Risk factors associated with poor lymph node harvest after colon cancer surgery in a national cohort

Immune microenvironment and lymph node yield in colorectal cancer

BACKGROUND

Lymph node (LN) harvesting is associated with outcomes in colonic cancer. We sought to interrogate whether a distinctive immune milieu of the primary tumour is associated with LN yield.

METHODS

A total of 926 treatment-naive patients with colorectal adenocarcinoma with more than 12 LNs (LN-high) were compared with patients with 12 or fewer LNs (LN-low). We performed immunohistochemistry and quantification on tissue microarrays for HLA class I/II proteins, beta-2-microglobulin (B2MG), CD8, CD163, LAG3, PD-L1, FoxP3, and BRAF V600E.

RESULTS

The LN-high group was comprised of younger patients, longer resections, larger tumours, right-sided location, and tumours with deficient mismatch repair (dMMR). The tumour microenvironment showed higher CD8+ cells infiltration and B2MG expression on tumour cells in the LN-high group compared to the LN-low group. The estimated mean disease-specific survival was higher in the LN-high group than LN-low group. On multivariate analysis for prognosis, LN yield, CD8+ cells, extramural venous invasion, perineural invasion, and AJCC stage were independent prognostic factors.

CONCLUSION

Our findings corroborate that higher LN yield is associated with a survival benefit. LN yield is associated with an immune high microenvironment, suggesting that tumour immune milieu influences the LN yield.

Advantages of ligating the rectum with gauze pad band in laparoscopic anterior resection of rectal cancer: a propensity score matched analysis

Purpose

It is difficult to maintain sufficient tension throughout laparoscopic anterior resection with total mesorectal excision, which causes a decline in surgical quality. We used a soft, inexpensive gauze pad band pulling the rectal tube to analyze the effect of surgery.

Methods

A gauze pad band was positioned at the proximal of the tumor, followed by fastening the rectal tube and ligating the rectum. 233 patients undergoing laparoscopic anterior resection for mid to low rectal cancer were enrolled between January 2018 and December 2020. After propensity score matching, 63 cases were selected in gauze pad band group and 126 cases were selected in traditional group. The two groups were compared in preoperative, intraoperative, and pathological characteristics.

Results

Compared to traditional group, the median operation duration (203 min vs. 233 min, p < 0.001) and the median intraoperative bleeding (48 ml vs. 67 ml, p < 0.001) were lesser in gauze pad band group. A higher percentage of one cartridge transection of rectum (36/63 vs. 51/126, p = 0.030), shorter length of cartridges used (6.88 ± 1.27 cm vs. 7.28 ± 1.25 cm, p = 0.040), and longer distal resection margin (2.74 ± 0.76 cm vs. 2.16 + 0.68 cm, p < 0.001) were found in the gauze pad band group. The completeness of total mesorectal excision (61/63 vs. 109/126, p = 0.022), harvested lymph nodes (19 vs. 17, p < 0.001) and positive lymph nodes (1 vs. 0, p = 0.046) were higher in gauze pad band group.

Conclusion

Ligation of the rectum with a gauze pad band allows for a reduction in operative time and intraoperative bleeding while increasing the rate of one cartridge transection. It also protected the quality of total mesorectal excision and membrane anatomy.

Trial registration: Not applicable.

Retrospective Cohort Analysis of the Effect of Age on Lymph Node Harvest, Positivity, and Ratio in Colorectal Cancer

Introduction: Colon cancer among young patients has increased in incidence and mortality over the past decade. Our objective was to determine if age-related differences exist for total positive nodes (TPN), total lymph node harvest (TLH), and lymph node ratio (LNR). Material and Methods: A retrospective review of stage III surgically resected colorectal cancer patient data in the National Cancer Database (2004−2016) was performed, reviewing TPN, TLH, and LNR (TPN/TLH). Results: Unadjusted analyses suggested significantly higher levels of TLH and TPN (p < 0.0001) in younger patients, while LNR did not differ by age group. On adjusted analysis, TLH remained higher in younger patients (<35 years 1.56 (CI 95 1.54, 1.59)). The age-related effect was less pronounced for LNR (<35 years 1.16 (CI 95 1.13, 1.2)). Conclusion: Younger patients have increased TLH, even after adjusting for known confounders, while age does not have a strong independent impact on LNR.

Prognostic Value of Lymph Node Ratio in Patients with Resected Synchronous Colorectal Liver Metastases and Less Than 12 Examined Lymph Nodes

BACKGROUND

Recent studies suggest that lymph node ratio (LNR) has significantly better prognostic power than N-status in patients with colorectal cancer, in particular when the number of evaluated lymph nodes (LNs) was insufficient. The aim of this study was to assess the prognostic value of LNR in patients with resected synchronous colorectal liver metastases (SCLMs) and less than 12 examined LNs.

