More Patients With Early-Stage Breast Cancer May Be Able to Avoid Chemotherapy in the Future
Women with early-stage breast cancer who had an intermediate risk recurrence score from a 21-gene expression assay had similar outcomes, regardless of whether they received chemotherapy, a new study from The University of Texas MD Anderson Cancer finds.
The research, published by Barcenas et al in Cancer, still needs to be validated in an ongoing international trial. If verified, women with intermediate scores may one day be able to avoid chemotherapy as standard of care.
Historically, the management of women with early-stage breast cancer has been aggressive, explained Carlos H. Barcenas, MD, Assistant Professor, Breast Medical Oncology, with many stage I and all stage II patients receiving chemotherapy.
Fortunately, over the last decade, research discoveries across the breast cancer landscape have evolved such that less is now more, for women with early-stage disease, said Dr. Barcenas.
“Through years of research discoveries, it became clear that we were overtreating many women with breast cancer, especially those with early-stage disease. In addition to chemotherapy’s obvious side effects, there were also long-term complications for these women as survivors,” explained Dr. Barcenas.
TAILORx
One such practice-changing clinical discovery was that a 21-gene expression assay could predict the risk of recurrence among some patients with early-stage breast cancer. In 2015, initial results from the international clinical trial TAILORx found that women with hormone receptor–positive, HER2-negative, and lymph node–negative early-stage disease with a low recurrence score of 0 to 10 could have chemotherapy omitted altogether.
While the findings dramatically changed care for women with a low recurrence score, many questions remain regarding the management of women with an intermediate recurrence score, defined by this trial as a score of 11 to 25. The conversation to give or not give chemotherapy is one Dr. Barcenas often has in his clinic, he said.
“This study evolved out of my patients’ frustration that I could not provide a definitive answer to their paramount question: ‘Do I need chemotherapy?’ As we wait for the TAILORx findings, we decided to look at MD Anderson’s own experience to glean insight on how best to care for these women with an intermediate risk recurrence score,” said Dr. Barcenas.
Study Findings
For the retrospective, single-institution analysis, Dr. Barcenas and his colleagues identified 1,424 patients with stage I and II breast cancer treated at the institution between 2005 and 2011. All underwent the 21-gene expression assay. In addition, the women were hormone receptor–positive, HER2-negative, and lymph node–negative. None of the MD Anderson patients identified participated in the TAILORx trial.
Dr. Barcenas and his colleagues used the same recurrence score cutoff scores as the TAILORx trial. Of the MD Anderson patients, the recurrence score distribution was: 297 (21%) scored 0 to 10; 894 (63%) scored 11 to 25; and 233 (16%) scored greater than 25. Of those groups, 1.7%, 15%, and 73.4% received chemotherapy, respectively.
With a median follow-up of 58 months, those with a recurrence score of 11 to 25 had an invasive disease–free survival rate at 5 years of 92.6%, regardless of whether patients received chemotherapy or not.
Among those patients who did not receive chemotherapy, the estimated rates of invasive disease–free survival and overall survival were 93% and 98%, respectively, which was comparable to those who did receive chemotherapy.
The study has a number of limitations, said Dr. Barcenas. 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.
While not practice-changing, the findings do provide more information when discussing the benefits of chemotherapy in early-stage breast cancer patients should their recurrence score score be 11 to 25.
“Our research is likely the most comprehensive data we will have about this patient population until the international randomized trial is published,” said Dr. Barcenas. “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.”
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
