Left-sided Colon Cancer Research Articles

Short-term Outcomes of Robotic Left Colectomy Reconstructed by Intracorporeal Overlap Anastomosis for Left-sided Colon Cancer: A Single-center Report from Japan.

Surgery for colon cancer requires covering a wide area and performing both tumor resection and precise lymph node dissection. Robotic left-sided colectomy (RLC) has not been thoroughly established due to the rarity of descending colon cancer. Therefore, we investigated 19 patients who underwent RLC for left-sided colon cancer. Between January 2023 and July 2024, a total of 19 consecutive patients underwent robotic radical left colectomy, which included mobilization of the splenic flexure. We compared the intra- and postoperative factors between left-sided colectomy with and without stent placement. Total operative time (p=0.002), console time (p=0.001), and lymph node harvest time (p=0.001) were significantly different. The total operative time with stent placement was longer than that without stent placement (421.6 vs. 302.0, p<0.01). Console time with stent placement was longer than that without stent placement (315.0 vs. 202.0, p<0.01). More lymph nodes were harvested with stent placement than without (33.1 vs. 11.0, p<0.01). We did not experience any conversions to open surgery, and two Grade II complications were observed according to the Clavien-Dindo classification. Both total operative and console times were longer in cases with stent placement compared to those without. Nevertheless, we safely performed robotic left colectomy, regardless of whether the left-sided colon cancer was treated with stent placement, even in cases where the anastomosis overlapped naturally. Our postoperative outcomes showed no anastomosis-related complications. Therefore, RLC reconstruction using an intracorporeal overlap anastomosis is feasible for left-sided colon cancer, both in terms of intraoperative and postoperative outcomes.

A Study on Lymph Node Distribution in the Main Lymph Node Area for Left-sided Colon Cancer.

In advanced left-sided colorectal cancer, cutting the root of the inferior mesenteric artery (IMA) branching from the aorta is recommended for complete lymph node dissection. However, this procedure sometimes causes severe complications. This study aimed to elucidate the lymph nodes' distribution around the IMA and identify the most critical sites for lymph node dissection. This study included 30 consecutive patients with left-sided colorectal cancer who underwent curative resection with main lymph node dissection in a single institution between January and June of 2022. The mesenteric sections (main lymph nodes, IMA, left colic artery [LCA], and inferior mesenteric vein) were removed from the surgically excised specimen. Subsequently, whole-tissue sections were prepared and stained with hematoxylin and eosin. The positional relationships between each blood vessel and respective lymph nodes were then assessed using the pathological findings. The main lymph nodes were identified in 26 out of 30 patients. The total number of dissected lymph nodes per patient was 0-30 (average: 5.3), and the median distance from the IMA to the main lymph node was 7.61 mm (1.87-43.26 mm). Dividing the lymph nodes into segments, we found 18%, 46%, and 36% of the lymph nodes in the proximal, middle, and distal segments, respectively. Additionally, all lymph nodes were found outside of the IMA sheath surrounding each arterial wall. In left-sided colorectal cancer, the main lymph nodes are mostly located around the LCA bifurcation, which may be essential to ensure main lymph node dissection for advanced stage cases.

MiR‑106b‑5p in stage II left‑sided and right‑sided colon cancer and its association with the prognostic characteristics of patients.

MicroRNA (miR)-106b-5p is highly expressed in colon cancer; however, data on its expression levels in left-sided colon cancer (LCC) vs. right-sided colon cancer (RCC) is lacking. The present study aimed to assess the differences in miR-106b-5p expression in stage II LCC and RCC, as well as its relationship with patient prognosis. From August 2018 to February 2020, 40 specimens of primary stage II colon cancer were collected from Huizhou First Hospital (Huizhou, China), which included 20 cases of LCC and 20 cases of RCC. The miR-106b-5p expression levels in cancer tissues were compared with normal adjacent tissues, as well as between LCC and RCC tissues, and survival outcomes were assessed. miR-106b-5p expression was significantly higher in stage II LCC tissues compared with RCC tissues. However, no significant difference in 5-year survival was observed between the two groups. Notably, 5-year survival was significantly lower in the high miR-106b-5p expression group compared with the low expression group among patients with RCC. By contrast, there were no survival differences between the high and low miR-106b-5p expression groups in LCC. Multivariate analysis indicated that miR-106b-5p expression was an independent prognostic factor for patients with RCC. In conclusion, miR-106b-5p expression was significantly upregulated in colon cancer tissues, with higher expression levels demonstrated in LCC compared with RCC. High miR-106b-5p expression in RCC was identified as an independent prognostic factor, whilst its expression in LCC did not show a significant association with prognosis.

