園田 洋史

AIM: The preoperative prediction of lymph node metastasis of well-differentiated rectal neuroendocrine tumours is highly desirable and useful in defining surgical indication more accurately. We aimed to evaluate lymph node metastasis in rectal neuroendocrine neoplasms using multiple imaging modalities. METHODS: The clinical records and radiological images of 70 patients with well-differentiated rectal neuroendocrine tumours who received treatment at the University of Tokyo Hospital between 2010 and 2022 were retrospectively analysed. The relationship between evaluation by multiple imaging modalities and pathological lymph node metastasis was analysed. RESULTS: The receiver operating characteristic curves showed that a maximum lymph node diameter ≥4 mm on computed tomography and ≥8 mm on magnetic resonance imaging were the optimal predictive factors for lymph node metastasis. Accumulation in the lymph nodes on somatostatin receptor scintigraphy (P = 0.058) and Delle's findings on colonoscopy (P = 0.014) were also significant predictors of pathological lymph node positivity, and combination of multiple modalities was useful. Pathologically, lymphatic (P = 0.0030)/venous (P = 0.0007) invasion were risk factors for lymph node metastasis. CONCLUSIONS: In addition to pathological risk factors, a combination of multiple radiological imaging modalities is useful for predicting lymph node metastasis in well-differentiated rectal neuroendocrine tumours.

Adenocarcinoma is a common histological type of ulcerative colitis-associated cancer (UCAC), whereas neuroendocrine carcinoma (NEC) is extremely rare. UCAC is generally diagnosed at an advanced stage, even with regular surveillance colonoscopy. A 41-year-old man with a 17-year history of UC began receiving surveillance colonoscopy at the age of 37 years; 2 years later, dysplasia was detected in the sigmoid colon, and he underwent colonoscopy every 3 to 6 months. Approximately 1.5 years thereafter, a flat adenocarcinoma lesion occurred in the rectum. Flat lesions with high-grade dysplasia were found in the sigmoid colon and surrounding area. The patient underwent laparoscopic total proctocolectomy and ileal pouch-anal anastomosis with ileostomy. Adenocarcinoma was diagnosed in the sigmoid colon and NEC in the rectum. One year postoperation, recurrence or metastasis was not evident. Regular surveillance colonoscopy is important in patients with long-term UC. A histological examination of UCAC might demonstrate NEC.

A 71-year-old man was diagnosed with advanced non-small cell lung carcinoma and treated with chemotherapy developed ileocecal diverticulitis three times over the last 2 months of receiving second-line treatment. During the fourth diverticulitis event, the patient presented with fever and abdominal pain, worsening after 5 days. Abdominal computed tomography showed ascites and intra-abdominal free air, suggesting bowel perforation with acute diffuse peritonitis. We performed emergency surgery; the surgical findings showed diverticulosis with perforated diverticula in the ileocecal region. We performed ileocecal resection, an ileostomy and a mucous fistula of the ascending colon. Histopathological examinations revealed pseudodiverticula at the perforation, where the mucosa was depressed through the muscularis propria. Hence, we diagnosed perforated ileal diverticulitis. Repeated diverticulitis triggered by chemotherapy might have resulted in perforation. Small bowel diverticula are rare, but diverticulitis can occur in patients receiving chemotherapy and with cases of unexplained fever and abdominal pain.

