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Multiple Endocrinology Immune-Related Adverse Events (irAEs) Related to Pembrolizumab as Neoadjuvant Treatment in Two Cases of TNBC Patients: Case Reports and Literature Review
by
Khashayar Yazdanpanah Ardakani
1,*, 
Gaia Passarella
2,3,
Andrea Gerardo Antonio Lania
4,5, 
Thoma Dario Clementi
1,
Alessandro Fanti
4,5,
Francesca Fulvia Pepe
2,
Serena Capici
2 and
Marina Elena Cazzaniga
1,2,* 1
School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
2
Phase 1 Research Center, Fondazione IRCC San Gerardo dei Tintori, 20090 Monza, Italy
3
Facoltà di Medicina e Chirurgia, Università degli studi di Brescia, 25121 Brescia, Italy
4
Endocrinology and Diabetology Unit, IRCCS Humanitas Research Hospital, 20089 Rozzano, Italy
5
Department of Biomedical Sciences, Humanitas University, 20072 Milan, Italy
*
Authors to whom correspondence should be addressed.
Curr. Oncol. 2026, 33(1), 28; https://doi.org/10.3390/curroncol33010028
Submission received: 15 November 2025
/
Revised: 31 December 2025
/
Accepted: 2 January 2026
/
Published: 4 January 2026
(This article belongs to the Section Breast Cancer)
Simple Summary
irAEs can happen in any patient receiving ICIs, either in a metastatic or non-metastatic setting. Given their increasing application in clinical practice, understanding the underlying causes and manifestations, as well as diagnosis and management, is of great importance, making it one of the most important topics to be investigated regarding the effect on a patient’s life quality as well as quality of treatment. Here, we discuss the cases of two patients with the diagnosis of TNBC, receiving an anti-PD1 mAb, pembrolizumab, in the neoadjuvant setting presenting with dual endocrine-related irAEs. The flow of diagnosis, treatment, and patient’s consideration as well as risk factors are explained and discussed by the authors, while the management of endocrine-related adverse events is explained by two endocrinologists with expertise in management of these complications.
Abstract
Pembrolizumab, an anti-PD-1 monoclonal antibody, showed promising results in the treatment of different types of solid tumors and generally an improvement in overall survival and patients’ outcome. However, as a drug that targets the immune system to enhance the anti-tumor response, it simultaneously increases the risk of autoimmune reactions, producing immune-related adverse events (irAEs). These irAEs might involve any body organ, and in some cases may lead to treatment discontinuation. In this article, we discuss two cases of triple-negative breast cancer (TNBC) patients, who developed irAEs during the course of neoadjuvant pembrolizumab, highlighting the mechanism of the reactions, possible clinical manifestations, and potential management.
