Yasushi Imai

Colonoscopic Diagnosis and Management of Nonpolypoid Early Colorectal Cancer

Nonpolypoid colorectal neoplasms are grossly classified into three groups: slightly elevated (small flat adenomas), laterally spreading, and depressed. Flat adenomas are not invasive until they are rather large, whereas depressed lesions can invade the submucosa even when they are extremely small. Nonpolypoid lesions are difficult to detect and are often overlooked. Keys to detect them are their slight color change, interruption of the capillary network pattern, slight deformation of the colonic wall, spontaneously bleeding spots, shape change of the lesion with insufflation and deflation of air, and interruption of the innominate grooves. Spraying of indigo carmine dye helps to clarify the lesions. A pit pattern analysis with a zoom colonoscope is useful for the diagnosis and staging of early colorectal cancer. Small flat adenomas are thought to be precursors of protruded polyps and lateral spreading tumors, whereas depressed lesions are thought to grow endophytically and become advanced cancers. Small depressed lesions are treated with an endoscopic mucosal resection (EMR) technique; but when they massively invade the submucosa, surgical resection is indicated. Laterally spreading tumors are not as invasive despite their large size and therefore are good indications for the EMR or piecemeal EMR method. Small flat adenomas need not be treated urgently, as almost none is invasive. Accurate diagnosis with dye-spraying and zoom colonoscopy is vital for deciding the treatment strategy.

Endoscopic mucosal resection of the colon: the Japanese technique.

Early colorectal neoplasms, especially flat-type and depressed-type lesions, should be treated with an EMR technique. In general because depressed-type lesions, in contrast to flat-type or protruded-type lesions, tend to invade the submucosa rapidly, they ought to be treated by EMR at an early stage. Histopathologically in the case of lesions that only minimally invade the submucosa without vessel invasion (sm1a and sm1b without vessel invasion), a treatment can be completed with EMR. Massive submucosal invasive cancers ought to be resected by surgical treatment because of the risk of recurrence or metastasis. In addition, pit pattern diagnosis with magnifying colonoscopy is useful to determine a therapeutic method for colonic neoplasms. Lesions with the type VN pit pattern represent malignancy and usually invade the submucosa massively, so it is better to treat them surgically from the outset. Endoscopic mucosal resection should be conducted under fully controlled endoscopy to prevent complications. EMR is a superior therapeutic method and will be performed frequently in the future. It is necessary for colonoscopists to determine a suitable therapy for each colorectal neoplastic lesion. They also need to master the EMR technique in the correct manner.

Randomised clinical study comparing the effectiveness and physiological effects of hypertonic and isotonic polyethylene glycol solutions for bowel cleansing

Objectives Bowel cleansing is necessary before colonoscopy, but is a burden to patients because of the long cleansing time and large dose volume. A low-volume (2 L) hypertonic polyethylene glycol-ascorbic acid solution (PEG-Asc) has been introduced, but its possible dehydration effects have not been quantitatively studied. We compared the efficacy and safety including the dehydration risk between hypertonic PEG-Asc and isotonic PEG regimens. Design This was an observer-blinded randomised study. Participants (n=310) were allocated to receive 1 of 3 regimens on the day of colonoscopy: PEG-Asc (1.5 L) and water (0.75 L) dosed with 1 split (PEG-Asc-S) or 4 splits (PEG-Asc-M), or PEG-electrolyte solution (PEG-ES; 2.25 L) dosed with no split. Dehydration was analysed by measuring haematocrit (Ht). Results The cleansing time using the hypertonic PEG-Asc-S (3.33±0.48 hours) was significantly longer than that with isotonic PEG-ES (3.05±0.56 hours; p<0.001). PEG-Asc-M (3.00±0.53 hours) did not have this same disadvantage. Successful cleansing was achieved in more than 94% of participants using each of the 3 regimens. The percentage changes in Ht from baseline (before dosing) to the end of dosing with PEG-Asc-S (3.53±3.32%) and PEG-Asc-M (4.11±3.07%) were significantly greater than that with PEG-ES (1.31±3.01%). Conclusions These 3 lower volume regimens were efficacious and had no serious adverse effects. Even patients cleansed with isotonic PEG-ES showed significant physiological dehydration at the end of dosing. The four-split PEG-Asc-M regimen is recommended because of its shorter cleansing time without causing serious nausea. Trial registration number UMIN000013103; Results.

