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Kazutomo Togashi

Publications and source records attributed to Kazutomo Togashi.

9 recordsLinked to original sources
PubMed2006

High prevalence of sessile serrated adenomas with BRAF mutations: a prospective study of patients undergoing colonoscopy.

BACKGROUND & AIMS: Sporadic colorectal cancers with a high degree of microsatellite instability are a clinically distinct subgroup with a high incidence of BRAF mutation and are widely considered to develop from serrated polyps. Previous studies of serrated polyps have been highly selected and largely retrospective. This prospective study examined the prevalence of sessile serrated adenomas and determined the incidence of BRAF and K-ras mutations in different types of polyps. METHODS: An unselected consecutive series of 190 patients underwent magnifying chromoendoscopy. Polyp location, size, and histologic classification were recorded. All polyps were screened for BRAF V600E and K-ras codon 12 and 13 mutations. RESULTS: Polyps were detected in 72% of patients. Most (60%) were adenomas (tubular adenomas, tubulovillous adenomas), followed by hyperplastic polyps (29%), sessile serrated adenomas (SSAs; 9%), traditional serrated adenomas (0.7%), and mixed polyps (1.7%). Adenomas were more prevalent in the proximal colon (73%), as were SSAs (75%), which tended to be large (64% >5 mm). The presence of at least one SSA was associated with increased polyp burden (5.0 vs 2.5; P < .0001) and female sex (P < .05). BRAF mutation was rare in adenomas (1/248 [0.4%]) but common in SSAs (78%), traditional serrated adenomas (66%), mixed polyps (57%), and microvesicular hyperplastic polyps (70%). K-ras mutations were significantly associated with goblet cell hyperplastic polyps and tubulovillous adenomas (P < .001). CONCLUSIONS: The prevalence of SSAs is approximately 9% in patients undergoing colonoscopy. They are associated with BRAF mutation, proximal location, female sex, and presence of multiple polyps. These findings emphasize the importance of identifying and removing these lesions for endoscopic prevention of colorectal cancer.

Adenoma↗
PubMed2006

Magnification chromo-colonoscopy.

Chromoscopic colonoscopy using indigo carmine is indispensable for the accurate detection of flat neoplastic lesions. In particular, the dye spray technique facilitates the detection of both flat hyperplastic polyps and highly dysplastic lesions. However, magnification chromo-colonoscopy discriminates adenomas from hyperplastic polyps with greater accuracy than conventional methods by showing distinct and visible pit patterns. A pit pattern represents crypt orifices, which reflect the underlying histological structures and colonoscopists can make histological predictions by observing the pit patterns without obtaining biopsy specimens. The pit patterns are classified as types I, II, IIIL, IIIs, IV and V based on histological characterization of normal mucosa, hyperplastic polyp, polypoid adenoma, flat adenoma, tubulo-villous adenoma and cancerous tissue, respectively. In previous reports, overall accuracy ranged from 80 to 95%. In addition, magnification chromo-colonoscopy is useful for the diagnosis of early cancer associated with substantial invasion of the submucosa, in which type V pits are subclassified as types V-I and V-N. The presence of type V-N pits is significant in correlation to cancer with substantial invasion of the submucosa. Magnification chromo-colonoscopy is useful in clinical decision-making when deciding whether endoscopic resection or bowel resection is the appropriate initial procedure to treat lesions.

Colonic Neoplasms↗
PubMed2005

Microsatellite instability caused by hMLH1 promoter methylation increases with tumor progression in right-sided sporadic colorectal cancer.

OBJECTIVE: A subset of sporadic colorectal cancers (SCRCs) exhibits microsatellite instability (MSI). Most MSI in SCRCs is caused by hMLH1 inactivation due to promoter methylation. However, the role of MSI in the progression of SCRCs remains unclear. METHODS: Thirty-two intramucosal cancers and 63 cancers with submucosal invasion were assigned to group 1 (early-stage cancer), and 30 Dukes' B and 26 Dukes' C cancers to group 2 (advanced-stage cancer). hMLH1 promoter methylation status was determined by methylation-specific PCR. MSI was determined using five markers. hMLH1 expression was determined immunohistochemically. RESULTS: MSI was found in 1 of 95 (1.1%) tumors in group 1, compared with 4 of 56 (7.1%) tumors in group 2. In right-sided tumors, the overall frequency of hMLH1-methylation-positive tumors in group 1 was not significantly different from that in group 2 (17 of 43, 39.5%, vs. 9 of 23, 39.1%). In right-sided tumors with hMLH1 promoter methylation, the frequency of MSI-positive tumors in group 1 was significantly lower than that in group 2 (1 of 17, 5.9%, vs. 4 of 9, 44.4%, p=0.0081). CONCLUSION: The frequency of MSI caused by hMLH1 promoter methylation increases with tumor progression in right-sided SCRCs.

Adaptor Proteins, Signal Transducing↗
PubMed2005

Distribution of lymph node metastasis in T1 sigmoid colon carcinoma: should we ligate the inferior mesenteric artery?

OBJECTIVE: In standard oncological sigmoid colectomy, the inferior mesenteric artery is ligated either at its origin or at the level of the left colic artery. However, in patients with early-stage carcinoma, the distribution of metastatic nodes may be limited. The aim of this study was to clarify the prevalence and distribution of lymph node metastasis in T1 sigmoid colon carcinoma and to determine the adequate range of lymph node dissection. MATERIALS AND METHODS: The study included 121 consecutive patients treated for T1 sigmoid colon carcinoma. Clinicopathologic factors associated with nodal metastasis and the distribution of metastatic nodes were analyzed. RESULTS: Of 121 patients, 12 (10%) had nodal involvement. The depth of invasion and the presence of lymphatic and vascular invasion were significantly associated with nodal metastasis. Of these 12 patients, 11 (92%) had lymph node metastasis confined to pericolic nodes. Nodes along the sigmoidal artery were involved in one patient. There was no involved node along the superior rectal artery or at the root of the inferior mesenteric artery. CONCLUSIONS: Lymph node dissection for T1 sigmoid colon carcinoma should be limited to the root of the sigmoidal artery, and the inferior mesenteric artery should be preserved.

