Breast cancer outcomes have improved significantly over the past 3 decades, with major gains in relapse-free survival and declines in mortality for all subtypes but particularly HER-2 positive breast cancer, a retrospective case-control study has found.
Researchers compared matched data from 7,178 women referred to the British Columbia Cancer Agency for breast cancer between 1986 and 1992 (C1) and mid-2004 and 2008 (C2) and found the risk of relapse halved in the second cohort, compared to the first, up to year 7 of follow-up, according to a paper published online Nov. 24 in the Journal of Clinical Oncology [doi:10.1200/JCO.2014.57.2461].
While there were similar patterns of disease relapse over time for both the estrogen receptor (ER)-negative and ER-positive patients between the two cohorts, the risk of relapse halved for ER-negative patients in the second cohort relative to the first, while the risk ratio for C2/C1 ranged from 0.26 to 0.56 in ER-positive patients.
“The greatest improvements in outcomes were achieved in the BC subtypes known to be more aggressive, namely the HER2-positive and ER-negative/HER2-negative patients,” wrote Dr. Rachel J.D. Cossetti and colleagues from the Vancouver (B.C.) Cancer Centre.The study was supported by coauthor Dr. Karen A. Gelmon, also of the Vancouver Cancer Centre.