Transverse Colon Primary Tumor Location as a Biomarker in Metastatic Colorectal Cancer: A Pooled Analysis of CCTG/AGITG CO.17 and CO.20 Randomized Clinical Trials.

PURPOSE: Sidedness is prognostic and predictive of anti-EGFR efficacy in metastatic colorectal cancer (mCRC). Transverse colon has been historically excluded from several analyses of sidedness and the optimal division between left- and right-sided colorectal cancer is unclear. We investigated transverse colon primary tumor location as a biomarker in mCRC. EXPERIMENTAL DESIGN: Pooled analysis of CCTG/AGITG CO.17 and CO.20 trials of cetuximab in chemotherapy-refractory mCRC. Outcomes of patients with RAS/BRAF wild-type (WT) mCRC from CO.17 and KRAS WT mCRC from CO.20 were analyzed according to location. RESULTS: A total of 553 patients were analyzed, 32 (5.8%) with cancers from the transverse, 101 (18.3%) from right, and 420 from (75.9%) left colon. Transverse mCRC failed to reach significant benefit from cetuximab versus best supportive care (BSC) for overall survival [OS; median, 5.9 vs. 2.1 months; HR, 0.63; 95% confidence interval (CI), 0.28-1.42; P=0.26] and progression-free survival (PFS; median, 1.8 vs. 1.3 months; HR, 0.57; 95% CI, 0.26-1.28; P=0.16). Analyzing exclusively patients randomized to cetuximab, right-sided and transverse had comparable outcomes for OS (median, 5.6 vs. 5.9 months; HR, 0.82; 95% CI, 0.50-1.34; P=0.43) and PFS (median, 1.9 vs. 1.8 months; HR, 0.78; 95% CI, 0.49-1.26; P=0.31). Patients with left-sided mCRC had superior outcomes with cetuximab compared with transverse for OS (median, 9.7 vs. 5.9 months; HR, 0.42; 95% CI, 0.27-0.67; P=0.0002) and PFS (median, 3.8 vs. 1.8 months; HR, 0,49; 95% CI, 0.31-0.76; P=0.001). Location was not prognostic in patients treated with BSC alone. CONCLUSIONS: Transverse mCRC has comparable prognostic and predictive features with right-sided mCRC.

Primary tumor resection improves prognosis of unresectable carcinomas of the transverse colon including flexures with pulmonary metastasis: a cohort study.

PURPOSE: Studies of unresectable colorectal cancer pulmonary metastasis (CRPM) have rarely analyzed patient prognosis from the perspective of colonic subsites. This study aimed to evaluate the effects of primary tumor resection (PTR) on the prognosis of patients with unresectable pulmonary metastases of transverse colon cancer pulmonary metastasis (UTCPM), hepatic flexure cancer pulmonary metastasis (UHFPM), and splenic flexure cancer pulmonary metastasis (USFPM). METHODS: Patients were identified from the Surveillance, Epidemiology, and End Results database between 2000 and 2018. The Cox proportional hazards regression models were used to identify prognostic factors of overall survival (OS) and cause-specific survival (CSS). The Kaplan-Meier analyses and log-rank tests were conducted to assess the effectiveness of PTR on survival. RESULTS: This study included 1294 patients: 419 with UHFPM, 636 with UTCPM, and 239 with USFPM. Survival analysis for OS and CSS in the PTR groups, showed that there were no statistical differences in the the UHFPM, UTCPM, and USFPM patients. There were statistical differences in the UHFPM, UTCPM, and USFPM patients for OS and CSS. Three non-PTR subgroups showed significant statistical differences for OS and CSS. CONCLUSION: We confirmed the different survival rates of patients with UTCPM, UHFPM, and USFPM and proved for the first time that PTR could provide survival benefits for patients with unresectable CRPM from the perspective of the colonic subsites of the transverse colon, hepatic flexure, and splenic flexure.

Laparoscopic radical surgery for locally advanced T4 transverse colon cancer and prognostic factors analysis: Evidence from multi-center databases.

