The effect of low HER2 expression on treatment outcomes in metastatic hormone receptor positive breast cancer patients treated with a combination of a CDK4/6 inhibitor and endocrine therapy: A multicentric retrospective study.
Breast
; 70: 56-62, 2023 Aug.
Article
in En
| MEDLINE
| ID: mdl-37343321
ABSTRACT
BACKGROUND:
CDK4/6 inhibitors combined with endocrine therapy have significantly improved treatment outcomes for metastatic hormone receptor-positive (HR+) breast cancer patients. However, the impact of low HER2 expression on treatment response and progression-free survival (PFS) remains unclear.METHODS:
This multicenter retrospective study included 204 HR+ breast cancer patients treated with a combination of CDK4/6 inhibitor and endocrine therapy. HER2-zero disease was detected in 138 (68%) and HER2-low disease in 66 (32%) patients. Treatment-related characteristics and clinical outcomes were analyzed, with a median follow-up of 22 months.RESULTS:
The objective response rate (ORR) was 72.7% in the HER2 low group and 66.6% in the HER2 zero group (p = 0.54). Median PFS was not significantly different between the HER2-low and HER2 zero groups (19 months vs.18 months, p = 0.89), although there was a trend toward longer PFS in the HER2-low group for first-line treatment (24 months progression-free survival rate 63% vs 49%). In recurrent disease, the median PFS was 25 months in the HER2-low group and 12 months in the HER2-zero group (p = 0.08), while in de novo metastatic disease, the median PFS was 18 months in the HER2-low group and 27 months in the HER2-zero group (p = 0.16). The order of CDK4/6 inhibitor use and the presence of visceral metastasis were identified as independent variables affecting PFS.CONCLUSION:
Low HER2 expression did not significantly impact treatment response or PFS in HR+ breast cancer patients treated with a CDK4/6 inhibitor and endocrine therapy. Because of the conflicting results in the literature, further prospective studies are needed to evaluate the clinical significance of HER2 expression in HR+ breast cancer.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Breast Neoplasms
Type of study:
Clinical_trials
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Female
/
Humans
Language:
En
Journal:
Breast
Journal subject:
ENDOCRINOLOGIA
/
NEOPLASIAS
Year:
2023
Document type:
Article