Adenocarcinoma↗
PubMed2003

Predictive factors for lymph node metastasis in T1 stage colorectal carcinomas.

PURPOSE: Selective endoscopic resection may cure early colorectal cancer (T1), but the management is controversial. There is concern about the small risk of lymph node metastasis, which will not be treated by endoscopic resection alone. The authors sought predictive markers of lymph node metastasis to assist patient management. METHODS: The authors retrospectively analyzed consecutive cases of T1 stage colorectal cancer resected using endoscopic resection or bowel surgery over the period 1979 to 2000. The risk of lymph node metastasis was analyzed using logistic regression model for the markers selected by univariate analysis: the type of initial treatment, depth of submucosal invasion, lymphatic channel invasion, differentiation of histology, and invasive front histology. RESULTS: Two hundred seventy-eight patients were available for study. Twenty-one had lymph node metastasis. Depth of submucosal invasion (> or = 2,000 microm) and lymphatic channel invasion significantly predicted risk of lymph node metastasis in multivariate analysis. When these two factors were adopted for the prediction of lymph node metastasis, sensitivity, specificity, positive predictive value, and negative predictive value were 100, 55.6, 15.6, and 100 percent, respectively. CONCLUSIONS: Depth of submucosal invasion and lymphatic channel invasion were accurate predictive factors for lymph node metastasis. These two factors could be used in selecting appropriate cases for surgery after endoscopic resection.

Aged↗
PubMed2003

Localized giant inflammatory polyposis of the cecum associated with distal ulcerative colitis.

This case report describes a 68-year-old man who presented with bronchiolitis obliterans organizing pneumonia (BOOP) and gastric carcinoma. During evaluation, including a colonoscopy, he was found to have distal colitis and a giant polypoid lesion in the cecum that was diagnosed as localized giant inflammatory polyposis (LGIP) by magnifying colonoscopy. The patient was treated over a period of 3 years without surgery, and the LGIP was reduced in size during the follow-up period. Magnifying observation was useful to distinguish LGIP from a neoplastic lesion.

Aged↗
PubMed2003

Appropriate operation for elderly colorectal cancer patients based upon an assessment of preoperative risk factors.

PURPOSE: The correlation between age and the outcome following an operation for colorectal cancer (CRC) has not yet been determined. We studied the appropriate operation for elderly CRC patients based upon the assessment of preoperative risk factors. METHODS: Seventy patients with Dukes' stages B or C CRC (more than 80 years old: aged group) and 66 stage-matched patients (50-69 years old: control group) were studied. The preoperative condition, the grade of surgical intervention, the perioperative activities of daily life (ADL), and the survival rate were compared between the two groups. RESULTS: The preoperative conditions were significantly worse and the frequencies of patients with a deterioration in ADL during the perioperative period were significantly higher in the aged group. In the aged group, the peripheral lymphocyte count was significantly lower in patients with major postoperative complications, and the 1.0% forced expiratory volume (FEV1.0%) was significantly lower in patients with a deterioration in ADL. The low grade of surgical intervention tended to be related to a poor prognosis in rectal cancer of the aged group. CONCLUSION: The indications for operation in elderly CRC patients should be determined based upon an appropriate assessment of preoperative conditions, such as the lymphocyte count and FEV1.0%.

Activities of Daily Living↗
PubMed2002

Microsatellite instability as a marker in predicting metachronous multiple colorectal carcinomas after surgery: a cohort-like study.

PURPOSE: In case-control studies, it was reported that microsatellite instability might be helpful in predicting the development of metachronous multiple colorectal cancers. The purpose of this cohort-like study was to determine whether microsatellite instability is a novel independent marker in predicting metachronous colorectal carcinomas after colorectal cancer surgery. METHODS: Three hundred twenty-eight colorectal carcinoma patients were surveyed by periodic colonoscopy for at least three years after surgery. Among these, DNA from paraffin-embedded sections was available for 272 cases. DNA of these cases was studied for six microsatellite markers (five dinucleotide repeats, one mononucleotide repeat). Microsatellite instability phenotype was defined as alterations in one or more loci. RESULTS: Median follow-up period was 74 months, and the median number of colonoscopies was 4.6. The percentage of microsatellite instability-positive cases was 26.4 percent (72/272). Seventeen metachronous colorectal carcinomas were detected during the follow-up period. Incidences of metachronous colorectal carcinomas in microsatellite instability-positive and microsatellite instability-negative cases were 15.3 and 3 percent, respectively (P < 0.001). The cumulative five-year incidence of metachronous colorectal carcinomas was significantly higher in microsatellite instability-positive cases than in microsatellite instability-negative cases (12.5 vs. 2.5 percent, P < 0.0001). Logistic regression analysis of the relationship between incidence of metachronous colorectal carcinomas and possible risk factors (namely, coexistence of adenoma at the time of surgery, family history of colorectal carcinoma, history of extracolonic malignancy, and microsatellite instability status) showed that microsatellite instability and coexistence of adenoma were significant independent risk factors for the occurrence of metachronous colorectal carcinomas, with values of P = 0.001 and 0.02, respectively. CONCLUSION: These data indicate that microsatellite instability can be regarded as a novel independent and important marker for predicting the development of metachronous colorectal carcinoma after surgery.

Carcinoma↗