Can Oncotype Predict Recurrence Risk in Older BC Patients?

TOPLINE:

Among older women with early-stage, estrogen receptor (ER)-positive breast cancer who underwent breast-conserving surgery, the Oncotype DX Recurrence Score was not a strong predictor of recurrence risk. At 6 years, cumulative rates of local recurrence were low and did not differ significantly between low- and high-risk Oncotype score groups (1.9% vs 0.76%; P = .5).

METHODOLOGY:

While several studies have demonstrated that the Oncotype DX Recurrence Score can help predict locoregional recurrence in patients with hormone receptor-positive breast cancer, it’s less clear whether it can predict recurrence risk in certain older patients.
Researchers evaluated 1587 women aged 65 years or older with T1N0, ER-positive, progesterone receptor-positive, and HER2-negative breast cancer who underwent breast-conserving surgery from 2006 to 2018 at Memorial Sloan Kettering Cancer Center.
Patients were stratified by Oncotype DX score into low-risk (≤ 25; 92%) and high-risk (> 25; 8%) groups. The median follow-up was 74.4 months.
Primary outcomes included cumulative incidence of local recurrence and disease-free survival (DFS).
Surgical axillary staging was performed in 99.9% of patients, with 99% undergoing sentinel node biopsy and 0.8% undergoing axillary node dissection. Most patients received adjuvant radiotherapy (77% in the low-risk group and 86% in the high-risk group).

TAKEAWAY:

Cumulative incidence of local recurrence at 6 years was low and did not differ significantly between patients with low-risk and high-risk scores (1.9% vs 0.76%; P = .5), with groups also having similar DFS rates (93% vs 95%; P = .5).
Among patients who did not receive radiotherapy (n = 350), those with high-risk scores (n = 19) had similar local recurrence rates to those with low-risk scores: 6-year cumulative incidence 5.6% vs 4.2% (P = .5).
Radiotherapy was associated with significantly reduced local recurrence risk on both univariable and multivariable analyses (hazard ratio, 0.20 for both).

IN PRACTICE:

In this older patient population, “Oncotype DX RS [Recurrence Score] did not further refine recurrence risk estimates for radiotherapy decision-making beyond the findings of landmark radiotherapy omission trials,” the authors of the study concluded.

SOURCE:

The study, led by Shoshana J. Rosenzweig, MD, and Lior Z. Braunstein, MD, Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York City, was published online in the International Journal of Radiation Oncology, Biology, Physics.

LIMITATIONS:

The number of patients with high Oncotype DX scores who did not receive radiotherapy was relatively small (n = 19), and the overall number of recurrences was modest, limiting statistical power to detect subtle differences in recurrence risk within this subgroup. Additionally, the long-term risk for recurrence may manifest beyond 6 years, suggesting that longer studies are needed. The study was conducted at a single institution, which may limit generalizability of findings. As a retrospective analysis, the study has potential for residual bias and unmeasured confounding because treatment decisions regarding radiotherapy and systemic therapy were not randomly assigned and may have been influenced by factors not captured in the dataset such as comorbidities, healthcare professional preferences, access to care, or personal preference and risk perception.

DISCLOSURES:

The study received support from the Achar Meyohas Family, the Lois Green Fund, the Rose-Margulies Family Research Fund, and National Institutes of Health or National Cancer Institute Cancer Center Support Grant No. P30CA008748. The authors reported having no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.