Introduction：Hyponatremia, which is frequently present in patients with end-stage cancer, causes delirium and disturbance of consciousness and is considered a poor prognostic factor. We report a case of hyponatremia with hypopituitarism in association with leptomeningeal metastasis, resulting in reversible disturbance of consciousness. Case report：A 77 year-old female received chemotherapy at our hospital for postoperative recurrence of lung cancer, and best supportive care due to a side effect. After transfer to another hospital, she experienced a sudden disturbance of consciousness and was returned to our hospital. A detailed examination resulted in a diagnosis of hyponatremia from hypopituitarism following leptomeningeal metastasis involving the cerebral ventricles. Hyponatremia was improved by NaCl supplement and hormone replacement, followed by recovery from disturbance of consciousness. Discussion：QOL of patients with end-stage cancer can be improved through the active treatment of reversible causes of disturbance of consciousness. Conclusion：When severe hyponatremia is detected in cancer patients, it is important to consider the possibility of hypopituitarism with brain metastasis or meninges dissemination in the differential diagnosis.

For patients with epidermal growth factor receptor (EGFR) mutation-positive lung cancer, the relationship between the dose or duration of treatment with tyrosine kinase inhibitor (TKI) and overall survival remains unclear. Here, we analyzed clinical data of 39 patients who were diagnosed with EGFR mutation-positive non-small cell lung cancer and treated with TKI, but subsequently died. Several parameters were measured in this study: overall survival; first, second, and overall TKI therapy durations; first TKI intensity (actual dose/normal dose); and TKI rate (overall TKI therapy duration/overall survival). The response rate to TKI therapy was 50%, and the median survival was 553 days. After TKI therapy failed, 38.5% patients were re-challenged with TKI. We observed a moderate relationship [r = 0.534, 95% confidential interval (CI) = 0.263 to 0.727, P < 0.001] between overall TKI therapy duration and overall survival. However, we found no relationship between overall survival and first TKI intensity (r = 0.073, 95% CI = -0.380 to 0.247, P = 0.657) or TKI rate (r = 0.0345, 95% CI = -0.284 to 0.346, P = 0.835). Non-small cell lung cancer patients with mutation-positive tumors remained on TKI therapy for, on average, 33% of the overall survival time. These findings suggest that patients with EGFR mutation-positive tumors should not stick to using TKIs.
Aged ; Aged, 80 and over ; Antineoplastic Agents ; administration & dosage ; therapeutic use ; Carcinoma, Non-Small-Cell Lung ; drug therapy ; genetics ; Dose-Response Relationship, Drug ; Erlotinib Hydrochloride ; Female ; Humans ; Lung Neoplasms ; drug therapy ; genetics ; Male ; Middle Aged ; Mutation ; Protein Kinase Inhibitors ; administration & dosage ; therapeutic use ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; Quinazolines ; administration & dosage ; therapeutic use ; Receptor, Epidermal Growth Factor ; genetics ; Survival Rate