The safety and efficacies of laparoscopic radical procedures are still controversial for locally advanced pathological T4 (pT4) TCC (transverse colon cancer). Therefore, the aim of this study is to evaluate the oncologic and perioperative outcomes and to recognize the prognostic factors in radical resection for pT4 TCC derived from multi-center databases. 314 patients with TCC who underwent radical resection between January 2004 and May 2017, including 139 laparoscopic resections and 175 open resections, were extracted from multicenter databases. Oncological as well as perioperative outcomes were investigated. The baseline characteristics of the 2 groups did not differ significantly. Nevertheless, the laparoscopic technique was found to be linked with a significantly longer duration of surgery (208.96 vs 172.89 minutes, P = .044) and a significantly shorter postoperative hospital stay (12.23 vs 14.48 days, P = .014) when compared to the conventional open approach. In terms of oncological outcomes, lymph node resection (16.10 vs 13.66, P = .886), 5-year overall survival (84.7% vs 82.7%, P = .393), and disease-free survival (82.7% vs 83.9%, P = .803) were similar between the 2 approaches. Based on multivariate analysis, it was determined that differentiation and N classification were both independent prognostic factors for overall survival. However, it was found that only N classification was an independent prognostic factor for disease-free survival. These findings underscore the significance of differentiation and N classification as key determinants of patient outcomes in this context. Overall, the laparoscopic approach may offer advantages in terms of shorter hospital stays, while maintaining comparable oncological outcomes. Laparoscopic radical procedure can gain a couple of short-term benefits without reducing long-term oncological survival for patients with pT4 TCC.

[A Case of Transverse Colon Cancer Associated with Lynch Syndrome with Excellent Response to Pembrolizumab].

A 47-year-old woman diagnosed with transverse colon cancer with liver, peritoneal, and lymph node metastases was admitted. Modified FOLFOX6(mFOLFOX6)regimen was given as a first line chemotherapy and was followed by pembrolizumab after 1 cycle of the mFOLFOX6, because microsatellite instability(MSI)test of the tumor showed high-frequency MSI. Because of the transverse colon obstruction after 2 cycles of pembrolizumab, she underwent right hemicolectomy. Histological examination of the resected specimen revealed no residual tumor cells in the primary tumor and reginal lymph nodes. Immunohistochemistry for mismatch repair proteins(IHC-MMR)showed loss of MSH2 and MSH6 expression. Genetic test identified a MSH2 pathogenic variant leading to the diagnosis of Lynch syndrome. The present case shows the importance of MSI test or IHC-MMR before the treatment of metastatic colorectal cancer.

[A Case of Stage â £c dMMR Transverse Colon Cancer with Complete Response to Combination Therapy with Immune Checkpoint Inhibitor in Stage â £B Lung Adenocarcinoma].

The patient is a 72-year-old man. He was diagnosed as a duplication of left upper lobe lung adenocarcinoma cStage ⅣB and transverse colon cancer cStage Ⅳc. Because he had symptoms of atelectasis and esophageal stricture due to the progression of lung cancer, we decided to precede immunochemotherapy(CBDCA plus PEM plus pembrolizumab)for lung cancer. After the start of treatment, both lung and colorectal cancer were shrinking, but after the 3 courses of treatment, he developed intestinal obstruction due to transverse colon cancer. Because generalized peritonitis due to perforation of the colon by endoscopic stenting for the obstruction and then emergency surgery was performed. The resected transverse colon lesion was diagnosed as pathologically complete response. Lung cancer was also diagnosed as clinically complete response. Since his ADL decreased postoperatively, he is under observation without reintroduction of immunochemotherapy. Fourteen months have passed since the last administration, and no progression has been observed in either lung nor colon cancers. Pembrolizumab is considered to be successful in the patient with dMMR colorectal cancer lacking MLH1 and PMS2.

Surgical management strategies for colorectal malignancies of the splenic flexure - A systematic review and network meta-analysis.

