Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2019 for the treatment of colorectal cancer

Prognostic factors and long-term outcomes with endoscopic submucosal dissection for colorectal tumors in patients aged 75 years or older

Background

Studies regarding the long-term outcomes of endoscopic submucosal dissection (ESD) performed in older patients with colorectal tumors are limited. Therefore, in this study, we aimed to analyze the long-term outcomes of older patients with colorectal tumors who underwent ESD and identify prognostic factors.

Methods

The data of patients aged ≥ 75 years who underwent ESD for colorectal tumors (adenoma and Tis/T1 colorectal cancer) at a single center were retrospectively analyzed. Prognostic factors for overall survival were analyzed using the Kaplan-Meier method and the Cox proportional hazard model.

Results

Of the 156 patients included, 51 patients died during the follow-up period, among whom two deaths were due to colorectal cancer. The univariate analysis revealed that an age ≥83 years, Charlson Comorbidity Index ≥2, prognostic nutritional index <46, and neutrophil-to-lymphocyte ratio (NLR) ≥3 were associated with poor overall survival. The multivariate analysis identified Charlson Comorbidity Index ≥2 (hazard ratio: 2.26; 95% confidence interval (CI): 1.24-4.13; p = 0.0008) and NLR ≥3 (hazard ratio, 1.98; 95% CI: 1.02-3.81; p = 0.042) as independent prognostic factors.

Conclusions

CCI and NLR may be useful parameters for decision-making in older patients undergoing colorectal ESD.

Short- and long-term outcomes of robot-assisted versus laparoscopic lateral lymph node dissection for rectal cancer

PURPOSE

The lateral pelvic cavity is an anatomically tricky site to access using a linear approach; therefore, robot-assisted lateral lymph node dissection (LLND) may be superior over existing laparoscopic procedures. In this study, we aimed to compare the short- and long-term outcomes of robot-assisted LLND (R-LLND) versus laparoscopic LLND (L-LLND) for locally advanced low rectal cancer and explore the potential advantages of robot-assisted surgery.

METHODS

This single-center, retrospective cohort study included patients aged ≥ 18 years who underwent minimally invasive total mesorectal excision (TME) plus LLND for low rectal adenocarcinoma. Patients were divided into L-LLND and R-LLND groups. The short- and long-term outcomes of the procedures were compared.

RESULTS

There were 41 patients in the L-LLND group and 21 in the R-LLND group. The incidence of postoperative complications was significantly lower in the R-LLND group (49% vs. 19%, p = 0.029), especially urinary retention (29% vs. 5%, p = 0.046). The median postoperative hospital stay was significantly shorter in the R-LLND group (22 vs. 15 days, p < 0.001). The 3-year relapse-free survival rates in the L-LLND and R-LLND groups were 75.3% (95% confidence interval [CI]: 58.9-85.9) and 65.7% (95% CI: 30.7-86.1), respectively. No significant differences were observed in long-term survival outcomes.

CONCLUSION

Patients with locally advanced rectal cancer who underwent TME plus R-LLND had a significantly lower incidence of postoperative complications and a significantly shorter postoperative hospital stay compared to those who underwent TME plus L-LLND. The long-term outcomes were comparable, and no oncological concerns associated with R-LLND were observed.

Defining the tumor location in rectal cancer - Practice variations and impact on treatment decision making

OBJECTIVE

To summarize differences in current guideline recommendations for rectal tumor localization and generate an overview of published MRI measurement methods and their correlation with endoscopy.

SUMMARYOF BACKGROUND DATA

Rectal tumor location is a well-known factor that impacts treatment planning, but there is currently no consensus on the optimal method to define it.

METHODS

A literature search was conducted to retrieve clinical and radiological rectal cancer guidelines as well as original research studies on MRI-based measurements. Guidelines were assessed for definitions, landmarks, modalities and measurement methods to define tumor location, and how these impact treatment planning. Research studies were evaluated to compare MRI-methods and their correlation with endoscopy.

RESULTS

18 clinical and 6 radiological guidelines were retrieved. In 83 % of clinical guidelines tumor location (low/middle/high) is included in the treatment algorithm as a factor impacting surgical and/or neoadjuvant treatment. Measurement cut-offs and landmarks vary significantly with the anal verge being the most commonly used landmark (28 %). Thirty-nine percent of clinical guidelines offer no definitions to define rectal tumor location. The majority of research studies (67 %) reported good-excellent agreement between MRI and endoscopy, though measurement differences of up to 2.5 cm were reported.

CONCLUSION

There is substantial variation in definitions and landmarks recommended in current guidelines to measure and classify rectal tumor location. This may affect treatment planning as well as trial inclusions, highlighting the need for standardized methods that better align between clinical and radiological guidelines.

Mesenteric benign lymph node enlargement in colorectal cancer: Friend or foe?

INTRODUCTION

Benign lymph node enlargement (BLNE) is common in colorectal cancer; however, few studies have investigated its influence on prognosis, clinicopathological features, and pathogenesis.

METHODS

A cohort study was conducted to analyze the clinicopathologic features and prognosis of colorectal cancer patients, categorized based on the presence or absence of BLNE. Given the correlation between lymph nodes and immune response, immunohistochemistry, transcriptome analysis, and exon sequencing were employed to further investigate the differences in the immune microenvironment of primary tumors.

RESULTS

Overall, 630 AJCC stage I/II patients were included in the study, with 131 in the BLNE group and 499 in the Non-BLNE (NBLNE) group. Patients in the BLNE group were found to have a significantly better disease-free survival (DFS) (hazard ratio [HR] 0.44, P = 0.016) and overall survival (OS) (HR 0.46, P = 0.011) than those in the NBLNE group. Pathologically, compared with the NBLNE group, the BLNE group had more mature tertiary lymphoid structures (66.7 % vs. 36.5 %, P = 0.002) and higher immunoscores (18.8 % vs. 2.1 %, P = 0.004) in primary tumor tissue. Also, transcriptome analysis showed that, compared with NBLNE, the genes upregulated in BLNE were enriched in immune-related pathways, such as adaptive immune response and immuno-regulatory interactions. Whole-exon sequencing analysis revealed a higher tumor mutation burden (TMB) in the BLNE group [6.03 (5.59, 7.59) vs. 5.33 (4.62, 6.34), P = 0.025].

CONCLUSION

BLNE is positively associated with the prognosis of colorectal cancer, possibly because patients with BLNE have a stronger anti-tumor immune response.

Liver metastases from colorectal cancer: A joint ESSO-EAHPBA-UEMS core curriculum collaboration

Colorectal liver metastases (CRLM) are a major indication for liver surgery in Europe, highlighting the need for standardized knowledge and training in surgical oncology. The European Society of Surgical Oncology (ESSO) has updated its core curriculum to provide a structured framework for education. Previous publications have addressed pancreatic, hepatocellular, and biliary tract cancers to support candidates preparing for the European Board of Surgery Qualification (EBSQ) exams in Surgical Oncology and Hepato-Pancreato-Biliary Surgery. However, a dedicated guide for CRLM remains absent. This article aims to fill that gap by offering a structured reference on CRLM, covering epidemiology, staging, genetics, and diagnosis of metastatic colorectal cancer. It also outlines multidisciplinary treatment strategies, including systemic, surgical, interventional, and palliative approaches. A structured literature review was conducted using PubMed to identify the most updated (inter)national management guidelines, prioritizing recent multicentre studies, systematic reviews, and meta-analyses published from January 2020 to January 2025. By bridging the gap between the ESSO core curriculum and detailed subspecialty training, this guide provides an essential resource for hepatobiliary surgeons and surgical oncologists. It serves as a valuable tool for those preparing for board examinations while promoting a standardized approach to CRLM education and management across Europe.

Comparison of short-term outcomes for robotic rectal surgery between the hinotori™ surgical robot system and da Vinci surgical system: a single-center retrospective study using propensity score matching analysis

BACKGROUND

Robotic surgery for rectal cancer has grown popular in recent years and has primarily used the da Vinci Surgical System (Intuitive Surgical, CA, USA; da Vinci). In 2020, Japan introduced the hinotori™ Surgical Robot System (Medicaroid, Kobe, Japan; hinotori). We report our initial surgical experiences with robotic surgery using hinotori for rectal cancer and its feasibility and safety comparing with da Vinci.

METHODS

A single-institution retrospective study was conducted. Between November 2022 and November 2023, 38 and 96 patients with rectal cancer underwent robotic surgery using hinotori and da Vinci, respectively. The primary endpoint was the incidence of postoperative complications of the Clavien-Dindo classification (CD) grade ≥ II within postoperative 30 days. Secondary endpoints included surgical and console time, blood loss, conversion to other approaches, number of dissected lymph nodes, and postoperative hospital stay. A propensity score matching (PSM) analysis was used to adjust for imbalance in baseline characteristics.

RESULTS

After PSM, a total of 76 patients (hinotori: 38, da Vinci: 38) were included. Compared to the da Vinci group, the hinotori group showed a similar postoperative complication rate of CD ≥ II (15.8% vs. 18.4%), comparable operative time (280.5 vs. 258 min), comparable console time (166 vs. 156 min), and less blood loss (9 vs. 17.5 mL, p = 0.025). There was no conversion in either group. The number of dissected nodes and postoperative stay were similar between the two groups.

CONCLUSION

Our findings support that robotic surgery for rectal cancer using hinotori is as safe as surgery performed using the da Vinci system.

Transition to lateral lymph node dissection in rectal cancer: Forty-five years of outcomes data

PURPOSE

To determine how outcomes of lateral lymph node dissection for rectal cancer have changed over time.

METHODS

This retrospective study included patients with rectal cancer without distant metastasis who underwent total mesorectal excision and lateral lymph node dissection at our institution between 1975 and 2020. We examined the association of surgical time period with relapse-free and overall survival. Multivariable analyses were performed using Cox proportional hazards regression models.

