Eiji Hidaka

Management of T1 colorectal cancers after endoscopic treatment based on the risk stratification of lymph node metastasis.

Recent advances in endoscopic technology have allowed many T1 colorectal carcinomas to be resected endoscopically with negative margins. However, the criteria for curative endoscopic resection remain unclear. We aimed to identify risk factors for nodal metastasis in T1 carcinoma patients and hence establish the indication for additional surgery with lymph node dissection.

Accuracy of diagnosing invasive colorectal cancer using computer-aided endocytoscopy

Background and study aims Invasive cancer carries the risk of metastasis, and therefore, the ability to distinguish between invasive cancerous lesions and less-aggressive lesions is important. We evaluated a computer-aided diagnosis system that uses ultra-high (approximately × 400) magnification endocytoscopy (EC-CAD). Patients and methods We generated an image database from a consecutive series of 5843 endocytoscopy images of 375 lesions. For construction of a diagnostic algorithm, 5543 endocytoscopy images from 238 lesions were randomly extracted from the database for machine learning. We applied the obtained algorithm to 200 endocytoscopy images and calculated test characteristics for the diagnosis of invasive cancer. We defined a high-confidence diagnosis as having a ≥ 90 % probability of being correct. Results Of the 200 test images, 188 (94.0 %) were assessable with the EC-CAD system. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were 89.4 %, 98.9 %, 94.1 %, 98.8 %, and 90.1 %, respectively. High-confidence diagnosis had a sensitivity, specificity, accuracy, PPV, and NPV of 98.1 %, 100 %, 99.3 %, 100 %, and 98.8 %, respectively. Conclusion: EC-CAD may be a useful tool in diagnosing invasive colorectal cancer.

Tumor diameter is an easy and useful predictor of recurrence in stage II colorectal cancer

Background/Aims: Adjuvant chemotherapy for stage II colorectal cancer (CRC) can generally be administered to high-risk subgroups. To better identify these patients, we aimed at assessing factors that affect recurrence. Methods: In our hospital, 432 colon and 96 rectal stage II cancer patients who underwent surgical resection between 2001 and 2011 were divided into recurrence and non-recurrence groups. Age, sex, lymphatic vessel invasion, venous invasion, tumor diameter, tumor depth, histological type, preoperative carcinoembryonic antigen level, number of sampled nodes, adjuvant chemotherapy, morphology, surgical approach, anastomotic leakage, preoperative bowel obstruction, and preoperative perforation were retrospectively compared between the groups. Results: For colon cancer, multivariate analysis revealed a significant association between tumor diameter ≥40 mm and recurrence (p = 0.039). For rectal cancer, multivariate analysis revealed that tumor diameter ≥50 mm (p = 0.001) and ≤12 sampled nodes (p = 0.021) were associated with recurrence. Tumor diameter in rectal cancer was associated with worse disease-free survival (p = 0.026). Conclusion: Tumor diameter is a significant predictor of recurrence in stage II CRC. This is an important finding because tumor diameter is easy to evaluate clinically and might help to identify candidates for adjuvant chemotherapy.

Transverse colon cancer occurring at a colostomy site 35 years after colostomy: a case report.

BackgroundCarcinomas occurring at colostomy sites are rare, and most of these are metachronous colorectal cancers. The median time between colostomy and development of a carcinoma at a colostomy site is 22 years, which exceeds the length of the recommended follow-up period. We report a rare case of a carcinoma of the transverse colon occurring at a colostomy site in a patient without a history of colorectal cancer.Case reportAn 89-year-old woman presented with a tumor occurring at a colostomy site. Thirty-five years previously, she had undergone a transverse loop colostomy for an iatrogenic colon perforation that occurred during left ureteral lithotomy. Upon physical examination, the patient had a hard nodule measuring 3 cm at the colostomy site. A biopsy of the nodule suggested adenocarcinoma, and the preoperative diagnosis was transverse colon cancer. A laparotomy was performed via a peristomal incision with 5-mm skin margins, and the tumor was covered by a surgical glove to avoid any tumor seeding. The colon was separated from the tumor by 5-cm margins, and the specimen was removed en bloc. An end colostomy was constructed to a new site on the right side of the abdomen. The deficit in the abdominal wall was repaired, and the skin was closed via a purse-string suture. The final diagnosis of the stoma tumor was transverse colon cancer (T2, N0, M0, stage I). One year and five months after surgery, there was no evidence of recurrence.ConclusionsThe occurrence of carcinomas at colostomy sites in patients without a history of colorectal cancer is rare. It is important to train ostomates to monitor the stoma for possible tumor recurrence.