METHODS

A prospectively maintained database of patients with resected SCLMs was queried for patients with less than 12 LNs evaluated at the time of surgery. X-tile software was used to determine the LNR cutoff value able to divide the patients in two subgroups with distinct prognosis. Overall survival (OS) and disease-free survival (DFS) rates were compared by log-rank test. A multivariate Cox regression analysis identified independent prognostic factors.

RESULTS

A cutoff LNR value of 0.22 divided patients into Low-LNR group (35 patients) and High-LNR group (36 patients). Both OS and DFS rates were significantly higher in Low-LNR group than those in High-LNR group. Independent predictors of poor OS were High-LNR (HR: 2.841, 95% CI: 1.480-5.453, p value = 0.002), bilobar SCLMs (HR: 2.253, 95% CI: 1.144-4.437, p value = 0.019) and lack of adjuvant chemotherapy (HR: 2.702, 95% CI: 1.448-5.043, p value = 0.002), while the only independent predictor of poor DFS was High-LNR (HR: 2.531, 95% CI: 1.259-5.090, p value = 0.009).

CONCLUSIONS

LNR > 0.22 was independently associated with poor OS and DFS in patients with resected SCLMs and less than 12 evaluated LNs.

Temporal improvements noted in life expectancy of patients with colorectal cancer; a Dutch population-based study

OBJECTIVE

Specific survival estimates are needed for the increasing number of colorectal cancer (CRC) survivors. The aim of this population-based study was to determine conditional loss in expectation of life (LEL) due to CRC.

STUDY DESIGN AND SETTING

All surgically treated patients with CRC registered in the Netherlands Cancer Registry with stage I-III between 1990-2016, were included (N = 203,216). Estimates of conditional LEL were predicted using flexible parametric models and the total life years lost due to cancer were estimated.

RESULTS

LEL decreased with older age and patients with rectal cancer or higher disease stage had highest LEL. In 2010, LEL for sixty-year old male and female patients was 2 vs. 2, 4 vs. 4, and 7 vs. 8 years for colon cancer, and 2 vs. 2, 4 vs. 5 and 7 vs. 8 years for rectal cancer, respectively. Conditional LEL in patients with CRC decreased during follow-up. Patients with combined stage I-III colon and rectal cancer in 2010 lost an estimated 18,628 and 11,336 life years.

CONCLUSION

This study quantified the impact of CRC on patient's life expectancy, both on individual and population level and demonstrated temporal improvements in CRC survival. These results provide meaningful information that can be used during follow-up.

A Preoperative Risk Prediction Model for Lymph Node Examination of Stage I-III Colon Cancer Patients: A Population-Based Study

Background: Lymph node examination is a prognostic indicator for colon cancer (CC) patients. The aim of this study was to develop and validate a preoperative risk prediction model for inadequate lymph node examination. Methods: 24284 patients diagnosed as stage I-III CC between 2010-2014 were extracted from SEER database and randomly divided into development cohort (N=12142) and internal validation cohort (N=12142). 680 patients diagnosed as stage I-III CC between 2012-2014 were extracted from our hospital as external validation cohort. Logistic regression analysis was performed and risk score of each factor was calculated according to model formula. Model discrimination was assessed using C-statistics. Results: Preoperative risk factors were identified as gender, age, tumor site and tumor size. Patients with total risk score of 0-6 were considered as low risk group while patients scored ≥13 were considered as high risk group. The model had good discrimination and calibration in all cohorts and could apply to patients in the SEER database (American population) and patients in our hospital (Chinese population). Conclusions: The model could accurately predict the risk of inadequate lymph node examination before surgery and might provide useful reference for surgeons and pathologists.

Identification of Risk Factors Associated With Stage III Disease in Nonmetastatic Colon Cancer: Results From a Prospective National Cohort Study

Purpose

This study aimed to identify possible patient- and tumor-related factors associated with risk of TNM stage III disease in nonmetastatic colon cancer.

Methods

The associations between stage III disease and age, sex, lymph node yield, pathological tumor (pT) stage, tumor subsite, type of surgery, and priority of surgery were assessed in a nationwide cohort of 13,766 patients treated with curative resection of colon cancer. Each level of age, lymph node yield, and pT stage was compared to the preceding level.

