Folinic Acid, Fluorouracil, and Oxaliplatin Therapy for Recurrent Esophageal Cancer with Syndrome of Inadequate Antidiuretic Hormone Secretion (SIADH) After Preoperative Cisplatin/5-Fluorouracil Therapy

Patient: Male, 77-year-old Final Diagnosis: Syndrome of inadequate antidiuretic hormone secretion (SIADH) Symptoms: Lightheadedness • diaphoresis • nausea • became unconscious Medication: — Clinical Procedure: — Specialty: Oncology OBJECTIVE: Rare disease BACKGROUND: Cisplatin/5-fluorouracil therapy is the standard therapy for unresectable and recurrent esophageal cancer. Cisplatin-based chemotherapy often causes adverse effects, such as nausea, vomiting, and renal dysfunction, which may necessitate dose modification or treatment prolongation. Therefore, novel combination therapies are urgently needed to improve the efficacy and overcome drug toxicity in this setting. CASE REPORT: A 77-year-old man with advanced esophageal cancer received cisplatin/5-fluorouracil therapy as neoadjuvant chemotherapy. On day 8 of administration, the patient had lightheadedness, diaphoresis, and nausea and became unconscious and developed severe hyponatremia. We diagnosed the patient with cisplatin-induced syndrome of inadequate antidiuretic hormone secretion (SIADH). Subsequently, water restriction was started, and treatment with a salt-added diet and 3% hypertonic saline infusion was initiated. The hyponatremia improved and the patient was discharged on day 16 of administration. Therefore, neoadjuvant chemotherapy was discontinued, and surgical treatment was performed. However, the tumor recurred and chemotherapy was required. The patient developed severe hyponatremia while receiving neoadjuvant chemotherapy; hence, folinic acid, fluorouracil, and oxaliplatin therapy (FOLFOX) were administered as an alternative treatment. The patient completed the FOLFOX therapy without developing SIADH. CONCLUSIONS: The cisplatin/5-fluorouracil therapy is currently the standard chemotherapy regimen for esophageal cancer. However, SIADH is a known adverse effect when using cisplatin. In patients with esophageal cancer, oxaliplatin appears to have a lower risk of SIADH than cisplatin, suggesting that oxaliplatin can be a therapeutic option for patients with esophageal cancer who are at high risk of SIADH.