Breast Cancer Relapse Prediction
Reported September 25, 2008
(Ivanhoe Newswire) — There may be a new way to predict whether a breast cancer patient can avoid chemotherapy or whether she needs aggressive therapy because shes at a high risk of relapse.
Researchers at the Washington University School of Medicine in St. Louis have developed a model — called the preoperative endocrine index (PEPI) — that predicts relapse in women with stage two or three breast cancer who have had endocrine therapy, such as tamoxifen or letrozole, before surgery to remove the tumor.
The study looked at surgical tumor samples from two previous studies in which women had endocrine treatment for several months before their surgery. Researchers validated the PEPI model in 203 women who were already treated in another clinical trial called IMPACT.
Results show the tumor stage, nodal status, Ki67 expression level, and ER status in the samples were associated with the breast cancer not relapsing. PEPI accurately predicted relapse-free survival in the women in the IMPACT study. None of the patients with the lowest PEPI score in the IMPACT trial had relapsed during the follow-up period — a median of 60.3 months.
Of particular note, patients with low pathological stage (stage 1 or 0) and a favorable biomarker profile (PEPI score 0) at surgery had such a low rate of relapse that further adjuvant systemic therapy beyond continuation of an endocrine agent appears unnecessary, study authors write. In striking contrast, patients with high pathological stage disease at surgery and a poor biomarker profile (PEPI group 3) had a statistically significant higher risk of early relapse, more typical of ER [negative] disease, and therefore should be offered all appropriate adjuvant treatments available.
Researchers say they need longer follow-up data to validate PEPIs ability to predict overall survival.
SOURCE: Journal of the National Cancer Institute, published online September 23, 2008