Positive lymph node status may not be a reliable indicator of the need for adjuvant chemotherapy, and sentinel node biopsy may be unnecessary in older women with certain low-risk cancers, according to a new study presented by Nicholson et al at the American Society of Breast Surgeons 23rd Annual Meeting. The study examined the correlation between nodal status and 21-gene recurrence score, which reflects a tumor’s individual biology and is considered among the most reliable tools for chemotherapy decision-making.
While 2016 Choosing Wisely guidelines advise against performing sentinel node biopsies on women aged 70 or older with hormone receptor–positive breast cancer, studies show physicians continue to do so for 65% to 85% of these patients. Lead study author Katharine Yao, MD, Vice Chair of Research, NorthShore University Health System and Clinical Professor of Surgery at the Pritzker School of Medicine, University of Chicago, hypothesized that one reason surgeons continue to perform sentinel node biopsy on this patient population is to obtain nodal status for adjuvant chemotherapy decisions. However, the new study found that regardless of their nodal status, a similar proportion of these women had 21-gene recurrence scores qualifying them for adjuvant chemotherapy.
More Study Information
Using the National Cancer Database, researchers analyzed 28,338 patients aged 70 and older who were treated for hormone receptor–positive, HER2-negative, AJCC clinical stage T1-T2 breast cancers between 2010 and 2018. They examined the correlation of nodal status with 21-gene recurrence results and also identified other clinical and demographic factors associated with high 21-gene recurrence scores and the need for chemotherapy. Of the patients studied, 5,640 (19.9%) were node-positive and 22,698 (80.1%) were node-negative on pathology examination. Overall, the proportion of patients with a 21-gene recurrence score greater than or equal to 26 was 3,330 (13.1%) for node-negative patients and 740 (14.7%) for node-positive patients. A score equal to or greater than 26 typically indicates that chemotherapy will be beneficial.
For both node-negative and -positive patients, a grade 3 tumor was associated most strongly with a high 21-gene recurrence score. Following this was negative progesterone receptor status. Additionally, women with tumors larger than 2 cm and patients covered by Medicaid were also more likely to have a cancer recurrence score greater than or equal to 26. Hispanic patients were less likely to have a 21-gene recurrence score qualifying them for chemotherapy compared to Black and Asian women.
“Sentinel node biopsy has some associated morbidity and is an additional procedure in the operating room,” said Dr. Yao. “However, it may not provide the necessary information for decision-making about adjuvant chemotherapy. For this patient population, consideration of other tumor factors—including possibly an Oncotype score—may be more useful than nodal status.”
“Women may request sentinel node biopsies because cancer that has spread to the lymph nodes has become virtually synonymous with poor prognosis in the popular media,” noted Dr. Yao. “However, we are learning that there is more to tumor biology then just nodal status. Sentinel node biopsy for women older than age 70 with hormone receptor–positive breast cancer is not really helpful for making adjuvant chemotherapy decisions. While eliminating sentinel node biopsy may seem counterintuitive to some patients, it is not likely to have a major impact on their outcomes.”