BACKGROUND: Extended right hemicolectomy (ERHC) or left hemicolectomy (LHC) are accepted as the standard-of-care for colonic tumours of the splenic flexure. Lymphatic drainage at this site is poorly defined and subject to significant heterogeneity. Nevertheless, emerging evidence demonstrates the potential oncological safety of segmental splenic flexure colectomy (SFC). AIM: To perform a systematic review and network meta-analysis (NMA) to compare outcomes following ERHC, LHC and SFC for splenic flexure tumours (SFTs). METHODS: A systematic review was performed as per PRISMA guidelines. NMA was performed using R Shiny and Netmeta packages. RESULTS: A total of 13 studies, involving 6176 patients (ERHC n = 785; LHC n = 1527; SFC n = 3864) were included in the NMA. There was no difference in overall survival (OS) (SFC vs LHC Hazard Ratio [HR] 1.0, 95% Credible Interval [CrI] 0.76,1.34; SFC vs ERHC HR 1.18, 95% CrI 0.85,1.58) between the groups. SFC had a shorter operation time (Mean 176.37 min; Mean Difference [MD] SFC vs LHC 20.34 min 95% CrI 10.9, 29.97; SFC vs ERHC MD 22.19 95% CrI 11.09, 33.29) but also had a lower average lymph node yield (LNY) compared with ERHC (MD 7.15, 95% CrI 5.71, 8.60). ERHC had a significantly higher incidence of post-operative ileus (Odds Ratio [OR] 3.47, 95% CrI 1.11, 10.84). There was also no difference observed for minimally invasive approaches, anastomotic leak rate, perioperative mortality, reoperation rates or length of stay. CONCLUSIONS: While SFC may allow for reduced operative duration and improved bowel function postoperatively. SFC, LHC, ERHC are all acceptable approaches for curative resection of cancers of the splenic flexure, with no difference in OS observed. Thus, surgeon preference and candidate-specific factors will likely determine the management of SFTs.

[A case of retrograde intussusception due to transverse colon cancer detected by abdominal ultrasonography].

A 78-year-old female patient presented to our hospital with abdominal pain and melena. Abdominal ultrasonography detected a multiple concentric ring sign and retrograde invagination mass near the hepatic flexure. Colonoscopy revealed a 40-mm diameter type 1 tumor in the transverse colon near the splenic flexure, and the biopsy specimen demonstrated a well-differentiated adenocarcinoma. Retrograde intussusception due to transverse colon cancer was diagnosed, and laparoscopic transverse colon resection with lymph node dissection was performed. The resected specimen revealed a 48×40mm diameter type 1 tumor in the transverse colon and was diagnosed as pT2N0M0 pStage I. Contrast-enhanced computed tomography was unavailable, but real-time assessment of the invaginated mass and bowel blood flow was possible by abdominal ultrasonography, which was useful in determining the diagnosis and treatment strategy.

Usefulness of the endoscopic surgical skill qualification system for laparoscopic colectomy for transverse colon cancer: a Japanese multicenter analysis.

PURPOSE: Laparoscopic colectomy for transverse colon cancer (TCC) can be technically demanding due to the anatomical complexity of the region. In Japan, the Endoscopic Surgical Skill Qualification System (ESSQS) was established to improve the skill of laparoscopic surgeons and further develop surgical teams. We examined the safety and feasibility of laparoscopic colectomy for TCC and evaluated the effects of the Japanese ESSQS in facilitating this approach. METHODS: We retrospectively reviewed 136 patients who underwent laparoscopic colectomy for TCC between April 2016 and December 2021. Patients were divided into an ESSQS-qualified surgeon group (surgery performed by an ESSQS-qualified surgeon, n = 52) and a non ESSQS-qualified surgeon (surgery performed by a non ESSQS-unqualified surgeon, n = 84). Clinicopathological and surgical features were compared between groups. RESULTS: Postoperative complications occurred in 37 patients (27.2%). The proportion of patients who developed postoperative complications was lower in the ESSQS-qualified surgeon group (8.0%) than that in the non ESSQS-qualified surgeon group (34.5%; p < 0.017). Multivariate analysis revealed "Operation by ESSQS-qualified surgeon surgeon" (odds ratio (OR) 0.360, 95% confidence interval (CI) 0.140-0.924; p = 0.033), blood loss (OR 4.146, 95% CI 1.688-10.184; p = 0.002), and clinical N status (OR 4.563, 95% CI 1.814-11.474; p = 0.001) as factors independently associated with postoperative complications. CONCLUSION: The present multicenter study confirmed the feasibility and safety of laparoscopic colectomy for TCC and revealed that ESSQS-qualified surgeon achieved better surgical outcomes.

Novel approach toward minimally invasive surgery for mid-transverse colon cancer: 'moving the left colon' technique.

