Long-Term Outcome of Sustained Endocrine Monotherapy for Elderly Breast Cancer Patients.

BACKGROUND: Among elderly breast cancer patients, endocrine therapy may be chosen as definitive treatment by patients or physicians. This study investigated the efficacy of endocrine monotherapy (ET) in terms of avoidance of invasive local treatment. METHODS: Elderly patients (≥70 years) with a diagnosis of estrogen receptor-positive breast cancer who underwent ET between 2008 and 2015 were identified through the Netherlands Cancer Registry. The primary outcome was the cumulative risk of undergoing invasive local treatment (radiotherapy or surgery) for the primary tumor. The secondary outcomes were development of uncontrolled local disease and overall survival (OS). RESULTS: Of the 105 patients (median age, 86 years) enrolled in this study, 91 (78 %) received ET as definitive treatment, whereas 14 received ET as a "bridge to surgery." For the 91 patients who used ET as intended definitive treatment, the 5-year cumulative risk of undergoing invasive local treatment and experiencing uncontrolled disease were respectively 28 % and 16 %. The 5-year cumulative OS was 42 %. Whereas 11 patients had metastatic or locally progressive breast cancer at the time of death, cardiovascular disease, infectious diseases, and old age or dementia were reported as contributing to the death of 39 patients. CONCLUSIONS: For a select group of elderly breast cancer patients who received sustained ET, the risk of undergoing invasive local treatment was surpassed by a twofold higher risk of dying. As an alternative to invasive local treatment, ET can be discussed as a safe and effective option for patients unwilling or unfit to undergo surgery.

The Changing Role of Gene-Expression Profiling in the Era of De-escalating Adjuvant Chemotherapy in Early-Stage Breast Cancer.

PURPOSE: We assessed the recent trends in the administration of adjuvant chemotherapy thereby evaluating the role of the 70-gene signature (70-GS) testing in decision-making in the systemic treatment of patients with lymph node negative (N0) and lymph node positive (N+) breast cancer. METHODS: Patients with a national guideline directed indication for 70-GS use treated between 2013 and 2016 were selected from the Netherlands Cancer Registry. Time trends in the administration of adjuvant chemotherapy were evaluated within guideline- and age-delineated subgroups. The influence of the 70-GS on chemotherapy use was assessed with logistic regression. RESULTS: During the study period, the overall administration of adjuvant chemotherapy decreased from 49 to 23% and 70-GS use increased from 24 to 51%. The 70-GS was not associated with a decreased likelihood for N0 patients to receive chemotherapy (odds ratio [OR] 1.0; 95% confidence interval [CI] 0.86-1.17), as the proportion of N0 patients who received chemotherapy in the absence of 70-GS use decreased during the study period. In patients with N1a disease, 70-GS testing was associated with a decreased likelihood to receive chemotherapy (OR 0.21; 95% CI 0.15-0.29). In patients < 50 years and 50-59 years of age, 70-GS use was associated with a consistent lower proportion of patients receiving chemotherapy throughout the study period (OR 0.17; 95% CI 0.13-0.23 and OR 0.53; 95% CI 0.43-0.65, respectively). CONCLUSIONS: In this population-based study, the administration of adjuvant chemotherapy in ER+ breast cancer strongly declined. For node-positive and younger patients, 70-GS use was associated with a decreased probability for patients to receive adjuvant chemotherapy.