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- Ellegård, Sander, 1985-
(författare)
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HER2-positive breast cancer : Clinical and molecular aspects
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- BackgroundHuman Epidermal Growth Factor Receptor 2 (HER2)-positive breast cancer is notable for its aggressive behavior, however with the introduction of trastuzumab in the early 2000’s, prognosis has improved. This thesis investigates the efficacy of trastuzumab in real-world settings after its introduction and evaluates the prognostic value of molecular biomarkers, aiming to optimize treatment approaches and improve patient outcomes.Material and MethodsHER2-positive patients treated in the advanced and early stages of breast cancer were retrospectively identified using Swedish patient registries and through the review of medical records.Study I included 46 patients with advanced breast cancer treated with trastuzumab between 2000 and 2007. Immunohistochemical analysis of several proteins hypothesized to be involved in trastuzumab resistance were evaluated. Additionally, gene copy number variations were analyzed using droplet digital PCR.Study II include 599 patients who received adjuvant trastuzumab between 2006 and 2014 in the Southeastern health care region, in order to evaluate the implementation of trastuzumab after its approval and to evaluate patient outcomes with regard to clinicopathological variables.Study III conducted quantitative analyses of stromal tumor-infiltrating lymphocytes (sTILs) in patients with available tumor material from the same cohort identified in study II. Additionally, a case-control study of 21 cases with 21 matched controls treated with trastuzumab were analyzed with RNA-sequencing in order to identify important differentially expressed genes.ResultsStudy I demonstrated that trastuzumab treatment in a real-world setting had similar survival as in pivotal clinical trials. Additionally, high amplification of HER2 correlated with improved progression-free survival (PFS) and overall survival (OS) in advanced breast cancer patients and PTPN2 gain was correlated with reduced PFS and OS.Study II confirmed trastuzumab's efficacy in a large real-world cohort. Trastuzumab treatment, estrogen receptor (ER) status and number of metastatic lymph nodes were the most important prognostic factors for breast cancer-specific survival and distant recurrence-free survival.Study III identified a significant association between high levels of sTILs and improved overall survival. Additionally, several G-protein coupled receptors (GPCRs) involved in EGFR and Wnt signaling were found to be upregulated in cases vs controls.ConclusionsTrastuzumab maintains its efficacy in clinical practice, affirming its role in current treatment regimens for HER2-positive breast cancer. The findings support the prognostic significance of sTILs and suggest HER2-amplification levels as a relevant prognostic factor. We propose PTPN2 and several GPCRs as areas for future research.
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| 2. |
- Papakonstantinou, Antroula, et al.
(författare)
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Efficacy and safety of tailored and dose-dense adjuvant chemotherapy and trastuzumab for resected HER2-positive breast cancer : Results from the phase 3 PANTHER trial
- 2020
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Ingår i: Cancer. - : Wiley. - 0008-543X .- 1097-0142. ; 126:6, s. 1175-1182
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Tidskriftsartikel (refereegranskat)abstract
- Background: Dose-dense (DD) adjuvant chemotherapy improves outcomes in early breast cancer (BC). However, there are no phase 3 randomized data to inform on its combination with trastuzumab for patients with human epidermal growth factor receptor 2 (HER2)–positive disease. Methods: This was a protocol-predefined secondary analysis of the randomized phase 3 Pan-European Tailored Chemotherapy (PANTHER) trial. Women 65 years old or younger with node-positive or high-risk, node-negative BC were randomized 1:1 to either tailored (according to hematologic nadirs) and DD epirubicin and cyclophosphamide followed by docetaxel or standard 5-fluorouracil, epirubicin, and cyclophosphamide plus docetaxel every 3 weeks. Patients with HER2-positive disease received 1 year of adjuvant trastuzumab. The primary endpoint was BC relapse–free survival. In addition, HER2-positive patients and an equal number of HER2-negative patients matched for age, treatment group, and institution who were enrolled at Swedish sites were asked to participate in a predefined study of cardiac safety and underwent echocardiography or multigated acquisition scanning and electrocardiography at the baseline and at 4 and 6 years of follow-up. Results: There were 342 HER2-positive patients; 335 received at least 1 dose of trastuzumab, and 29 patients discontinued trastuzumab prematurely. Relapse-free survival was not statistically significantly in favor of the tailored and DD group (hazard ratio, 0.68; 95% confidence interval, 0.37-1.27; P =.231). Cardiac outcomes after 4 and 6 years of follow-up did not differ significantly between HER2-positive and HER2-negative patients or between the 2 treatment groups. Conclusions: The combination of DD chemotherapy and trastuzumab decreased the relative risk for relapse by 32% in comparison with standard treatment, a statistically nonsignificant difference. Its efficacy and safety merit further evaluation as part of both escalation and de-escalation strategies.
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