Kousuke Tobita

Natural history of branch duct intraductal papillary mucinous neoplasm with mural nodules: a Japan Pancreas Society multicenter study.

Objective This study aimed to elucidate the natural history of intraductal papillary mucinous neoplasm (IPMN) of the pancreas with mural nodules (MNs) in branch duct IPMN (BD-IPMN). Methods Among the 402 registered patients with BD-IPMN on long-term follow-up at 10 institutions in Japan, 53 patients with MNs of less than 10 mm in height detected by endosonography were included in this study. The morphological changes of the BD-IPMN in these patients and histologic findings of the resected specimen were investigated. Results The median height of the MNs at the initial diagnosis was 3 mm (range, 1–8 mm), and 12 (23%) of the 53 patients showed an increase in the height of the MNs during follow-up (mean duration, 42 months). Six patients underwent surgery because of an increase in the height of MNs, yielding high-grade dysplasia in 1 patient and low-grade dysplasia in 5 patients. No patients developed invasive carcinoma derived from IPMN, and distinct pancreatic ductal adenocarcinoma developed in 1 (2%) patient. The incidence of the development of malignancy in BD-IPMNs, including distinct pancreatic ductal adenocarcinoma, was similar to that of those without MNs. Conclusions In patients who have BD-IPMN with MNs of less than 10 mm in height, observation instead of immediate resection is considered to be possible.

Stage II/III cancer of the rectosigmoid junction: An independent tumor type?

The 5-year relapse-free survival rate (5Y-RFS) and 5-year overall survival rate (5Y-OS) were investigated in 766 patients with stage II/III colorectal cancer (CRC). The Stage II group included 283 patients with colon cancer (CC), 40 patients with rectosigmoid junction cancer (RSC), and 74 patients with rectal cancer (RC), while the Stage III group comprised 226 patients with CC, 52 patients with RSC, and 91 patients with RC. Stage III patients with RC were further divided into 68 patients with Ra cancer (Ra, rectum/above the peritoneal reflection) and 23 patients with Rb cancer (Rb, rectum/below the peritoneal reflection). Then the 5Y-RFS and 5Y-OS were calculated for each category or subcategory. The 5Y-RFS/5Y-OS was 80.3/80.6% for Stage II patients and 63.7% (p<0.001)/66.2% (p<0.001) for Stage III patients. In the Stage II group, the survival rates were 82.9/81.2% for CC, 77.6/74.8% for RSC, and 72.9/80.5% for RC, with no significant differences between each category. In the Stage III group, the survival rates were 69.3/72.8% for CC, 71.6/77.7% for RSC, and 46.5/46.2% for RC. There was no significant difference of survival for CC vs. RSC, but significant differences were noted for CC vs. RC (p<0.001/p<0.001) and RSC vs. RC (p=0.008/p=0.007). In the Stage III group, survival rates were 71.6/77.7% for RSC, 47.6/44.8% for Ra, and 45.7/51.3% for Rb, with significant differences for RSC vs. Ra (p=0.013/p=0.005) and RSC vs. Rb (p=0.026/p=0.180), but not for Ra vs. Rb. These results suggest that Stage II/III RS cancer should be classified as colon cancer and should not be considered an independent tumor type.

Segmental Resection of the Duodenum for Early Cancer of Papilla of Vater

近年, 十二指腸乳頭部早期癌や良性疾患に対して, 根治的かつ縮小手術として, 膵温存の十二指腸下行脚分節切除, 部分切除の報告が散見される. 紹介した本術式は膵温存が可能で膵管, 胆管共通管を十二指腸壁外, 膵外で切離して十二指腸乳頭部を完全摘出でき, 十二指腸腔内の水平方向へ進展した腫瘍に対応できる. 今回, 我々は十二指腸乳頭部早期癌の2症例に膵温存十二指腸下行脚分節切除を行ったので文献的考察を含め報告する. 症例1は61歳の女性で, 非露出腫瘤型の早期癌の診断で上記手術を行い, H0, P0, M (-), pN0, pEM0, m, stage Iであった. 症例2は77歳の女性で, 露出腫瘤型の乳頭部早期癌の診断で手術を行い, 病理診断はH0, P0, M (-), pN0, pEM0, od, stage1であった. 2症例ともに術後若干の胃排泄遅延を認めたが, その後の食事摂取は良好であった. 本症例は今後, 長期の経過観察を要するが, 十二指腸乳頭部早期癌に対する根治術式として有用であると考えた.