Genetic Test Reduces Post-Surgery Chemotherapy for Breast Cancer Patients

A genetic test identified a large group of patients for whom five-year distant metastasis-free survival was equally good whether or not they received adjuvant chemotherapy, chemotherapy given post-surgery.

Among patients with early-stage breast cancer who were considered at high risk for disease recurrence based on clinical and biological criteria, according to results from the randomized, phase III microarray in node negative disease may avoid chemotherapy.

A large group of international scientists led by those at the Jules Bordet Institute (Brussels, Belgium) enrolled in a trial 6,693 women out of 11,288 women screened, who had undergone surgery for early-stage breast cancer, from 111 centers in nine countries, from 2007 to 2011. All participants were categorized as low or high risk for tumor recurrence in two ways: first, through analysis of tumor tissue using a 70-gene profile test at a central location; and second, using a tool that calculates risk of breast cancer recurrence based on common clinical and biological criteria.

The participants were then divided into four groups: 2,745 were categorized as having low risk of recurrence by both risk-assessment methods (G-low/C-low), 1,806 were categorized as having high risk of recurrence by both risk-assessment methods (G-high/C-high), 592 were categorized as having high risk of recurrence by MammaPrint (Agendia Inc.; Amsterdam, The Netherlands) and low risk of recurrence by Adjuvant! Online (Adjuvant Inc.; San Antonio, TX, USA) (G-high/C-low), and 1,550 were categorized as having low risk of recurrence by MammaPrint and high risk of recurrence by Adjuvant! Online (G-low/C-high).

Among the 3,356 patients enrolled in the trial who were categorized as having a high risk of breast cancer recurrence based on common clinical and pathological criteria (C-high), treatment according to MammaPrint reduced the chemotherapy prescription by 46%. Five-year distant metastasis-free survival for the discordant G-low/C-high group was in excess of 94%, whether patients received adjuvant chemotherapy (CT) or not. There was an absolute 14% reduction in adjuvant CT administration when using the G versus C treatment strategy.

Martine Piccart, MD, PhD, head of the Medicine Department at the Jules Bordet Institute, and lead author of the study, said, “At present, most oncologists make recommendations for adjuvant chemotherapy after considering common clinical and biological criteria such as patient's age, and the stage and grade, as well as the hormonal receptor and human epidermal growth factor receptor 2 (HER2) status of his or her tumor. The MINDACT trial results provide level 1A evidence that using MammaPrint could change clinical practice by substantially de-escalating the use of adjuvant chemotherapy and sparing many patients an aggressive treatment they will not benefit from.” The study was presented at the American Association for Cancer Research (AACR) Annual Meeting, held April 16–20, 2016, in New Orleans (LA, USA).

Related Links:
Jules Bordet Institute
Agendia
Adjuvant