A rare case of a patient with a high grade neuroendocrine tumor developing neutropenic sepsis after receiving PRRT combined with Capecitabine or Temozolomide: A case report

Neuroendocrine tumors (NET) are rare and demonstrate variable clinical behavior depending on the degree of tumor differentiation. Patients with poorly differentiated tumors (NET G3) have a poor prognosis. Systemic treatment with cytotoxic chemotherapy is considered to be the treatment of choice. In patients that are refractory or intolerant to first-line therapy, experts recommend peptide receptor radionuclide therapy (PRRT) in tumors that express somatostatin receptors. Recently, combinations of PRRT and chemotherapy were tested in patients with NET. Available data have reported promising tumor control rates and an excellent toxicity profile in cases where PRRT had been administered with capecitabine/temozolomide, even when administered as salvage therapy. The current study reported an exceptional case of advanced NET G3 with severe toxicity upon receiving PRRT in combination with capecitabine/temozolomide as third line therapy. The patient developed a life-threatening neutropenic fever, fungal pneumonia and necrotizing mastitis 23 days after the first cycle of therapy was administered. However, the treatment led to a significant reduction in tumor size. A total of 5 months after treatment initiation, the patient was alive and in excellent clinical condition with sustained tumor response. In summary, the current study presented a rare case of high grade NET exhibiting an almost complete response to PRRT in combination capecitabine/temozolomide, despite facing unexpected severe toxicity.