George Douganiotis1, George Kesisis2, Efthalia Lalla1, Ippokratis Korantzis2, Ioannis Boukovinas3, Konstantinos Papazisis4. 1. 3rd Department of Medical Oncology, Theageneion Cancer Hospital, Thessaloniki, Greece. 2. Oncology Department, Saint Luke Private Hospital, Thessaloniki, Greece. 3. Oncology Department, BioClinic Thessaloniki, Thessaloniki, Greece. 4. Medical Oncology Department, Euromedica General Clinic, Thessaloniki, Greece.
Abstract
BACKGROUND/AIM: Low expression of HER2 has defined a new "HER2-low" subgroup of breast cancer with distinct clinicopathological characteristics and both prognostic and predictive implications. The impact of low HER2 expression in metastatic hormone receptor-positive HER2-negative breast cancer treated with first-line CDK4/6 inhibitors has not been studied. Using real-world patient data, we aimed to identify prognostic differences in this patient population according to HER2 expression with immunohistochemistry. PATIENTS AND METHODS: We retrospectively analyzed 191 patients from 5 Oncology Department databases in Thessaloniki, Greece, with hormone receptor-positive HER2-negative metastatic breast cancer treated with CDK4/6 inhibitors in the first line, for whom detailed immunohistochemical HER2 data could be retrieved. RESULTS: Median progression-free survival was numerically different among the different HER2 subgroups (3.35 years for HER2 0 tumors, 2.18 years for HER2 +1 tumors, 1.74 years for HER2 +2/ISH-negative tumors), but this difference was not statistically significant (p=0.477). Median PFS was statistically significantly longer in patients without visceral metastases (5.45 years) compared to patients with visceral metastases (1.61 years) (p=0.017). Median PFS was also statistically significantly longer in patients taking an aromatase inhibitor (2.99 years) compared to patients taking fulvestrant (1.33 years) (p<0.0001). There were no statistically significant differences in the other subgroups examined. CONCLUSION: CDK4/6 inhibitors are equally effective as first-line treatment agents, regardless of the exact level of HER2 expression. Numerical differences, however, do exist among the different HER2 subgroups, and merit further evaluation in future studies to better study this phenomenon. Copyright 2022, International Institute of Anticancer Research.
BACKGROUND/AIM: Low expression of HER2 has defined a new "HER2-low" subgroup of breast cancer with distinct clinicopathological characteristics and both prognostic and predictive implications. The impact of low HER2 expression in metastatic hormone receptor-positive HER2-negative breast cancer treated with first-line CDK4/6 inhibitors has not been studied. Using real-world patient data, we aimed to identify prognostic differences in this patient population according to HER2 expression with immunohistochemistry. PATIENTS AND METHODS: We retrospectively analyzed 191 patients from 5 Oncology Department databases in Thessaloniki, Greece, with hormone receptor-positive HER2-negative metastatic breast cancer treated with CDK4/6 inhibitors in the first line, for whom detailed immunohistochemical HER2 data could be retrieved. RESULTS: Median progression-free survival was numerically different among the different HER2 subgroups (3.35 years for HER2 0 tumors, 2.18 years for HER2 +1 tumors, 1.74 years for HER2 +2/ISH-negative tumors), but this difference was not statistically significant (p=0.477). Median PFS was statistically significantly longer in patients without visceral metastases (5.45 years) compared to patients with visceral metastases (1.61 years) (p=0.017). Median PFS was also statistically significantly longer in patients taking an aromatase inhibitor (2.99 years) compared to patients taking fulvestrant (1.33 years) (p<0.0001). There were no statistically significant differences in the other subgroups examined. CONCLUSION: CDK4/6 inhibitors are equally effective as first-line treatment agents, regardless of the exact level of HER2 expression. Numerical differences, however, do exist among the different HER2 subgroups, and merit further evaluation in future studies to better study this phenomenon. Copyright 2022, International Institute of Anticancer Research.
Entities:
Keywords:
Breast cancer; CDK 4/6 inhibitors; HER2-low; hormone receptor positive
Authors: George Douganiotis; Loukas Kontovinis; Efrosini Markopoulou; Alexandra Ainali; Thomas Zarampoukas; Ioannis Natsiopoulos; Konstantinos Papazisis Journal: Cancer Diagn Progn Date: 2022-05-03
Authors: Gabriel N Hortobagyi; Salomon M Stemmer; Howard A Burris; Yoon-Sim Yap; Gabe S Sonke; Lowell Hart; Mario Campone; Katarina Petrakova; Eric P Winer; Wolfgang Janni; Pierfranco Conte; David A Cameron; Fabrice André; Carlos L Arteaga; Juan P Zarate; Arunava Chakravartty; Tetiana Taran; Fabienne Le Gac; Paolo Serra; Joyce O'Shaughnessy Journal: N Engl J Med Date: 2022-03-10 Impact factor: 176.079