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Many breast cancer patients can skip chemo TAILORx/MAC.12 study finds

Presented at ASCO and published in New England Journal of Medicine

Clinical trials are not always about finding a new drugs that works, sometimes they look at what treatments, or what doses, are necessary for patients.

New results from the groundbreaking “Trial Assigning Individualized Options for Treatment Rx” (TAILORx) MAC.12 breast cancer trial have been recently published in the New England Journal of Medicine and presented to an international audience at the American Society of Clinical Oncology (ASCO) annual meeting. The practice changing study indicates that there is no benefit from chemotherapy for seventy percent of women with the most common type of breast cancer.

Doctors in the US and Canada are reporting from a landmark study that used genetic testing to gauge each patient's risk and found that most women with the most common form of early-stage breast cancer can safely skip chemotherapy.

"The impact is tremendous," said the study leader, Dr. Joseph Sparano of Montefiore Medical Centre in New York. Most women in this situation don't need treatment beyond surgery and hormone therapy, and "the rest of them are receiving chemotherapy unnecessarily."

The study is the largest ever done of breast cancer treatment, and the results are expected to spare up to 70,000 patients a year in the United States and many more elsewhere the ordeal and expense of these drugs.

There was a significant contribution from the CCTG Canadian network, through combined efforts from accross the nation the trial screened 943 women and enrolled 838. Thanks to everyone who contributed to help us show that that women with a common early-stage breast cancer can safely skip chemotherapy without hurting their chances of beating the disease!

Sample of media coverage

Publication

Sparano JA, Gray RJ, Makower DF, Pritchard KI, Albain KS, Hayes DF, Geyer CE, Dees EC, Goetz MP, Olson JA, Lively T, Badve SS, Saphner TJ, Wagner LI, Whelan TJ, Ellis MJ, Paik S, Wood WC, Ravdin PM, Keane MM, Gomez Moreno HL, Reddy PS, Goggins TF, Mayer IA, Brufsky AM, Toppmeyer DL, Kaklamani VG, Berenberg JL, Abrams J, Sledge GW. Adjuvant Chemotherapy Guided by a 21-Gene Expression Assay in Breast Cancer (ONLINE). N Engl J Med 2018.
 

Background: In hormone receptor (HR)-positive, HER2-negative, axillary node (AN)-negative breast cancer, the 21-gene expression assay (Oncotype DX Recurrence Score [RS]) is prognostic for distant recurrence, prognostic for low recurrence with endocrine therapy alone if low (0-10), and predictive of chemotherapy benefit if high (26 or higher). We performed a prospective, randomized trial of endocrine therapy (ET) versus chemoendocrine therapy (CET) in women with a mid-range RS of 11-25. Methods: Eligibility criteria included women 18-75 years of age with HR-positive, HER2-negative, axillary node (AN)-negative breast cancer and tumors 1.1-5.0 cm in size (or 0.6-1.0 cm and int/high grade) and agreed to have chemotherapy assigned or randomized based on the RS. Women with a mid-range RS (11-25) were randomized to receive ET or CET. The primary endpoint was invasive disease-free survival (iDFS), and the trial was designed to show non-inferiority for ET alone by not rejecting equality (hazard ratio [HR] margin up to 1.322 for omission of chemotherapy, 1-sided type I error rate 10%, type II error rate 5%). The target sample size was adjusted to compensate for non-adherence to randomized treatment, and the protocol-specified final analysis was triggered after 835 iDFS events. Results: Of the 10,253 eligible women enrolled between 4/7/06-10/6/10, 6711 (65.5%) had a RS of 11-25 and adequate information. There were 836 iDFS events at final analysis with a median followup of 90 months. ET was non-inferior to CET for iDFS (HR 1.08, 95% confidence intervals [CI] 0.94, 1.24, p=0.26) in the intention-to-treat (ITT) population. ET was also non-inferior for distant recurrence-free interval (DRFI; HR 1.03, p=0.80), recurrence-free interval (RFI; HR 1.12, p=0.28), and overall survival (OS; HR 0.97, p=0.80). Nine year rates were similar for iDFS (83.3% vs. 84.3%), DRFI (94.5% vs. 95.0%), RFI (92.2% vs. 92.9%), and OS (93.9% vs. 93.8%). Recurrence accounted for 338 (41.6%) the first iDFS event, of which 199 (23.8%) were distant recurrences. Treatment interaction tests were significant for age (iDFS p=0.03; RFI p= 0.02), but not menopause, tumor size, grade, or RS (continuous or RS 11-15, 16-20, 21-25). Conclusions: In women with HR-positive, HER2-negative, AN-negative breast cancer and a RS of 11-25, adjuvant ET was not inferior to CET in the ITT analysis. (Funded by NCI, BCRF, and Komen Foundation.) Clinical trial information: NCT00310180