RESULTS

Among a total of 992 patients, 386 underwent surgery in 1975-2000, 296 in 2001-2010, and 310 in 2011-2020. Overall, 924 patients (93%) underwent surgery without preoperative therapy. The respective 5-year relapse-free survival rates were 64.2%, 64.2%, and 68.2% (P = .314), and the 5-year overall survival rates were 72.3%, 84.0%, and 89.3% (P < .001). Overall survival could be stratified by surgical time period, especially stage III (P < .001). In patients with lateral lymph node metastasis, the 5-year overall survival rate was 43.5% in 1975-2000, 61.1% in 2001-2010, and 71.1% in 2011-2020 (P = .003). Multivariable analysis revealed significant differences in overall survival between 2011-2020 and 1975-2000 (hazard ratio, 2.81; P < .001) and between 2011-2020 and 2001-2010 (hazard ratio, 1.59; P = .040), but not in relapse-free survival.

CONCLUSION

The impact of lateral lymph node dissection on rectal cancer treatment may not have changed in 45 years, given the lack of difference in relapse-free survival. Treatment outcomes after recurrence may have improved. The prognosis remains poor for lateral lymph node metastasis, highlighting the need for further development of multimodality treatments.

Perioperative changes in the quality of life and the impact of preoperative quality of life on the time to return to work after surgery among patients with colorectal cancer: a prospective, multicenter, cohort study

PURPOSE

This study investigated perioperative changes in quality of life (QOL) and the impact of preoperative QOL on the time to return to work (RTW) after surgery in patients with colorectal cancer.

METHODS

Patients with clinical stage I-III colorectal cancer who were employed at the diagnosis and scheduled for curative surgery between 2019 and 2020 were prospectively enrolled at 7 hospitals in Japan. The patients' EORTC-QLQ-C30 scores and employment status were collected before and at 6 and 12 months after surgery and compared using a paired t test. The Kaplan-Meier method and multivariable Cox regression model were applied to examine the impact of preoperative QOL on the time to RTW.

RESULTS

A total of 127 patients were analyzed. Regarding financial difficulties, 48% of patients had low preoperative scores, which significantly improved at 6 (preoperatively: 21.7 vs 6 months: 11.3; p < 0.001) and 12 months (6 months: 11.3; 12 months: 7.9; p = 0.016) postoperatively. RTW was significantly delayed in patients with a low preoperative cognitive function (p = 0.039) and severe fatigue (p = 0.024). The adjusted hazard ratio was 0.73 for a low cognitive function and 0.62 for strong fatigue.

CONCLUSION

Working patients with colorectal cancer experienced severe financial difficulties preoperatively, which decreased postoperatively. The preoperative cognitive function and fatigue affected the postoperative time to RTW.

Salvageable locoregional recurrence and stoma rate after local excision of pT1-2 rectal cancer - A nationwide cross-sectional cohort study

BACKGROUND

Screening has increased the incidence of early-stage rectal cancer and interest in rectal-preserving treatment strategies. Although guidelines recommend completion total mesorectal excision (cTME) in the presence of histological risk factor(s) after local excision, surgery-related morbidity often deters patients from cTME. Additionally, locoregional recurrences (LR) identified during surveillance may still be salvageable. This study evaluates oncological and surgical outcomes in pT1-2 rectal cancer patients who received local excision with or without additional therapy.

METHODS

A retrospective cross-sectional national cohort study was conducted in 67 Dutch hospitals, including all patients who underwent curative surgical resection for rectal cancer in 2016. Patients with pT1-2 tumours who received surveillance, cTME or adjuvant chemoradiotherapy after local excision were selected. The primary outcome was LR. Secondary endpoints included ostomy rate, disease-free survival (DFS), and overall survival (OS).

RESULTS

Of 3057 patients, 219 underwent local excision, followed by surveillance in 74 % (n = 162), cTME in 23 % (n = 51), and adjuvant (chemo)radiation in 3 % (n = 6). Median follow-up was 46 months (IQR 29-54). Four-year LR rates were 14 % and 4 % after surveillance and cTME, respectively (p = 0.033). In the surveillance group, 16 of 20 patients (80 %) who developed LR were treated with curative intent. cTME resulted in a substantially higher ostomy rate (43 % vs 4 %, p = 0.001). No significant differences were found in 4-year DFS and OS.

CONCLUSION

Despite a LR rate of 14 % after local excision alone, the majority of these recurrences could be treated with curative intent. Additionally, the risk of stoma was 10-fold lower after surveillance compared to cTME.

TRIAL REGISTRATION

ClinicalTrials.gov, identifier: NCT05539417, https://www.

CLINICALTRIALS

gov/ct2/show/NCT05539417.

SEC61G promotes colorectal cancer progression by regulating cytosolic Ca2+ concentration

BACKGROUND

Intracellular calcium (Ca2+) signaling regulates key cancer processes. Research findings suggest that the SEC61 complex, involved in protein translocation, contributes to calcium leakage from the endoplasmic reticulum. However, the mechanism by which SEC61 Translocon Subunit Gamma (SEC61G), a component of this complex, influences colorectal cancer (CRC) progression remains unclear.

METHODS

Bioinformatics analysis was performed using The Cancer Genome Atlas data sets to identify candidate genes on chromosome 7p, examine their association with DNA copy number amplification. In addition, SEC61G expression in CRC cells and tissues was validated using reverse-transcription quantitative polymerase chain reaction and immunohistochemistry. Moreover, in vitro and in vivo experiments were performed to investigate the effects of SEC61G overexpression and knockdown on CRC cell proliferation. Furthermore, publicly available single-cell RNA sequencing (scRNA-seq) and spatial transcriptome sequencing (ST-seq) data were used to validate the role of SEC61G in CRC.

RESULTS

SEC61G was significantly upregulated in CRC tissues and was correlated with poor prognosis in patients with CRC. SEC61G overexpression enhanced cell proliferation and activated the EGFR pathway, promoting cell cycle progression from the G1 to S phase. In addition, SEC61G overexpression increased cytosolic Ca2+ levels, which activated EGFR signaling via calmodulin. Moreover, analyses of scRNA-seq and ST-seq data confirmed that SEC61G expression was higher in tumor epithelial cells and that it was co-expressed with EGFR pathway-related genes.

CONCLUSIONS

SEC61G promotes CRC progression by regulating cytosolic Ca2+ concentration, EGFR activation, and cell cycle progression, highlighting its potential as a prognostic biomarker and therapeutic target in CRC.

National Guidelines for Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (HIPEC) in Peritoneal Malignancies: A Worldwide Systematic Review and Recommendations of Strength Analysis

BACKGROUND

National guidelines (GLs) for surgical cytoreduction (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in the management of peritoneal malignancies (PMs) vary across countries, scientific societies, and government agencies. This study aimed to systematically review and compare the recommendations for CRS/HIPEC in the treatment of ovarian cancer (EOC), gastric cancer, colorectal cancer (CRC), mesothelioma, and pseudomyxoma peritonei (PMP).

METHODS

Medical databases, search engines, and national websites of 193 countries were queried using artificial intelligence (AI)-powered software for scientific societies and/or government agencies guidelines. The study excluded consensus statements and guidelines without appropriate references. Non-English guidelines were translated, and data, including GRADE strength of recommendations, were extracted.

RESULTS

The study analyzed 138 guidelines, 24 for gastric cancer, 36 for colorectal cancer, 29 for primary ovarian cancer (p-)EOC, 28 for recurrent ovarian cancer (r-)EOC, 10 for mesothelioma, and 11 for PMP. Guidelines were retrieved from 51 (26.4%) nations, mostly from developed countries (62.1%; p < 0.001). The CRS procedure received robust positive recommendations (GRADE I/IIa) for CRC (74.2%), p-/r-EOC (100%/78.5%), PMP (90.9%), and mesothelioma (90.0%). Conversely, CRS was not indicated for gastric cancer (61.6%, GRADE III; p < 0.001). The HIPEC procedure had robust positive recommendations for PMP (90.9%) and mesothelioma (90.0%), but was controversial for p-EOC (42.3%) and CRC (38.0%) and contraindicated for r-EOC (80.0%) and gastric cancer (62.4%) (p < 0.001).

CONCLUSION

National guidelines concordantly recommend CRS for colorectal cancer, ovarian cancer, PMP, and mesothelioma. In contrast, HIPEC recommendations are less homogeneously shared, except for PMP and mesothelioma. No positive concordance exists among guidelines on gastric cancer for CRS nor HIPEC. Furthermore, high-level evidence is needed to strengthen future guidelines on peritoneal metastases.

Deep Learning and Radiomic Signatures Associated with Tumor Immune Heterogeneity Predict Microvascular Invasion in Colon Cancer

RATIONALE AND OBJECTIVES

This study aims to develop and validate a deep learning radiomics signature (DLRS) that integrates radiomics and deep learning features for the non-invasive prediction of microvascular invasion (MVI) in patients with colon cancer (CC). Furthermore, the study explores the potential association between DLRS and tumor immune heterogeneity.

MATERIALS AND METHODS

This study is a multi-center retrospective study that included a total of 1007 patients with colon cancer (CC) from three medical centers and The Cancer Genome Atlas (TCGA-COAD) database. Patients from Medical Centers 1 and 2 were divided into a training cohort (n = 592) and an internal validation cohort (n = 255) in a 7:3 ratio. Medical Center 3 (n = 135) and the TCGA-COAD database (n = 25) were used as external validation cohorts. Radiomics and deep learning features were extracted from contrast-enhanced venous-phase CT images. Feature selection was performed using machine learning algorithms, and three predictive models were developed: a radiomics model, a deep learning (DL) model, and a combined deep learning radiomics (DLR) model. The predictive performance of each model was evaluated using multiple metrics, including the area under the curve (AUC), sensitivity, and specificity. Additionally, differential gene expression analysis was conducted on RNA-seq data from the TCGA-COAD dataset to explore the association between the DLRS and tumor immune heterogeneity within the tumor microenvironment.