Comparative clinicopathological characteristics of colon and rectal T1 carcinoma

Lymph node metastasis significantly influences the management of patients with colorectal carcinoma. It has been observed that the biology of colorectal carcinoma differs by location. The aim of the current study was to retrospectively compare the clinicopathological characteristics of patients with colon and rectal T1 carcinomas, particularly their rates of lymph node metastasis. Of the 19,864 patients who underwent endoscopic or surgical resection of colorectal neoplasms at Showa University Northern Yokohama Hospital, 557 had T1 surgically resected carcinomas, including 457 patients with colon T1 carcinomas and 100 patients with rectal T1 carcinomas. Analysed clinicopathological features included patient age, gender, tumor size, morphology, tumor budding, invasion depth, vascular invasion, histological grade, lymphatic invasion and lymph node metastasis. Rectal T1 carcinomas were significantly larger than colon T1 carcinomas (mean ± standard deviation: 23.7±13.1 mm vs. 19.9±11.0 mm, P<0.01) and were accompanied by significantly higher rates of vascular invasion (48.0% vs. 30.2%, P<0.01). Significant differences were not observed among any other clinicopathological factors. In conclusion, tumor location itself was not a risk factor for lymph node metastasis in colorectal T1 carcinomas, even though on average, rectal T1 carcinomas were larger and accompanied by a significantly higher rate of vascular invasion than colon T1 carcinomas.

Fecal Volume after Laparoscopic Low Anterior Resection Predicts Anastomotic Leakage

Background/Aim: Anastomotic leakage (AL) is a major complication after laparoscopic low anterior resection (Lap-LAR). Many surgeons encounter AL following severe postoperative diarrhea. However, little is known about the relationship between postoperative fecal volume and AL. This study determined whether postoperative fecal volume can predict AL. Methods: A retrospective assessment was performed with data from 176 patients with rectal cancers who underwent Lap-LAR between April 2011 and August 2015. A transanal tube was routinely placed in all cases. The fecal volume from the transanal tube was measured daily. The total fecal volume for 3 days after surgery was compared between the AL and non-AL groups. Results: AL occurred in 11 patients. There were 3 patients with a fecal volume ≥1,000 mL for 3 days after surgery. AL occurred in these 3 patients. In patients with a fecal volume <1,000 mL, the total fecal volume was significantly greater in the AL group than that in the non-AL group (p = 0.0003). The cut-off value of the total fecal volume in AL was 118 mL. Conclusions: The volume of fecal discharge for 3 days after surgery is associated with the incidence of AL, and a fecal volume ≥118 mL may be a reliable predictor for AL.