Sidedness and Molecular Pattern in Defining the Risk of Lymph Node Metastasis in Nonmetastatic Colorectal Cancer: Single-Center Retrospective Study.

Background: Lymphadenectomy plays a central role in the treatment of localized colon cancer. While in left colon cancer the D3 lymphadenectomy/CME is considered the standard of care, lymphatic stations to be removed in right colon cancer are still a matter of discussion. The individuation of LNM risk factors could help in choosing the lymphadenectomy in right-sided tumors. This study aims to analyze the correlation of histopathological and molecular characteristics with lymph node metastasis, both in right- and left-sided colon cancer, and their impact on survival; Methods: We conducted a single-center observational retrospective study. The following data were collected and analyzed for each patient: demographics, histopathological and molecular data, and intraoperative and perioperative data. Statistical analyses were performed, including descriptive statistics, multivariate logistic regression and survival analysis; Results: An association between tumor size (pT, p < 0.001), grading (p = 0.013), budding (p < 0.001), LVI (79,4% p < 0.001) and LNM was observed. A multivariate analysis identified pT4 (OR 5.45, p < 0.001) and LVI+ (OR 10.7, p < 0.001) as significant predictors of LNM. Right-sided patients presented a worse OS when associated with LNM, while no significant difference was observed in N0 patients; Conclusions: histological and molecular analysis can help identify high risk patients, which could benefit from extended lymphadenectomies. These patients could be ideal candidates for the D3 lymphadenectomy/CME.

Research progress on the distribution patterns and surgical dissection of central lymph nodes in left-sided colon cancer

Lymphatic metastasis is one of the main pathways of colorectal cancer spread and also a crucial factor in patient long-term prognosis. Lymph node dissection in the possible tumor drainage area, particularly the central group of lymph nodes at the root of the tumor-associated supplying artery, is a key and challenging aspect of surgical techniques. Currently, the patterns of lymphatic drainage and the distribution of central lymph nodes in left-sided colon cancer are not well illustrated, and there is no consensus on the necessity and extent of central lymph node dissection. This has led to significant variability in the extent of lymph node dissection among different surgeons in clinical practice, a lack of quality control standards for surgical procedures, and impacts on postoperative treatment strategy and long-term outcomes. Moreover, current research on lymphatic drainage and metastasis is primarily based on traditional anatomy, whereas individualized, precise approaches to lymph node dissection have not been realized. The application of preoperative and intraoperative lymph node imaging techniques based on functional anatomy in colorectal cancer patients is still under exploration.

Pan-immune-inflammation value as a prognostic biomarker for colon cancer and its variation by primary tumor location.