OBJECTIVE: This study evaluated the clinical implications of sarcopenia for patients with rectal cancer according to cancer progression. SUMMARY BACKGROUND DATA: The negative impact of body composition on long-term outcome has been demonstrated for various malignancies. METHODS: We retrospectively reviewed 708 patients with rectal cancer who underwent curative resection at our institution between 2003 and 2020. Factors contributing to long-term outcomes and the incidence of secondary cancer (ISC) were analyzed. Psoas muscle mass index (PMI) was assessed using preoperative computed tomography. Sarcopenia was defined using the PMI cut-off values for Asian adults (6.36 cm2/m2 for males and 3.92 cm2/m2 for females). RESULTS: Sarcopenia was identified in 306 patients (43.2%). Sarcopenia was associated with advanced age, low body mass index, smoking history, and advanced T-stage. Multivariate analysis showed sarcopenia was an independent poor prognostic factor for OS (HR 1.71; P = .0102) and cancer-specific survival (HR 1.64; P = .0490). Patients with sarcopenia had significantly higher mortality due to cancer-related death in stages III and IV, whereas non-rectal cancer-related death, including secondary cancer, was markedly increased in stage 0-II sarcopenic rectal patients. Five-year cumulative ISC in patients with and without sarcopenia was 11.8% and 5.9%, respectively. Multivariate analysis revealed that sarcopenia was an independent predictive factor for ISC (HR 2.05; P = .0063). CONCLUSIONS: Sarcopenia helps predict survival outcomes and cause of death according to cancer stage for patients with middle/lower rectal cancer who underwent radical surgery. Furthermore, sarcopenia increased the development of secondary cancer in those patients.

Total mesorectal excision (TME) for rectal cancer is often technically challenging. We aimed to develop a method for three-dimensional (3D) visualization of the TME dissection plane and to evaluate its ability to predict surgical difficulty. Sixty-six patients with lower rectal cancer who underwent robot-assisted surgery were retrospectively analyzed. A 3D TME dissection plane image for each case was reconstructed using Ziostation2. Subsequently, a novel index that reflects accessibility to the deep pelvis during TME, namely, the TME difficulty index, was defined and measured. Representative bony pelvimetry parameters and clinicopathological factors were also analyzed. The operative time for TME was used as an indicator of surgical difficulty. Univariate regression analysis revealed that sex, body mass index, mesorectal fat area, and TME difficulty index were associated with the operative time for TME, whereas bony pelvimetry parameters were not. Multivariate regression analysis found that TME difficulty index (β = - 0.398, P = 0.0025) and mesorectal fat area (β = 0.223, P = 0.045) had significant predictability for the operative time for TME. Compared with conventional bony pelvimetry parameters, the TME difficulty index and mesorectal fat area might be more useful in predicting the difficulty of rectal cancer surgery.

BACKGROUND: During restorative proctocolectomy with ileal pouch-anal anastomosis for ulcerative colitis-associated colorectal cancer or dysplasia, ileal pouch-anal handsewn anastomosis (IAA) is preferred to avoid the risk of cancer development in the remaining rectal mucosa. However, there is a risk of the ileal pouch not reaching the anus with this procedure. Here, we created deformable 3-dimensional (3D) models for simulation. METHOD: Six patients who underwent IAA without vessel ligation and 5 patients who underwent ileal pouch-anal canal double-stapled anastomosis (IACA) because the ileal pouch did not reach the anus were studied. A 3D printer was used to create deformable 3D models from the data obtained from computed tomography scans. The positional relationship among the mesenteric arteries, pubis, and coccyx were evaluated. RESULT: The distance between the superior mesenteric artery root and the tip of the ileal artery was longer in the IAA group than that in the IACA group (IAA vs IACA: 26.2 ± 2.1 cm vs 20.9 ± 1.6cm). The distance from the tip of the ileal artery to the coccyx (IAA vs IACA: 6.7 ± 1.7 cm vs 12.1 ± 2.1 cm) and the distance from the tip of the ileal artery to the lower edge of the pubis (IAA vs IACA; 8.1 ± 1.3 cm vs 12.7 ± 2.4 cm) were longer in the IACA group than those in the IAA group. CONCLUSIONS: We established a method for creating 3D deformable models of patients with ileal pouch-anal anastomosis. These 3D models may be useful for preoperative simulation.