AIM: During surgery for mid-transverse colon cancer (MTC), surgeons often face the dilemma of whether to mobilize the hepatic or splenic flexure. There is no established optimal minimally invasive surgical procedure for MTC. METHODS: We present our novel minimally invasive surgical technique, called the 'moving the left colon' technique for MTC, along with a video demonstration. The procedure involves four main steps: (i) mobilization of the splenic flexure using a medial-to-lateral approach, (ii) dissection of lymph nodes around the middle colic artery from the left side of the superior mesenteric artery approach, (iii) separation of the pancreas and transverse mesocolon and (iv) 'moving the left colon' and performing an intracorporeal anastomosis. By mobilizing the splenic flexure, anatomical landmarks are revealed, which enables safer dissection. Combining this technique with intracorporeal anastomosis allows for a safe and easy anastomosis. RESULTS: Between April 2021 and January 2023, a single-skilled colorectal surgeon performed laparoscopic transverse colectomies using our new approach on three consecutive patients with MTC. The patients had a median age of 75 years (range 46-89 years). The median operative time was 194 min (range 193-228 min) and blood loss was 8 mL (range 0-20 mL). None of the patients experienced any perioperative complications and the median postoperative hospital stay was 6 days. CONCLUSION: We introduced a novel approach for laparoscopic surgery for MTC. This technique can be performed safely and may help standardize minimally invasive surgery for MTC.

Analysis of surgical outcomes of laparoscopic versus open surgery for locally advanced mid-transverse colon cancer.

PURPOSE: This study compared the surgical outcomes between laparoscopic colectomy (LC) and open colectomy (OC) for mid-transverse colon cancer (MTC). METHODS: This multicenter retrospective study compared the short- and long-term surgical outcomes for patients with advanced MTC (T3 and T4 with or without nodal involvement) who underwent LC or OC between January 2008 and December 2019 using a propensity score-matched analysis. RESULTS: A total of 177 patients with advanced MTC were enrolled. After matching, 58 cases for the OC and LC groups were selected. No significant differences in age, sex, tumor progression, or procedure type (extended resection or segmental resection) existed between groups. The LC group had significantly less blood loss (20 mL vs. 50 mL, p=0.048) and a shorter postoperative hospital stay (8 days vs. 12 days, p<0.001) than the OC group. Postoperative complications (Clavien-Dindo grade ≥ 2) occurred in 27.6% and 25.9% of the OC and LC groups respectively (p=1). Three patients (5.2%) and one patient (1.7%) of the OC and LC groups respectively developed anastomotic leakage (p=0.62). Re-operation was required in five patients (8.6%) in the OC group and one patient (1.7%) in the LC group (p=0.21). No surgery-related deaths occurred in either group. The 3-year overall survival rates (stage II: LC 100% vs. OC 92.8%, p=0.15; stage III: 88.9% vs. 84.3%, p=0.88, respectively) were similar between the two groups. CONCLUSION: LC is a minimally invasive technique with lesser blood loss, shorter postoperative hospital stays, and oncologic equivalence to OC. Hence, LC is useful for MTC treatment. TRIAL REGISTRATION: UMIN000042676.

Right colon cancer: The influence of specific location on recurrence and survival.

AIM: This study aimed to investigate whether the site of the tumour within the right colon affects survival in patients who underwent right colectomy for colon cancer. METHODS: An observational retrospective longitudinal study was performed in patients who underwent right colectomy for non-metastatic, invasive right-sided colon cancer. Patients were categorized into two groups based on tumour location: (i) caecum and ascending colon; (ii) hepatic flexure and proximal transverse colon. Demographic and clinical features were characterized, and a survival analysis was performed. RESULTS: Of the 198 patients enroled in the study, 134 (67.8%) had caecal or ascending colon cancer and 64 (32.3%) had hepatic flexure or transverse colon cancer. Seventy (35.4%) were female and the mean age at the time of surgery was 71.6 (SD 11.4). The groups were comparable with respect to the number of lymph nodes sampled, the pTNM stage, the histological differentiation grade and the likelihood of patients receiving adjuvant chemotherapy. Recurrence rate was nearly twice as high in the hepatic flexure and proximal transverse colon group (12.5% vs 6.7%), but this difference was not statistically significant (p = 0.174). Kaplan-Meier analysis showed no differences in disease-free (p = 0.255) and overall survival (p = 0.258) between the groups. CONCLUSION: In our population, specific location of right-sided colon cancers does not appear to have an influence on survival. Further investigation is needed to determine if tumour subsite has an impact on the recurrence rate, and whether it should be considered in defining prognosis and treatment.

Prediction of death probability in adenocarcinoma of the transverse colon: competing-risk nomograms based on 21,469 patients.

