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During the first American Society of Clinical Oncology (ASCO) Breast Cancer Symposium researchers from The University of Texas M. D. Anderson Cancer Center presented two research updates on the genomic predictors in the breast cancer.

In one poster results from two studies involving 960 patients validating a Affymetrix U133 microarray-based 200-gene index test that predicts a patient’s response to hormone-suppressing therapy (sensitivity to endocrine therapy (SET index)) are presented. It was developed by M.D. Anderson in collaboration with Nuvera Biosciences Inc.
In these two studies, the Sensitivity to Endocrine Therapy (SET) Index score predicted distant relapse free survival (DRFL) among 453 patients who received tamoxifen, an anti-estrogen therapy, for five years, but revealed no prognostic information in the absence of endocrine therapy.

“We believe this is the first genomic test to predict sensitivity to hormone therapy independent of a patient’s prognosis if no post-surgical treatment is received,” (via)

Poster abstract here.

The other poster presents results from combined use of three genomic prognostic and treatment response predictors tests in lymph node-negative breast cancer.

The 3 clinical outcome predictors are;

• A 76-gene prognostic test that indicates whether a patient is at high or low risk of the cancer recurring after surgery developed by investigators at Erasmus University (Rotterdam, Netherlands) andVeridex LLC.

• A 30-gene predictor of the cancer’s sensitivity to chemotherapy developed by M.D. Anderson investigators.

• The 200-gene index (SET) of sensitivity to hormone (endocrine) therapy developed by M.D. Anderson in collaboration with Nuvera Biosciences Inc.

The ASCO poster describes gene expression profiles analyzed from 198 patients with stage 1 or stage 2 breast cancer that had not spread to the lymph nodes and who had not been given chemotherapy or endocrine therapy after surgery.

Among the 198 patients, 55 were predicted to be at relatively low risk that the cancer would return. Of those low-risk patients, 21 were predicted to have cancer vulnerable to chemotherapy and 16 were predicted to have tumors susceptible to endocrine therapy. Two had cancers sensitive to both therapies.

Of the 143 patients predicted to have a high risk of recurrence, the analysis predicted 109 had cancer unlikely to respond to endocrine therapy, 64 were predicted to be insensitive to chemotherapy, and 38 were predicted to be unlikely to respond to both therapies (via).

Conclusion: A substantial proportion of low risk-patients appears to be highly sensitive to systemic treatment modalities, and many high-risk patients are predicted to be refractory to existing therapies. Simultaneous prediction of risk of recurrence and sensitivity to therapies may lead to more appropriate treatment decisions for individuals because the predicted sensitivity to chemotherapy and endocrine therapy could be weighed against the risk of relapse.

“Let’s say a new patient has a needle biopsy performed, and the microarray analysis of the tumor’s gene expression predicts she is at low risk of recurrence and also has cancer that is insensitive to both chemo- and endocrine therapies; in this cases the best option is relatively clear; surgery alone. However, it is important to know the sensitivity of the cancer to chemo- or endocrine therapies independent of the risk of recurrence alone. For example, a person even with low risk for cancer recurrence might elect to receive further therapy if her cancer is known to be highly susceptible to treatment.” , investigators explain.

Poster abstract here.

A collection of posters from section “familial breast cancer/genetic testing” available here.