A group of German researchers attempting to identify predictors for a decision against an antihormonal treatment (AHT) were unable to show that patients benefited from chemotherapy. They presented their results on Thursday, December 7, during a poster session at the San Antonio Breast Cancer Symposium.
Patients with breast cancer who have metastases that are not life threatening usually exhaust all AHT options before undergoing chemotherapy. The PRAEGNANT metastatic breast cancer registry has main study goals of biomarker research and the description of real-world treatment. (Until 2011, only everolimus was an additional option to overcome endocrine resistance; in 2011, cyclin D–dependent kinase (CDK) 4/6 inhibitors were also approved.)
This analysis was restricted to patients with first-line, metastatic disease who were hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative. Patients who did or did not receive chemotherapy were compared to determine overall survival rates in the two groups.
A total of 389 HR-positive and HER2-negative patients with detailed treatment information were included. Of those patients, 173 (44.5%) received chemotherapy, 190 received AHT (48.8%), and 26 (6.7%) received everolimus plus AHT. In the multiple logistic regression model, older patients, lower-graded tumors, bone-only disease, and previous adjuvant chemotherapy were associated with a lower rate of first-line chemotherapies.
No discerning diseases nor body mass indexes influenced the choice of first-line metastatic therapy. More than half of the patients with visceral metastases (58.1%) were treated with first-line chemotherapy, which was more than patients with brain metastases (55.6%) or bone-only metastases (26.9%).
Patients with grade 1, grade 2, or grade 3 tumors were treated with first-line chemotherapy in 28.0%, 38.4% and 63.2% of the cases, respectively. Patients who received chemotherapy seemed to have worse overall survival than patients who did not receive chemotherapy (adjusted hazard ratio = 1.58, 95% CI = 0.89–2.18), but this was not significant (p = 0.12). Overall survival was primarily influenced by Eastern Cooperative Oncology Group score and location of metastasis.
“Further studies with larger sample sizes are needed” to significantly determine whether patients treated with chemotherapy have poorer overall survival, the authors said.