Estrogen receptor-negative/progesterone receptor-positive and her-2
negative breast cancer might no longer be classified as hormone receptor
positive breast cancer
Abstract
Background: The estrogen receptor (ER)-negative/progesterone receptor
(PR)-positive (sPR positive) phenotype is an infrequent and independent
biological entity. However, the prognosis of patients with sPR positive
and her-2 negative phenotype is still controversial, and it is not
always easy to decide treatment strategies for them. Methods: Patients
during 2010–2014 were identified from Surveillance, Epidemiology, and
End Results (SEER) database. The Kaplan-Meier method was used to
evaluate cancer-specific survival (CSS). The propensity score matching
(PSM) method was used to balance differences of characteristics in
groups. The Life-Table method was used to calculate 5-year CSS rates and
the annual hazard rate of death (HRD). Results: A total of 97,527
patients were included, and only 745 (0.76%) patients were sPR positive
phenotype. The majority of sPR positive breast cancer were basal-like
subtype. Survival analysis showed that the sPR positive breast cancer
had similar prognosis comparing to ER-negative/PR-negative (dHR
negative) breast cancer, and had the highest HRD during the initial 1-2
years of follow-up, then maintained the HRD of almost zero during the
late years of follow-up. Conclusions: The patients with sPR positive and
her-2 negative breast cancer, similar to dHR negative breast cancer, had
a worse survival, and could benefit from chemotherapy significantly.
However, the escalating endocrine therapy was not recommended for sPR
positive patients. The patients with sPR positive should be excluded
from future clinical trials concerning endocrine therapy.