Isolated Adrenocorticotropic Hormone Deficiency during Preoperative Chemotherapy with Pembrolizumab—A Case Report—

Abstract

The KEYNOTE-522 trial demonstrated the efficacy of pembrolizumab (pembro) in a patient with early high-risk triple-negative (TN) breast cancer. Perioperative treatment with pembro was also implemented at our institution. Herein, we report a case of isolated adrenocorticotropic hormone (ACTH) deficiency and secondary adrenal insufficiency due to immune-related hypohysitis during pembro administration.

A 56-year-old woman was diagnosed with invasive ductal carcinoma, high-grade TN breast cancer, and T2N1M0 Stage IIB. After completing the first four cycles of treatment, she experienced worsening fatigue, loss of appetite, hyponatremia, and a marked decrease in cortisol and ACTH levels. She was diagnosed with isolated ACTH deficiency and secondary adrenal insufficiency caused by pembro. Her symptoms improved with steroid replacement therapy. For the remaining treatment cycle, only epirubicin and cyclophosphamide (EC) were administered, followed by surgery. The final pathology revealed pathological complete response (pCR). Postoperatively, pembro was continued with steroid treatment.

Early diagnosis and timely intervention are crucial to prevent life-threatening complications. To the best of our knowledge, this is the first reported case of isolated ACTH in a patient with breast cancer. Further accumulation of cases is required to better characterize this adverse effect.