A growing body of research indicates significant differences between left-sided colon cancers (LCC) and right-sided colon cancers (RCC). Pan-immune-inflammation value (PIV) is a systemic immune response marker that can predict the prognosis of patients with colon cancer. However, the specific distinction between PIV of LCC and RCC remains unclear. To investigate the prognostic and clinical significance of PIV in LCC and RCC patients. This multicenter retrospective cohort study included 1510 patients with colon cancer, comprising 801 with LCC and 709 with RCC. We used generalized lifting regression analysis to evaluate the relative impact of PIV on disease-free survival (DFS) in these patients. Kaplan-Meier analysis, as well as univariate and multivariate analyses, were used to examine the risk factors for DFS. The correlation between PIV and the clinical characteristics was statistically analyzed in these patients. A total of 1510 patients {872 female patients (58%); median age 63 years [interquartile ranges (IQR): 54-71]; patients with LCC 801 (53%); median follow-up 44.17 months (IQR 29.67-62.32)} were identified. PIV was significantly higher in patients with RCC [median (IQR): 214.34 (121.78-386.72) vs 175.87 (111.92-286.84), P < 0.001]. After propensity score matching, no difference in PIV was observed between patients with LCC and RCC [median (IQR): 182.42 (111.88-297.65) vs 189.45 (109.44-316.02); P = 0.987]. PIV thresholds for DFS were 227.84 in LCC and 145.99 in RCC. High PIV (> 227.84) was associated with worse DFS in LCC [PIV-high: Adjusted hazard ratio (aHR) = 2.39; 95% confidence interval: 1.70-3.38; P < 0.001] but not in RCC (PIV-high: aHR = 0.72; 95% confidence interval: 0.48-1.08; P = 0.114). These findings suggest that PIV may predict recurrence in patients with LCC but not RCC, underscoring the importance of tumor location when using PIV as a colon cancer biomarker.

A commentary on 'Timing of restoration of bowel continuity after decompressing stoma, in left-sided obstructive colon cancer: a nationwide retrospective cohort'.

A commentary on 'Timing of restoration of bowel continuity after decompressing stoma, in left-sided obstructive colon cancer: a nationwide retrospective cohort'.

Accuracy of Clinical Staging of Localized Colon Cancer: A National Cancer Database Cohort Analysis.

This study aimed to assess concordance between clinical and pathologic assessment of colon cancer. A retrospective cohort analysis of patients with stage I-III colon cancer in the National Cancer Database (2010-2019) was conducted. Concordance between clinical and pathologic assessment of colon cancer was calculated using Kappa coefficients and 95% confidence intervals (CIs). A total of 125,473 patients (51.2% female; mean age 68.2 years) were included. There was moderate concordance between clinical and pathologic T stage (Kappa = 0.606, 95%CI: 0.602-0.609) and between clinical and pathologic N stage (Kappa = 0.506, 95%CI: 0.501-0.511). For right-sided colon cancer, there was moderate agreement between clinical and pathologic T stage (Kappa = 0.594, 95%CI: 0.589-0.599) and N stage (Kappa = 0.530, 95%CI: 0.523-0.537). For left-sided colon cancer, there was substantial agreement between clinical and pathologic T stage (Kappa = 0.624, 95%CI: 0.619-0.630) and moderate agreement between N stage (Kappa 0.472, 95%CI: 0.463-0.480). Sensitivity of clinical assessment of T and N stage ranged from 64.3% to 77.2% and 41.6% to 54.5%, respectively. Specificity ranged from 96.7% to 97.7% for T stage and 95.7% to 97.3% for N stage. Clinical assessment of T and N stages of colon cancer had good diagnostic accuracy with moderate concordance withthe final pathologic stage. While clinical assessment was highly specific with < 3% of patients being over-staged, it had modest sensitivity, especially for detection of nodal involvement. Diagnostic accuracy of clinical assessment of right and left colon cancers was similar, except for higher sensitivity and accuracy of assessment of nodal involvement in right than left colon cancers.

Innovative pancreas-guided technique for splenic flexure mobilization in laparoscopic left hemicolectomy.

Splenic flexure mobilization (SFM) is a major challenge in laparoscopic left hemicolectomy. This study aims to assess the safety and effectiveness of the pancreas-guided SFM technique during laparoscopic left hemicolectomy. From January 2018 to December 2023, 352 patients with left-sided colon cancer underwent laparoscopic left hemicolectomy. Based on the SFM method used, the patients were divided into the pancreas-guided group (167 cases) or the "Three Approaches Roundabout"/classic group (185 cases). Clinicopathologic characteristics and intraoperative and postoperative variables were compared between the two groups. The two groups had no significant differences in baseline indicators (P > 0.05). All surgeries were successful without needing to convert to laparotomy, and there were no combined organ resections involving the spleen or pancreas in either group. The mean duration of surgery was significantly lower in the pancreas-guided group than in the classic group (P < 0.01). The median volume of intraoperative blood loss in the pancreas-guided group was lower than that in the classic group (P < 0.01). Through video playback, it was found that the retro-pancreaticspace had been entered during operation in 8 cases (4.3%) in the classic group, while there were no such occurrences in the pancreas-guided group. This difference was statistically significant (P < 0.05). The difference in the number of lymph nodes cleared, postoperative hospital stays, and incidence of complications were not statistically significant (all P > 0.05) between the groups. The pancreas-guided SFM technique is a safe and feasible option for laparoscopic left hemicolectomy. Our study's findings suggest that this approach facilitates accurate access to the correct anatomic plane, potentially improving surgical efficiency.

