Safe neoadjuvant trastuzumab-based treatment in HER2 + inflammatory early breast cancer in a glucose 6-phosphate dehydrogenase-deficient postmenopausal woman: A case report and review of the literature.

Glucose 6-phosphate dehydrogenase (G6PD) is a basic antioxidant pathway for erythrocytes, being its deficiency the most common gene mutation worldwide. As breast cancer is one of the most frequent tumors, many of these patients may present with G6PD deficiency prior treatment without notice.We present the case of a woman deficient for G6PD with the diagnosis of Stage IIIB (cT4d cN1 cM0) HER2-enriched early breast cancer.

The patient underwent neoadjuvance with trastuzumab and anthracycline-free chemotherapy, based on docetaxel (75 mg/m², 120 mg) and carboplatin (AUC 5, 560 mg). She did not present hemolytic crisis and no blood transfusions were needed. She achieved a good pathologic response and completed one-year adjuvant trastuzumab without incidences.

Although the role of HER2 and trastuzumab in oxidative stress is not yet completely understood, we suggest that trastuzumab may be a suitable agent for treatment in patients with HER2-enriched breast cancer in a non-oxidative chemotherapy scheme, with acceptable responses and no triggering hemolytic crisis.