BACKGROUND: Indoleamine 2,3-dioxygenase 1 (IDO1) is an enzyme that converts tryptophan to kynurenine. IDO1 expression is found not only in tumor cells but also in immune cells and is associated with tumor proliferation and immune responses. IDO1 inhibitors and radiation may cooperatively suppress tumor proliferation through the alterations in the Wnt/β-catenin pathway, cell cycle, and immune response. We investigated the antitumor effects of combination therapy of an IDO1 inhibitor, 1-methyl tryptophan (1-MT), and radiation on colorectal cancer. METHODS: In vitro experiments were conducted using human and murine colon cancer cell lines (HCT116, HT-29, and Colon26). Cell growth inhibition was assessed using a MTS assay and Clonogenic assay. Cells were cultured for 48 h with or without 500 µM 1-MT after exposure to radiation (4 Gy). Cell cycle effects and modulation of Wnt/β-catenin pathway were evaluated using western blot analysis, flow cytometry, RT-PCR. Subcutaneous Colon26 tumors in BALB/c mice were treated by oral 1-MT (6 mg/mL) for 2 weeks and/or local radiation (10 Gy/10 fr). Bromodeoxyuridine (BrdU) incorporation in tumor cells and expression of differentiation markers of immune cells were evaluated using immunohistochemistry. RESULTS: 1-MT and a small interfering RNA against IDO1 suppressed proliferation of all cell lines, which was rescued by kynurenine. Clonogenic assay showed that administration of 1-MT improved radiosensitivity by suppressing the Wnt/β-catenin pathway activated by radiation and enhancing cell cycle arrest induced by radiation. Combination therapy showed a further reduction in tumor burden compared with monotherapies or untreated control, inducing the highest numbers of intratumoral CD3 + and CD8 + T cells and the lowest numbers of Foxp3 + and BrdU-positive tumor cells. CONCLUSIONS: The combination of 1-MT and radiation suppressed colon cancer cells in vitro and in vivo via multiple mechanisms.

BACKGROUND: A muco-submucosal elongated polyp is a non-neoplastic growth composed of mucosa and submucosa. Although muco-submucosal elongated polyps are commonly reported in the large intestine, they are rare in the small intestine, in which they are called enteric muco-submucosal elongated polyps. We herein present a case of jejunal intussusception and perforation due to an enteric muco-submucosal elongated polyp. CASE PRESENTATION: A 46-year-old woman presented with abdominal pain and vomiting. Computed tomography revealed jejunal intussusception, which was reduced via a nasointestinal ileus tube. Oral double-balloon endoscopy showed an elongated polyp in the proximal jejunum. The patient refused surgical resection and thus, the polyp was monitored. Six months later, the patient was readmitted with the recurrence of jejunal intussusception and underwent emergency surgery. Intraoperative findings revealed an intussuscepted bowel with an elongated polyp and multiple perforations in the proximal jejunum. We resected approximately 90 cm of the bowel, including the intussuscepted segment and perforated sites. The pedunculated polyp, which was 60 mm in length, was located on the oral side of the resected specimen. Histopathologically, the polyp was covered by normal mucosa and the submucosa consisted of edematous loose connective tissue. The histopathological diagnosis confirmed an enteric muco-submucosal elongated polyp. CONCLUSIONS: Symptomatic patients with enteric muco-submucosal elongated polyps may be at risk of complications, as observed in the present case, and need to undergo timely resection.

BACKGROUND: Carcinoembryonic antigen (CEA) monitoring facilitates the detection of recurrence in patients with colorectal cancer (CRC) after resection. False-positive CEA has been reported in CRC patients with certain comorbidities or smokers. However, limited information is currently available on the frequency of and changes in falsely elevated CEA levels in patients without these conditions. MATERIALS AND METHODS: We retrospectively examined CRC patients who underwent surgical resection at our hospital between 2001 and 2017, had no recurrence for at least five years, and were free of known factors that may increase CEA. Postoperative CEA levels were retrieved until 2 years before the last contact. For comparison, we similarly selected patients who developed recurrence after resection of CRC during the same period, and CEA levels at initial presentation, at nadir, and at the time of recurrence were reviewed. The patterns of elevated CEA (>5 ng/ml) were classified as transient, repeated, or persistent based on longitudinal changes. The relationships between CEA and carbohydrate antigen 19-9, transaminases, creatinine, and C-reactive protein were examined. RESULTS: CEA elevation occurred in 90 (20%) out of 446 eligible patients without recurrence at least once during the mean postoperative period of 50.5 months, whereas CEA was >5 ng/ml in 117 (53%) of 221 patients when they developed recurrence. Twenty-seven patients without recurrence showed a transient elevation in CEA, 45 repeated elevations, and 18 a persistent elevation; the frequency of a high preoperative CEA level increased in this order. The majority (98%) of false elevations ranged between 5 and 15 ng/ml. CEA was not associated with other laboratory data. CONCLUSIONS: Unexplained CEA elevations were observed in 20% of recurrence-free CRC patients after surgery, and were classified into three patterns based on longitudinal changes. A more detailed understanding of patient-specific fluctuations in CEA will prevent unnecessary imaging studies and reduce medical costs.