Retrospective Study of Clinicopathologic Features and Outcome of Colonic Cancer in Relation to Primary Tumor Location

Abstract Background Colon cancer is one of the most common cancers worldwide and outcomes of colon cancer are different according to the primary tumor location and could be considered as distinct disease entities of the same organ. Objectives Analyzing and comparing clinical, epidemiological, pathologic features and outcome of colon cancer according to primary location whether the patients are right sided colon cancer (RSCC) and left sided colon cancer (LSCC) patients in different situations. Patients and Methods This is a retrospective, descriptive and analytical study conducted between January 1st, 2013 and January 1st 2019. One hundred and fifty patients diagnosed with colon cancer were enrolled in GIT unit, Department of Clinical Oncology, Ain Shams University Hospital. Results In our study right sided colon cancer patients were more females and clinically presented with higher frequency of anaemia (P value = 0.001) and perforation (P value = 0.02). Left sided colon cancer on the other side were more males (P value = 0.032) and was associated with more constipation (P value &amp;lt;0.001) and intestinal obstruction (P value = 0.085). RSCC was more associated mucinous adenocarcinoma, more advanced T stage (T4), lymphovascular invasion, larger tumor sizes and more poorly differentiated tumor. LSCC was associated with more advanced stage and lymph node positivity. Right side tumor has highest disease-free survival period which is 34.63 months (95% confidence interval [CI] 28.39-40.86) comparing with the left side tumor which was 24.94 months (95% confidence interval [CI] 19.61-30.27). left side tumor has highest progressive free survival period which is 4.77 months (95% confidence interval [CI] 3.33-8.22) comparing with the right-side tumor which was 2.21 months (95% confidence interval [CI] 0.63-3.79). Conclusion RSCCs and LSCCs show different characteristics in clinical presentation and prognostic features, so we can consider the side of tumor is helpful in determining the behavior and the outcome of the disease. We can consider RSCC and LSCC as two separate disease entities.

Surgery for Infrarenal Retroperitoneal Node Metastases from Colon Cancer.

Treatment of retroperitoneal lymph node metastases (RPN) from colon cancer (CC) is a therapeutic challenge. Available evidence supporting a curative approach is weak and uncertainties remain concerning the extent of the dissection, the optimal timing for surgery, and the role of adjuvant radiotherapy. We report the outcomes of a curative intent strategy in a recent monocentric series of patients. We did a retrospective review of all curative intent surgical treatment of RPN from CC performed consecutively in a French university hospital from June 2015 to April 2021. Demographics, clinicopathological, and molecular characteristics were evaluated. We describe recurrence-free and overall survival and factors related to recurrence. Records from 18 patients were reviewed. The median age was 69years. Most of the patients were male (55%), ASA 1-2 (94%), had a left-sided primary colon cancer (73%), and had metachronous RPN (62%). Thirteen patients (72%) experienced recurrence. Recurrence was often limited to RPN (27%) or liver (22%). Four patients underwent a second surgery for RPN recurrence. Median disease-free and overall survival were 22months and 50months after RPN surgery. We did not find any factor associated with recurrence. Short-term recurrence (< 6months) was associated with shorter overall survival (0.031). The current results suggest that RPN resection is feasible and associated with long survival in selected patients. Further studies evaluating the benefit of curative strategies including radical surgery for patients with potentially resectable RPN are warranted.

Impact of Circular Stapler Size on the Risk of Anastomotic Complications in Patients With Left-sided Colorectal Cancer: A Propensity Score-matched Study.

