(ChemotherapyAdvisor) – Patients with completely resected, isolated locoregional recurrences of breast cancer who received adjuvant chemotherapy had higher rates of disease-free survival (DFS) and overall survival (OS), a study reported during the 2012 CTRC-AACR San Antonio Breast Cancer Symposium.
“This is the first randomized controlled study that shows that adjuvant chemotherapy works in these patients,” said Stefan Aebi, MD, head of the division of medical oncology at Luzerner Kantonsspital in Luzern, Switzerland.
From 2002-2010, Dr. Aebi and colleagues from the Breast International Group, the National Surgical Adjuvant Breast and Bowel Project, and the International Breast Cancer Study Group randomly assigned 162 patients with isolated local and regional recurrences of breast cancer in the CALOR (Chemotherapy as Adjuvant for Locally Recurrent breast cancer) trial to at least four courses of multidrug chemotherapy selected at the discretion of the investigator (n=85) or no treatment (n=77; control arm).
“Slow accrual led to premature closure of the trial before achieving the planned sample size of 265,” Dr. Aebi noted.
Baseline characteristics were balanced between the two arms; median age was 56 years (range, 38-71 years) in the chemotherapy arm and 56 years (range, 31-81 years) in the control arm. At the time of recurrence, 76% of patients in the chemotherapy arm and 82% in the control arm were postmenopausal. Median disease-free interval from primary surgery to recurrence was 5 years (range, 0.3-32 years) in the chemotherapy arm and 6 years (range, 0.4-22 years) in the control arm. In the chemotherapy arm, 58% had received prior adjuvant chemotherapy, as did 68% of controls.
At a median follow up of 4.9 years, 5-year DFS was 69% in the chemotherapy arm vs 57% in the control arm (HR 0.59; 95% CI 0.35–0.99; P=0.046); 5-year OS was 88% vs 76% (HR 0.41; 95% CI 0.19–0.89; P=0.02), respectively.
These results remained significant after controlling for location of recurrence, disease-free interval, estrogen-receptor status, and prior adjuvant chemotherapy.
Adjuvant chemotherapy was particularly effective in patients with estrogen-receptor negative recurrences, Dr. Aebi noted. Five-year DFS was 67% in the chemotherapy arm vs 35% in the control arm (HR=0.32, 95% CI [0.14-0.73] P=0.007) and 5-year OS, 79% vs 69% (HR=0.43, 95% CI [0.15-1.24] P=0.12). For patients with estrogen-receptor positive disease, 5-year DFS was 70% vs 69% (HR=0.94, 95% CI [0.47-1.89] P=0.87) and OS, 94% vs 80% (HR=0.40, 95% CI [0.12-1.28] P=0.12).
This research was funded by the National Cancer Institute, the Swiss Cancer League, and other national cancer research agencies.