RESULTS

Compared to the standalone radiomics and deep learning models, DLR fusion model demonstrated superior predictive performance. The AUC for the internal validation cohort was 0.883 (95% CI: 0.828-0.937), while the AUC for the external validation cohort reached 0.855 (95% CI: 0.775-0.935). Furthermore, stratifying patients from the TCGA-COAD dataset into high-risk and low-risk groups based on the DLRS revealed significant differences in immune cell infiltration and immune checkpoint expression between the two groups (P < 0.05).

CONCLUSION

The contrast-enhanced CT-based DLR fusion model developed in this study effectively predicts the MVI status in patients with CC. This model serves as a non-invasive preoperative assessment tool and reveals a potential association between the DLRS and immune heterogeneity within the tumor microenvironment, providing insights to optimize individualized treatment strategies.

Contouring atlas and essential points for radiotherapy in rectal cancer

In the last decade, the role of radiotherapy in rectal cancer has changed significantly with the introduction of total neoadjuvant therapy (TNT) and nonoperative management (NOM). For the setting of irradiation field in rectal cancer, the pararectal, lateral lymph nodes, and those along the inferior mesenteric artery (IMA) are most important. In total mesorectal excision (TME), the root of the IMA is dissected. In the atlas of pelvic irradiation for rectal cancer, the setting of the upper margin of the mesorectum varies from atlas to atlas, and no atlas sets the upper margin of the mesorectum to the root of the IMA. In particular, there is no consensus on the definition of anatomical boundaries regarding the lymph nodes along the superior rectal artery (SRA). The upper margin of the irradiation field in clinical trials of preoperative radiotherapy and TNT is generally set at the level of the internal and external iliac artery branches, L5/S1, or S2/S3. However, it is not necessary to include the entire mesorectum to the root of the IMA in patients undergoing preoperative radiotherapy plus TME. Conversely, for patients receiving NOM, the irradiation field may have to include the mesorectum to the IMA root, though the incidence of lymph node metastasis and gastrointestinal adverse events merits consideration. It is increasingly important to determine the extent of clinical target volume around the SRA region and the setting of the upper margin of the irradiation field after formulating the treatment policy together with the surgeons and medical oncologists.

Protocol digest of a single-arm confirmatory trial for less intensive postoperative surveillance in low-risk colorectal cancer patients: JCOG1915 (less study)

The Japanese Society for Cancer of the Colon and Rectum guidelines recommend intensive surveillance for curatively resected pathological stage I-III colorectal cancer. However, there is still no global consensus on the optimal method, duration, or frequency of surveillance, and no clinical trials have demonstrated the usefulness of surveillance. We are conducting a clinical trial to confirm the efficacy of less-intensive surveillance after R0 resection with lymph node dissection for stage I or low-risk stage II colorectal cancer in patients without risk factors for recurrence. If this less intensive surveillance method proves effective, medical costs will be considerably reduced. The primary endpoint is overall survival. A total of 680 patients will be enrolled from 59 institutions over 2 years. This trial has been registered at the Japan Registry of Clinical Trials (jRCT) as study number jRCT1030220350.

Predictors of difficulty in robotic splenic flexure mobilization during rectal cancer surgery

PURPOSE

In surgery for rectal cancer, splenic flexure mobilization is sometimes necessary to ensure a tension-free colorectal anastomosis with adequate blood supply. Splenic flexure mobilization is regarded as a challenging and risky maneuver, but there are no clear indicators of its difficulty in rectal cancer surgery. This study evaluated the impact of clinical and anatomical factors, including splenic flexure height measured qualitatively on the basis of vertebral level using computed tomography, on the difficulty of splenic flexure mobilization during rectal cancer surgery.

METHODS

The enrolled patients underwent robotic splenic flexure mobilization during rectal surgery for primary rectal cancer at Shizuoka Cancer Center in Japan between December 2011 and March 2022. All patients were scheduled to undergo splenic flexure mobilization preoperatively, and all procedures were carried out following a standardized approach. Linear regression analysis was conducted to determine the clinical and anatomical factors significantly influencing the operative time of the abdominal phase, which is defined as the duration from lymph node dissection around the inferior mesenteric artery to the mobilization of the sigmoid and descending colon, including the splenic flexure.

RESULTS

The median operative time for the abdominal phase was 88 min (range, 39-179 min). Univariate analysis revealed that the following variables were significantly correlated with a prolonged abdominal phase: higher body mass index, larger visceral fat area, and higher splenic flexure. In a multiple linear regression analysis, only higher splenic flexure remained significantly associated with a longer abdominal phase (p < 0.01).

CONCLUSIONS

Splenic flexure height measured on the basis of vertebral level using computed tomography may be useful for predicting the difficulty of robotic splenic flexure mobilization in surgery for rectal cancer.

Short- and long-term outcomes of robotic versus conventional laparoscopic surgery for middle or lower rectal cancer: a propensity score-matched analysis

PURPOSE

The potential benefits of robotic surgery (RS) for rectal cancer (RC) remain uncertain. The objective of this study was to evaluate the short- and long-term outcomes of RS compared to conventional laparoscopic surgery (LS) for stage I-III middle or lower RC.

METHODS

This study retrospectively analyzed 350 consecutive patients with stage I-III middle or lower RC who underwent curative surgery from 2017 to 2021, employing propensity score matching (PSM) analysis.

RESULTS

Of 350 patients, 128 patients underwent RS. After PSM, we enrolled 256 patients. Median follow-up was 59.8 months. Before PSM, significant differences were observed between groups regarding primary tumor site (p = 0.02). After PSM, no significant differences between groups were observed in terms of operative time, blood loss, conversion rate, intra-operative and postoperative complications, or number of lymph nodes harvested. After PSM, 3- and 5-year cumulative LR rates were 3.2% and 3.2% in the RS group, and 2.8% and 3.2% in the LS group, respectively. The cumulative distant recurrence (DR) rates in the RS group were 13.4% at 3-year and 15.1% at 5-year, whereas in the LS group, they were 14.9% and 18.7%, respectively. No notable differences in cumulative LR or DR rates were evident between groups. Furthermore, no notable differences were observed between groups regarding overall, cancer-specific, or recurrence-free survival according to stage.

CONCLUSIONS

RS appears to be viable and safe treatment approach for patients with middle or lower RC, offering short- and long-term outcomes comparable to those of LS.

Personalized surveillance in colorectal cancer: Integrating circulating tumor DNA and artificial intelligence into post-treatment follow-up

Given the growing burden of colorectal cancer (CRC) as a global health challenge, it becomes imperative to focus on strategies that can mitigate its impact. Post-treatment surveillance has emerged as essential for early detection of recurrence, significantly improving patient outcomes. However, intensive surveillance strategies have shown mixed results compared to less intensive methods, emphasizing the necessity for personalized, risk-adapted approaches. The observed suboptimal adherence to existing surveillance protocols underscores the urgent need for more tailored and efficient strategies. In this context, circulating tumor DNA (ctDNA) emerges as a promising biomarker with significant potential to revolutionize post-treatment surveillance, demonstrating high specificity [0.95, 95% confidence interval (CI): 0.91-0.97] and robust diagnostic odds (37.6, 95%CI: 20.8-68.0) for recurrence detection. Furthermore, artificial intelligence and machine learning models integrating patient-specific and tumor features can enhance risk stratification and optimize surveillance strategies. The reported area under the receiver operating characteristic curve, measuring artificial intelligence model performance in predicting CRC recurrence, ranged from 0.581 and 0.593 at the lowest to 0.979 and 0.978 at the highest in training and validation cohorts, respectively. Despite this promise, addressing cost, accessibility, and extensive validation remains crucial for equitable integration into clinical practice.

Chronopharmacokinetic model analysis of 5-fluorouracil following S-1 administration in rats: comparison with infusion and other prodrugs for chronochemotherapy

Circadian rhythms influence the pharmacokinetics of chemotherapeutic agents, including 5-fluorouracil, a cornerstone drug for colorectal cancer treatment. While chronomodulated chemotherapy for 5-fluorouracil infusion regimens can improve patient outcomes, the impact of circadian rhythms on oral 5-fluorouracil prodrug regimens remains poorly understood, and no dose-timing strategies have been established. This study investigated circadian variations in the pharmacokinetics of 5-fluorouracil after administering S-1, an oral fluoropyrimidine-based anticancer drug, in rats using a cosinor-based chronopharmacokinetic model. Plasma tegafur exposure showed significant circadian variation, peaking at 01:00 (17 h after light onset), whereas plasma 5-fluorouracil exposure exhibited no significant time-of-dosing differences. Chronopharmacokinetic analysis revealed minimal circadian variation in 5-fluorouracil clearance with S-1 (amplitude-to-mesor ratio: ±14.6 %) compared to long-term 5-fluorouracil infusion (±28.0 %) and other oral prodrugs including capecitabine (±43.0 %) and uracil-tegafur (±36.7 %), which showed pronounced fluctuations. These results suggest that S-1 provides consistent 5-fluorouracil exposure regardless of dosing time, offering a practical advantage by simplifying treatment schedules and reducing the need for chronomodulated therapy. This study could advance the development of 5-fluorouracil-based chronochemotherapy using oral prodrug regimens, enabling more personalized and effective cancer treatment strategies.

Impact of D3 lymph node dissection on short-term and long-term outcomes in elderly patients with colon cancer

BACKGROUND

The oncologic impact of D3 lymph node dissection (LND) for colon cancer (CC) has been reported to be favorable. However, D3 LND is potentially more invasive than non-D3 LND, and whether it is beneficial for elderly patients with CC remains unclear. This study aimed to evaluate the perioperative safety and short- and long-term oncologic outcomes of D3 LND in elderly patients with CC.

