In this JCO Precision Oncology Article Insights episode, host Dr. Carolyn Lineen summaries the article, "Concordance of Oncotype DX Breast Recurrence Score Assay Results Between Paired Core Needle Biopsy and Surgical Excision Specimens in Hormone Receptor Positive, HER2-Negative Early-Stage Breast Cancer," by Nassar et al.

TRANSCRIPT

Carolyn Lineen: Hello and welcome to JCO Precision Oncology Article Insights. I'm your host, Carolyn Lineen, from St. James's Hospital, Dublin, and today we will be discussing the JCO Precision Oncology article titled "Concordance of Oncotype DX Breast Recurrence Score Assay Results Between Paired Core Needle Biopsy and Surgical Excision Specimens in Hormone Receptor Positive, HER2-Negative Early-Stage Breast Cancer" by Dr. Aziza Nassar and colleagues.

The Oncotype DX Breast Recurrence Score assay is a 21-gene expression test that provides both prognostic information regarding distant recurrence risk and predictive information regarding the benefit of adjuvant chemotherapy in hormone receptor-positive, HER2-negative early-stage breast cancer. The recurrence score ranges from 0 to 100, with higher scores indicating a greater risk of recurrence and a potentially higher likelihood of benefit from chemotherapy.

Traditionally, genomic testing is performed on surgical excision specimens following tumor resection. However, this approach can potentially delay access to biological risk stratification, which may be important when early treatment planning or neoadjuvant therapy is being considered.

The primary objective of this study was to evaluate the level of concordance between recurrence scores derived from paired core needle biopsy specimens and surgical excision specimens obtained from the same untreated primary breast tumors. Investigators specifically evaluated both continuous recurrence score agreement and categorical risk classification concordance.

The study included 134 patients with paired biopsy and surgical specimens. The median patient age was 62 years, with a wide age range from 33 to 99 years. Approximately 17% of patients were aged 50 years or younger, while 83% were older than 50 years. All patients had hormone receptor-positive, HER2-negative early-stage breast cancer and had not received prior systemic treatment before either specimen collection. Each patient contributed two tumor samples: a core needle biopsy specimen obtained at initial diagnosis and a surgical excision specimen obtained during definitive tumor resection. Both samples underwent Oncotype DX testing, allowing direct within-patient comparison.

The investigators reported mean recurrence scores of 15.6 for core needle biopsy specimens and 16.6 for surgical excision specimens. Although this absolute mean difference between specimen types did reach statistical significance with a P value of 0.003, the authors note that this numerical difference was small at one recurrence score unit and may not therefore be clinically meaningful. Additionally, categorical recurrence score results did not differ significantly.

The primary measure of agreement between recurrence scores was the Lin's concordance correlation coefficient. The study demonstrated a Lin concordance correlation coefficient of 0.86 with a 95% confidence interval ranging from 0.80 to 0.90, indicating strong agreement between biopsy and surgical specimens. Additionally, categorical agreement was assessed using Cohen's kappa statistic. The study reported a kappa value of 0.64 with a 95% confidence interval from 0.44 to 0.83, indicating substantial agreement between specimen types.

Comparing this study to previously published evidence, the authors referenced prior smaller studies examining concordance between paired tissue samples. For example, earlier research evaluating 50 patients demonstrated correlation coefficients of approximately 0.8 and categorical concordance rates ranging from 72% to 78%, depending on the classification cut points used. Compared with earlier studies, the present study provides stronger evidence supporting consistency between biopsy and surgical testing.

These findings have several important implications for clinical practice. First, early availability of recurrence score results may enhance multidisciplinary care planning. Obtaining genomic risk data at the time of diagnosis allows tumor boards to integrate molecular risk stratification into initial treatment discussions rather than waiting for postoperative results. Second, biopsy-based testing may support decision making regarding treatment sequencing. Earlier genomic information may help guide selection of neoadjuvant therapy or inform early decisions about adjuvant chemotherapy necessity. Third, early testing may reduce delays in treatment initiation. Separate research evaluating presurgical Oncotype DX testing has demonstrated potential reductions in time to initiation of adjuvant therapy by approximately 8 days, suggesting potential improvements in care efficiency. Additionally, biopsy-based testing demonstrates strong technical feasibility. Studies examining real-world implementation have reported test success rates as high as 99.1% when performed on core biopsy specimens.

Despite the encouraging results, certain limitations must be considered. Core needle biopsy samples evaluate only a portion of the tumor, and intratumoral heterogeneity could theoretically influence recurrence score results in selected cases. Preanalytical factors, including tissue fixation and sample handling, may also affect RNA integrity and assay performance. Standardization of specimen processing protocols will be essential if biopsy-based testing becomes routine. Furthermore, although analytical concordance is strong, prospective outcome studies demonstrating equivalent long-term clinical outcomes based on biopsy-directed treatment decisions would further strengthen the evidence base.

In conclusion, this study demonstrates strong concordance between Oncotype DX Breast Recurrence Scores derived from core needle biopsy specimens and surgical excision specimens in patients with hormone receptor-positive, HER2-negative early-stage breast cancer. With a concordance correlation coefficient of 0.86 and overall categorical agreement exceeding 90%, the findings support the clinical feasibility of performing genomic testing at the time of diagnostic biopsy. If validated through additional prospective studies, this approach may enable earlier risk stratification and improve multidisciplinary treatment planning.

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