Could lymph node evaluation be eliminated in nearly 50% of women with early stage ER/PR positive breast cancer?

The Society of Surgical Oncology introduced guidance discouraging routine axillary staging in women 70 years or older with invasive, clinically node negative, hormone-receptor positive breast cancer. Due to concerns this could result in patients missing necessary treatment, researchers from the Mayo Clinic developed a rule to distinguish between those at low/high-risk of having positive nodes. The purpose of this study was to validate the Mayo Clinic rule in women of all ages. A retrospective review was conducted on patients seen in one breast surgeon’s practice from January 1, 2006 through March 1, 2018. The Mayo Clinic rule was applied, and accuracy was evaluated. Utilizing the Mayo Clinic rule, 46.8% (n = 289) of women met low-risk criteria. Unexpected positive lymph nodes in low-risk women was 10.0% (n = 29), which was similar to the Mayo Clinic study finding (7.8%, P = 0.167). These data suggest the Mayo Clinic rule is reproducible. Nearly 50% of women with hormone receptor positive breast cancer could avoid axillary staging, but about 10% will have unexpected positive lymph nodes. •The Mayo clinic rule was applied to all patients in one breast surgeon’s practice.•Nearly 50% of women were considered low-risk by the rule.•Unexpected positive lymph nodes were found in 10% of low-risk women.•This study suggests that the Mayo clinic rule is reproducible.