METHODS

Subjects were 442 elderly patients aged ≥ 70 years who underwent curative surgery for pathologic stage (pStage) I-III CC between 2011 and 2022. Background clinical factors and short- and long-term outcomes were compared between patients who received D3 LND (D3 group; n = 363) and those who received non-D3 LND (non-D3 group; n = 79).

RESULTS

The D3 group had a significantly higher number of retrieved lymph nodes (median 20 vs. 12, p < 0.001) and a lower rate of postoperative complications (18% vs. 32%, p = 0.040) than the non-D3 group. In the overall cohort, overall survival (OS) did not differ between the two groups. Among pStage III patients, however, OS was significantly better (69.8% vs. 34.1%, p = 0.028), and RFS tended to be better (60.7% vs. 42.6%, p = 0.075) in the D3 group than in the non-D3 group. Multivariable analysis revealed that D3 LND was independently associated with better OS (HR 0.477; 95% CI 0.245-0.931, p = 0.030) and tended to be associated with better RFS (HR 0.588; 95% CI 0.329-1.051, p = 0.073).

CONCLUSION

D3 LND is safe and effective in improving the prognosis of elderly patients with pStage II/III CC.

Personalized prognostic model for colorectal cancer in the era of precision medicine: a dynamic approach based on real-world data

BACKGROUND

Predicting individual prognosis is required for patients with colorectal cancer in the era of precision medicine. However, this may be challenging for the conventional survival analysis such as the Cox proportional hazards model. This study aims to develop a personalized prognostic prediction that incorporates longitudinal data to improve predictions for colorectal cancer patients.

METHODS

Patients with advanced or recurrent colorectal cancer, who received treatment at Kyoto University Hospital between April 2015 and December 2021, were retrospectively analyzed. The Joint model is one of the dynamic prediction models. Using longitudinal clinical data, a carcinoembryonic antigen (CEA) prediction equation was developed for each patient. Additionally, a personalized prognostic prediction model was created using the Joint model. The prediction accuracy of the Joint model was compared with one of the Cox proportional hazards model.

RESULTS

Among the 1010 patients, 614 patients were enrolled. The median frequency of tumor marker measurement (per patient) was 20 times (range: 3-117 times). CEA values could be predicted accurately and the Pearson's correlation coefficient between measured CEA and predicted CEA was 0.931. In the Joint model, the significant prognostic factors were baseline age (HR, 1.039; 95% CI, 1.025-1.054), poor-differentiated tumor (HR, 2.600; 95% CI 1.446-4.675) and log2 (predicted CEA) (HR, 1.551; 95% CI 1.488-1.617). The areas under the curve at 2, 3, 4, and 5 were significantly higher for the Joint model than for the Cox proportional hazards model, respectively.

CONCLUSION

The Joint model may accurately predict personalized prognosis that reflects changes in longitudinal tumor marker values.

Phase II Trial of Capecitabine Plus Bevacizumab for Elderly Patients With Metastatic Colorectal Cancer: OGSG 1102

BACKGROUND/AIM

The combination of capecitabine and bevacizumab is a standard first-line chemotherapy regimen for vulnerable patients with unresectable colorectal cancer. However, the safety and efficacy of this regimen in Japanese patients have not been sufficiently investigated.

PATIENTS AND METHODS

This phase II study included patients aged ≥76 years or those aged 65-75 years who were unsuitable for intensive chemotherapy. Capecitabine at 2000 mg/m2/day (days 1-14) plus bevacizumab at 7.5 mg/kg (day 1) were administered every 3 weeks. The primary endpoint was progression-free survival. Secondary endpoints included overall survival, response rate, disease control rate, and toxicities.

RESULTS

Thirty-six patients were enrolled between July 2011 and July 2014, of whom 33 were included in the analysis. The median patient age was 78 years (range=67-86 years). A total of 28 patients had a performance status of 0 or 1, and five of 2. The median progression-free and overall survival were 10.3 (95% confidence interval=9.2-15.4) and 27.9 (95% confidence interval=24.2-50.1) months, respectively. The response and disease control rates were 30.3% and 91.0%, respectively. The major grade 3 or 4 toxicities were hypertension (n=12, 36%) and hand-foot syndrome (n=4, 12%). One patient experienced a grade 4 gastrointestinal perforation.

CONCLUSION

The combination of capecitabine and bevacizumab demonstrated favorable efficacy and tolerability in Japanese patients with metastatic colorectal cancer who were unsuitable for intensive chemotherapy.

Multivisceral resection as a key indicator of recurrence in locally advanced colorectal cancers with pathologic T3 tumors

PURPOSE

This study aimed to elucidate the clinical outcomes of patients with pathologic T3 (pT3) and pathologic T4 (pT4) tumors who underwent radical resection with multivisceral resection (MVR) and to assess the prognostic significance of MVR in locally advanced colorectal cancers (CRCs) in pT3 and pT4 tumors.

METHODS

This multicenter retrospective analysis evaluated the characteristics, clinicopathologic stages, perioperative factors, and clinical outcomes of patients who underwent primary colorectal resection. Patients were divided into 4 groups: those with a pT3 tumor who did not undergo MVR (pT3 - MVR; n = 1108), those with a pT3 tumor who underwent MVR (pT3 + MVR; n = 56), those with a pT4 tumor who did not undergo MVR (pT4 - MVR; n = 306), and those with a pT4 tumor who did underwent MVR (pT4 + MVR; n = 123). Univariate and multivariate regression analyses were performed to identify risk factors for recurrence.

RESULTS

The pT3 + MVR group exhibited a higher 5-year recurrence rate than the pT3 - MVR group, with recurrence rates similar to those of the pT4 - MVR or pT4 + MVR groups (pT3 - MVR, 17.4%; pT3 + MVR, 31.6%; pT4 - MVR, 33.4%; pT4 + MVR, 35.1%). Multivariate analysis identified MVR as an independent risk factor for recurrence, particularly peritoneal dissemination, in pT3 tumors, whereas MVR had less effect on recurrence in pT4 tumors.

CONCLUSION

pT3 tumors requiring MVR had a higher recurrence rate than pT4 tumors. The surgeon's clinical assessment of potential T4 tumors requiring MVR at the time of surgery was an important prognostic indicator in advanced CRC.

Timing of ctDNA Analysis Aimed at Guiding Adjuvant Treatment in Colorectal Cancer

PURPOSE

Multiple clinical trials are investigating ctDNA to guide adjuvant chemotherapy (ACT) in colorectal cancer. Timely ACT initiation necessitates early ctDNA testing, but the impact of postoperative cell-free DNA (cfDNA) and ctDNA dynamics remains unclear, particularly with cost-reducing input caps employed in some assays. This study investigates ctDNA detection at day 14 versus day 30, comparing whole-sample analysis with capping the cfDNA input, and evaluates single and dual timepoint assessments for ACT allocation.

EXPERIMENTAL DESIGN

From 2019 to 2023, 611 patients with stage I to III colorectal cancer were enrolled. Blood was collected preoperatively and postoperatively on ∼day 14 and ∼day 30. The cfDNA levels were assessed using digital PCR, and ctDNA was assessed using tumor-informed digital PCR or targeted sequencing analyzing all cfDNA from 8 mL of plasma.

RESULTS

Despite elevated cfDNA in 85% of day 14 samples, performance was comparable between the two timepoints (sensitivity, 31% vs. 32% and specificity, both 98%). A 50-ng cfDNA input cap reduced ctDNA detection probability, affecting 78% of day 14 samples and 65% of day 30 samples. At both timepoints, ctDNA detection was prognostic of recurrence (day 14; HR, 9.0, 95% confidence interval, 5.5-14.8 and day 30: HR, 12.5, 95% confidence interval, 7.6-20.4). In 74% of ctDNA-positive recurrence patients, both samples had ctDNA detected. An increase in the ctDNA level from day 14 to day 30 was associated with a shorter time to recurrence (Pearson R = -0.63, P = 0.003). Combining the timepoints would increase sensitivity (36%) and allow earlier ACT start in 80% of patients.

CONCLUSIONS

Early ctDNA sampling is feasible and highly prognostic. Supplemental later testing may improve sensitivity while allowing early ACT initiation for most ctDNA-positive patients.

Utility of comprehensive genomic profiling combined with machine learning for prognostic stratification in stage II/III colorectal cancer after adjuvant chemotherapy

BACKGROUND AND PURPOSE

Accurate recurrence risk evaluation in patients with stage II and III colorectal cancer (CRC) remains difficult. Traditional histopathological methods frequently fall short in predicting outcomes after adjuvant chemotherapy. This study aims to evaluate the use of comprehensive genomic profiling combined with machine learning for prognostic risk stratification in patients with CRC.

METHODS

A machine learning model was developed using a training cohort of 52 patients with stage II/III CRC who underwent curative surgery at Fujita Health University Hospital. Genomic DNA was isolated from formalin-fixed, paraffin-embedded tissue sections and analyzed with a 160 cancer-related gene panel. The random forest algorithm was used to determine key genes affecting recurrence-free survival. The model was validated by developing a risk score with internal and external cohorts, including 44 patients from Keio University Hospital.

RESULTS

Six key genes (KRAS, KIT, SMAD4, ARID2, NF1, and FBXW7) were determined as significant prognostic risk predictors. A risk score system integrating these genes with clinicopathological factors effectively stratified patients in both internal (p < 0.001) and external cohorts (p = 0.017).

CONCLUSIONS

This study reveals that machine learning, combined with comprehensive genomic profiling, significantly improves prognostic risk stratification in patients with stage II/III CRC after adjuvant chemotherapy. This approach provides a promising tool for individualized treatment strategies, warranting further validation with larger cohorts.

