Application of a 21-Gene Recurrence Score in a Swiss Single-Center Breast Cancer Population: A Comparative Analysis of Treatment Administration before and after TAILORx

In patients with hormone receptor positive, human epidermal receptor 2 negative (HR+/HER2-) negative breast cancer (BC), the TAILORx study showed the benefit of adding chemotherapy (CHT) to endocrine therapy (ET) in a subgroup of patients under 50 years with an intermediate Oncotype DX recurrence score (RS 11-25). The aim of the present study was to determine if the TAILORx findings, including the changes in the RS categories, impacted CHT use in the intermediate RS (11-25) group in daily practice, as well as to identify the main factors for CHT decisions. We conducted a retrospective study on 326 BC patients (59% node-negative), of which 165 had a BC diagnosis before TAILORx (Cohort A) and 161 after TAILORx publication (Cohort B). Changes in the RS categories led to shifts in patient population distribution, thereby leading to a 40% drop in the low RS (from 60% to 20%), which represented a doubling in the intermediate RS (from 30% to 60%) and an increase of 5% in the high RS (from 8-10% to 15%). The overall CHT recommendation and application did not differ significantly between cohort B when compared with A (19% vs. 22%, resp., p = 0.763). In the intermediate RS (11-25), CHT use decreased by 5%, while in the high-risk RS category (>25), there was an increase of 13%. The tumor board recommended CHT for 90% of the patients according to the new RS guidelines in cohort A and for 85% in cohort B. The decision for CHT recommendation was based on age (OR 0.93, 95% CI 0.08-0.97, p = 0.001), nodal stage (OR 4.77, 95% CI 2.03-11.22, p < 0.001), and RS categories (RS 11-25 vs. RS 0-10: OR 0.06 (95% CI 0.02-0.17), p < 0.001; RS > 26 vs. RS 11-25: OR 618.18 95% CI 91.64-4169.91, p < 0.001), but did not depend on the cohort. In conclusion, while the tumor board recommendation for CHT decreased in the intermediate RS category, there was an increase being reported in the high RS category, thus leading to overall minor changes in CHT application. As expected, among the younger women with intermediate RS and unfavorable histopathological factors, CHT use increased.

Ovarian Function Suppression: A Deeper Consideration of the Role in Early Breast Cancer and its Potential Impact on Patient Outcomes: A Consensus Statement from an International Expert Panel

It has been suggested that the benefit of adjuvant chemotherapy (CT) in premenopausal women with hormone receptor-positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) early breast cancer may be related, at least in part, to CT-induced ovarian function suppression (OFS) in this subgroup of patients. Although this hypothesis has not been directly tested in large randomized clinical trials, the observations from prospective studies have been remarkably consistent in showing a late benefit of CT among the subgroup of patients who benefit (ie, women who were close to menopause). The hypothesis has important clinical implications, as it may be possible to spare the associated adverse effects of adjuvant CT in a select group of women with early breast cancer, in favor of optimizing OFS and endocrine therapy (ET), without compromising clinical outcomes. Such an approach has the added benefit of preserving the key quality of life outcomes in premenopausal women, particularly by preventing the irreversible loss of ovarian function that may result from CT use. For this reason, we convened an international panel of clinical experts in breast cancer treatment to discuss the key aspects of the available data in this area, as well as the potential clinical implications for patients. This article summarizes the results of these discussions and presents the consensus opinion of the panel regarding optimizing the use of OFS for premenopausal women with HR+, HER2- early breast cancer.

A Validated Model for Identifying Patients Unlikely to Benefit From the 21-Gene Recurrence Score Assay

BACKGROUND

Predicting recurrence risk and chemotherapy benefit in early-stage breast cancer can be challenging, and Oncotype DX (ODX) is often used to gain insight. However, it is still unclear whether ODX can benefit in all cases. To clarify ODX's usefulness we sought to develop a model using readily available pathologic markers to help clinicians make that determination.

PATIENTS AND METHODS

Clinical pathologic data from 221 hormone receptor-positive, HER2-negative invasive breast cancer patients was used to create a model. The model was then validated on a second institution's set of 319 patients.

RESULTS

The model has 2 simple rules: low grade and positive progesterone receptor tumors (LG+PR) are low risk, and high grade or low estrogen receptor (ER) (ER < 20%) tumors (HG/LER) are high risk. The TAILORx (Trial Assigning Individualized Options for Treatment (Rx)) trial thresholds of Recurrence Score (RS) ≤ 10, when chemotherapy is of little benefit, and RS ≥ 26 when chemotherapy might be beneficial were used to judge model performance. Impressively, the misclassifications of an HG/LER patient who has an RS ≤ 10 were 0% and 2%, and for LG+PR patients who had an RS ≥ 26 were 0% and 2.6%. In the validation set, 28% (66 of 232) of the indeterminate group (neither in the HG/LER nor the LG+PR groups) had an RS ≤ 10 or an RS ≥ 26; this group might clinically benefit from ODX.

CONCLUSION

A simple 2-rule model based on readily available pathologic data was developed and validated, which categorized patients into high and low risk for recurrence. Identification of patients who are unlikely to benefit from ODX testing could result in significant cost avoidance.