Results

Age, lymph node yield, pT stage, tumor subsite, and priority of surgery were associated with stage III disease. Odds ratios (95% confidence interval [CI]) were as follows: age < 65/65–75 years: 1.28 (95% CI, 1.15–1.43) and 65–75/ > 75 years: 1.22 (95% CI, 1.13–1.32); lymph node yield 0–5/6–11: 0.60 (95% CI, 0.50–0.72), lymph node yield 6–11/12–17: 0.84 (95% CI, 0.76–0.93), and lymph node yield 12–17/ ≥ 18: 0.97 (95% CI, 0.89–1.05); pT1/pT2: 0.74 (95% CI, 0.57–0.95), pT2/pT3: 0.35 (95% CI, 0.30–0.40), and pT3/pT4: 0.49 (95% CI, 0.47–0.54). Only tumors of the transverse colon were independently associated with lower risk of stage III disease than tumors in the sigmoid colon (sigmoid colon: 1, transverse colon: 0.84 [95% CI, 0.73–0.96]; elective surgery: 1, acute surgery: 1.43 [95% CI, 1.29–1.60]).

Conclusion

In this study, stage III disease in colon cancer was significantly associated with age, lymph node yield, pT stage, tumor subsite, and priority of surgery but was not associated with right-sided location compared with stage I and II cancers.

How does lymph node yield affect survival outcomes of stage I and II colon cancer?

Background

According to the American Joint Committee on Cancer staging for cancer of the colon, a minimum of 12 lymph nodes (LN) has to be sampled for accurate staging. This has bearing on the long-term prognosis and the need for adjuvant chemotherapy. The aim of this study was to revisit the association of lymph node yield and the long-term survival in patients with stages I and II, i.e. node-negative, colon cancer.

Method

Consecutive patients who underwent elective or emergency curative resections for cancer of colon between the years 2003 and 2012 were retrospectively reviewed. Only patients with stage I or II diseases (AJCC 8th edition) were included. They were analysed in three groups, LN<12, LN12-19 and LN≥20. Their clinic-pathological characteristics were compared. The disease-free (DFS) and overall survival (OS) were estimated with the Kaplan-Meier method and compared with the log-rank test.

Results

There was a total of 659 patients included in the analysis. Twelve or more LN were found in 65.6% of the specimens. The mean follow-up was 83.9 months. LN≥20 had significantly better DFS (p = 0.015) and OS (p = 0.036), whereas LN<12 had similar DFS and OS when compared to LN12-19. The advantage in DFS and OS were mainly seen in those with stage II diseases. A lymph node yield of greater than 20 was one of the predictors of favourable DFS, hazard ratio 0.358; 95% CI 0.170–.756, p = 0.007.

Conclusion

The lymph node yield had a significant association with survival outcomes. A lymph node yield of 20 or more was associated with better survival outcomes. On the other hand, lymph node yield less than 12 was not shown to have inferior survival outcomes when compared to those between 12 and 19.

Factors affecting retrieval of 12 or more lymph nodes in pT1 colorectal cancers

Objective

The aim of this study was to identify clinicopathological factors that affect the number of lymph nodes (LNs) (12 or more) retrieved from patients with colorectal cancer (CRC), particularly those with pathologic T1 (pT1) disease.

Methods

From 429 CRC patients, 75 pT1 cancers were identified and digitally scanned. Binary logistic regression analysis was performed to identify the clinicopathological factors affecting the number of LNs retrieved from all 429 patients and from the subset of patients with pT1 CRC.

Results

For the 429 patients, the mean number of harvested LNs per specimen was 20 (median, 19). The number of retrieved LNs was independently associated with maximum tumor diameter > 2.3 cm and right-sided tumor location. The mean number of LNs retrieved from the 75 patients with pT1 CRC was 14 (median, 15); retrieval of 12 or more LNs from this group was independently associated with maximum tumor diameter > 14.1 mm.

Conclusion

The number of LNs retrieved from patients with CRC was associated with maximum tumor diameter and right-sided tumor location. For patients with pT1 CRC, maximum tumor diameter was independently associated with the harvesting of 12 or more LNs.

The adequacy of lymph node clearance in colon cancer surgery performed in a non-specialist centre; implications for practice

BACKGROUND

Despite recent medical advances, surgery remains the mainstay treatment in colon cancer. It is well established that better patient outcomes are achieved when complex surgery including pancreatic, oesophageal and rectal surgeries are carried out in high-volume centres. However, it is unclear as to whether or not colon cancer patients receive the same benefit. Lymph node adequacy is a key performance indicator of successful oncological colonic resection which impacts on patient outcome.

AIM

To assess the adequacy of lymph node clearance during colonic resection performed with curative intent in a non-specialist centre post introduction of the National Cancer Strategy.