Prognostic value of carcinoembryonic antigen (CEA) and CA 19-9 levels in patients with obstructive colorectal cancer treated with a self-expandable metallic stent and curative surgery

PURPOSE

The importance of tumor markers is well established; yet little is known about their prognostic value for patients with obstructive colorectal cancer (OCRC). We investigated the clinical significance of carcinoembryonic antigen (CEA) and CA 19-9 levels in patients with non-metastatic OCRC, who underwent insertion of a self-expandable metallic stent and curative surgery.

METHODS

Clinical data on 91 patients with OCRC were analyzed retrospectively to evaluate the associations of preoperative serum values of tumor makers with short- and long-term outcomes.

RESULTS

The 91 patients comprised 53 men and 38 women, with a median age of 71 years. Twelve patients had an elevated preoperative CA 19-9 level. Multivariate analyses revealed that an elevated CA 19-9 level was independently associated with poor disease-free survival (DFS) [hazard ratio (HR) = 4.57, 95% confidence interval (CI) 2.06-10.14, P < 0.001] and overall survival (HR = 4.06, 95% CI 1.46-11.24, P = 0.007). A CEA level > 5 ng/ml had no prognostic value, whereas a CEA level > 10.8 ng/ml was significantly associated with worse DFS (P = 0.032).

CONCLUSION

Measuring the CA 19-9 level concomitantly with the CEA level for patients with advanced CRC, including OCRC, may provide a valuable means to improve prognostication.

Three timepoint perioperative CEA levels are a prognostic factor for recurrence after adjuvant chemotherapy in patients with Stage II and III colorectal cancer

Aim

To investigate the relationship between the three timepoint perioperative CEA (ttpCEA) calculated at three timepoints and recurrence during the perioperative period in Stage II and III colorectal cancer (CRC) patients.

Methods

We performed a multi-institutional retrospective analysis of patients with Stage II and III CRC who underwent surgery and adjuvant chemotherapy from 2010 to 2020. Patient data from three facilities were used as training data, and data from three other facilities were used as validation data. The primary endpoint was the time to recurrence (TTR).

Results

A total of 538 patients were included for the training data. To validate the feasibility of ttpCEA, 329 patients were included for the validation data. Training data patients were categorized as ttpCEA low (n = 365) and ttpCEA high (n = 173). The 5-y TTR was significantly greater in the ttpCEA-low subgroup than in the ttpCEA-high subgroup (84.3% vs. 69.6%, respectively; p < 0.001). Validation data patients were categorized as ttpCEA low (n = 221) and ttpCEA high (n = 108). The 5-y TTR was significantly greater in the ttpCEA-low subgroup than in the ttpCEA-high subgroup (82.9% vs. 68.7%, respectively; p = 0.003).

Conclusion

The ttpCEA calculated from perioperative CEA levels at different timepoints was a prognostic factor for recurrence in Stage II and III CRC patients who underwent adjuvant chemotherapy according to both the training and validation data.

Cost-Effectiveness Analysis of SOX Plus Bevacizumab Versus SOX Plus Cetuximab for First-Line Treatment of KRAS Wild-Type Metastatic Colorectal Cancer in Japan

PURPOSE

In this study, we aimed to evaluate the cost-effectiveness of S-1 and oxaliplatin (SOX) plus bevacizumab (Bmab group) compared with SOX plus cetuximab (Cmab group) as a first-line treatment for patients with Kirsten rat sarcoma virus (KRAS) wild-type metastatic colorectal cancer (mCRC) in Japan from the perspective of healthcare payers.

METHODS

A partitioned survival model was developed using data from the randomized phase II Osaka Multicenter Study Group on Colorectal Cancer-1107 study, which included overall survival, progression-free survival, and treatment regimens for the Bmab and Cmab groups. Treatment costs were estimated from the Japanese medical claims database and the National Health Insurance drug price list. The utilities were derived from the literature. Outcomes were reported as incremental cost, incremental quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER). The willingness-to-pay (WTP) threshold was set at 7.5 million JPY per QALY. The time horizon of the model was set to 20 years. Sensitivity analyses were conducted to assess the uncertainty of the model for various parameters.

FINDINGS

Compared with the Cmab group, the Bmab group had an incremental cost of 911,373 JPY (6,528 USD), an incremental effectiveness of 0.79 QALY, and an ICER of 1,146,745 JPY (8,215 USD) per QALY. One-way sensitivity analysis showed that the cost of progressive disease treatment in the Bmab group had the greatest impact on the ICER. According to the probabilistic sensitivity analysis, the Bmab group had a 94.9% probability of being cost-effective compared with the Cmab group.

IMPLICATIONS

Considering a WTP threshold of 7.5 million JPY (approximately 53,700 USD) per QALY, Bmab might be a cost-effective treatment option for patients with KRAS wild-type mCRC in Japan. Further studies on economic evaluations based on personalized drugs and patient selection based on clinical and genetic information are warranted.

Angiopoietin-like Protein 2 Expression is Associated With Host Wasting-Related Poor Prognosis in Colorectal Cancer

INTRODUCTION

Tumor-induced host wasting marked by malnutrition, systemic inflammation, or altered body composition is associated with poor prognosis in cancer patients. Tumor cell-derived angiopoietin-like protein 2 (ANGPTL2) reportedly functions as a tumor promoter in some cancer contexts. This study aims to assess whether ANGPTL2 expression in tumor cells is associated with host wasting in patients with colorectal cancer.

METHODS

We retrospectively enrolled 88 patients with all-stage colorectal cancer who underwent surgical resection of the primary tumor between January 2017 and December 2017 in a single institution. Based on immunohistochemistry staining, we assessed ANGPTL2 expression in tumor cells in paraffin-embedded tumor samples from resected specimens. The association of the ANGPTL2 expression with clinicopathological factors, biomarkers of host wasting, and survival were analyzed.

RESULTS

Host wasting was associated with significantly high other causes-mortality rates in ANGPTL2-high patients (P = 0.0261) but not in ANGPTL2-low patients (P = 0.4719), suggesting that ANGPTL2 expression in colorectal cancer cells is associated with host wasting-related poor prognosis. Furthermore, ANGPTL2 expression in tumor cells was correlated with the advanced lung cancer inflammation index, which is a biomarker of host wasting (ρ = -0.3119, P = 0.0031).

CONCLUSIONS

ANGPTL2 is associated with host wasting-related poor prognosis through its association with systemic inflammation in patients with colorectal cancer. These findings overall provide novel insight into ANGPTL2 function and illustrate the essential role of tumor-host interactions in the prognosis of cancer survivors.

D3 lymph node dissection improves perioperative outcomes and overall survival in patients with cT2N0 colorectal cancer

Background

The extent of lymphadenectomy undertaken in patients with cT2N0 colorectal cancer (CRC) remains controversial. The aim of our study was to compare survival in such patients by level of lymph node dissection (LND) performed.

Methods

This retrospective cohort study was conducted at a high-volume cancer center in Japan. Eligible patients (n=524) submitted to radical resections for cT2N0 CRC between April 2007 and December 2020 were included. Subjects were subsequently stratified by nature of LND (D2 vs. D3) and propensity score matched at 1:2 ratio. We then analyzed group rates of overall survival (OS) and relapse-free survival (RFS) before and after matching.

Results

Before matching, the D3 (vs. D2) LND group experienced a shorter mean operative time, less intraoperative blood loss, fewer postoperative complications, and a briefer average hospital stay, showing significantly better OS (P=0.001) as well. The estimated hazard ratio (HR) was 2.0 [95% confidence interval (CI): 1.0-3.9; P=0.04]. After matching, a significant difference in OS (P=0.007) was still observed, with an estimated HR of 2.3 (95% CI: 1.0-5.1; P=0.044).

Conclusions

D3 LND improves perioperative outcomes and OS in patients with cT2N0 CRC. Accurate preoperative imaging diagnostics are critical for proper surgical management for cT2N0 CRC.

Development and validation of machine learning models for predicting no. 253 lymph node metastasis in left-sided colorectal cancer using clinical and CT-based radiomic features

BACKGROUND

The appropriate ligation level of the inferior mesenteric artery (IMA) in left-sided colorectal cancer (CRC) surgery is debated, with metastasis in No. 253 lymph node (No. 253 LN) being a key determining factor. This study aimed to develop a machine learning model for predicting metastasis in No. 253 LN.

METHODS

We retrospectively collected clinical data from 2,118 patients with left-sided CRC and contrast-enhanced CT images from 310 of these patients. From this data, a test set, a training set, and a temporal validation set were constructed. Logistic regression models were used to develop a clinical model, a CT model, and a radiomics model, which were then integrated into a combined model using logical rules. Finally, these models were evaluated using metrics such as the area under the receiver operating characteristic curve (AUC), precision-recall (PR) curves, decision curve analysis (DCA), net reclassification improvement (NRI), and integrated discrimination improvement (IDI).

RESULTS

A clinical model, a CT model, and a radiomics model were constructed using univariate logistic regression. A combined model was developed by integrating the clinical, CT, and radiomics models, with positivity defined as all three models being positive at a 90% sensitivity threshold. The clinical model included six predictive factors: tumor site, endoscopic obstruction, CEA levels, growth type, differentiation grade, and pathological classification. The CT model utilized largest lymph node average CT value, short-axis diameter and long-axis diameter. The radiomics model incorporated maximum gray level intensity within the region of interest, large area high gray level emphasis, small area high gray level emphasis and surface area to volume ratio. In the test set, the AUCs for the clinical, CT, radiomics, and combined models were 0.694, 0.663, 0.72, and 0.663, respectively, while in the temporal validation set, they were 0.743, 0.629, 0.716, and 0.8. Specifically, the combined model demonstrated a sensitivity of 0.8 and a specificity of 0.8 in the temporal validation set. By comparing the PR and DCA curves, the combined model demonstrated better performance. Additionally, the combined model showed moderate improvements in INR and IDI compared to other models.