The present study examined the impact of circular stapler size on anastomotic complications, including leakage and stricture in patients undergoing double-stapling technique (DST) anastomosis for left-sided colon or rectal cancer. A total of 403 patients were enrolled in this study, with circular stapler sizes of 25, 28, and 29 mm. A small circular stapler (25 mm) was used in 170 cases (42.2%), and a medium-sized circular stapler (28/29 mm) was used in 233 cases (57.8%). After propensity score matching, there was no marked difference in the incidence of anastomotic leakage/stricture between the groups (13.9% vs. 10.9%, 3.0% vs. 1.0%, respectively). The size of the circular stapler was not associated with the incidence of anastomotic leakage or stricture in this cohort.

An artificial intelligence-designed predictive calculator of conversion from minimally invasive to open colectomy in colon cancer

Minimally invasive surgery is safe and effective in colorectal cancer. Conversion to open surgery may be associated with adverse effects on treatment outcomes. This study aimed to assess risk factors of conversion from minimally invasive to open colectomy for colon cancer and impact of conversion on short-term and survival outcomes. This case–control study included colon cancer patients undergoing minimally invasive colectomy from the National Cancer Database (2015–2019). Logistic regression analyses were conducted to determine independent predictors of conversion from laparoscopic and robotic colectomy to open surgery. 26,546 patients (mean age: 66.9 ± 13.1 years) were included. Laparoscopic and robotic colectomies were performed in 79.1% and 20.9% of patients, respectively, with a 10.6% conversion rate. Independent predictors of conversion were male sex (OR: 1.19, p = 0.014), left-sided cancer (OR: 1.35, p < 0.001), tumor size (OR: 1, p = 0.047), stage II (OR: 1.25, p = 0.007) and stage III (OR: 1.47, p < 0.001) disease, undifferentiated carcinomas (OR: 1.93, p = 0.002), subtotal (OR: 1.25, p = 0.011) and total (OR: 2.06, p < 0.001) colectomy, resection of contiguous organs (OR: 1.9, p < 0.001), and robotic colectomy (OR: 0.501, p < 0.001). Conversion was associated with higher 30- and 90-day mortality and unplanned readmission, longer hospital stay, and shorter overall survival (59.8 vs 65.3 months, p < 0.001). Male patients, patients with bulky, high-grade, advanced-stage, and left-sided colon cancers, and patients undergoing extended resections are at increased risk of conversion from minimally invasive to open colectomy. The robotic platform was associated with reduced odds of conversion. However, surgeons’ technical skills and criteria for conversion could not be assessed.

Effects of tumor location and mismatch repair on clinicopathological features and survival for non-metastatic colon cancer: A retrospective, single center, cohort study