Su1532 Evaluation of One-Split and Four-Split Dosing of Hypertonic Polyethylene Glycol Solution and No Split Dosing of Isotonic Polyethylene Glycol Solution for Bowel Cleansing Before Colonoscopy

Su1531 Comparison of Quality of Bowel Preparation Between 4L Polyethylene Glycol and 2L Polyethylene Glycol Plus Ascorbic Acid With and Without Simethicone a Preliminary Report Sun Mi Kang*, Eun Young Kim, Si Hye Kim, Byung Seok Kim, Jimin Han, Jin Tae Jung, Joong Goo Kwon, Chang Hyeong Lee, Ho Gak Kim Department of Internal Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea (the Republic of) Background/Aim: Optimal bowel preparation is essential for the high quality colonoscopic procedure. Polyethylene glycol based solution is the most commonly used bowel preparation agent. This study has investigated the quality of bowl preparation between two preparation regimen with and without supplemetal use of simethicone. Methods: Prospective, single-blind, randomized comparative study was carried out from a single center. Patients were randomly assigned into 4 groups: 4L polyethylene glycol(4L-PEG), 4L PEG with simethicone(4L-PEG+S), 2L polyethylene glycol plus ascorbic acid(2L-PEG-Asc), 2L PEG-Asc with simethicone(2L-PEG-Asc+S). In groups with simethicone, patients took 400mg of simethicone after second split dose of PEG based solution. Boston Bowel Preparation Scale was used to evaluate the quality of bowel preparation. Degree of bubble formation was recorded for three colonic segments (the right side of the colon-including the cecum and ascending colon/ the transverse section of the colon-including the hepatic and splenic flexures/ and the left side of the colon-including the descending colon, sigmoid colon, and rectum) during the withdrawal of colonoscope. Adenoma detection rate (ADR) and polyp detection rate (PDR) were compared between the groups. Tolerability and willingness to repeat colonoscopy with same preparation regimen were also evaluated by using the questionnaire. Results: Overall, 191 patients were enrolled and randomly allocated to the 4 groups. There was no significant difference in the degree of bowel cleansing according to the preparation regimen (Boston Bowel Preparation Scale: 4L-PEG/4L-PEG+S/2L-PEG-Asc/2L-PEG-Asc+S 6.581/6.571/6.54/ 6.98, PZ0.350). Degree of foam and bubble formation was significantly decreased in both simethicone groups (total bubble grade score: 4L-PEG+S/2L-PEG-Asc+S 5.633/ 5.633 vs 4L-PEG/2L-PEG-Asc 4.93/4.98, PZ0.002). In the subgroup analysis, female showed more significant improvement in the bubble score: 4L-PEG+S/2L-PEGAsc+S 5.923/5.733 vs 4L-PEG/2L-PEG-Asc 4.636/5.125, PZ0.000). ADR and PDR were 39%/35%/38%/36% and 56%/54%/53%/52% respectively for 4L-PEG/4L-PEG+S/2LPEG-Asc/2L-PEG-Asc+S. Patients had more satisfaction with 2L PEG-Asc regimen (2LPEG-Asc/2L-PEG-Asc+S 92%/89.8% vs 4L-PEG/4L-PEG+S 74.42%/69.39%, PZ0.007). The patients were more willing to repeat colonoscopy with 2L PEG-Asc (2L-PEG-Asc/ 2L PEG-Asc+S 94%/85.71% vs 4L-PEG/4LPEG+S 62.79%/63.2739%, PZ0.000). Conclusions: Low volume PEG-Asc showed similar effectiveness in bowel preparation compared to large volume PEG. Supplemental use of simethicone decreased the occurrence of foam and bubbles, especially in female. 2L PEG-Asc regimen was better tolerated and patients were willing to repeat colonoscopy with 2L PEG-Asc regimen.