CONCLUSION

A clinical and CT-based radiomics model shows promise in predicting No. 253 LN metastasis in left-sided CRC and provides insights for optimizing IMA ligation strategies.

Predicting lateral pelvic lymph node metastasis in rectal cancer patients using MRI radiomics: a multicenter retrospective study

MRI has relatively low sensitivity and specificity in detecting lymph node metastases. This study aimed to develop and validate an MRI radiomics-based model for predicting lateral pelvic lymph node (LPLN) metastasis in rectal cancer patients who underwent LPLN dissection, and to compare its performance with that of radiologists. This multicenter retrospective study included 336 rectal cancer patients (199 men; mean age, 58.9 years ± 11.1 [standard deviation]) who underwent LPLN dissection. Patients were divided into development (n = 190) and validation (n = 146) cohorts. Radiomics features were extracted from MR images, and the Least Absolute Shrinkage and Selection Operator regression was used to construct radiomics and clinical-radiomics models. Model performance was compared with radiologists using receiver operating characteristic (ROC) analysis. Malignant LPLN was diagnosed in 32.4% of the development cohort (65/190) and 32.9% of the validation cohort (48/146) (P = 0.798). Seven radiomics features and two clinical features were selected. The radiomics and clinical-radiomics models demonstrated area under the curves (AUCs) of 0.819 and 0.830 in the development cohort and 0.821 and 0.829 in the validation cohort, respectively. The optimal cut-off (- 0.47) yielded sensitivities of 72.3% and 45.8% and specificities of 82.4% and 87.8% in the development and validation cohorts, respectively. Decision curve analysis indicated no additional net benefit from the clinical-radiomics model compared to the radiomics-only model. Radiologists' AUCs were significantly lower than that of the radiomics model (0.842) and improved with radiomics probability scores (0.734 vs. 0.801; 0.668 vs. 0.791). The MRI-based radiomics model significantly improves the prediction of LPLN metastasis in rectal cancer, outperforming conventional criteria used by radiologists.Trial registration: Retrospectively registered.

The Outcome of Colonoscopy-Assisted Laparoscopic Wedge Resections (CAL-WR) for Colon Cancer: A Retrospective Cohort Study

Local excision is gaining acceptance as standard treatment for T1 colon cancer (CC); however, not all patients are eligible for endoscopic resection. Colonoscopy-assisted laparoscopic wedge resection (CAL-WR) is a relatively new technique that could fill the gap between endoscopic resection and major surgery. The aim of this study was to analyze the oncological safety of CAL-WR for CC.

METHODS

A retrospective cohort study was performed, including patients that underwent CAL-WR for CC. Exclusion criteria were double tumors, <1 year follow-up, previous other colorectal malignancy, inflammatory bowel disease or synchronous metastases. The primary outcome was disease recurrence and the secondary outcome was overall survival.

RESULTS

Fifty-three patients were included; 35 patients were diagnosed with T1 CC. CAL-WR was radical (R0) for all T1 CC in 94.3% and 94.7% for tumors with deep submucosal invasion (sm2-3 Kikuchi). The mean follow-up was 3.3 years (Q1: 2.0; Q3: 4.3) for disease recurrence and 4.2 years (Q1: 2.8; Q3: 5.2) for overall survival. None of the patients with T1 CC had disease recurrence or died due to their malignancy. There were 14 patients with a T2 and 4 patients with a T3 CC, 17/18 patients underwent completion surgery. Three patients with T2 and one with T3 CC developed a locoregional recurrence (peritoneal). One patient with T3 CC developed lung metastases. Two patients with T3 and one with T2 CC died due to their malignancy.

CONCLUSIONS

This study suggests that CAL-WR is oncologically safe as treatment for T1 CC. The safety of incidental CAL-WR for >T1 CC, followed by completion surgery, remains unclear. Prospective studies are needed to evaluate these results.

Primary tumor location is a risk factor for postoperative development of sarcopenia as a predictive marker for unfavorable outcomes in patients with colorectal cancer

BACKGROUND

The impact of the skeletal muscle volume after colorectal cancer surgery is unclear. Thus, we investigated the change of skeletal muscle mass after surgery and its effects on long-term outcomes.

METHODS

This retrospective analysis included clinical stage I-IV colorectal cancer patients who underwent curative resection between April 2012 and March 2014 in our hospital. The psoas muscle area at the third lumbar vertebra level was evaluated by computed tomography and was divided by the square of height to obtain the psoas muscle mass index (PMI). Sarcopenia was defined using the PMI cut-off values for Asian adults of 6.36 cm2/m2 for males and 3.92 cm2/m2 for females.

RESULTS

Among eligible 354 patients, 166 and 145 had pre- and postoperative sarcopenia one year after surgery, respectively. Five-year disease-free survival (DFS) and overall survival (OS) rates were 81.7% and 94.5%, respectively. In multivariate analysis, postoperative sarcopenia was an independent risk factor for shorter DFS [hazard ratio (HR) 1.71, p = 0.0171] and OS (HR 2.42, p = 0.0455), respectively, but preoperative sarcopenia was not a prognosticactor for either. One year after colorectal resection, 24 patients (6.8%) were newly diagnosed with sarcopenia, while 45 (12.7%) recovered from sarcopenia. Rectal cancer was identified as an independent risk factor for the postoperative development of sarcopenia (odds ratio 3.12, p = 0.0440).

CONCLUSION

Postoperative sarcopenia one year after surgery was associated with poor DFS and OS. Thus, clinicians need to consider skeletal muscle loss during postoperative surveillance, particularly in rectal cancer patients without sarcopenia before surgery.

External Lymphatic Fistula After Radical Surgery for Colorectal Cancer: A Case Series

BACKGROUND

The incidence of external lymphatic fistula (ELF) represents a relatively rare complication after surgery for colorectal cancer, especially in Western countries. However, the rate of this complication is progressively increasing following the introduction of complete mesocolic excision and central vascular ligation with consequent extensive lymphadenectomy. There are no guidelines for the management of ELF, with therapeutic options varying from conservative procedures to more invasive surgeries. The aim of this study was to retrospectively quantify the rate of ELF after surgery for colorectal cancer, to describe its management, and to evaluate its clinical impact on early postoperative outcomes in a tertiary referral European centre.

METHODS

Data on all patients who underwent surgery for colorectal cancer at our institution between July 2022 and December 2024 were entered into a database. Preoperative, perioperative, and early (within 30 days) postoperative data were recorded.

RESULTS

A total of 279 patients underwent elective surgery for colorectal cancer (205 colon and 74 rectum). No postoperative deaths occurred within 30 days after surgery, and the rates of overall and major (grade ≥ 3) postoperative morbidity were 34.7% and 7.1%, respectively. The anastomotic leakage and reoperation rates were 2.8% and 5.3%, respectively. ELFs occurred in 15 patients (5.3%). In all patients, conservative treatment (based on fasting, total parenteral nutrition (TPN), and a prolonged medium-chain triglyceride (MCT) diet) was administered successfully. A recurrent ELF (after the first oral feeding resumption) occurred in four (26.6%) patients, but all were successfully treated with a conservative approach. The occurrence of an ELF prolonged the postoperative length of stay which was 12 days, a length higher than that recorded in patients without ELF.

CONCLUSIONS

The occurrence of an ELF was found to be a relatively frequent complication after surgery for colorectal cancer and appears to negatively influence only the postoperative length of stay. Conservative management appeared to be a successful treatment.

Short-term Outcomes of Robotic Lateral Pelvic Lymph Node Dissection for Lower Rectal Cancer

INTRODUCTION

Rectal cancer is among the main causes of cancer-related mortalities worldwide, necessitating more effective treatment strategies.　It is considered that lateral pelvic lymph node dissection (LPND) for rectal cancer patients can contribute to local tumor control and that robotic LPND (Rob-LPND) may be more suitable for LPND, due to technical advantages of precise manipulation in a narrow pelvic space.

METHODS

In this retrospective study, we evaluated the short-term outcomes of laparoscopic-LPND (Lap-LPND) versus Rob-LPND in patients undergoing radical surgery for rectal cancer.　Operative time, blood loss, urethral catheter reinsertion, duration of pelvic drainage tube placement, drainage volume, and postoperative hospital stay were compared between Lap-LPND and Rob-LPND.

RESULTS

Our findings revealed that Rob-LPND was associated with longer total operation time, but there was no significant difference in operation time between the two LPND techniques.　Urinary catheter re-insertion rates were lower in Rob-LPND; also, significant reductions in drainage tube duration, total drainage volume, and postoperative hospital stay were observed.

CONCLUSION

Rob-LPND may reduce postoperative total drainage volume and shorten postoperative hospital stays.　These improvement in short-term outcomes suggest potential clinical advantages of Rob-LPND.

Tailored lymph node dissection in right hemicolectomy: a retrospective study focusing on the anterior tissue of the superior mesenteric vein surgical trunk

Background

The optimal extent of lymph node dissection in right hemicolectomy for colon cancer remains a topic of debate. This study aimed to refine lymph node dissection strategies by investigating the histopathological characteristics of the anterior tissue of the superior mesenteric vein (SMV) surgical trunk.

Methods

One hundred sixty-two patients underwent surgery, with their medial resection border determined to be either to the right or left of the SMV. Pathological and perioperative variables were assessed, and the anterior tissue of the SMV was analyzed to quantify lymph nodes and nerve fibers.

Results

Of the patients included, 84 were in the SMV-right group and 78 in the SMV-left group. After propensity score matching (PSM), the SMV-left group with dissection extending to the left side of the SMV and removal of the anterior tissue of SMV surgical trunk, retrieved more lymph nodes (36.9 vs. 26.8, P < 0.001) than the SMV-right group. However, there was no difference in node-positive staging. The SMV-left group also experienced more postoperative complications (16.7% vs. 1.7%, P = 0.011) and prolonged postoperative defecation times (4.2 vs. 3.5, P = 0.035), accompanied by a higher resection of nerve fibers (12.1 ± 4.2/case). Multivariate analysis identified tumor location above the ileocolic vein (ICV) root and elevated preoperative CA 19-9 levels as independent risk factors for metastasis to main lymph nodes.