Objective: To analyze the differences in clinicopathological features of colon cancers and survival between patients with right- versus left-sided colon cancers. Methods: This was a retrospective cohort study. Information on patients with colon cancer from January 2016 to August 2020 was collected from the prospective registry database at Peking Union Medical College Hospital . Primary tumors located in the cecum, ascending colon, and proximal two-thirds of the transverse colon were defined as right-sided colon cancers (RCCs), whereas primary tumors located in the distal third of the transverse colon, descending colon, or sigmoid colon were defined as left-sided colon cancers (LCCs). Clinicopathological features were compared using the χ2 test or Mann-Whitney U test. Survival was estimated by Kaplan-Meier curves and the log-rank test. Factors that differed significantly between the two groups were identified by multivariate survival analyses performed with the Cox proportional hazards function. One propensity score matching was performed to eliminate the effects of confounding factors. Results: The study cohort comprised 856 patients, with TNM Stage I disease, 391 (45.7%) with Stage II, and 336 (39.3%) with Stage III, including 442 (51.6%) with LCC and 414 (48.4%) with RCC and 129 (15.1%). Defective mismatch repair (dMMR) was identified in 139 patients (16.2%). Compared with RCC, the proportion of men (274/442 [62.0%] vs. 224/414 [54.1%], χ2=5.462, P=0.019), body mass index (24.2 [21.9, 26.6] kg/m2 vs. 23.2 [21.3, 25.5] kg/m2, U=78,789.0, P<0.001), and well/moderately differentiated cancer (412/442 [93.2%] vs. 344/414 [83.1%], χ2=22.266, P<0.001) were higher in the LCC than the RCC group. In contrast, the proportion of dMMR (40/442 [9.0%] vs. 99/414 [23.9%], χ2=34.721, P<0.001) and combined vascular invasion (106/442[24.0%] vs. 125/414[30.2%], χ2=4.186, P=0.041) were lower in the LCC than RCC group. The median follow-up time for all patients was 48 (range 33, 59) months. The log-rank test revealed no significant differences in disease-free survival (DFS) (P=0.668) or overall survival (OS) (P=0.828) between patients with LCC versus RCC. Cox proportional hazards model showed that dMMR was significantly associated with a longer DFS (HR=0.419, 95%CI: 0.204‒0.862, P=0.018), whereas a higher proportion of T3-4 (HR=2.178, 95%CI: 1.089‒4.359, P=0.028), N+ (HR=2.126, 95%CI: 1.443‒3.133, P<0.001), and perineural invasion (HR=1.835, 95%CI: 1.115‒3.020, P=0.017) were associated with poor DFS. Tumor location was not associated with DFS or OS (all P>0.05). Subsequent analysis showed that RCC patients with dMMR had longer DFS than did RCC patients with pMMR (HR=0.338, 95%CI: 0.146‒0.786, P=0.012). However, the difference in OS between the two groups was not statistically significant (HR=0.340, 95%CI:0.103‒1.119, P=0.076). After propensity score matching for independent risk factors for DFS, the log-rank test revealed no significant differences in DFS (P=0.343) or OS (P=0.658) between patients with LCC versus RCC, whereas patient with dMMR had better DFS (P=0.047) and OS (P=0.040) than did patients with pMMR. Conclusions: Tumor location is associated with differences in clinicopathological features; however, this has no impact on survival. dMMR status is significantly associated with longer survival: this association may be stronger in RCC patients.

Primary Tumor Sidedness Associated with Clinical Characteristics and Postoperative Outcomes in Colon Cancer Patients: A Propensity Score Matching Analysis.

Background: Recent investigations have suggested that-sidedness is associated with the prognosis of colon cancer patients. However, the role of sidedness in surgical outcome is unclear. In this study, we tried to demonstrate the real role of sidedness in postoperative results for colon cancer patients receiving surgical intervention. Methods: This is a propensity score matching study using the database of the American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) from 2009 to 2013. Sidedness groups including right-sided and left-sided colon cancer were created according to the associated diagnosis and procedure codes. Postoperative 30-day mortality, morbidity, overall complications, and total length of hospital stay were analyzed after performing propensity score matching. Results: Out of a total of 24,436 colon cancer patients who received associated operations, 15,945 patients had right-sided cancer and 8941 patients had left-sided cancer. Right-sided colon cancer patients were accompanied by more preoperative comorbidities including old age, female sex, hypertension, dyspnea, anemia, hypoalbuminemia, and a high American Society of Anesthesiologists grade (SMD > 0.1). Postoperative mortality, morbidities including re-intubation, bleeding, urinary tract infection and deep vein thrombosis, postoperative overall complications, and total length of hospital stay were significantly associated with right-sided cancer (p < 0.05). After 1:1 propensity score matching, postoperative mortality was not significantly different between right-sided cancer (2.3%) and left-sided cancer (2.4%) patients. The patients with left-sided colon cancer had significantly more postoperative morbidities, more overall complications, and longer total length of hospital stay. Conclusions: Poor clinical characteristics and postoperative outcomes were noted in right-sided cancer patients. After propensity score matching, left-sided cancer patients had worse postoperative outcomes than those with right-sided cancer.

Modified oral antibiotics and mechanical bowel preparation (OAMBP) versus conventional OAMBP for sigmoid colon and rectal surgery: A multicenter randomized non-inferiority trial.

