術前化学療法後に腹腔鏡下内肛門括約筋切除と腟後壁合併切除を行った高度局所進行直腸癌の1例

Neoadjuvant chemotherapy followed by laparoscopic intersphincteric resection combined with the posterior wall of the vagina for locally advanced rectal cancer : report of a case

◆要旨：患者は33歳の未婚女性．主訴は下痢と体重減少．大腸内視鏡検査にて下部直腸から肛門管にかかる腫瘍を認め，生検で中分化腺癌と診断された．CTおよびMRI検査では腫瘍は腟後壁への浸潤を認め，肛門挙筋に接して存在した．また左閉鎖リンパ節の腫大を認めた．強い肛門温存と挙児希望があり，術前化学療法として〔XELOX（オキサリプラチン＋カペシタビン）＋ベバシズマブ〕を導入した．4コース施行後の治療効果はPRと腫瘍は著明な縮小を認めたため，腹腔鏡下内肛門括約筋切除術，腟後壁合併切除＋両側側方郭清を施行した．最終病理診断では残存腫瘍は認めず，病理学的完全奏効（pCR）と判定された．

　A 33-year-old unmarried female with a chief complaint of diarrhea and weight loss was referred to our hospital. Colonoscopy revealed a low rectal tumor and biopsy of the tumor demonstrated moderately differentiated adenocarcinoma. Computed tomography（CT） and magnetic resonance imaging（MRI） showed that the tumor involved the posterior wall of the vagina and was very close to the levator ani. Although abdominoperineal resection combined resection of the posterior wall of the vagina was recommended for complete surgical resection, the patient strongly hoped to preserve sphincter function. She agreed to participate a multicenter phase II trial of neoadjuvant chemotherapy without radiotherapy for locally advanced rectal cancer and 4 cycles of XELOX（oxaliplatin ＋ capecitabin）＋ bevacizumab regimen was inducted. Bevacizumab was not included in the 4th cycle. CT and MRI after 4 cycles of chemotherapy showed a remarkable regression of the tumor and the response was judged to be partial response according to the Response Evaluation Criteria in Solid Tumors. Therefore, she underwent laparoscopic intersphincteric resection combined resection of the posterior wall of the vagina, and bilateral lateral pelvic lymph node dissection. Pathological findings demonstrated no residual cancer cells（pathological complete response : pCR）.