S Senba

Publications (7)21.75 Total impact

• Article: Efficacy of magnifying endoscopy in the differential diagnosis of neoplastic and non-neoplastic polyps of the large bowel.

  K Togashi, F Konishi, T Ishizuka, T Sato, S Senba, K Kanazawa
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  ABSTRACT: We have introduced magnifying colonoscopy into clinical practice and analyzed its diagnostic efficacy, especially regarding the ability to distinguish neoplastic from non-neoplastic polyps. The materials consisted of 923 polyps. After identifying the lesions during normal colonoscopy, a dye was sprayed, and then the zoom apparatus of the colonoscope was used to make a magnified observation at a maximum 100 times magnification. We classified the crypt orifices into six categories and labeled them A to F as follows: A, a medium round appearance; B, an asteroid appearance; C, an elliptic appearance; D, a small, round appearance; E, a cerebriform appearance; F, no apparent structural appearance. Forty-two of 923 polyps did not reveal any clear images of crypt patterns. The percentage of histologically neoplastic change in the lesions classified as A, B, C, D, E, and F were 10, 15.9, 93.7, 100, 94.8, and 87.5 percent, respectively. When we considered types A and B to represent a crypt pattern of non-neoplastic lesions, and types C, D, E, and F to represent neoplastic lesions, and when the lesions that did not show any clear images were classified as a misjudgment, the diagnostic accuracy of neoplastic lesions (sensitivity) was 92 percent and that of non-neoplastic lesions (specificity) was 73.3 percent. Overall, the diagnostic accuracy in differentiating neoplastic from non-neoplastic lesions was 88.4 percent. Twenty-three neoplastic lesions that were misjudged to be non-neoplastic were histologically adenoma with mild atypia in 22 and adenoma with moderate atypia in 1. Magnifying colonoscopy was considered to be useful in determining the indications for colonoscopic removal.
  Diseases of the Colon & Rectum 12/1999; 42(12):1602-8. · 3.13 Impact Factor
• Article: Rectal cancer in a 13-year-old boy without a detectable germline mutation in FAP and HNPCC genes.

  H Kashiwagi, S Senba, F Konishi, M Konishi, M Miyaki, M Shoji, K Kanazawa
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  ABSTRACT: Hereditary non-polyposis colorectal cancer (HNPCC) is characterized by familial clustering and early onset. It is unclear, however, whether the early onset of colorectal cancer necessarily represents HNPCC. A 13-year-old patient had rectal cancer and underwent curative surgery. DNA from this patient was examined for replication errors (RER) and genes related to familial colorectal cancer (APC, hMSH2, and hMLH1). The patient had a negative family history of colorectal cancer, did not show the RER phenotype, and had no germline mutation of the APC, hMSH2, and hMLH1 genes. The present case suggests that an unusually young patient with colorectal cancer is not always an HNPCC proband. Observation over time, however, will be needed, as a first mutator of familial colorectal cancer could be missed.
  Journal of Gastroenterology 07/1999; 34(3):341-4. · 4.16 Impact Factor
• Article: The significance of microsatellite instability in predicting the development of metachronous multiple colorectal carcinomas in patients with nonfamilial colorectal carcinoma.

  S Masubuchi, F Konishi, K Togashi, T Okamoto, S Senba, K Shitoh, H Kashiwagi, K Kanazawa, T Tsukamoto
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  ABSTRACT: Patients with metachronous multiple colorectal carcinomas have been reported to have a higher frequency of a family history of colorectal carcinoma, associated colorectal adenomas, and extracolonic malignancies. These clinicopathologic factors also are considered to be related to the development of metachronous multiple colorectal carcinomas after surgery for colorectal carcinoma. In this article, the authors investigated whether genetic markers such as microsatellite instability (MSI) were helpful in predicting the development of metachronous multiple colorectal carcinomas. Between 1990-1997, 312 colorectal carcinoma patients underwent yearly surveillance colonoscopy after surgery. Among these patients, there were 19 with nonfamilial colorectal carcinoma in whom metachronous multiple colorectal carcinomas were diagnosed during the yearly surveillance colonoscopy. A control group was comprised of 28 patients who did not demonstrate either synchronous or metachronous carcinomas over a period of > or =5 years. Six microsatellite markers (D2S123, D3S1029, D3S1611, TP53, Mfd26, and Mfd36) were used to determine MSI by polymerase chain reaction. The frequency of MSI positive cases was significantly higher in patients with sporadic metachronous multiple colorectal carcinomas than in those with a single carcinoma (17/19 [89%] vs. 4/28 [14%]; P<0.0001). In tumors occurring in the distal colon and rectum, the percentage of MSI positive carcinomas was significantly higher in the patients with metachronous multiple carcinomas than in those with a single carcinoma (13/15 [87%] vs. 0/19 [0%]; P<0.0001). No such difference was observed in the proximal colon. Based on the findings of the current study, the analysis of MSI in sporadic carcinomas of the distal colon and rectum may be helpful in predicting the development of metachronous multiple colorectal carcinomas.
  Cancer 06/1999; 85(9):1917-24. · 4.77 Impact Factor
• Article: Significance of microsatellite instability in different types of early-stage nonfamilial colorectal carcinomas.

