Pyrotinib monotherapy for advanced HER2-positive esophageal adenocarcinoma with trastuzumab resistance and chemotherapy intolerance: a case report and literature review

HER2-positive advanced esophageal adenocarcinoma (EAC) cases demonstrate a poor prognosis because of drug resistance that develops after standard first-line trastuzumab therapy. The patient was initially diagnosed with stage cT2N1M0 III EAC. He underwent neoadjuvant chemotherapy, radical esophageal resection, and postoperative adjuvant radiotherapy. However, four months after treatment, the lesion relapsed and progressed to the right back, rendering the case inoperable. Pathological analysis revealed HER2 amplification. Given a poor tolerance to chemotherapy, the patient was administered cadonilimab and trastuzumab for three months. Subsequently, the second-line therapy was switched to pyrotinib monotherapy as a salvage treatment. Remarkably, after one month of treatment, the tumor showed significant reduction, with mild toxic side effects. Pyrotinib can be used for salvage later-line therapy in HER2-positive advanced EAC with trastuzumab resistance or poor chemotherapy tolerance, which deserves further promotion.