To evaluate whether the use of a laxative with reduced patient burden in oral antibiotics and mechanical bowel preparation (OAMBP) could prevent surgical site infection (SSI) in left-sided colon and rectal cancers. This multicenter, non-blinded, randomized, non-inferiority trial included patients who underwent elective colorectal surgery for colorectal cancer in a university and community hospital in Japan from April 1, 2021 to March 31, 2023. We compared conventional OAMBP (polyethylene glycol, metronidazole, and kanamycin) (cOAMBP group) with modified OAMBP (sodium picosulfate hydrate, metronidazole, and kanamycin) (mOAMBP group). The primary outcome was overall incidence of SSI. Secondary outcomes were postoperative complications, degree of patient burden, and intraoperative bowel dilatation. Among 119 patients, 112 were randomly assigned to the two groups, with 56 patients in each group. SSI occurred in three (5.4%) and five patients (8.3%) in the mOAMBP and cOAMBP groups, respectively (90% confidence interval [CI]: -12.8-5.3), with a 15% margin of non-inferiority. Anastomotic leakage occurred in no patient in the mOAMBP group and three patients (5.4%) in the cOAMBP group (p = 0.24). The cOAMBP group reported significantly more pain than the mOAMBP group (50 [90.9%] vs. 7 [12.5%] participants). The mOAMBP group showed significantly lesser bowel dilatation than the cOAMBP group (1 [1.8%] vs. 21 [37.5%] participants). mOAMBP is safe and less burdensome, can reduce intraoperative bowel dilatation, and is non-inferior compared with cOAMBP in preventing SSI. Therefore, mOAMBP may be more suitable for sigmoid colon and rectal cancer. UMIN000043162 (http://www.umin.ac.jp/ctr/). Registered on January 28, 2021.

A registry-based study on universal screening for defective mismatch repair in colorectal cancer in Denmark highlights disparities in screening uptake and counselling referrals

Universal screening for defective mismatch repair (dMMR) in colorectal cancer utilizes immunohistochemical staining for MLH1, MSH2, MSH6 and PSM2. Additionally, BRAF V600E mutations status and MLH1 hypermethylation should be performed to distinguish germline and somatic dMMR alterations. A decade of Danish population-based registries has been analysed regarding screening uptake, detection rate and referral to genetic counselling. MMR testing was performed in 71·8% (N = 34,664) of newly diagnosed colorectal cancers with an increasing trend to 88·8% coverage in the study's final year. The likelihood of undergoing MMR testing was reduced in males with 2% (95% CI 0·4–2·7, p = 0·008), with 4·1% in patients above age 70 years (95% CI 1·5–6·6, p = 0·003) compared in patients below age 51 years, with 16·3% in rectal cancers (95% CI 15·1–17·6, p < 0·001) and 1·4% left-sided colon cancers (95% CI 0·1–1·7, p = 0·03) compared to right-sided colon cancers. Tumour stage II and III increased the likelihood of being tested, with 3·7% for stage II (95% CI 2·2–5·6, p < 0·001) and 3·3% for stage III tumours (95% CI 1·8–4·8, p < 0·001) compared to stage I tumours, whereas the likelihood for stage IV tumours is reduced by 35·7% (95% CI 34·2–37·2, p < 0·001). Test rates significantly differed between the Danish health care regions. dMMR was identified in 15·1% (95% CI 14·8–15·6, p < 0·001) cases with somatic MMR inactivation in 6·7% of the cases. 8·3% tumours showed hereditary dMMR expression patterns, and 20·0% of those were referred to genetic counselling. Despite the high uptake rates, we found disparities between patient groups and missed opportunities for genetic diagnostics.

