Comparison of recurrence and outcome patterns shows that current treatments for breast cancer are more effective than previous therapies, according to research published in the Journal of Clinical Oncology.
Rachel J.D. Cossetti, M.D., of the Vancouver Cancer Centre in Canada, and colleagues analyzed patterns of relapse for women with biopsy-proven stage I to stage III breast cancer who were diagnosed between 1986 and 1992 (cohort 1, or C1) or between mid-2004 and 2008 (cohort 2, or C2). Each cohort had 3,589 patients.
The researchers found the following distribution of breast cancer subtypes: estrogen-receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative, 70.8 percent; ER-negative/HER2-negative, 15.8 percent; ER-positive/HER2-positive, 6.9 percent; and ER-negative/HER2-positive, 6.6 percent. In the initial five intervals, differences in hazard rate of relapse (HRR) between the cohorts were greater for HER2-positive and ER-negative/HER2-negative breast cancer.
For all disease stages and grades, the HRR decreased in C2 compared with C1. The hazard rate of death also decreased for C2 versus C1 but to a lesser extent.
“Although current treatments are more effective, we still see late relapses in patients with ER-positive tumors and an early peak of recurrence in patients with ER-negative cancers,” the authors write.