decrease in Ki67 with neoadjuvant antihormonal treatment predicts outcome/prognosis

[Lani]

forER+ breastcancer--articleNot online yet, so I don't know if they examined her2 status

Biomarker May Forecast Probability of Recurrence in Breast Cance [Eureka News Service]
Testing tumors for a protein called Ki67 after short-term treatment for breast cancer may help doctors predict whether a patient is likely to have a recurrence, a new study shows.

The presence of Ki67 indicates tumor cell growth, and researchers have used Ki67 measurements as a marker of whether experimental cancer treatments effectively stop cancer growth. To determine whether this marker also indicates a clinical benefit, such as improved recurrence-free survival, Mitch Dowsett, Ph.D., of The Royal Marsden Hospital, in London, and colleagues studied Ki67 levels in tumor biopsy samples taken before and after 2 weeks of presurgical treatment with anastrozole, tamoxifen, or both drugs from 158 women with hormone receptor-positive breast cancer.

The researchers found that higher Ki67 expression after 2 weeks of presurgical therapy was associated with worse recurrence-free survival. There was no association between the Ki67 level before therapy and recurrence-free survival. They also found that larger tumor size before therapy and lower estrogen receptor level after 2 weeks of treatment were associated with worse recurrence-free survival.

"Measurements of tumor Ki67 expression after short-term endocrine treatment may improve the prediction of recurrence-free survival for breast cancer patients," the authors conclude. They add that larger studies are needed to confirm the results before such testing is made widely available to patients.


ABSTRACT: Prognostic Value of Ki67 Expression After Short-Term Presurgical Endocrine Therapy for Primary Breast Cancer [Journal of the National Cancer Institute]
Tumor expression of the proliferation antigen Ki67 is widely used to assess the prognosis of cancer patients. A change in the expression of Ki67 after short-term exposure of patients to therapeutic agents is frequently used as a pharmacodynamic marker of efficacy, particularly among breast cancer patients before undergoing surgery. To determine the clinical significance of the level of tumor cell proliferation during endocrine therapy for breast cancer, we measured the expression of Ki67 in tumor biopsy samples taken before and after 2 weeks of presurgical treatment with anastrozole or tamoxifen or the combination of anastrozole plus tamoxifen in 158 patients with hormone receptor-positive primary disease. In a multivariable analysis, we found that higher Ki67 expression after 2 weeks of endocrine therapy was statistically significantly associated with lower recurrence-free survival (P = .004) whereas higher Ki67 expression at baseline was not. Larger baseline tumor size and lower estrogen receptor level after 2 weeks of treatment were also statistically significantly associated with poorer recurrence-free survival (P<.001 and P = .04, respectively). Our data indicate that measurements of tumor Ki67 level after short-term endocrine treatment may improve the prediction of recurrence-free survival by integrating the prognostic value of Ki67 level at baseline with changes in Ki67 level that are associated with treatment benefit.