title: [Two cases of surgical resection of rectal gastrointestinal stromal tumor after neoadjuvant therapy with imatinib mesylate].
abstract: Case 1: A 58-year-old man who initially presented with diarrhea was diagnosed with rectal gastrointestinal stromal tumor (GIST). The patient initially received neoadjuvant therapy with imatinib mesylate. After imatinib therapy( 400 mg/day) for 23 weeks, the patient's abdominal computed tomography (CT) and magnetic resonance imaging (MRI) scans showed a reduction of approximately 67% in tumor size. He underwent sphincter-preserving surgery with intersphincteric resection, and the tumor was resected radically and safely. Case 2: A 66-year-old man with a complaint of hematochezia was diagnosed with rectal GIST during treatment for infective endocarditis. Neoadjuvant imatinib therapy (400 mg/day) was started. However, the treatment was stopped after 11 weeks because of rhabdomyolysis, which was suspected to be an adverse effect of imatinib administration. Abdominal CT and MRI revealed a reduction of approximately 53% in tumor size. A radical operation was considered feasible and sphincter-preserving surgery with intersphincteric resection was performed. Currently, neoadjuvant imatinib mesylate therapy is performed in the setting of clinical trials, but the cases suggest that it can be a promising strategy for locally advanced rectal GIST, improving the complete resection rate and the safety of operations by reducing the size of the tumor.
authors.affiliation: Dept. of Surgery, Saiseikai Shigaken Hospital, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Nakashima
authors.forename: Yuji
authors.initials: Y
authors.lastname: Fujita
authors.forename: Hisataka
authors.initials: H
authors.lastname: Matsuo
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Ariyoshi
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Fukuda
authors.forename: Junshin
authors.initials: J
authors.lastname: Fujiyama
authors.forename: Mamoru
authors.initials: M
authors.lastname: Masuyama
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D006801:Humans; D000068877:Imatinib Mesylate; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D010879:Piperazines / Q000627:therapeutic use*; D011743:Pyrimidines / Q000627:therapeutic use*; D012004:Rectal Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery
chemical_list: D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate