Prognostic impact of lymph node dissection is different for male and female colon cancer patients: a propensity score analysis in a multicenter retrospective study

Gender-specific dysregulations of nondifferentially expressed biomarkers of metastatic colon cancer

Colon cancer is a common cancer type in both sexes and its mortality rate increases at the metastatic stage. Most studies exclude nondifferentially expressed genes from biomarker analysis of metastatic colon cancers. The motivation of this study is to find the latent associations of the nondifferentially expressed genes with metastatic colon cancers and to evaluate the gender specificity of such associations. This study formulates the expression level prediction of a gene as a regression model trained for primary colon cancers. The difference between a gene's predicted and original expression levels in a testing sample is defined as its mqTrans value (model-based quantitative measure of transcription regulation), which quantitatively measures the change of the gene's transcription regulation in this testing sample. We use the mqTrans analysis to detect the messenger RNA (mRNA) genes with nondifferential expression on their original expression levels but differentially expressed mqTrans values between primary and metastatic colon cancers. These genes are referred to as dark biomarkers of metastatic colon cancer. All dark biomarker genes were verified by two transcriptome profiling technologies, RNA-seq and microarray. The mqTrans analysis of a mixed cohort of both sexes could not recover gender-specific dark biomarkers. Most dark biomarkers overlap with long non-coding RNAs (lncRNAs), and these lncRNAs might have contributed their transcripts to calculating the dark biomarkers' expression levels. Therefore, mqTrans analysis serves as a complementary approach to identify dark biomarkers generally ignored by conventional studies, and it is essential to separate the female and male samples into two analysis experiments. The dataset and mqTrans analysis code are available at https://figshare.com/articles/dataset/22250536.

Feasibility and Safety of Laparoscopic Complete Mesocolic Excision (CME) for Right-sided Colon Cancer: Short-term Outcomes. A Randomized Clinical Study

OBJECTIVE

The aim of this prospective clinical study is to compare short-term outcome of laparoscopic right hemicolectomy using the Complete Mesocolic Excision (CME group) with patients who underwent conventional right-sided colonic resection (NCME group).

SUMMARY BACKGROUND DATA

Although CME with central vascular ligation in laparoscopic right hemicolectomy is associated with a significant decrease in local recurrence rates and improvements in cancer-related 5-year survival, there may be additional risks associated with this technique because of increased surgical complications. As a result, there is controversy surrounding its use.

METHODS

In this randomized controlled trial, several primary endpoints (operative time, intraoperative blood loss, other complications, conversion rate, and anastomotic leak) and secondary endpoints (overall postoperative complications) were evaluated. In addition, we evaluated histopathologic data, including specimen length and the number of lymph nodes harvested, as objective signs of the quality of CME, related to oncological outcomes.

RESULTS

The CME group had a significantly longer mean operative time than the NCME group (216.3 minutes vs 191.5 minutes, P = 0.005). However, the CME group had a higher number of lymph nodes (23.8 vs 16.6; P < 0.001) and larger surgical specimens (34.3 cm vs 29.3 cm; P = 0.002). No differences were reported with respect to intraoperative blood loss, conversion rate, leakage, or other postoperative complications.

CONCLUSIONS

In this study laparoscopic CME were a safe and feasible technique with improvement in lymph nodes harvesting and length of surgical specimens with no increase of surgical intraoperative and postoperative complications.

Complete mesocolic excision versus conventional surgery for colon cancer: A systematic review and meta-analysis

AIM

Complete mesocolic excision (CME) lacks consistent data advocating operative superiority compared to conventional surgery for colon cancer. We performed a systematic review and meta-analysis, analysing population characteristics and perioperative, pathological and oncological outcomes.

METHODS

D3 extended lymphadenectomy dissection was considered comparable to CME, and D2 and D1 dissection to be comparable to conventional surgery. Outcomes reviewed included lymph node yield, R1 resection, overall complications, overall survival and disease-free survival.

RESULTS

In all, 3039 citations were identified; 148 studies underwent full-text reviews and 31 matched inclusion criteria: total cohort 26 640 patients (13 830 CME/D3 vs. 12 810 conventional). Overall 3- and 5-year survival was higher in the CME/D3 group compared with conventional surgery: relative risk (RR) 0.69 (95% CI 0.51-0.93, P = 0.016) and RR 0.78 (95% CI 0.64-0.95, P = 0.011) respectively. Five-year disease-free survival also demonstrated CME/D3 superiority (RR 0.67, 95% CI 0.52-0.86, P < 0.001), with similar findings at 1 and 3 years. There were no statistically significant differences between the CME/D3 and conventional group in overall complications (RR 1.06, 95% CI 0.97-1.14, P = 0.483) or anastomotic leak (RR 1.02, 95% CI 0.81-1.29, P = 0.647).

CONCLUSIONS

Meta-analysis suggests CME/D3 may have a better overall and disease-free survival compared to conventional surgery, with no difference in perioperative complications. Quality of evidence regarding survival is low, and randomized control trials are required to strengthen the evidence base.

Complete Mesocolic Excision and D3 Lymphadenectomy versus Conventional Colectomy for Colon Cancer: A Systematic Review and Meta-Analysis

BACKGROUNDS

Previous systematic reviews suggest that the implementation of 'complete mesocolon excision' (CME) for colon tumors entails better specimen quality but with limited long-term outcomes. We performed a meta-analysis to compare the pathological, perioperative, and oncological results of CME with conventional surgery (CS) in primary colon cancer.

METHODS

Embase, MEDLINE and CENTRAL databases were searched using Medical Subject Headings for CME and D3 lymphadenectomy. The systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

A total of 18,989 patients from 27 studies were included. Postoperative complications were higher in the CME group (relative risk [RR] 1.13, 95% confidence interval [CI] 1.04-1.22, I² = 0%), while no differences were observed in terms of anastomotic leak (I² = 0%) or perioperative mortality (I² = 49%). CME was associated with a higher number of lymph nodes harvested (I² = 95%), distance to high tie (I² = 65%), bowel length (I² = 0%), and mesentery area (I² = 95%). CME also had positive effects on 3- and 5-year overall survival (RR 1.09, 95% CI 1.04-1.15, I² = 88%; and RR 1.05, 95% CI 1.02-1.08, I² = 62%, respectively) and 3-year disease-free survival (RR 1.10, 95% CI 1.04-1.17, I² = 22%), as well as decreased local (RR 0.35, 95% CI 0.24-0.51, I² = 51%) and distant recurrences (RR 0.71, 95% CI 0.60-0.85, I² = 34%).

CONCLUSIONS

Limited evidence suggests that CME improves oncological outcomes with a higher postoperative adverse events rate but no increase in anastomotic leak rate or perioperative mortality, compared with CS.

Comparing complete mesocolic excision versus conventional colectomy for colon cancer: A systematic review and meta-analysis

Conventional colectomy, and the Japanese Society for Cancer of the Colon and Rectum (JSCCR) D2 Lymphadenectomy (LND2), are currently considered standard of care for surgical management of colon cancer. Colectomy with complete mesocolic excision (CME) and JSCCR D3 Lymphadenectomy (LND3) are more radical alternative approaches and provide a greater degree of lymph nodal clearance. However, controversy exists over the long-term benefits of CME/LND3 over non-CME colectomies (NCME)/LND2. In this study, we performed a systematic review and meta-analysis to compare the surgical, pathological, and oncological outcomes of CME/LND3 with NCME/LND2. Embase, Medline and CENTRAL databases were searched from inception until May 15, 2020, in accordance with PRISMA guidelines. Studies were included if they compared curative intent CME/LND3 with NCME/LND2. Weighted mean differences (WMD) and odds ratios (OR) were estimated for continuous and dichotomous outcomes respectively. Out of 1310 unique citations, 106 underwent full-text review, and 30 were included for analysis. In total, 21,695 patients underwent resection for colon cancer. 11,625 received CME/LND3, and 10,070 underwent NCME/LND2. No significant differences were found in post-operative morbidity and mortality. Both overall and disease-free survival favored CME/LND3 (5-year OS: OR = 1.29; 95% CI 1.02 to 1.64, p = 0.03; 5-year DFS: OR = 1.61; 95% CI 1.14 to 2.28; p = 0.007). This is the first systematic review and meta-analysis to demonstrate that CME/LND3 has superior long-term survival outcomes compared to NCME/LND2.

