Sentinel lymph node biopsy may not be necessary for some older women with breast cancer
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Similar proportions of older women with node-negative and node-positive early breast cancer had Oncotype Dx breast recurrence scores that would qualify them for adjuvant chemotherapy, according to study results.
The findings, presented during an American Society of Breast Surgeons Annual Meeting press briefing, indicate sentinel lymph node biopsy may not be useful in making adjuvant chemotherapy decisions for patients aged 70 years or older with hormone receptor-positive, HER2-negative, American Joint Committee on Cancer (AJCC) clinical stage I breast cancer.
“However, certain tumor factors may be helpful, such as tumor grade, tumor size and progesterone receptor status,” Katharine Yao, MD, vice chair of research for NorthShore University Health System and clinical professor of surgery at Pritzker School of Medicine at The University of Chicago, said during the briefing.
Rationale and methodology
The Society of Surgical Oncology and American Society of Breast Surgeons have adopted Choosing Wisely guidelines that recommend against routine use of sentinel node biopsies for clinically node-negative women aged 70 years or older with early-stage hormone receptor-positive, HER2-negative invasive breast cancer. Yao pointed out that the guidelines provide for individual consideration of axillary staging “if the results may impact radiation therapy recommendations and/or systemic therapy decisions.” Moreover, use of sentinel node biopsy remains high, with rates as high as 88.5% in 2018.
“We suppose that many surgeons continue to perform sentinel node biopsy for the patients to make adjuvant chemotherapy decisions,” she said.
Two previous studies showed postmenopausal women with a recurrence score of 26 or greater using the 21-gene Oncotype Dx assay (Exact Sciences) would derive a survival benefit from adjuvant chemotherapy in addition to hormonal therapy, according to Yao.
“Therefore, we wanted to see if the Oncotype Dx score would be a better differentiator of who would benefit from adjuvant chemotherapy than a sentinel node biopsy,” she said.
Yao and colleagues also sought to examine distribution of the recurrence scores and identify clinical and demographic factors that correlated with a high score among this older patient population.
The analysis included 28,338 patients aged 70 years or older in the National Cancer Database who underwent treatment between 2010 and 2018 for hormone receptor-positive, HER2-negative, AJCC clinical stage T1 and T2 breast cancers. Pathology examination showed 5,389 had node-positive disease and 22,698 had node-negative disease.
Researchers compared Oncotype scores between the node-positive and node-negative patients and used multivariable logistic regression, adjusted for patient and tumor characteristics, to evaluate factors associated with a score of 26 or greater.
Key findings
Results showed similar proportions of patients with recurrence scores of 26 or greater in the node-negative (13.1%) and node-positive (14.7%) groups.
A grade 3 tumor vs. grade 1 appeared most strongly associated with a high score for node-negative (OR = 18; 95% CI, 15.57-20.81) and node-positive (OR = 12.61; 95% CI, 9.16-17.34) patients, followed by PR status (OR = 7.19; 95% CI, 6.51-7.93 for node-negative; OR = 6.53; 95% CI, 5.22-8.16 for node-positive).
Patients with tumors greater than 2 cm also had a significantly higher likelihood of having a recurrence score of 26 or greater (P < .0001), as did those in the node-negative group covered by Medicaid (OR = 1.45; 95% CI, 1.04-2.03).
Hispanic patients had a lower likelihood of having a recurrence score of 26 or greater compared with Black and Asian patients.
Limitations of the study include selection bias, as Oncotype Dx testing is ordered at the discretion of the clinician.
Implications
After the presentation, Yao said many clinicians may be using sentinel node biopsy to make adjuvant radiation decisions, but it probably should not be used to make adjuvant chemotherapy decisions.
“Perhaps an Oncotype test might be a better option, or even just looking at the clinical tumor factors and the patient’s comorbidities or health status,” she said.
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Nicholson K, et al. Oncotype Dx scores and nodal status in patients over 70 years old — Continue to Choose Wisely. Presented at: American Society of Breast Surgeons Annual Meeting (hybrid meeting); April 6-10, 2022; Las Vegas.
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