ESR1 mutations are frequent in newly diagnosed metastatic and loco-regional recurrence of endocrine-treated breast cancer and carry worse prognosis.
Breast Cancer Res
; 22(1): 16, 2020 02 03.
Article
in En
| MEDLINE
| ID: mdl-32014063
ABSTRACT
BACKGROUND:
Emerging mutations in the ESR1 gene that encodes for the estrogen receptor (ER) are associated with resistance to endocrine therapy. ESR1 mutations rarely exist in primary tumors (~ 1%) but are relatively common (10-50%) in metastatic, endocrine therapy-resistant cancers and are associated with a shorter progression-free survival. Little is known about the incidence and clinical implication of these mutations in early recurrence events, such as local recurrences or newly diagnosed metastatic disease.METHODS:
We collected 130 archival tumor samples from 103 breast cancer patients treated with endocrine therapy prior to their local/metastatic recurrence. The cohort consisted of 41 patients having at least 1 sample from local/loco-regional recurrence and 62 patients with metastatic disease (of whom 41 newly diagnosed and 28 with advanced disease). The 5 most common ESR1 hotspot mutations (D538G, L536R, Y537S/N/C) were analyzed either by targeted sequencing or by droplet digital PCR. Progression-free survival (PFS), disease-free survival (DFS), and distant recurrence-free survival (DRFS) were statistically tested by Kaplan-Meier analysis.RESULTS:
The prevalence of ESR1 mutations was 5/41 (12%) in newly diagnosed metastatic patients and 5/28 (18%) for advanced metastases, detected at allele frequency > 1%. All mutations in advanced metastases were detected in patients previously treated with both tamoxifen (TAM) and aromatase inhibitors (AI). However, in newly diagnosed metastatic patients, 4/5 mutations occurred in patients treated with TAM alone. PFS on AI treatment in metastatic patients was significantly shorter for ESR1 mutation carriers (p = 0.017). In the local recurrence cohort, ESR1 mutations were identified in 15/41 (36%) patients but only 4/41 (10%) were detected at allele frequency > 1%. Again, most mutations (3/4) were detected under TAM monotherapy. Notably, 1 patient developed ESR1 mutation while on neoadjuvant endocrine therapy. DFS and DRFS were significantly shorter (p = 0.04 and p = 0.017, respectively) in patients that had ESR1 mutations (> 1%) in their loco-regional recurrence tumor.CONCLUSIONS:
Clinically relevant ESR1 mutations are prevalent in newly diagnosed metastatic and local recurrence of endocrine-treated breast cancer. Since local recurrences are amenable to curative therapy, these mutations may inform the selection of subsequent endocrine therapies.Key words
Full text:
1
Database:
MEDLINE
Main subject:
Breast Neoplasms
/
Drug Resistance, Neoplasm
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Antineoplastic Agents, Hormonal
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Estrogen Receptor alpha
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Mutation
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Neoplasm Recurrence, Local
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Neoplasms, Hormone-Dependent
Type of study:
Diagnostic_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Adult
/
Aged
/
Aged80
/
Female
/
Humans
/
Middle aged
Language:
En
Journal:
Breast Cancer Res
Journal subject:
NEOPLASIAS
Year:
2020
Type:
Article
Affiliation country:
Israel