Neither fulvestrant alone nor fulvestrant plus anastrozole improved the endocrine-sensitive disease rate (ESDR) versus anastrozole alone as neoadjuvant endocrine therapy in postmenopausal women with locally advanced estrogen receptor-positive HER2-negative (ER+ HER2–) breast cancer in the phase 3 ALTERNATE trial.
The ESDRs were 22.7% in 431 evaluable patients randomized to receive fulvestrant alone, 20.5% in 434 patients who received fulvestrant + anastrozole, and 18.6% in 434 who received anastrozole alone, Cynthia X. Ma, MD, PhD, reported as part of the American Society of Clinical Oncology virtual scientific program.
, said Dr. Ma, a professor at Washington University in St. Louis.
Study subjects had a median age of 64 years, clinical stage II/III ER+ HER2– breast cancer, and were randomized 1:1:1 between February 2014 and November 2018 to receive 6 months of treatment with 500 mg of intramuscular fulvestrant given every 4 weeks following a loading dose, fulvestrant plus a 1 mg daily oral does of anastrozole, or anastrozole alone prior to breast conserving surgery.
The groups were similar with respect to baseline characteristics, and more than 70% were eligible for breast conserving surgery prior to the start of neoadjuvant therapy, Dr. Ma noted, adding that the treatments were well tolerated.
Grade 3 or 4 adverse events were rare, and the percentage of patients experiencing arthralgia, myalgia, or hot flashes was low and similar across arms, she said.
“Neoadjuvant therapy downstages the tumor and improves the rate of breast conserving surgery,” Dr. Ma said, adding that pathologic tumor size, nodal status, Ki67 level, and ER status of resected tumors after neoadjuvant therapy have been shown to be independent prognostic factors for relapse-free survival.