Abstract

Background: Traditionally, breast cancer is staged using TNM criteria: tumor size (T), nodal status (N), and metastasis (M). The Oncotype DX assay provides a recurrence score (RS) based on genomics that predicts the likelihood of distant recurrence in estrogen receptor–positive (ER+)/human epidermal growth factor receptor 2–negative (HER2–)/lymph node–negative (LN–) tumors.Methods: We retrospectively reviewed the medical records of patients with ER+/HER2–/LN– breast cancer tumors who were evaluated between 2007 and 2017 with Oncotype DX RS. We compared the RS to tumor size, patient age, progesterone receptor (PR) status, and LN immunohistochemistry to assess for factors that may independently predict recurrence risk. We also compared tumor size to tumor grade.Results: The data set included 296 tumors: 248 ER+/PR-positive (PR+)/HER2– and 48 ER+/PR-negative (PR–)/HER2–. RS ranged from 0 to 66, patient age ranged from 33 to 77 years, and tumor size ranged from 1 to 65 mm. No significant correlation was found between age and RS (r=–0.073, P=0.208). PR– tumors had a significantly higher RS regardless of size (PR– mean RS 30.8 ± 12.7; PR+ mean RS 16.3 ± 7.3; t(53)=7.6, P<0.0001). No significant correlation was seen between tumor size and RS for all tumors (r=–0.028, P=0.635), and this finding remained true for the PR+ tumor subgroup (r=0.114, P=0.072). However, a significant negative correlation was seen between tumor size and RS in the PR– subgroup (r=–0.343, P=0.017). Further analysis to ensure that differences in tumor grade did not account for this correlation showed equal distribution of well differentiated, moderately differentiated, and poorly differentiated tumors with no significant correlation between tumor size and grade.Conclusion: Increasing tumor size may not be associated with increasing biological aggressiveness. Traditionally, smaller tumors are thought to be lower risk and larger tumors higher risk, with a tendency to use chemotherapy with large tumors. However, our data showed a negative correlation between tumor size and RS in the PR– subgroup. A tumor with PR negativity that reaches a large size without metastasizing may suggest a favorable tumor biology. These tumors may not receive as much benefit from chemotherapy as previously thought. Also, the higher RS seen in smaller PR– tumors may demonstrate PR– status as a predictor for higher risk of distant recurrence. We propose that all tumors meeting the ER+/PR–/LN– criteria, regardless of size, should be considered for genotyping, with the RS used to guide chemotherapy benefit.

Highlights

  • Breast cancer is the most common non–skin cancer worldwide

  • After receiving institutional review board approval for a retrospective medical records review, we obtained data from the electronic medical record and the Genomic Health Physician Portal for patients with estrogen receptor (ER)+/human epidermal growth factor receptor 2 (HER2)–/LN– breast cancer who were seen at Ochsner Health between 2007 and 2017 and had an Oncotype DX report

  • One tumor was from a male patient, and the remainder were from female patients

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Summary

Introduction

Breast cancer is the most common non–skin cancer worldwide. Approximately 1 in 8 women will be diagnosed with invasive breast cancer in their lifetimes, accounting for an estimated 276,480 women in 2020 alone. Volume 20, Number 4, Winter 2020 to early screening measures, approximately 64% of newly diagnosed patients are lymph node negative (LN–) without obvious metastatic disease. These screening measures have led to a decline in breast cancer mortality; 1 in 39 women will die from this diagnosis.[1] Most. A significant negative correlation was seen between tumor size and RS in the PR– subgroup (r=–0.343, P=0.017). A tumor with PR negativity that reaches a large size without metastasizing may suggest a favorable tumor biology These tumors may not receive as much benefit from chemotherapy as previously thought. We propose that all tumors meeting the ER+/PR–/LN– criteria, regardless of size, should be considered for genotyping, with the RS used to guide chemotherapy benefit

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