METHODS

Retrospective analysis was performed of a prospectively maintained database examining the lymph node clearance of all oncological resections for colon cancer over a 7-year period (Nov 2010-Dec 2017) at a satellite unit with links to a regional specialist centre. Primary outcome measured was the number of lymph nodes retrieved. Secondary outcomes included resection margins, 30-day complication rate and survival at 1 year. Statistical analysis was performed using SPSS Statistics for Windows, version 24.0 (IBM Corp, Armonk, N.Y., USA).

RESULTS

One hundred sixty-seven patients were included. Mean age was 71.0 ± 11.6 years. Majority were male (n = 90, 53.6%). The majority of resections was right sided (n = 112.66.7%) with 78.6% of all resections being undertaken electively. All margins were free of tumour. The average lymph node count was 19.93 ± 8.63 (4.62) with only 17 (10.2%) of specimens containing < 12 nodes. The anastomotic leak rate was 3.3%. There was no association between surgeon or pathologist volume, nor emergent status and achieving oncological lymph node count (p = 0.14, 0.29, 0.97). 90.5% of patients were alive at 1 year.

CONCLUSIONS

This study demonstrates that colonic cancer surgery can be safely performed in a non- specialist centre with technical outcomes comparable to nationally reported figures.

Positive impact of the negative lymph node count on the survival rate of stage III colon cancer with pN1 and right-side disease

Background: We aimed to investigate the role of the negative lymph node count (NLN) as a predictor of prognosis in patients with stage III colon cancer.

Methods: We conducted a retrospective study on patients who were diagnosed with stage III colon cancer at Sun Yat-sen University Cancer Center. According to the number of negative lymph nodes, all patients were divided into the low or high NLN group. Overall survival (OS) and disease-free survival (DFS) were assessed using the Kaplan-Meier method and log-rank test between the two groups. Univariate and multivariate Cox proportional hazards models were used to evaluate the risk factors for survival.

Results: The time-dependent receiver operating characteristic (ROC) curve showed that the optimal cutoff value of NLN was nine. In total, 167 and 298 patients were distributed into the low and high NLN groups, respectively. Patients in the high NLN group tended to present with a greater proportion of right-side colon cancer and pN1 stage disease, superior DFS (P < 0.001) and OS (P = 0.001) than those in the low NLN group. Multivariable analyses confirmed increased NLN as a positive prognostic variable, independent of other potential confounding factors. Subgroup analysis showed that in patients with a right-side location, those with 9 or fewer negative lymph nodes had a 5-year OS rate of 35.4% versus 77.1% in those with more than 9 negative lymph nodes evaluated (P < 0.001). For patients with stage pN1, those with NLN ≤9 exhibited an inferior 5-year OS rate than those with NLN > 9 (71.1% vs 84.8%, respectively; P = 0.009). There was no association between the number of negative lymph nodes identified and survival for patients with stage pN2 and left-side disease.

Conclusion: NLN is an important prognostic factor for stage III colon cancer patients with right-side and stage pN1 disease other than for patients with stage pN2 and left-side disease, which can be partly explained in terms of inflammation and immunity.

Predictors of adequate lymph node harvest during colectomy for colon cancer

BACKGROUND

Consensus guidelines recommend a yield of 12 lymph nodes in resections for colon cancer. Factors affecting this yield are not well defined.

METHODS

Retrospective study using the colectomy-targeted American College of Surgeons National Surgical Quality Improvement Program for years 2014-2016. Primary outcome was resection of at least 12 nodes. Univariate and multivariate analyses determined factors associated with ≥12 LN yield.

RESULTS

17,612 colectomies for colon cancer were extracted from the NSQIP database. 7.26% of cases did not reach a 12 LN harvest. Harvesting ≥12 LN was 74% more likely (p = 0.001) if the resection was laparoscopic and 72% more likely (p < 0.0001) if hand-assisted. Advanced T and N stage had a higher likelihood of reaching 12 LN harvest. Older age, female gender and smoking history decreased the likelihood of ≥12 LN harvest.

CONCLUSIONS

Laparoscopic and robotic colectomies were 1.5-2.5 times more likely to achieve adequate LN harvest compared to open surgery. Several non-modifiable patient and disease related factors may render adequate LN yield challenging.

Lymph node ratio as a valuable prognostic factor for patients with colorectal liver-only metastasis undergoing curative resection

Background

Recent studies have suggested that the lymph node ratio (LNR) is a prognostic indicator for various malignancies. However, LNR has not been evaluated in colorectal liver-only metastasis (CRLM). This study aimed to investigate the prognostic value of LNR in patients with CRLM after curative resection.

