21-Gene Expression Assay May Clarify Need For Chemotherapy in Early Breast Cancer

MedicalResearch.com Interview with:

Carlos H. Barcenas M.D., M.Sc. Assistant Professor Department of Breast Medical Oncology MD Anderson Cancer Center

Dr. Carlos Barcenas

Carlos H. Barcenas M.D., M.Sc.
Assistant Professor
Department of Breast Medical Oncology
MD Anderson Cancer Center

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Over the last decade we have realized that we were over-treating many early stage breast cancer patients. In addition to the chemotherapy’s obvious side effects, there are also long term complications for breast cancer survivors. Since 2005, we are using a 21-gene-expression assay that predicts the risk of distant recurrence among early stage breast cancer patients. In 2015, initial results from the international clinical trial, TAILORx, found that women with hormone receptor positive, HER2 and lymph node negative early stage disease that had a low recurrence score (RS) of 0-10 from this assay could have chemotherapy omitted altogether. While these findings changed care for women with a low RS, questions remain regarding the management of women with an intermediate RS, defined by this trial as a RS of 11-25. For our retrospective, single-institution study we identified 1,424 stage I and II breast cancer patients with hormone receptor positive, HER2 and lymph node negative treated between 2005 and 2011 who underwent the 21-gene expression assay. The RS distribution was: 297 (21 percent) scored 0–10; 894 (63 percent) scored 11-25; and 233 (16 percent) scored >25.

Of those groups, 1.7, 15 and 73.4 percent received chemotherapy, respectively. With a median follow up of 58 months, those with a RS of 11-25 had an invasive disease-free survival (IDFS) rate at five years of 92.6 percent, regardless if patients received chemotherapy or not. Among those patients who did not receive chemotherapy, the estimated rates of IDFS and overall survival was 93 percent and 98 percent, respectively, which was comparable to those who did receive chemotherapy.

MedicalResearch.com: What should readers take away from your report?

Response: While not practice changing, the findings do give more information when discussing the benefits of chemotherapy in early-stage breast cancer patients, should the RS score be 11-25. Our research is likely the most comprehensive data we will have about this patient population until the final results of TAILORx are published. Hopefully our findings will serve as a discussion point between physicians and patients as they are making critical decisions regarding a woman’s breast cancer care.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: We will continue following these patients over time with the expectation of more events and to compare our results with TAILORx once this gets published

MedicalResearch.com: Is there anything else you would like to add?

Response: The study has a number of limitations. Due to a relatively short follow-up and the few number of outcome events, the researchers feel that the benefit of chemotherapy cannot be ruled out yet in this group of patients.

MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.


Carlos H. Barcenas, Akshara Raghavendra, Arup K. Sinha, Masood Pasha Syed, Limin Hsu, Modesto G. Patangan, Mariana Chavez-MacGregor, Yu Shen, Gabriel H. Hortobagyi, Vicente Valero, Sharon H. Giordano, Naoto T. Ueno, Debu Tripathy. Outcomes in patients with early-stage breast cancer who underwent a 21-gene expression assay. Cancer, 2017; DOI: 10.1002/cncr.30618

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