Long-Term Outcomes of the Obstruction Treatment in Benign and Malignant Colonic Obstruction: A Multicentre Study

Abstract Introduction Patients with colonic obstruction are at risk for emergency resection, which is a risk factor for increased mortality and morbidity. In left-sided obstructive colon cancer, the principle of bridge-to-surgery is already recommended to reduce complications. From this treatment strategy, the obstruction treatment is derived. In this treatment strategy, bowel wall distention is reduced by minimizing stool production through laxatives and dietary measures. Short-term outcomes have already shown promising results. This study aims to evaluate long-term outcomes in patients treated with this obstruction treatment. Methods This is a multicenter prospective study that included patients who presented with symptomatic colonic obstruction and radiologic confirmation of obstruction between May 2019 and August 2020 in the contributing hospitals. Patients with malignant and benign colonic obstruction were included. Follow-up in this study consisted of at least 36 months. Endpoints of the study included 1- and 3-year stoma and mortality rates. Results Ninety-eight patients were included in this study. For the overall cohort complication, reoperation, and readmission rates after one year were 37%, 14%, and 10% respectively. Overall, 3-year mortality was 21%. The presence of a stoma after 1 year was 18%, and after 3 years 17% in this cohort. Conclusion Long-term results of this study indicate that obstruction treatment has acceptable long-term outcomes in terms of mortality and stoma rates, compared to literature on emergency surgery and bridge-to-surgery alternatives. Permanent stoma rates are lower, compared to the literature on other treatment strategies in bowel obstruction.

Prognostic factors and survival disparities in right-sided versus left-sided colon cancer

Right-sided colon cancer (RCC) and left-sided colon cancer (LCC) differ in features and outcomes because of variations in embryology, epidemiology, pathology, and prognosis. This study sought to identify significant factors impacting patient survival through Bayesian modelling. Data was retrospectively analysed from a colorectal neoplasia database. Data on demographics, perioperative risks, treatment, mortality, and survival was analysed from patients who underwent colon cancer surgery from January 2010 to December 2021. This study involved 2475 patients, with 58.7% having RCC and 41.3% having LCC. RCC patients had a notably higher mortality rate, and their overall survival (OS) rates were slightly lower than those with LCC (P < 0.05). RCC stages I–IV consistently exhibited worse OS and relapse-free survival (RFS) than LCC (P < 0.05). Factors like age, BMI, ASA score, cancer stage, and comorbidities had significant associations with OS and RFS. Poor and moderate differentiation, lower lymph node yield, and organ resection were linked to lower survival while receiving chemotherapy; higher BMI levels and elective surgery were associated with better survival (all P < 0.05). Our study reveals key differences between RCC and LCC, emphasising the impact of age, BMI, ASA score, cancer stage, and comorbidities on patient survival. These findings could inform personalised treatment strategies for colon cancer patients.

Deep neural network for the prediction of KRAS, NRAS, and BRAF genotypes in left-sided colorectal cancer based on histopathologic images

BackgroundThe KRAS, NRAS, and BRAF genotypes are critical for selecting targeted therapies for patients with metastatic colorectal cancer (mCRC). Here, we aimed to develop a deep learning model that utilizes pathologic whole-slide images (WSIs) to accurately predict the status of KRAS, NRAS, and BRAFV600E. Methods129 patients with left-sided colon cancer and rectal cancer from the Third Affiliated Hospital of Sun Yat-sen University were assigned to the training and testing cohorts. Utilizing three convolutional neural networks (ResNet18, ResNet50, and Inception v3), we extracted 206 pathological features from H&E-stained WSIs, serving as the foundation for constructing specific pathological models. A clinical feature model was then developed, with carcinoembryonic antigen (CEA) identified through comprehensive multiple regression analysis as the key biomarker. Subsequently, these two models were combined to create a clinical-pathological integrated model, resulting in a total of three genetic prediction models. Result103 patients were evaluated in the training cohort (1782,302 image tiles), while the remaining 26 patients were enrolled in the testing cohort (489,481 image tiles). Compared with the clinical model and the pathology model, the combined model which incorporated CEA levels and pathological signatures, showed increased predictive ability, with an area under the curve (AUC) of 0.96 in the training and an AUC of 0.83 in the testing cohort, accompanied by a high positive predictive value (PPV 0.92). ConclusionThe combined model demonstrated a considerable ability to accurately predict the status of KRAS, NRAS, and BRAFV600E in patients with left-sided colorectal cancer, with potential application to assist doctors in developing targeted treatment strategies for mCRC patients, and effectively identifying mutations and eliminating the need for confirmatory genetic testing.