Conclusion

Right hemicolectomy with extended lymph node dissection improves lymph node retrieval but increases complication risks and prolongs bowel recovery time. For patients with tumors located below the ICV root, a more limited dissection with the right side of the SMV as the medial boundary may be a preferable option, given the low rate of main lymph node metastasis.

GLUT1 inhibition by BAY-876 induces metabolic changes and cell death in human colorectal cancer cells

BACKGROUND

Glucose transporter 1 (GLUT1) is known to play a crucial role in glucose uptake in malignant tumors. GLUT1 inhibitors reportedly exhibit anti-tumor effects by suppressing cancer cell proliferation. BAY-876, a selective GLUT1 inhibitor, has been shown to inhibit tumor growth in ovarian and breast cancers. In this study, we investigated the anti-proliferative effects of BAY-876 treatment in human colorectal cancer (CRC) cell lines.

METHODS

We investigated the metabolic changes and effects on proliferation from BAY-876 treatment in HCT116, DLD1, COLO205, LoVo, and Caco-2 cells in vitro. Additionally, a mouse xenograft model was established using HCT116 cells to examine the tumor-inhibitory effects of BAY-876 treatment in vivo.

RESULTS

BAY-876 treatment inhibited cell proliferation in HCT116, DLD1, COLO205, and LoVo cells. Reduced GLUT1 protein expression levels were observed through western blot analysis. Flux analysis indicated enhanced mitochondrial respiration, accompanied by increased reactive oxygen species levels and apoptosis rates. Tumor-inhibitory effects were also observed in the xenograft model, with the BAY-876-treated groups showing GLUT1 suppression.

CONCLUSIONS

BAY-876 treatment induced metabolic changes and inhibited cell proliferation in human CRC cell lines. Using BAY-876 is a potential novel approach for treating CRC.

Cold snare endoscopic mucosal resection versus standard hot technique for large flat nonpedunculated colonic lesions: a randomized controlled trial

BACKGROUNDS

 Cold snare EMR (CS-EMR) in large flat nonpedunculated colonic lesions (LFNPCLs) is an alternative to the standard EMR procedure with a better safety profile, but scientific evidence on its efficacy is unavailable. This study aimed to compare the recurrence rate between the two techniques at 6 months. Secondary aims were comparison of the safety profile and procedure-related outcomes.

METHODS

 This was a noninferiority, multicenter, open-label, randomized controlled trial of consecutive large (≥ 20 mm) LFNPCLs without suspicious features of submucosal invasion.

RESULTS

 229 patients were randomized to receive CS-EMR (n = 115) or EMR (n = 114). The median lesion size was 25 mm and 74.6 % were adenomas. The trial was stopped early by clinical consensus according to a safety monitoring board. At first surveillance colonoscopy (n = 220) the recurrence rate was significantly greater in the CS-EMR group than in the EMR group: 33.0 % vs. 16.2 % (P = 0.004) and 34.7 % vs. 14.8 % (P = 0.001) in the intention-to-treat and per-protocol analyses, respectively. According to the subgroup analysis, the recurrence rate was significantly greater after CS-EMR for LFNPCLs ≥ 30 mm (43.1 % vs. 18.2 %). There was no difference in the rate of adverse events. The use of clips was more common in the EMR group (52.6 % vs. 27.8 %).

CONCLUSIONS

 The recurrence rate of LFNPCLs after CS-EMR was significantly greater than after the standard hot technique. A similar safety profile was found between groups.

Postoperative Pain and Incisional Hernia of Specimen Extraction Sites for Minimally Invasive Rectal Cancer Surgery: Comparison of Periumbilical Midline Incision Versus Pfannenstiel Incision

Background: Recent studies indicate that minimally invasive surgery is widely accepted as the optimal procedure for colorectal cancer. However, the ideal location of the specimen extraction site remains unclear. This study aimed to compare the conventional periumbilical midline incision with the Pfannenstiel incision for specimen extraction during minimally invasive surgery for rectal cancer. Methods: This retrospective cohort study included 76 patients who underwent minimally invasive surgery (double-stapling technique anastomosis) for rectal cancer between January 2022 and June 2023. The postoperative short- and mid-term outcomes were compared between the periumbilical midline incision and Pfannenstiel incision groups. Results: The patients' backgrounds were comparable between the two groups. There were no significant differences in the surgical outcomes or short-term postoperative complications. The Pfannenstiel incision demonstrated advantages, including reduced postoperative pain at rest and during movement, and a lower incidence of incisional hernia (p = 0.038). Conclusions: The Pfannenstiel incision is a safe and effective option associated with reduced postoperative pain and a lower risk of incisional hernia. Therefore, it can serve as a useful alternative for specimen extraction during minimally invasive rectal cancer surgery.

Effect of gastroenterology resident use of a social network workgroup on skills in characterizing colorectal neoplasia: Prospective study

Background and study aims

Accurate endoscopic characterization of colorectal lesions is essential for predicting histology but remains difficult. We studied the impact of a social network workgroup on level of characterization of colorectal lesions by gastroenterology residents.

Methods

We prospectively involved residents who characterized 25 and 40 colorectal lesions in two different questionnaires over 1 year. Three groups were considered: regulars who were already part of the workgroup before the first evaluation, newcomers who joined in during evaluation, and reluctant who did not. Participants rated each lesion according to the CONECCT classification (hyperplastic polyp [IH], sessile serrated lesion [IS], adenoma [IIA], high-risk adenoma or superficial adenocarcinoma [IIC], borderline invasive adenocarcinoma [IIC+], or deeply invasive adenocarcinoma [III]) and their progression score over 1 year was assessed. Correct histological status was defined by pathology reports or combined criteria between histology and expert opinion for high-risk adenoma or adenocarcinoma.

Results

Of the 117 participants, 82.9% completed the two questionnaires, with 16.5% regulars, 71.1% newcomers, and 12.4% reluctant. For similar starting levels, progression in characterization was +2 (95% confidence interval [CI] 1-3; P <0.001) for newcomers and +2 (95% CI -0.5-4); P = 0.122) for reluctant. The regulars had a higher starting level with a +0.5 (95% CI -2 to 2; P = 0.691) progression score.

Conclusions

Gastroenterology resident 1-year use of a social network workgroup does not improve their skills in characterizing colorectal neoplasia. Further intensive training is needed to improve the characterization level of gastroenterology residents.

Dynamic Prediction of Rectal Cancer Relapse and Mortality Using a Landmarking-Based Machine Learning Model: A Multicenter Retrospective Study from the Italian Society of Surgical Oncology-Colorectal Cancer Network Collaborative Group

Background: Almost 30% of patients with rectal cancer (RC) who submit to comprehensive treatment experience relapse. Surveillance plays a leading role in early detection. The landmark approach provides a more flexible and dynamic framework for survival prediction. Objective: This large retrospective study aims to develop a machine learning algorithm to profile the patient prognosis, especially the risk and the onset of RC relapse after curative resection. Methods: A cohort of 2450 RC patients were analyzed using landmark analysis. Model A applied a classical cause-specific Cox approach with a landmarking approach, while Model B implemented a landmarking-based RSF (random survival forest) competing risk algorithm. The two models were compared in terms of predictive and interpretative ability. A bootstrapped validation strategy was employed to validate the model's performance and prevent overfitting. The best-performing hyperparameters were selected systematically, ensuring the model's robustness within the landmark approach. The study assessed these factors' importance and interactions using RSF and compared the predictive accuracy to that of the classical Cox model. Results: Model B outperformed Model A (mean C-index 0.95 vs. 0.78), capturing complex interactions and providing dynamic, individualized relapse predictions. Clinical factors influencing survival outcomes were identified across time with the landmark approach allowing for more accurate and timely predictions. Conclusions: The landmark approach offers an improvement over traditional methods in survival analysis. By accommodating time-dependent variables and the evolving nature of patient data, this approach provides a precise tool for profiling RC survival, thereby supporting more informed and dynamic clinical decision-making.

Transanal total mesorectal excision for locally advanced rectal cancer following neoadjuvant chemoradiotherapy

PURPOSE

To examine the clinical impact of transanal total mesorectal excision (TaTME) for locally advanced rectal cancer after neoadjuvant chemoradiotherapy (NACRT).

METHODS

This retrospective study included 91 patients undergoing surgery for rectal cancer after NACRT between 2011 and 2022. Among them, 24, 22, and 45 patients underwent open (Open), conventional laparoscopic (Lap), and TaTME surgeries, respectively. We compared their clinical outcomes.

RESULTS

Operative time, blood loss, transfusion, morbidity, and hospital stay were significantly lower in the TaTME group than in the Open or Lap groups. The multivariate regression analyses identified only the TaTME approach as a significant factor for reducing morbidity. Both 3 yrear relapse-free survival (RFS) and local recurrence-free survival (LRFS) were significantly better in the TaTME group than in the Open or Lap groups (3 yr RFS: 94.7%, 80.4%, and 66.7%, and 3 yr LRFS: 100%, 90.5%, and 82.2% for the TaTME, Lap, and Open groups, respectively). Multivariate analyses of potential risk factors for recurrence identified body mass index, combined resection, and pathological stage, but not the TaTME approach, as significant predictors of recurrence.

CONCLUSION

TaTME reduced morbidity significantly in patients with locally advanced rectal cancer undergoing NACRT, compared with open or laparoscopic surgery.

PERITUMORAL BUDDING AS A PREDICTOR FOR LYMPH NODE METASTASES IN COLORECTAL CARCINOMAS: WHAT IS THE IMPORTANCE?