PURPOSE: Tumors in parts of the colon other than the transverse colon have been well studied, but little is known about adenocarcinoma of the transverse colon (ATC).The aim of this study was to construct nomograms using competing-risk model for accurately predicting the probability of cancer-specific and non-cancer-specific death in patients with ATC. METHODS: Data on eligible patients recorded during 2000-2019 in the Surveillance, Epidemiology, and End Results database were extracted and screened. Factors that influencing prognosis were screened for death from ATC (DATC) and death from other causes (DOC) using competing-risk analysis, including univariate and multivariate analyses based on Gray's test and the Fine-Gray model, respectively. Independent prognostic factors were identified and nomograms were constructed. For comparison, we also constructed a Cox model and an AJCC stage-only competing-risk model (AJCC model) for patients with DATC. Performance evaluations of the nomograms and comparison between the models were performed using calibration plots, Harrell's concordance index (C-index), receiver operating characteristic (ROC) curves, and the areas under the ROC curve (AUCs). The nomograms and models were validated using a validation cohort. The net reclassification index, integrated discrimination improvement, decision curves, and risk stratification were not assessed because no accepted methods were suited for competing-risk model. RESULTS: This study included 21,469 patients with ATC, and 17 and 9 independent influencing factors were identified for the construction of DATC nomograms (DATCN) and DOC nomograms (DOCN), respectively. In both the training and validation cohorts, the calibration curves indicated good agreement between the nomogram-based predictions and the actual observations in the two nomograms, respectively. The C-index of the DATCN was higher than 80% (80.3-83.3%) at 1, 3 and 5 years in both the training and validation cohorts, significantly outperforming the AJCC (76.7-78%) and Cox (75.4-79.5%) model. The C-index of the DOCN was also higher than 69% (69.0-73.6%). In terms of ROC curves at each time point, those of the DATCN were very close to the upper-left corner of the coordinate axis in both the training and validation cohorts, and their AUCs were larger than 84% (84.2-85.4%).The AUCs of the AJCC (78.4-81.1%) and Cox (79.4-81.5%) models were significantly lower (p < 0.05), and the curves were closer to the diagonal. The ROC curves of the DOCN was similar to those of the DATCN, and the AUCs were 68.5-74%. The DATCN and DOCN therefore had good consistency, accuracy, and stability, respectively. CONCLUSION: This study was the first to construct competing-risk nomograms for ATC. These nomograms have proved useful for accurately assessing patient prognoses and allowing more-individualized follow-up strategies, thereby reducing the mortality.

High grade leiomyosarcoma of the transverse colon with positive lymph node metastasis: to treat or not to treat with adjuvant radiation therapy?

Intra-abdominal leiomyosarcomas (LMSs) are aggressive malignant tumours arising from smooth muscle cells. These neoplasms are extremely rare and account for 10%-20% of primary soft tissue sarcomas and approximately 0.1% of all colorectal malignancies. Intra-abdominal LMS has a very poor prognosis with an estimated 5-year survival rate between 20% and 50% and the size of the tumour being the main determinant of prognosis. Treatment is further complicated by different anatomic variants with differing clinical behaviours impacting prognosis. Newer techniques in radiation treatment such as intensity-modulated, intraoperative electron and proton beam radiotherapies allow for cases with high probability of local recurrence or likelihood of residual microscopic disease after surgical resection to be treated with precise radiation doses to the targeted tumour volume. We present a case of high grade LMS of the distal transverse colon with positive lymph node metastasis treated by surgical excision followed by adjuvant radiotherapy and discuss the current role of radiotherapy.

Clinical outcomes and radiological assessment of vascular anatomy in patients who underwent D3 left hemicolectomy.

