson Cancer Center, Houston, and his colleagues.
“A previous publication of this study’s primary analysis reported that breast pCR in patients treated with paclitaxel and trastuzumab followed by FEC [fluorouracil, epirubicin, cyclophosphamide] and trastuzumab did not differ significantly from that of patients receiving FEC followed by paclitaxel and trastuzumab. We now report the findings concerning the secondary outcomes, that is, with a median follow-up of approximately 5 years, DFS is similar among the two treatment arms,” they wrote in JAMA Oncology.
The purpose of the current analysis was to evaluate long-term outcomes associated with the two treatment approaches.
In the trial, conducted at 36 centers in the continental United States and Puerto Rico, 280 women (median age, 50 years; range, 28-76 years) were treated with 500 mg/m2 of fluorouracil, 75 mg/m2 epirubicin, and 500 mg/m2 cyclophosphamide every 3 weeks for 12 weeks with concurrent weekly paclitaxel at 80 mg/m2 and trastuzumab at 2 mg/kg – after an initial dose of 4 mg/kg – or the same paclitaxel/trastuzumab combination delivered weekly for 12 weeks, followed by FEC every 3 weeks with weekly trastuzumab for 12 weeks.
Women who also had hormone receptor–positive disease received endocrine therapy. Radiotherapy was delivered at the discretion of the attending physician.
As noted, there were no differences in either DFS rates (adjusted hazard ratio, 1.02; P = .96) or overall survival rates (adjusted HR, 1.17; P = .73) between the trial arms.
The authors concluded that “concurrent administration of trastuzumab with FEC was not found to offer additional clinical benefit and is not warranted.”
The study was supported by grants to participating institutions from the National Cancer Institute. Dr. Buzdar reported no conflicts of interest. Three coauthors reported research support, consulting fees, travel support, and/or other relationships with multiple companies.
SOURCE: Buzdar AU et al. JAMA Oncol. 2018 Sept 6. doi: 10.1001/jamaoncol.2018.3691.