Abstract
PI3KCA mutation prevalence and outcome among patients with metastatic breast cancer in Bulgaria treated with first-line endocrine therapy.
Author
person
Radostina Gencheva
MHAT “Nadezhda”, Sofia, Bulgaria, Sofia, Bulgaria
info_outline
Radostina Gencheva, Savina Hadjidekova, Mila Petrova, Dimo Krustev, Petya Kraleva, Georgi Zhbantov, Nikolay Vladimirov Conev, Dragomir Svetozarov Stoyanov, Jeliazko Iliev Arabadjiev, Eliz Tazimova, Svitlana Bachurska, Ivan Galev, Mariyana Eneva, Mariela Tsvetkova, Rada Staneva, Eleonora Dimitrova, Rossen Hadjiev, Ivan Donev
Full text
Authors
person
Radostina Gencheva
MHAT “Nadezhda”, Sofia, Bulgaria, Sofia, Bulgaria
info_outline
Radostina Gencheva, Savina Hadjidekova, Mila Petrova, Dimo Krustev, Petya Kraleva, Georgi Zhbantov, Nikolay Vladimirov Conev, Dragomir Svetozarov Stoyanov, Jeliazko Iliev Arabadjiev, Eliz Tazimova, Svitlana Bachurska, Ivan Galev, Mariyana Eneva, Mariela Tsvetkova, Rada Staneva, Eleonora Dimitrova, Rossen Hadjiev, Ivan Donev
Organizations
MHAT “Nadezhda”, Sofia, Bulgaria, Sofia, Bulgaria, Genetic Laboratory MHAT “Nadezhda”, Sofia, Bulgaria, MHAT "Nadezhda", Sofia, Bulgaria, Department of Anatomy and Histology, Medical University of Sofia, Sofia, Bulgaria, Medical Oncology Dept, MHAT Nadezhda Hospital, Sofia, Bulgaria, Medical University of Varna, Varna, Bulgaria, UMHAT Sveta Marina EAD, Varna, Bulgaria, Tokuda Hospital Sofia, Sofia, Bulgaria, Acibadeu City Clinic, Sofia, Bulgaria, Department of general and clinical pathology, University Specialized Oncology Hospital, Sofia, Bulgaria, Sofia, Bulgaria, Department of clinical pathology, University Hospital Acibadem City Clinic Tokuda, Sofia, Bulgaria, Hospital Pharmacy MHAT “Nadezhda”, Sofia, Bulgaria, Novartis Oncology, Sofia, Bulgaria, Genetic Laboratory MHAT "Nadezhda", Sofia, Bulgaria, Forensic department, University Hospital Lozenetz, Sofia, Bulgaria, Department of Medical Oncology, Nadezhda Hospital, Sofia, Bulgaria
Abstract Disclosures
Research Funding
Pharmaceutical/Biotech Company
Novartis
Background:
There are phosphatidylinositol-4,5-biphosphate 3-kinase catalytic subunit alpha (
PIK3CA
) mutations in 30-40% of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2) tumor samples. Nevertheless, clinical outcomes in this group vary amongst research trials.
Methods:
We sought to determine the incidence of
PIK3CA
mutations in Bulgarian patients with metastatic HR+, HER2-negative breast cancer, as well as to evaluate and compare progression-free survival (PFS) in the real world between wild-type (WT) and mutant cohorts. In this multicentric retrospective analysis, 250 tissue samples were collected between 2016 and 2022 from three Bulgarian oncology centers. Qualitative real-time PCR was used to determine the existence of
PIK3CA
mutations. The median follow-up time was 28 months.
Results:
The mean age was 57.6±11.6 years for the mutant cohort and 56.5±12.2 for the wild-type cohort (p=0.52). The percentage of patients with visceral metastatic disease was 58.8% (n=147). Postmenopausal patients were 84.3% (n=210).
PIK3CA
mutation prevalence was 29.2% (n=73). The most prevalent mutation was found in exon 20: H1047R (9.2%). Among all clinicopathological features, we observed only a significant relation between the presence of a mutation and a metastatic stage at diagnosis (p = 0.002). 67.1% of the patients received endocrine therapy (ET) + CDK4/6 inhibitor as first-line therapy, while the remainder receive ET monotherapy. Patients with PIK3CA mutation did not have significantly different median PFS compared to WT patients (32 months (95%, CI: 22-40) versus 24 months ((95%, CI: 21-36) (p=0.45)); HR=0.86 (95%, CI: 0.5-1.3) (p=0.46). In propensity matching score analysis (matched for treatment utilized as a first line ET, menopausal status, and locations of metastatic disease), we confirmed our finding (36 months (95%, CI: 20-40) versus 26 months (95%, CI: 21-38), p = 0.69).
Conclusions:
We demonstrated that the prevalence of
PIK3CA
mutations in Bulgarian patients is comparable to that reported in other countries. Our findings suggest that the presence of a
PIK3CA
mutation has no effect on the efficacy of endocrine therapy of first-line treatment. In summary, our study provides valuable insights into the topic, but limitations including the retrospective design and small sample size suggest that the findings need to be replicated by more robust studies and larger sample sizes to draw definitive conclusions.
15 organizations
1 drug
1 target
Organization
MHAT “Nadezhda”Organization
Genetic Laboratory MHAT “Nadezhda”Organization
Medical Oncology Dept, MHAT Nadezhda HospitalOrganization
Medical University of VarnaOrganization
UMHAT Sveta Marina EADOrganization
Tokuda Hospital SofiaOrganization
Acibadeu City ClinicOrganization
Hospital Pharmacy MHAT “Nadezhda”Organization
Novartis OncologyOrganization
Genetic Laboratory MHAT "Nadezhda"Drug
PIK3CATarget
PIK3CA