[A case of neuroendocrine carcinoma of the anal canal with multiple bone metastases successfully treated with combined modality therapy].

Neuroendocrine carcinoma (NEC) of the anal canal is a comparatively rare tumor with a poor prognosis. We report herein a case of NEC of the anal canal with multiple bone metastases that was successfully treated with combined therapy. A 63-year-old man was referred to our hospital with the chief complaint of anal and back pain. A tumor was found in the anal canal, and pathologic examination revealed it to be NEC( Ki-67 expression>50%); fluorodeoxyglucose( FDG) positron emission tomography (PET)-computed tomography (CT) showed multiple bone metastases. Initially, a l-leucovorin/5- fluorouraci(l 5-FU)/oxaliplatin( L-OHP)(: mFOLFOX6)/bevacizumab( Bmab) regimen and octreotide were administered to treat the unresectable and advanced NEC. Strontium-89 and zoledronate were used to treat pain related to the bone metastases. After 3 months, the tumor and bone metastases became difficult to identify. The patient experienced grade 2 neurotoxicity after 5 months, and thus, we stopped L-OHP administration. After 10 months, we reintroduced L-OHP because of additional progression of the bone metastases.