Oncological reasons for performing a complete mesocolic excision: a systematic review and meta-analysis

BACKGROUND

While complete mesocolic excision (CME) has been shown to have an oncological benefit as compared to conventional colonic surgery for colon surgery, this benefit must be weighed up against the risk of major intra-abdominal complications. This paper aimed to assess the comparative oncological benefits of CME.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, a systematic review of the literature until May 2020 was performed. Comparative studies assessing CME versus conventional colonic surgery for colon cancer were compared, and outcomes were pooled.

RESULTS

A total of 700 publications were identified, of which 19 were found to meet the inclusion criteria. A total of 25 886 patients were compared, with 14 431 patients in the CME arm. CME was associated with a significantly higher rate of vascular injury (odds ratio 3, P < 0.001). Rates of local and distant recurrence were lower in the CME group (odds ratio 0.66 and 0.73, respectively, both P < 0.001). CME patients had a significantly higher lymph node yield (P < 0.001). While no significant differences were noted between the two groups in terms of pooled 3- or 5-year disease-free survival, pooled 5-year overall survival was significantly higher in the CME group (relative risk 0.82, P < 0.001).

CONCLUSION

Based on the available evidence, CME is associated with improved oncologic outcomes at the expense of higher complication rates, including vascular injury. The oncological benefits need to weighed up against a multitude of factors including the level of hospital support, surgeon experience, patient age, and associated comorbidities.

Comparison between conventional colectomy and complete mesocolic excision for colon cancer: a systematic review and pooled analysis : A review of CME versus conventional colectomies

BACKGROUND

Complete mesocolic excision (CME) is advocated based on oncologic superiority, but not commonly performed in North America. Many data are case series with few comparative studies. Our aim was to perform a systematic review comparing outcomes between CME and non-CME colectomy.

METHODS

A systematic review was performed according to PRISMA guidelines of MEDLINE, EMBASE, HealthStar, Web of Science, and Cochrane Library. Studies were included if they compared conventional resection (non-CME) to CME for colon cancer. Quality was assessed using methodological index for non-randomized studies (MINORS). The main outcome measures were short-term morbidity and oncologic outcomes. Weighted pooled means and proportions with 95% CI were calculated using a random-effects model when appropriate.

RESULTS

Out of 825 unique citations, 23 studies underwent full-text reviews and 14 met inclusion criteria. Mean MINORS score was 13.3 (range 11-15). The mean sample size in CME group was 1166 (range 45-3756) and 945 (range 40-3425) in non-CME. Four papers reported plane of dissection, with CME plane achieved in 85.8% (95% CI 79.8-91.7). Mean OR time in CME group was 167 min (163-171) and 138 min (135-142) in conventional group. Perioperative morbidity was reported in six studies, with pooled overall complications of 22.5% (95% CI 18.4-26.6) for CME and 19.6 (95% CI 13.6-25.5) for non-CME. Anastomotic leak occurred in 6.0% (95% CI 2.2-9.7) of CME resections versus 6.0% (95% CI 4.1-7.9) in non-CME. CME had more lymph nodes, longer distance to high tie, and specimen length in all studies. Nine studies compared long-term oncologic outcomes and only three reported statistically significant higher disease-free or overall survival in favor of CME. Local recurrence was lower after CME in two of four studies.

CONCLUSIONS

The quality of evidence is limited and does not consistently support the superiority of CME. Better data are needed before CME can be recommended as the standard of care for colon cancer resections.

T1 colon cancer in the era of screening: risk factors and treatment

BACKGROUND

The aim of this study was to identify risk factors for lymph node positivity in T1 colon cancer and to carry out a surgical quality assurance audit.

METHODS

The sample consisted of consecutive patients treated for early-stage colon lesions in 15 colorectal referral centres between 2011 and 2014. The study investigated 38 factors grouped into four categories: demographic information, preoperative data, indications for surgery and post-operative data. A univariate and multivariate logistic regression analysis was performed to analyze the significance of each factor both in terms of lymph node (LN) harvesting and LN metastases.

RESULTS

Out of 507 patients enrolled, 394 patients were considered for analysis. Thirty-five (8.91%) patients had positive LN. Statistically significant differences related to total LN harvesting were found in relation to central vessel ligation and segmental resections. Cumulative distribution demonstrated that the rate of positive LN increased starting at 12 LN harvested and reached a plateau at 25 LN.

CONCLUSIONS

Some factors associated with an increase in detection of positive LN were identified. However, further studies are needed to identify more sensitive markers and avoid surgical overtreatment. There is a need to raise the minimum LN count and to use the LN count as an indicator of surgical quality.