Background: Adequate blood supply is one of the key factors for colorectal anastomosis healing. Various variants of vascular anatomy often come as a surprise to surgeons during operations. Objectives: The aims of this study were to carry out a comparative analysis of three-dimensional-computed tomography (3D-CT) angiography data with intraoperative data and a detailed analysis of variants of the anatomy of splenic flexure. Material and methods: In this study, we included 103 patients (56 males and 47 females; mean age 64.2 ± 11.6) with the left-sided colon and rectal cancer who underwent preoperative 3D-CT angiography at Ternopil University Hospital between 2016 and 2022. Results: According to the recently proposed classification, there are four types of blood supply to the splenic flexure of the colon: Our analysis showed that type 1 was found in 83 (80.6%) patients, type 2 in 9 (8.7%), type 3 in 10 (9.7%), and type 4 in 1 (1%). All patients underwent local left radical hemicolectomy with resection of complete mesocolic excision (CME), central vascular ligation (CVL) and resección (R0). Seven cases were operated laparoscopically; and the median quantity of removal lymph nodes was 21.54 ± 7.32. Positive lymph nodes were revealed in 24.3% cases. AL was diagnosed in one patient. Conclusions: Careful pre-operative analysis of vascular anatomy on 3D-CT angiography will assess the vascularization of the splenic flexure of the colon, reduce intraoperative time to identify structures, and develop a personalized strategy for surgery which potentially can reduce the risk of anastomotic leakage.

Antecedentes: El suministro de sangre adecuado es uno de los factores clave para la curación de la anastomosis colorrectal. Varias variantes de la anatomía vascular a menudo sorprenden a los cirujanos durante las operaciones. Objetivo: Realizar un análisis comparativo de los datos de la angiografía tridimensional por tomografía computarizada (3D-TC) con los datos intraoperatorios y un análisis detallado de las variantes de la anatomía del ángulo esplénico. Método: Se incluyeron en el estudio 103 pacientes con cáncer de colon y recto del lado izquierdo que se sometieron a una angiografía 3D-TC preoperatoria en el Hospital Universitario de Ternopil. Resultados: De acuerdo con la clasificación propuesta recientemente, existen cuatro tipos de irrigación del ángulo esplénico del colon. Nuestro análisis mostró que el tipo 1 se encontró en 83 (80.6%) pacientes, el tipo 2 en 9 (8.7%), el tipo 3 en 10 (9.7%) y el tipo 4 en 1 (1%). Todos los pacientes fueron sometidos a hemicolectomía radical izquierda local con resección de escisión mesocólica completa (CME), ligadura vascular central (CVL) y resección (R0). Siete pacientes fueron operados por vía laparoscópica. La mediana de ganglios extirpados fue de 21.54 ± 7.32. Se revelaron ganglios linfáticos positivos en el 24.3% de los casos. Se diagnosticó fuga anastomótica en un paciente. Conclusiones: El análisis preoperatorio cuidadoso de la anatomía vascular en la angiografía 3D-TC evaluará la vascularización del ángulo esplénico del colon, reducirá el tiempo intraoperatorio para identificar estructuras y desarrollará una estrategia personalizada para la cirugía.

The impact of laparoscopic, open, extended right, and left colectomy on clinical outcomes of splenic flexure colon cancer: A meta-analysis.

BACKGROUND: Surgical intervention is the recommended line for the management of colon cancer. The aim of this study was to evaluate the impact of different surgical techniques (laparoscopic, open, extended right, and left colectomy) on clinical outcomes such as mortality, postoperative complications, operation and hospitalization time, and oncological factors. METHODS: A total of 15 studies have been included in the current study. The outcomes of these studies were analyzed using a random-effect model and it was used to calculate the mean difference with 95% confidence intervals to quantify the impact of open, laparoscopic, extended right, and left colectomy. Inclusion criteria included studies in which subjects undergo splenic flexure colon cancer surgery with 2 comparable different surgical techniques. RESULTS: Laparoscopic splenic flexure colon cancer surgery showed a significant beneficial impact on the length of hospital stay (P < .001), the volume of blood loss during surgery (P < .001), postoperative complications (P < .001), and time to an oral diet (P < .001). On the other hand, there was no significance regarding anastomotic leakage, infection of the surgical site, and operation time. Regarding the comparison between extended right colectomy (ERC) and lift colectomy (LC), analysis findings showed a significant (P = .001) higher efficacy of ERC in harvested number of lymph nodes compared with LC. On the other hand, there was no significant difference for the rest of the parameters. The neoadjuvant therapy as an influencing factor on postoperative outcome showed a beneficial impact regarding the overall survival rate. CONCLUSION: Laparoscopic splenic flexure colon cancer surgery showed a significant beneficial impact compared with open surgery as proved by clinical outcomes. On the other hand, ERC and LC resulted in similar findings except for harvested lymph nodes, results were in favor of ERC.

Cutaneous Metastasis of Transverse Colon Cancer with an Aberrant Pattern of CK7/CK20/CDX2 and High Microsatellite Instability.