4514 Characteristics of large flat colorectal tumors (so-called laterally spreading tumors).

Some flat adenomas spread extensively and circumferentially along the colonic wall although being very short in height compared with the large diameter of more than 10 mm. These large flat adenomas or so-called laterally spreading tumors (LSTs) are sometimes malignant, but not so advanced compared with their large diameter. Despite the large diameter, LSTs are often difficult to find, because they are extremely short and almost normal in color. The keys to detect them are a minimal color change, which is usually faintly red and a slight irregularity of the intestinal wall or interruption of the mucosal capillary network pattern. Dyespraying (usually 0.2-0.4% indigo carmine) helps clarify the margin and the extent of the tumor. [Materials and Methods] From April 1985 to August 1999, 522 LSTs were resected endoscopically and/or surgically. These lesions were classified into granular and non-granular. Endoscopic features of submucosal involvement Dukes A carcinomas in LSTs were analyzed. [Results] Rate of submucosal invasion in LST was 9.2% (48 out of 522). This rate was 9.6% (25 out of 261) in granular type and 8.8% (23 out of 261) in non-granular type. Granular LST consists of many small aggregated nodules. But sometimes it has the remarkable protruding part. Rate of submucosal invasion in Granular LST with the remarkable protruding part was 22.0% (24 out of 109). On the other hand, 68.8% of these 24 submucosal involvement Dukes A carcinomas became invasive in the protruding part exactly. Non-granular LST does not have nodules. Sometimes it has the ill-defined pseudodepression which appears after dye-spraying. This is different from the depressed carcinoma, which has the well-demarcated depression. Rate of submucosal invasion in non-granular LST with the pseudodepression was 18.0% (11 out of 61). All of these 11 submucosal involvement Dukes A carcinomas became invasive in the depressed part. [Conclusion] LSTs are good indication for EMR or endoscopic piecemeal mucosal resection (EPMR). Lesions up to 25 mm in diameter can be removed en bloc by EMR technique. Those over 25 mm would be treated with EPMR method. However, if the part of LST shows coarse protruding structure or psudodepression, the lesion is suspected to be deeply invasive, and therefore should be treated surgically. It is very important to recognize these significant laterally spreading colorectal tumors by careful observation and dye-spraying method.

4515 The management of submucosal invading carcinoma in colorectal neoplasm.

It is thought that submucosal invading cancer should be in the middle of adenoma and advanced cancer. And we can find some cases with vessel invading and lymph node metastasis. However, we must decide to choose either method between endoscopic and surgical resection. This study was carried out to clarify the management of endoscopic treatment for submucosal invading carcinoma. MATERIALS and METHODS: During the period from April 1985 to March 1999, we experienced 323 cases of submucosal invading carcinoma, which were resected by endoscopic and surgical method. In this study, we divided submucosal layer equally into three as following; sm1, sm2 and sm3. Moreover, we classified those carcinoma into three further according to the difference of each lateral width: sm1a, b, and c. the ratio of lateral width less than 1/4 is called sm1a, the one from 1/2 to 1/4 is sm1b, and more than 1/2 is sm1c. And we analyzed each category about shape, size, pathological feature, vessels invading, and lymph node metastasis. RESULTS: As a result of this study, we show the ratio of vessels invading on each specific categories as follows; sm1a was 8.3%, sm1b was 26.7%, sm1c was 33.3%, sm2 was 70.5%, sm3 was 78.9%, and the grand total was 50.8%. The ratio of lymph node metastasis; sm1a and sm1b were 0%, sm1c was 2.9%, sm2 was 11.7%, sm3 was 20.4%, and the grand total was 10.9%. There was no lymph node metastasis to be seen in the submucosal carcinomas without vessels invasion. CONCLUSION: We must resect submucosal invading carcinomas with lymph node metastasis surgically, and assume that lymph node metastasis is caused by vessels invasion.We have concluded that the sm1a and sm1b carcinomas without vessels invasion can be adapted to endoscopic resection.