Is Routine Recurrence Score Testing in Patients Older than 70 Years of Age Warranted? An Evaluation of the National Cancer Database After TAILORx

The Utility of the Oncotype DX Test for Breast Cancer Patients in an Australian Multidisciplinary Setting

Introduction

The Oncotype DX test is a genomic assay that generates a Recurrence Score (RS) predicting the 10-year risk of recurrence and response to adjuvant chemotherapy in ER+/HER2− breast cancer patients. The aims were to determine breast cancer distant recurrence and correlate with adjuvant chemoendocrine prescribing patterns based on the Oncotype DX recurrence score.

Methods

We conducted a retrospective single-institution case series of 71 patients who had Oncotype DX assay testing after definitive surgery between 2012 and 2016. Both node-positive and node-negative patients were included. Patients were divided into Oncotype DX low risk (RS < 11) (n = 10, 14%), intermediate risk (RS 11–25) (n = 45, 63%), and high risk (RS > 25) (n = 16, 23%). Median follow-up was 6.1 years (range 4–8.9 years). Adjuvant treatment regimens and oncological outcomes were determined. Results. Mean age at diagnosis was 56 years (range, 33–77). Invasive ductal carcinoma (IDC) accounted for the majority (87%), with most tumors measuring between 10–20 mm (52%). 48% of the cohort were node positive. 15 of 16 high-risk patients (94%) received chemotherapy. 96% of intermediate-risk patients received endocrine therapy alone, one patient received chemoendocrine therapy (2%), and one declined systemic therapy (2%). In the low-risk group, 100% received endocrine therapy only. The high-risk group had the lowest mean ER% (P < 0.05), greatest mean mitotic rate (P < 0.05), and greatest proportion of Ki67% > 14. Five patients developed distant recurrence (7%): three from the intermediate-risk group (7%), one from the low-risk group (10%), and one from the high-risk group (6%).

Conclusion

This is the first Australian study reporting the experience with medium-term recurrence outcomes of using the Oncotype DX assay in breast cancer. Chemotherapy was rarely given for patients with low-to-intermediate RS and always offered in high RS. This pattern of prescribing was associated with low rates of distant recurrence. National funding models should be considered.

Evaluation of whether adjuvant chemotherapy can be safely omitted for older female patients with ER-positive, HER2-negative N1 breast cancer: a study based on the SEER database

Background

This study evaluated the trends and practice patterns associated with adjuvant chemotherapy (CT) use for patients aged ≥70 years with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2–) N1 (1–3 positive lymph nodes) breast cancer (BC). Furthermore, the relationship between adjuvant CT and survival in this set of patients was determined.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database was used to identify 6,711 women with ER+, HER2– N1 BC who were aged ≥70 years between 2010 and 2015. Demographic, clinical, and pathological predictors of CT use were identified using logistic regression. Multivariable Cox regression was used to identify variables that correlated with overall survival (OS), before and after propensity score matching (PSM).

Results

Younger age at diagnosis, other histological types, higher tumor grade, larger tumor size, breast reconstruction surgery, progesterone receptor-negative (PR–), and increased nodal involvement were associated with an increased probability of receiving CT. CT use was associated with improved 5-year OS, both before and after PSM [hazard ratio (HR): 0.66, 95% confidence interval (CI): 0.58–0.75 and HR: 0.81, 95% CI: 0.68–0.96, respectively]. The exploratory subgroup analysis showed that although the benefit of CT was significant in the grade III subgroup, it was not significant in the grades I–II subgroups.

Conclusions

Adjuvant CT improved 5-year OS in patients with ER+, HER2– N1 BC who were aged ≥70 years; however, the benefit of CT was more significant in the grade III subgroup than in the grades I–II subgroups.