Outcome of breast cancer patients with low hormone receptor positivity: analysis of a 15-year population-based cohort

BACKGROUND

Guideline recommendations for the treatment of breast cancer with low hormone receptor (HR) expression (1%-9%) are ambiguous and several studies showed more similarities with HR-negative tumors than with HR strongly positive tumors (≥10%). We used a population-based 15-year cohort to compare patient characteristics and outcome of HR low positive tumors with HR-negative and HR strongly positive tumors, respectively.

PATIENTS AND METHODS

A total of 38  560 women diagnosed with early invasive breast cancer between 2004 and 2018 within the scope of the Munich Cancer Registry with 4.9 million inhabitants were included. Descriptive analyses of prognostic factors, treatment, and outcome analyses using the Kaplan-Meier method; cumulative incidence in consideration of competing risks; and multivariate analyses (Cox regression and Fine-Gray model) were conducted. Endpoints were time to local recurrence (TTLR), time to lymph node recurrence (TTLNR), time to metastasis (TTM), overall survival (OS), and relative survival (RS).

RESULTS

A total of 861 patients (2%) had HR low positive, 4862 (13%) HR-negative, and 32  837 (85%) HR strongly positive tumors. Within the HER2-negative cohort (n = 33  366), survival of HR low positive tumors was significantly worse than that of HR strongly positive tumors [OS hazard ratio 0.66 (95% confidence interval 0.55-0.78)], whereas between HR low positive and HR-negative tumors no significant survival difference could be detected [OS hazard ratio 0.93 (95% confidence interval 0.78-1.11)]. TTLR, TTLNR, and TTM showed similar results. By contrast, within the HER2-positive cohort (n = 5194), no statistically significant differences between the three HR groups could be detected in multivariate analyses.

CONCLUSION

Current definitions for HR positivity and its clinical relevance should be reconsidered. Patients with HR low positive/HER2-negative tumors could be regarded and treated similar to patients with triple-negative tumors.

Abstract P1-17-09: Use of Oncotype DX ® testing in nodal positive breast cancer patients: Real-life data from a single center in Munich, Germany

Introduction: Despite a large body of prospective studies showing good prognostic and predictive value of the Oncotype DX ® testing in ER+/HER2- early breast cancer patients after breast surgery, the test is currently not reimbursed in Germany by most national health insurance companies. Nevertheless, this multigene assay has been offered to node negative (N-) and increasingly to node positive (N1) patients with 1-3 positive lymph nodes by medical- and gyneco-oncologists for several years. The aim of the present study was to analyze real life data of the test in N1 patients from a German single center with special respect to the intermediate-risk recurrence score (RS) group and event-free survival (EFS).

Patients and Methods: Patients with ER+/HER2- node positive breast cancer after breast surgery, to whom Oncotype DX ® testing was consecutively recommended by the interdisciplinary local tumor board from 1/2012 through 12/2016 at the Breast Center of the Red Cross Hospital Munich, Germany, were included in the study. Data was retrospectively retrieved from medical records (e.g. stage and histology), patient interviews as well as from the Munich Cancer Registry (outcome measurements). Patients were stratified according to Oncotype DX ® RS distribution (<11 low-risk, 11-25 intermediate risk and > 25 high-risk). Proportion of patients choosing adjuvant chemotherapy (CT) within the different RS groups and outcome were analyzed.

Results: Oncotype DX ® testing was recommended and performed in 500 (17%) out of 2942 patients with ER+/HER2- tumors. Nodal status was positive in 159 (31.8%) of these patients. Patients with more than 3 positive lymph nodes and with missing data on follow-up were excluded, leaving 121 patients for the main analysis. According to RS distribution, n=19 (15.7%) were low-risk, n=83 (68.6%) intermediate-risk and n=19 (15.7%) high-risk, respectively. Although CT was generally discussed with all N1 patients with RS>10, only 39 patients (38.2%) of the intermediate and high-risk RS-group opted for systemic chemotherapy (24.1% of RS 11-25 and 100% of RS>25). In 13 of the patients (11%) within a median follow-up of 40 months an event occurred (4 loco-regional and 2 contralateral relapses, 5 distant metastases (3 bone, 2 visceral) and 2 deaths of other causes). Of those patients with events, three presented with RS <11, six with RS 11-25 and three with RS >25. In the intermediate group (n=83) EFS was 90% for patients receiving CT followed by endocrine therapy (ET) and 91.9% for patients with ET alone (p= 0,583).

Conclusions: Using real life data from a large single breast center, only around 25% of patients with 1-3 positive lymph nodes from the intermediate RS group decided to undergo CT after Oncotype DX ® testing. The outcome of patients receiving ET only in this group was not inferior compared to CT followed by ET.

Citation Format: Kriegmair A, Szeterlak N, Schrodi S, Stoetzer O, Pölcher M, Braun M. Use of Oncotype DX ® testing in nodal positive breast cancer patients: Real-life data from a single center in Munich, Germany [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-17-09.