Colonic metastasis from ovarian cancer is extremely rare, with only seven reported cases. A 77-year-old woman who had previously undergone surgery for ovarian cancer was admitted to a local hospital with anal bleeding. Histopathological analysis confirmed the presence of adenocarcinoma. Colonoscopy revealed a descending colon tumor. The patient was diagnosed with Union for International Cancer Control T3N0M0 descending colon cancer or colon metastasis of the ovarian cancer. Laparoscopic left colectomy was performed; intraoperative frozen section diagnosis confirmed metastasis from ovarian cancer, and the absence of invasion to the serosal surface suggested hematogenous metastasis. This is the first case of colonic metastasis from ovarian cancer that was diagnosed using an intraoperative frozen section and laparoscopically treated.

PURPOSE: We investigated the surgical outcomes of robotic low anterior resection (LAR) for lower rectal cancer after preoperative chemoradiotherapy (pCRT). METHODS: A total of 175 patients with lower rectal cancer who underwent LAR after pCRT between 2005 and 2020 were stratified into open (OS, n = 65), laparoscopic (LS, n = 64), and robotic surgery (RS, n = 46) groups. We compared the clinical, surgical, and pathological results among the three groups. RESULTS: The RS and LS groups had less blood loss than the OS group (p < 0.0001). The operating time in the RS group was longer than in the LS and OS groups (p < 0.0001). The RS group had a significantly longer mean distal margin than the LS and OS groups (25.4 mm vs. 20.7 mm and 20.3 mm, respectively; p = 0.026). There was no significant difference in the postoperative complication rate among the groups. The local recurrence rate in the RS group was comparable to those in the LS and OS groups. CONCLUSION: Robotic LAR after pCRT was performed safely for patients with advanced lower rectal cancer. It provided a longer distal margin and equivalent local control rates.

BACKGROUND: Anastomotic recurrence is thought to be caused by implantation of tumor cells to the anastomotic line; however, its risk factors and prognostic significance remain unclear. OBJECTIVE: This study aimed to clarify the risk factors for anastomotic recurrence in colorectal cancer and assess the prognosis in comparison to non-anastomotic local recurrence. DESIGN: A single-center retrospective observational study. SETTINGS: The medical records of the study participants were retrospectively collected from the Department of Surgical Oncology at the University of Tokyo Hospital database. PATIENTS: This study included 1584 patients with colorectal cancer who underwent surgical resection between January 2005 and December 2017. We focused on 15 patients who had anastomotic recurrence. MAIN OUTCOME MEASURES: The main outcome measures were the risk factors of anastomotic recurrence at the primary resection, and prognosis data in comparison to non-anastomotic local recurrence. RESULTS: There were 15 patients (0.95%) with anastomotic recurrence and 35 (2.21%) with non-anastomotic local recurrence. Univariate analysis revealed that lymph node metastasis and advanced T stage are the risk factors for anastomotic recurrence. The prognosis of patients with anastomotic recurrence was similar to that of those with non-anastomotic local recurrence who underwent resection. LIMITATIONS: The small number of patients with anastomotic recurrence is a major limitation of this study. Additionally, the retrospective study design may have increased the risk of selection bias. CONCLUSIONS: Lymph node metastasis and advanced T stage were associated with anastomotic recurrence. The prognosis of patients with anastomotic recurrence was similar to that with resected non-anastomotic local recurrence. Thus, surveillance should be carefully continued while considering the poor prognosis of patients with anastomotic recurrence. See Video Abstract at http://links.lww.com/DCR/C92 .