A 79-year-old woman was diagnosed with transverse colon cancer, moderately differentiated adenocarcinoma. She underwent surgery and postoperative adjuvant chemotherapy. At 80 years old, the patient exhibited changes in skin tone at the chest and abdomen with CK7+/CK20-/CDX2- immunostaining that was later identified as poorly differentiated adenocarcinoma. The diagnosis was cancer of unknown primary origin. The patient passed away three months after the detection of the skin lesion. Autopsy revealed recurrence at the transverse colon, multiple organ metastases, a similar postmortem immunostaining pattern, and high-frequency microsatellite instability (MSI-high). We herein report this case of CK7+/CK20-/CDX2- and MSI-high transverse colon cancer showing cutaneous metastasis.

[A Case of Medullary Carcinoma of the Colon].

The patient is a 79-year-old woman who visited her local doctor with a chief complaint of abdominal pain. A lower gastrointestinal endoscopy revealed a circumferential type 3 mass in the transverse colon. The patient was diagnosed with transverse colon cancer (cT3N0M0, cStage Ⅱa)and underwent laparoscopic transverse colectomy(D3). The postoperative course was good, and she was discharged on POD 9. Pathological results showed a diagnosis of medullary carcinoma(pT3N0M0, pStage Ⅱa)with MSI-high. The patient was treated with UFT/UZEL for 6 months as postoperative adjuvant chemotherapy. The patient has been recurrence-free for 1 year and 6 months postoperatively and is under outpatient follow-up. Medullary carcinoma is a rare histologic type that is estimated to account for 2-3% of all colorectal cancers. Medullary carcinoma of the colon is more common in elderly patients, women, and the right side of the colon, with a relatively favorable prognosis. We report a case of medullary carcinoma of the transverse colon in which the patient had a relatively long survival, with some discussion of the literature.

Infrapyloric (No. 206) and greater curvature (No. 204) lymph node metastasis in adenocarcinoma located in the right half of the transverse colon (InCLART Study): protocol for a multicentre prospective observational study.

INTRODUCTION: In the case of right-sided transverse colon cancer (RTCC) and hepatic flexure colon cancer (HFCC), there is a potential connection of lymph drainage between mesentery and greater omentum. However, most previous reports have been limited case series with No. 206 and No. 204 lymph node (LN) dissection for RTCC and HFCC. METHODS AND ANALYSIS: The InCLART Study is a prospective observational study aiming to enrol 427 patients with RTCC and HFCC treated at 21 high-volume institutions in China. The prevalence of infrapyloric (No. 206) and greater curvature (No. 204) LN metastasis and short-term outcomes will be investigated in a consecutive series of patients with T2 or deeper invasion RTCC or HFCC, following the principle of complete mesocolic excision with central vascular ligation. Primary endpoints were performed to identify the prevalence of No. 206 and No. 204 LN metastasis. Secondary analyses will be used to estimate prognostic outcomes, intraoperative and postoperative complications, the consistency of preoperative evaluation and postoperative pathological results of LN metastasis. ETHICS AND DISSEMINATION: Ethical approval for the study has been granted by the Ruijin Hospital Ethics Committee (approval number: 2019-081) and has been or will be approved successively by each participating centre's Research Ethics Board. The findings will be disseminated in peer-reviewed publications. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT03936530; https://clinicaltrials.gov/ct2/show/NCT03936530).

[A Case of Pancreatic Tail Cancer Causing Gastrointestinal Hemorrhage Due to Transverse Colon Invasion].

An 81-year-old woman was admitted to our hospital due to frequent bleeding and hemorrhagic shock. Blood tests revealed anemia and contrast-enhanced abdominal CT revealed a pancreatic tail tumor with a diameter of 60 mm. The boundary between pancreatic tumor and the transverse colon, stomach and spleen was unclear, and invasion of the transverse colon as well as the stomach and spleen was suspected. Hemorrhage due to colon invasion of the pancreatic tail cancer and intra-tumoral hemorrhage were suspected. Due to persistent bleeding, the patient had emergency surgery to control bleeding. The pancreatic tail tumor invaded not only the colon but also stomach and spleen, distal pancreatectomy, partial gastrectomy and splenectomy was performed in combination with resection of the transverse colon, and transverse colon colostomy. We report a case of gastrointestinal bleeding caused by transverse colon invasion of pancreatic tail cancer, which resulted in emergency surgery.