BACKGROUND

Microscopic analysis of tumor budding (TB) may be an essential predictive tool for regional lymph node metastases in colorectal cancer, especially among patients in intermediate stages, who exhibit considerable prognostic variability.

AIMS

The aim of this study was to assess the predictive power of BT regarding the presence of lymph node metastases and its association with other characteristics related to colorectal carcinoma progression.

METHODS

This is a cross-sectional, retrospective study with a quantitative approach, focusing on the review of medical records and histopathological reports of patients who underwent oncologic surgery for colorectal cancer.

RESULTS

A total of 153 patient records were examined, with a predominance of the 61-70 age group and a male majority (50.98%). Adenocarcinoma not otherwise specified was the most common histological type (60.78%), with the majority exhibiting moderate differentiation (87.58%). From the total sample, 97 cases (63.39%) exhibited TB, with 51.55% classified as a high budding score. Invasion of adipose tissue/subserosa was the most prevalent, occurring in 46.41% of cases. Regional lymph node metastases and angiolymphatic invasion were observed in 66 and 101 patients, respectively. Cross-tabulation analysis showed a statistically significant association between TB and lymph node metastasis (p<0.05).

CONCLUSIONS

The relationship between TB and lymph node metastasis highlights the significance of this histological factor in the risk stratification and prognosis of patients with colorectal cancer, complementing TNM staging. Therefore, the assessment of tumor budding is crucial in histopathological reports, potentially influencing additional therapeutic decisions.

En bloc Right Hemicolectomy with Pancreaticoduodenectomy for Advanced Ascending Colon Cancer

INTRODUCTION

While simultaneous complex surgical procedures such as right hemicolectomies with pancreaticoduodenectomies (RHPD) may increase overall surgical complexity, complications, and risk of death, it is the only cure for advanced ascending colon cancer (AACC) that has directly invaded the duodenum/pancreas. There are a few reports, especially from Japan. Here, we report an extremely rare case of a patient who underwent RHPD for AACC with direct invasion to the duodenum and liver and describe the patient's long-term survival after en bloc resection.

CASE PRESENTATION

The patient was a 76-year-old man who presented with a chief complaint of right abdominal pain and weight loss of 12 kg over the past month. Colonoscopy revealed the entire circumference of a type 2 tumor in the ascending colon. Preoperative computed tomography showed a 12 cm mass lesion with wall thickening in the ascending colon which was also invading the second portion of the duodenum. MSI-H/dMMR was negative. RHPD and partial hepatectomy were performed with open surgery because of a preoperative diagnosis of clinical T4b (duodenum and liver) N1bM0 stage IIIc cancer. Although grade 2 adverse effects, which delayed gastric emptying was observed during the patient's postoperative course, the patient's condition resolved through conservative therapy. Oral intake started on postoperative day 17, and the patient was discharged on postoperative day 25. Capecitabine plus oxaliplatin was administered as adjuvant chemotherapy for 6 months. Hematoxylin and eosin staining revealed moderately differentiated adenocarcinoma invading the duodenum and liver. The patient was diagnosed as pathological T4b (duodenum and liver) N1bM0 stage IIIc cancer. No recurrence was noted up to 40 months after the surgery.

CONCLUSIONS

The only curative therapy for AACC with involvement of the duodenum is en bloc RHPD. Here, we described a case in which long-term survival was achieved by ensuring R0 with en bloc resection.

Recurrence Timing and Risk Following Curative Resection of Colorectal Liver Metastases: Insights From a Hazard Function Analysis

INTRODUCTION

There is no consensus on the optimal surveillance interval for patients undergoing resection of colorectal liver metastases (CRLM). We sought to assess the timing and intensity of recurrence following curative-intent resection of CRLM utilizing a recurrence-free survival (RFS) hazard function analysis.

METHODS

Patients with CRLM who underwent curative-intent resection were identified from a multi-institutional database. The RFS hazard function was used to plot hazard rates and identify the peak of recurrence over time.

RESULTS

Among 1804 patients, the median RFS was 19.9 months. In the analytic cohort, the RFS hazard curve peaked at 5.9 months (peak hazard rate: 0.054) and gradually declined, indicative of early recurrence. In subgroup analyses, patients with high and medium tumor burden scores (TBS) had RFS hazard peaks at 4.9 months (peak hazard rate: 0.060) and 5.8 months (peak hazard rate: 0.054), respectively. In contrast, patients with low TBS had a later peak at 7.5 months, with the lowest peak hazard rate of 0.047.

CONCLUSIONS

The recurrence peak for CRLM patients occurred approximately 6 months postsurgery, highlighting the need for intensified early postoperative surveillance. Patients with high TBS experienced earlier recurrence, underscoring the importance of close monitoring, particularly during the first 6 months after surgery.

Role of Adjuvant Chemotherapy After Surgical Resection of Paraaortic Lymph Node Metastasis from Colorectal Cancer-A Multicenter Retrospective Study

BACKGROUND

Surgical removal of metastasized paraaortic lymph nodes (PALNs) can prolong the survival of certain patients with colorectal cancer (CRC). However, the role of postoperative chemotherapy in such patients remains unknown.

PATIENTS AND METHODS

This multicenter retrospective study examined 97 patients with PALN metastasis from CRC who underwent surgical resection at 36 centers in Japan between 2010 and 2015. On the basis of adjuvant chemotherapy (AC) after the lymphadenectomy, patients were classified into non-AC and AC groups (27 and 70 patients, respectively). After the exclusion of patients receiving irinotecan, the latter group was further categorized into 5-fluorouracil (5-FU) and oxaliplatin (L-OHP) subgroups (14 and 52 patients, respectively) according to the use of L-OHP. Background characteristics and postoperative survival were compared among the groups.

RESULTS

Marked differences were not seen in background characteristics, except for neoadjuvant treatment, between the non-AC and AC groups. The AC group exhibited better recurrence-free survival (RFS; p = 0.009) and overall survival (OS; p = 0.040 by the Wilcoxon test) than the non-AC group. However, RFS and OS of the 5-FU group did not differ from those of the L-OHP group (p = 0.73 and p = 0.92 by the Wilcoxon test, respectively).

CONCLUSIONS

AC may be associated with improved prognosis of patients after the removal of PALN metastasis from CRC, but L-OHP did not offer additional survival benefits. Prospective studies comparing non-AC with 5-FU- and L-OHP-based AC are needed to confirm these findings.

Prognostic significance of the retroperitoneal surgical resection margin on computed tomography colonography in retroperitonealized colon cancer

BACKGROUND

A positive pathologic retroperitoneal surgical resection margin in the retroperitonealized colon is reported to predict distant metastases. However, no studies have investigated retroperitoneal surgical resection margin positivity on computed tomography colonography and its prognostic significance.

METHODS

Patients who underwent primary resection for ascending or descending colon cancer at our institution between 2013 and 2018 were retrospectively evaluated (n = 206). Retroperitoneal surgical resection margin on computed tomography colonography was defined on the basis of the relationship between the advanced tumor area and the retroperitoneum. The relationship between retroperitoneal surgical resection margin on computed tomography colonography and relapse-free survival was analyzed by dividing the patients into positive and negative retroperitoneal surgical resection margin on computed tomography colonography groups.

RESULTS

Two doctors independently evaluated the images. The interobserver agreement rate was 93.7% with a kappa coefficient of 0.78 (95% confidence interval, 0.66-0.90). Retroperitoneal surgical resection margin on computed tomography colonography positivity was observed in 32 of the 206 patients (15.5%). Univariate analysis showed that a positive retroperitoneal surgical resection margin on computed tomography colonography was a poor prognostic factor for relapse-free survival (hazard ratio, 7.07; 95% confidence interval, 2.77-18.0, P < .001). Multivariate analysis with carcinoembryonic antigen, clinical T and N stage as covariates (all P < .10 in univariate analysis) identified only retroperitoneal surgical resection margin on computed tomography colonography positive as a significant independent poor prognostic factor for relapse-free survival (hazard ratio, 3.99; 95% confidence interval, 1.30-12.3, P = .02).

CONCLUSION

In conclusion, this study revealed that retroperitoneal surgical resection margin on computed tomography colonography positivity is a poor prognostic factor. In cases in which retroperitoneal surgical resection margin on computed tomography colonography is positive, it is recommended not only to secure a wider margin, such as by resecting the Gerota fascia, but also to consider retroperitoneal surgical resection margin on computed tomography colonography positivity as a potential indication for preoperative chemotherapy.

Lymph node metastasis risk factors in T2 colorectal cancer

OBJECTIVES

This study evaluates risk factors for lymph node metastasis (LNM) in T2 colorectal cancer to refine patient selection for endoscopic resection.

METHODS

We reviewed records from consecutive patients who had undergone curative surgical resection of T2 colorectal cancer at our institution in Japan between April 2001 and December 2021. Data on conventional clinicopathologic variables were retrieved from the pathology reports at the time of surgery. The clinicopathological features included patient age, sex, tumor diameter, morphology, tumor location, lymphatic invasion, vascular invasion, tumor differentiation, carcinoembryonic antigen and carbohydrate antigen 19-9 levels, number of lymph node dissections, presence of adenoma component, and LNM.

RESULTS

Among the patients (338 men, 320 women), 170 (25.8%) exhibited LNM. Multivariate logistic regression identified three independent risk factors for LNM: lymphatic invasion (odds ratio [OR], 32.6; 95% confidence interval [CI], 17.3-61.4; p < 0.0001), female sex (OR, 1.70; 95% CI, 1.10-2.62; p = 0.02), and elevated carcinoembryonic antigen levels (OR, 2.56; 95% CI, 1.10-5.96; p = 0.03).

CONCLUSIONS

Lymphatic invasion, female sex, and high carcinoembryonic antigen levels significantly increase the risk of LNM in T2 colorectal cancer.