Odoribacter splanchnicus was recently reclassified from the genus Bacteroides. We present the first case of Odoribacter splanchnicus bacteremia following appendicitis. The species was identified using MALDI-TOF mass spectrometry and later confirmed with 16S rRNA sequencing. The patient was successfully managed with surgery and antibiotic administration for two weeks.

BACKGROUND/AIM: Even though epithelial-mesenchymal transition markers in primary tumors are identified as a helpful indicator of cancer metastasis and prognosis, their expression in lymph node metastases (LNMs) remains poorly described. We aimed to investigate the difference between snail family transcriptional repressor 1 (SNAI1) and E-cadherin expression in primary tumors and LNMs, and how it affects prognosis. PATIENTS AND METHODS: From 2010 to 2014, 127 patients who underwent radical surgery for stage III colonic adenocarcinoma without preoperative treatment were retrospectively reviewed for SNAI1 and E-cadherin expression in primary tumors and LNMs. RESULTS: High SNAI1 expression was found in 76% and 70% of primary tumors and LNMs, respectively, and low E-cadherin expression was found in 73% and 84%, respectively. High expression of SNAI1 in LNMs significantly correlated with poor overall and relapse-free survival rates. Even though the rate of liver metastasis at 5 years was similar for the groups with high and low SNAI1 expression in LNMs, the incidence in the group with low SNAI1 expression in the second year was higher than that in the first year (33% vs. 17%), whilst in the group with high SNAI1 expression, the incidence in the first year was higher than in the second year (71% vs. 29%). The rate of recurrence of lung metastasis was significantly lower when SNAI1 expression in LNMs was low (p=0.031). CONCLUSION: Low expression of SNAI1 in LNMs of colonic adenocarcinoma may indicate delayed recurrence in the liver and lung.

BACKGROUND/AIMS: Restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis and handsewn anastomosis for ulcerative colitis requires pulling down of the ileal pouch into the pelvis, which can be technically challenging. We examined risk factors for the pouch not reaching the anus. METHODS: Clinical records of 62 consecutive patients who were scheduled to undergo RPC with handsewn anastomosis at the University of Tokyo Hospital during 1989-2019 were reviewed. Risk factors for non-reaching were analyzed in patients in whom hand sewing was abandoned for stapled anastomosis because of nonreaching. Risk factors for non-reaching in laparoscopic RPC were separately analyzed. Anatomical indicators obtained from presurgical computed tomography (CT) were also evaluated. RESULTS: Thirty-seven of 62 cases underwent laparoscopic procedures. In 6 cases (9.7%), handsewn anastomosis was changed to stapled anastomosis because of non-reaching. Male sex and a laparoscopic approach were independent risk factors of non-reaching. Distance between the terminal of the superior mesenteric artery (SMA) ileal branch and the anus > 11 cm was a risk factor for non-reaching. CONCLUSIONS: Laparoscopic RPC with handsewn anastomosis may limit extension and induction of the ileal pouch into the anus. Preoperative CT measurement from the terminal SMA to the anus may be useful for predicting non-reaching.