Comparison of the endocytoscopic and clinicopathologic features of colorectal neoplasms

Background and aim: Permeation of a vein or lymphatic vessel by a tumor is a key risk factor for lymph node metastasis. We examined the features of colorectal tumor vessel permeation using endocytoscopy, an ultra-high magnifying endoscopic system combined with a narrow-band imaging capability (EC-NBI). Patients and methods: We examined 188 colorectal lesions using EC-NBI before treatment was started. We measured the diameters of tumor vessels on EC-NBI images. We used the tumor vessel diameter (the mean diameter of four tumor-associated vessels) and the variation in tumor vessel caliber (the difference between the maximum and minimum diameters of the vessels expressed as a proportion) to judge changes in vessel formation. We examined the relationship between these variables and the extent of venous or lymphatic vessel permeation (vessel invasion) established by immunohistochemical examination of the resected specimen using monoclonal antibodies against the CD34 and D2 – 40 antigens. We also analyzed the relationships between tumor vessel diameter, tumor vessel caliber variation, and depth of tumor invasion. Results: There were significant differences in tumor vessel diameter and caliber variation between tumors in situ and T1 – T3 carcinomas. In T1 carcinomas, larger tumor vessel diameter and greater tumor vessel caliber variation were significantly associated with venous permeation. In T2 and T3 carcinomas, greater tumor vessel caliber variation was significantly associated with venous permeation. Conclusions: The vessel diameter and caliber variation of colorectal tumor microvasculature are associated with depth of invasion and venous permeation, especially in T1 carcinomas.

Laparoscopic Extirpation of a Schwannoma in the Lateral Pelvic Space

Schwannomas in the lateral pelvic space are very rare. Here, we report the case of a 48-year-old woman who had a tumor detected in her abdomen by abdominal ultrasonography. Abdominal computed tomography and magnetic resonance imaging revealed a well-defined solid tumor of 65 mm in diameter in the right lateral pelvic space. We performed laparoscopic surgery under a diagnosis of a gastrointestinal tumor or neurogenic tumor. The tumor was safely dissected and freed from the surrounding tissues using sharp and blunt maneuvers. The tumor originated from the right sciatic nerve. Complete laparoscopic extirpation was performed with preservation of the right sciatic nerve. Pathological examination suggested schwannoma. The patient recovered well but had remaining sciatic nerve palsy in her right foot. Laparoscopic extirpation for a schwannoma in the lateral pelvic space was safe and feasible due to the magnified surgical field afforded by laparoscopy.

Complete laparoscopic surgery for early colorectal cancer after endoscopic resection

Laparoscopic‐assisted colorectal surgery requires a mini‐laparotomy to extract the specimen and insert the anvil head of the circular stapler into the proximal colon. However, such a mini‐laparotomy occasionally causes local pain and surgical‐site infection. To avoid mini‐laparotomy, we invented a new laparoscopic technique, complete laparoscopic surgery for colorectal cancer.

Retrospective analysis of large bowel obstruction or perforation caused by oral preparation for colonoscopy

Background and study aims  Patients undergoing bowel preparation for colonoscopy are at risk of potentially severe adverse events such as large-bowel obstruction (LBO) and perforation. These patients usually need emergency surgery and the consequences may be fatal. Little is known about the risk factors for LBO and perforation in these circumstances. We sought to establish the natural history of LBO and perforation caused by oral preparation for colonoscopy. Patients and methods  We retrospectively analyzed data from 20 patients with LBO or perforation associated with oral preparation for colonoscopy. All patients were treated at the Showa University Northern Yokohama Hospital (SUNYH) between April 2001 and December 2015. Drugs used for bowel preparation, age, sex, indication for colonoscopy, pathogenesis and treatment were recorded. Results  Eighteen of the patients had LBO and 2 had perforation. Fourteen events occurred at SUNYH, which accounted for 0.016 % of patients who underwent bowel preparation during this period. Seventeen patients were symptomatic when the decision to undertake colonoscopy was made (including 7 who complained of constipation and 4 who complained of abdominal pain; 3e were asymptomatic). Nineteen patients ultimately required surgery, 13 within 3 days of presentation. Eleven patients ultimately required colostomy. There was no perioperative mortality in our cases. Conclusion  Large bowel obstruction and perforation are rare events associated with oral preparation for colonoscopy, but frequently require surgery. Exacerbation of constipation might be a risk factor for LBO or perforation. Potentially catastrophic situations can be avoided by early detection and treatment.