Neoadjuvant Chemo May Top Endocrine Therapy in Strongly HR-Positive, ERBB2-Negative Breast Cancer

By Megan Brooks

March 17, 2021

NEW YORK (Reuters Health) - For women with strongly HR-positive and ERBB2-negative invasive ductal carcinoma (IDC), neoadjuvant chemotherapy is preferable to neoadjuvant endocrine therapy, a new study suggests.

"Although neoadjuvant chemotherapy (NACT) is conventionally used to downstage locally advanced and unresectable primary breast cancers, numerous studies have identified neoadjuvant endocrine therapy (NET) as an alternative to chemotherapy for strongly HR-positive and ERBB2-negative tumors," Dr. Szu-Yuan Wu, director of the Cancer Center at Lo-Hsu Medical Foundation, Lotung Poh-Ai Hospital, in Yilan, Taiwan, told Reuters Health.

"We suggest that NACT may be considered the first choice for neoadjuvant treatment for patients with strongly HR-positive and ERBB2-negative IDC," said Dr. Wu.

Using the Taiwan Cancer Registry database, the researchers analyzed data on 640 women with strongly HR-positive and ERBB2-negative IDC who underwent NET (23%) or NACT (77%).

In the multivariate Cox regression analysis, the adjusted hazard ratio for all-cause mortality was significantly higher in the NET group (aHR, 2.67; P<0.001).

Rates of breast-conserving surgery were similar with NACT and NET, in line with prior studies. But NET was associated with inferior survival, even among women with strongly HR-positive and ERBB2-negative breast IDC sensitive to NET, the researchers report.

In multivariable analysis, the preneoadjuvant treatment factors independently associated with poor prognosis for overall survival were older age, premenopausal status, Charlson Comorbidity Index (CCI) score of 2 or greater, advanced cT stage (2 to 4), advanced cN stage (1 to 3), and poor differentiation (grade 2 or 3).

More than 90% of women in the cohort had a CCI score of 0 to 1 and outcomes might be hard to extrapolate to women with multiple comorbidities (CCI score 2 or greater receiving NACT or NET), the researchers note in JAMA Network Open.

To their knowledge, this is the first head-to-head study to compare NACT and NET with regard to outcomes in this specific patient population.

Dr. Wu told Reuters Health, "According to our findings, NACT for strongly HR-positive and ERBB2-negative breast IDC is associated with better overall survival. This finding should be considered in clinical practice and in future prospective clinical trials."

In an email to Reuters Health, Dr. Amy Tiersten, professor of medicine, hematology and medical oncology at Icahn School of Medicine at Mount Sinai in New York said these study results are "disappointing and are in contrast with large randomized adjuvant clinical trials that show that, in many cases, chemotherapy can be avoided in hormone receptor-positive, HER2/neu-negative breast cancer."

"The results, of course, must be taken with a grain of salt as it is not a randomized prospective trial," said Dr. Tiersten, a breast oncologist at Dubin Breast Center, Mount Sinai Hospital, who was not involved in the study.

The study had no commercial funding and the authors have declared no conflicts of interest.

SOURCE: JAMA Network Open, online March 12, 2021.