BACKGROUND: The diagnosis of colitis-associated cancer or dysplasia is important in the treatment of ulcerative colitis. Immunohistochemistry of p53 along with hematoxylin and eosin (H&E) staining is conventionally used to accurately diagnose the pathological conditions. However, evaluation of p53 immunohistochemistry in all biopsied specimens is expensive and time-consuming for pathologists. In this study, we aimed to develop an artificial intelligence program using a deep learning algorithm to investigate and predict p53 immunohistochemical staining from H&E-stained slides. METHODS: We cropped 25 849 patches from whole-slide images of H&E-stained slides with the corresponding p53-stained slides. These slides were prepared from samples of 12 patients with colitis-associated neoplasia who underwent total colectomy. We annotated all glands in the whole-slide images of the H&E-stained slides and grouped them into 3 classes: p53 positive, p53 negative, and p53 null. We used 80% of the patches for training a convolutional neural network (CNN), 10% for validation, and 10% for final testing. RESULTS: The trained CNN glands were classified into 2 or 3 classes according to p53 positivity, with a mean average precision of 0.731 to 0.754. The accuracy, sensitivity (recall), specificity, positive predictive value (precision), and F-measure of the prediction of p53 immunohistochemical staining of the glands detected by the trained CNN were 0.86 to 0.91, 0.73 to 0.83, 0.91 to 0.92, 0.82 to 0.89, and 0.77 to 0.86, respectively. CONCLUSIONS: Our trained CNN can be used as a reasonable alternative to conventional p53 immunohistochemical staining in the pathological diagnosis of colitis-associated neoplasia, which is accurate, saves time, and is cost-effective.

BACKGROUND: Persistent descending mesocolon (PDM) is a fetal abnormality in which the left-sided colon is not fused to the retroperitoneum, and it is often accompanied by the adhesion between the mesocolon and small bowel mesentery. Due to its rarity, whether PDM exhibits anatomical characteristics of the inferior mesenteric artery (IMA) and left colic artery (LCA), and how the anomaly affects laparoscopic surgery are largely unknown. We investigated the branches of these arteries and outcomes of patients who underwent laparoscopic surgery. METHODS: Based on computed tomography (CT) and three-dimensional CT angiography, branching patterns of the IMA, LCA and branches originating from the LCA were analysed in 954 patients with left-sided colon or rectal cancer. PDM was diagnosed by preoperative CT colonography, and confirmed at time of surgery. The anatomical features of the vessels and short-term outcomes of laparoscopic surgery were compared between patient groups stratified by PDM. RESULTS: Twelve patients (1.3%) were diagnosed with PDM. No branching pattern of the IMA specific to PDM was noted. On the other hand, patients with PDM had fewer branches (mean: 1.0) from the LCA than those without PDM (mean: 1.8, p = 0.009). In patients undergoing laparoscopic surgery, outcomes such as operative time, intraoperative blood loss, and number of harvested nodes were comparable between the two patient groups. CONCLUSION: Few branches of the LCA characterize PDM. PDM does not complicate laparoscopic surgery of the left-sided colon and rectum. However, the above anatomical feature increases the risk of poor colonic perfusion when dividing the LCA.

BACKGROUND: Several studies have demonstrated that right-sided tumors have poorer prognosis than left-sided tumors in patients with unresectable colorectal cancer (CRC). The predictive ability of the tumor sidedness in CRC treated with chemotherapy in each sex is unclear. METHODS: Subjects were 964 unresectable recurrent patients treated with chemotherapy with stage II-III CRC after curative resection between 2004 and 2012. Post-recurrence cancer-specific survival (CSS) for each sex was examined. RESULTS: Patients were 603 males (222 right-side tumors (cecum to transverse colon) and 381 left-sided tumors (descending colon to rectum)), and 361 females (167 right-side tumors and 194 left-sided tumors). Right-sided tumors developed peritoneal recurrences in males and females. Left-sided tumors were associated with locoregional recurrences in males and with lung recurrences in females. Right-sided tumors were associated with shorter post-recurrence CSS in both sexes. In males, multivariate analyses showed that right-sided tumors were associated with shorter post-recurrence CSS (HR: 1.53, P < 0.0001) together with the presence of regional lymph node metastasis histopathological type of other than differentiated adenocarcinoma, the recurrence of liver only, the recurrence of peritoneal dissemination only, and relapse-free interval less than one-year. In females, multivariate analyses showed that right-sided tumors were associated with shorter post-recurrence CSS (HR: 1.50, P = 0.0019) together with advanced depth of invasion, the presence of regional lymph node metastasis, and recurrence of liver only. CONCLUSIONS: Primary tumor sidedness in both sexes in unresectable recurrent CRC patients treated with chemotherapy may have prognostic implications for post-recurrence CSS.