  T Okamoto, F Konishi, M Kojima, S Senba, K Kanazawa, T Tsukamoto
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  ABSTRACT: The aim of this study was to investigate the genetic alterations of early-stage nonfamilial colorectal carcinomas regarding microsatellite instability, with special reference to the shape of the tumors and the site of the lesions. Formalin-fixed, paraffin-embedded specimens of 44 early-stage nonfamilial colorectal carcinomas were examined for microsatellite instability with use of polymerase chain reaction. The 44 carcinomas consisted of 16 flat carcinomas and 28 polypoid carcinomas. Nineteen carcinomas were located in the proximal colon (9 flat type and 10 polypoid type), whereas 25 were in the distal colon and rectum (7 flat type and 18 polypoid type). Ten (22.7 percent) of the 44 carcinomas had at least one positive locus, whereas five (11.4 percent) of them had two or more positive loci. In the proximal colon the percentage of flat carcinomas with at least one positive locus was significantly greater than that of the polypoid carcinomas (4/9 (44 percent) vs. 0/10; P = 0.04). Six patients had synchronous or metachronous colorectal carcinomas or both. They harbored microsatellite instability more frequently than patients with single colorectal carcinomas, and the differences were statistically significant (P < 0.02). These data suggest that in nonfamilial carcinomas in the proximal colon, the genetic pathway in flat carcinomas may be different from that in polypoid carcinomas.
  Diseases of the Colon & Rectum 12/1998; 41(11):1385-91. · 3.13 Impact Factor
• Article: Important microsatellite markers in the investigation of replication errors (RER) in colorectal carcinomas.

  K Shitoh, F Konishi, S Masubuchi, S Senba, T Tsukamoto, K Kanazawa
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  ABSTRACT: DNA replication errors (RER) have been found in hereditary nonpolyposis colorectal carcinomas and in sporadic colorectal carcinomas. The incidence of RER depends on which and how many markers are examined. The main purpose of the present study was to determine the key markers for detecting RER most efficiently. The RER status of 76 sporadic advanced colorectal carcinomas in the proximal colon were investigated. Seven microsatellite markers (D2S123, D3S1029, D3S1611, D2S72, TP53, Mfd26 and BAT26) were chosen to determine the RER status by PCR using the non-Rl method, because these seven markers have frequently been used in other studies and also detect RER. It was found that 44.7% of sporadic colorectal advanced carcinomas in the proximal colon (34 of 76) showed RER at one or more loci. Among these 34 cases, RER was present at three or more markers (severe RER) in 22. All 22 of these cases showed RER at BAT26 and TP53. The other 12 cases with RER showed RER at one or two markers (mild RER). Eleven of these 12 cases (91%) showed RER at Mfd26 and there were one or two cases with mild RER at each of the other loci. When one intends to analyze routinely a large number of cases, an analysis of two or three markers (Mfd26 and BAT26 or TP53) is considered to be sufficient for detecting mild and severe RER.
  Japanese Journal of Clinical Oncology 10/1998; 28(9):538-41. · 1.78 Impact Factor
• Article: Clinicopathologic and genetic features of nonfamilial colorectal carcinomas with DNA replication errors.

  S Senba, F Konishi, T Okamoto, H Kashiwagi, K Kanazawa, M Miyaki, M Konishi, T Tsukamoto
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  ABSTRACT: DNA replication errors (RERs) are closely associated with hereditary nonpolyposis colorectal carcinoma (HNPCC). Recently, alterations in DNA mismatch repair genes, including hMSH2, hMLH1, and hPMS2, have been implicated in the pathogenesis of HNPCC: Several studies have demonstrated RER in 13-17% of nonfamilial colorectal carcinomas. It is unclear, however, as to whether or not these RER positive nonfamilial colorectal carcinomas are incomplete forms of HNPCC or are caused by incidental alterations of DNA mismatch repair genes. Consequently, the authors studied the characteristics of RER positive nonfamilial colorectal carcinomas, placing particular emphasis on hMSH2 and hMLH1 gene mutations. Fresh or frozen samples of 103 nonfamilial colorectal carcinomas were examined for RERs using the polymerase chain reaction (PCR) and specific microsatellite primers. The authors also identified mutations of the hMSH2 and hMLH1 genes in RER positive samples by a PCR single strand conformational polymorphism analysis followed by direct nucleotide sequencing. The incidence of RER was 15.7% (17/103) in nonfamilial colorectal carcinomas, and only 1 case, which was found in the ascending colon, showed a somatic mutation at exon 12 in the hMSH2 gene. Neither germline nor somatic mutations of the hMSH2 or hMLH1 genes could be found in any of the remaining RER positive tumors. RER positive nonfamilial carcinomas tended to be located more frequently in the right colon. There was no increased prevalence in young patients, and the clinicopathologic characteristics of HNPCC were absent in the patients with RER positive nonfamilial colorectal carcinoma. Based on these findings, the carcinogenesis of RER positive nonfamilial colorectal carcinoma is considered different from that of HNPCC:
  Cancer 02/1998; 82(2):279-85. · 4.77 Impact Factor
• Article: [Recent advance in laparoscopic-assisted colectomy for colon cancer].

  F Konishi, H Nagai, M Okada, A Ozawa, S Senba, K Kanazawa
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  ABSTRACT: Laparoscopic-assisted colectomy for colon cancer has been tried in these 5-6 years in Western countries. In Japan, this procedure has been used since about three years ago. In this country, the indication for laparoscopic-assisted colectomy has been either colonic adenomas or carcinomas in early stage which are not suitable for colonoscopic removal. The application of this procedure to more advanced carcinomas with invasion in the muscularis propria or invasion penetrating the muscularis propria is controversial. This is because of the technical difficulties involved in the lymph node dissection which is usual procedure for these invasive carcinomas in the usual laparotomy operation. We have carried out laparoscopic-assisted colectomy and lymph node dissection for colorectal carcinomas with invasion in the submucosa or deeper. In this study, we present the technical aspect of lymph node dissection in the laparoscopic procedure, and discuss the indication and technical problems in this procedure.
  Gan to kagaku ryoho. Cancer & chemotherapy 04/1997; 24(5):538-43.