Cancer-Related Fever in Metastatic Prostate Cancer: A Case Report.

Fever in cancer patients is often mistakenly attributed to infection, leading to unnecessary antibiotic use. Neoplastic fever, though well-documented in hematologic malignancies, is rare in solid tumors, particularly prostate cancer. This case report presents an 81-year-old male with metastatic prostate cancer, who was admitted to Razi Hospital in Qaemshahr, Mazandaran, with persistent fever, chills, and urinary symptoms following radiotherapy. Despite broad-spectrum antibiotics, the fever persisted, and extensive infectious workups yielded no identifiable source. The patient's condition was further complicated by hyponatremia, elevated inflammatory markers, and a negative initial blood culture. As the fever continued, oncological evaluation was initiated, leading to the diagnosis of neoplastic fever. Chemotherapy with docetaxel and zoledronic acid resulted in the resolution of fever, confirming the oncologic nature of the fever. This case underscores the importance of recognizing neoplastic fever in cancer patients with persistent fever of unknown origin, particularly when infectious causes have been excluded. Early oncologic intervention, rather than prolonged antibiotic therapy, can prevent unnecessary treatments and improve patient outcomes. This case highlights the need for a high index of suspicion in managing cancer patients with fever, especially in the absence of an infectious etiology.