Surgical treatment of the transverse colon is difficult because of the many variations of blood vessels. We reviewed the patterns of vascular anatomy and the definition of the vessels around the splenic flexure. We searched the PubMed database for studies on the vascular anatomy of the splenic flexure that were published from January 1990 to October 2020. After screening of full texts, 33 studies were selected. The middle colic arteries were reported to arise independently without forming a common trunk in 8.9-33.3% of cases. The left colic artery was absent in 0-7.5% of cases. The accessory middle colic artery was present in 6.7-48.9% of cases and was present in > 80% of cases without a left colic artery. The reported frequency of Riolan's arch was 7.5-27.8%. The frequency was found to vary widely across studies, partially due to the ambiguous definition of Riolan's arch. A comprehensive preoperative knowledge of the branching patterns of the middle colic artery and left colic artery and the presence of collateral arteries would be helpful in surgery for colon cancer in the splenic flexure.

PURPOSE: We investigated whether or not computed tomographic colonography (CTC) is a viable alternative to double-contrast barium enema (BE) for a preoperative rectal cancer evaluation. METHODS: The size and distance from the anal canal to the lower or upper tumor borders were laterally measured in 147 patients who underwent CTC and BE. Measurements were grouped into early cancer, advanced, and after chemoradiation therapy (CRT). RESULTS: In the early and advanced cancer groups, all lesions were visualized by BE. In contrast, 3 (7.8%) early and 8 (7.3%) advanced cases, located at the anterior wall near the anal canal, were not visualized by CTC because of liquid level formation. In the CRT group, 16 (23.5%) and 4 (5.8%) cases were not visualized by CTC and BE, respectively. The BE and CTC size measurements were similar among cohorts. However, the distance from the anal canal's superior margin tended to be longer with BE, especially in early cancer. The differences in distance from the anal canal were significantly larger in the early cancer group than in the other two groups (p = 0.0024). CONCLUSION: CTC may be a viable alternative imaging modality in some cases. However, BE should be employed in anterior wall cases near the anal canal and CRT cases.

BACKGROUND: In recent years, it has become clear that, in addition to normal cytokines, phospholipid mediators play an important role in the development, growth, infiltration, and metastasis of cancer and in the cancer microenvironment. A phospholipid analysis method using tandem mass spectrometry (LC-MS/MS) with high detection sensitivity has enabled quantification of phospholipids, even when using a very small sample. To date, we had applied this MS technology to colorectal cancer tissue. Therefore, in this study, this mass spectrometry technique was applied to ulcerative colitis (UC) and UC-related colorectal cancer, and an analysis was conducted with the aim of clarifying which lysophospholipids specifically change in each type of tissue. MATERIALS AND METHODS: UC-associated colorectal cancer tissue and UC mucosa were collected from surgical specimens of colitic cancer (n=3). Cancerous and non-cancerous tissues were collected from surgical specimens from patients with sporadic colorectal cancer (n=11). After extraction from these tissues, the amounts of lysophospholipids were quantified by LC-MS/MS. In addition, lysophosphatidylserine (LPS) and lysophosphatidylinositol (LPI) were quantified for each molecular species of fatty acids. RESULTS: Compared to normal mucosa, LPI was increased 3.8-fold (p<0.001) and LPS 3.5-fold (p<0.001) in UC-related colorectal cancer. Molecular species of LPI which were increased in UC-related colorectal cancer were 18:0 (p=0.001), 16:0 (p=0.03) and 20:4 (p=0.004), and of LPS were 18:0 (p<0.001) and 22:6 (p=0.014). CONCLUSION: Lysophospholipids increased in colorectal cancer and in UC-associated colorectal cancer. In particular, LPI may have contributed significantly to colitis-associated carcinogenesis.