Patients and methods

We retrospectively investigated the clinicopathologic features of 154 CRLM patients who underwent curative resection between 2005 and 2015. We classified patients into low and high groups based on their LNR by using the X-tile software. Survival curves were plotted through Kaplan–Meier method and compared by log-rank test. Cox proportional hazards analysis was performed to identify the factors associated with recurrence-free survival (RFS) and overall survival (OS).

Results

The patients were divided into two groups in which 124 patients were identified as LNR ≤0.33 and 30 patients as LNR >0.33. Compared to low LNR, high LNR was significantly associated with poor 3-year RFS (47.2% vs 16.7%, P=0.001) and OS (72.8% vs 45.3%, P=0.003) rates. Multivariate analysis indicated that the LNR was an independent predictor for 3-year RFS (hazard ratio, 2.124; 95% CI, 1.339–3.368; P=0.001) and OS (HR, 2.287; 95% CI, 1.282–4.079; P=0.005). However, the node (N) stage and lymph node distribution were not significantly associated with the 3-year RFS (P=0.071, P=0.226) or OS (P=0.452, P=0.791) in patients with CRLM.

Conclusion

This study demonstrated that LNR was an independent predictor for 3-year RFS and OS in patients with CRLM who underwent curative resection and that its prognostic value was superior to that of N stage and lymph node distribution.

Reconsideration of the optimal minimum lymph node count for young colon cancer patients: a population-based study

BACKGROUND

Currently, young colon cancer (CC) patients continue to increase and represent a heterogeneous patient group. The aim of this study was to explore the optimal minimum lymph node count after CC resection for young patients.

METHODS

We performed a comprehensive search of the Surveillance, Epidemiology, and End Results (SEER) database, 2360 CC patients aged from 20 to 40 were analyzed. X-tile was used to determine the optimal cut-off point of lymph node based on survival outcomes of young patients. The cancer specific survival (CSS) was estimated with Kaplan-Meier method, the Cox proportional hazards regression model was used to analyse independent prognostic factors and exact 95% confidence intervals (CIs).

RESULTS

Using X-tile analysis, 22-node measure was identified as the optimal choice for CC patients aged < 40. The 5-year CSS were 85.8% and 80.9% for patients examining ≥22 nodes and < 22 nodes. Furthermore, we identified that examining < 22 nodes was an independent adverse prognostic factor in patients aged < 40. In addition, the revised 22-node measure could examine more positive nodes than the standard 12-node measure in young patients.

CONCLUSIONS

For young colon cancer patients, the lymph node examination should be differently evaluated. We suggest that 22-node measure may be more suitable for CC patients aged < 40.

TRIAL REGISTRATION

Retrospectively registered.

Neoadjuvant Chemotherapy is Associated with Lower Lymph Node Counts in Colon Cancer

Adequate lymphadenectomy is associated with improved survival in patients who undergo oncologic resection of colorectal cancer and has been identified as a quality metric. Neoadjuvant chemotherapy has been found to be associated with collection of <12 lymph nodes in patients with rectal cancer. The purpose of this study was to evaluate patient and operative risk factors for inadequate lymph node retrieval during oncologic colectomy. The 2014 American College of Surgeons National Surgical Quality Improvement Program Participant Use File data set for oncologic colectomy (n = 9077) was analyzed. Patient- and operation-related factors were assessed by univariate and multivariate regression analyses to determine factors associated with the number of lymph nodes collected. Adequate lymphadenectomy was defined by collection of >12 lymph nodes. Of 9077 patients with a diagnosis of colon cancer who underwent colectomy, a minimum of 12 lymph nodes was harvested in 7897 (87%). Significant factors independently associated with inadequate lymphadenectomy included preoperative chemotherapy, emergent surgery, and T1 tumors (all P < 0.05). A large majority of patients who undergo colectomy for colon cancer have at least 12 lymph nodes collected. Preoperative chemotherapy is a major risk factor for inadequate lymph node retrieval. Recognition of factors associated with inadequate lymphadenectomy may improve colectomy lymph node yield and survival in patients with colon cancer.

Rectal cancer and the pathologist

Examination of the rectum by pathologists is instrumental in the management of patients affected by rectal carcinoma. That role includes evaluation of multiple gross and microscopic features that convey prognostic implications. The analysis is based on the authors' experience handling rectal specimens along with review of the pertinent literature in these areas: margins of excision, quality of the mesorectum, diligence and techniques to sample lymph nodes, tumor budding, grading of residual amount of carcinoma after preoperative therapy, vascular/perineural invasion, and staging the tumor. Pathologists must communicate the findings in a clear manner. Evaluation of margins and completeness of mesorectum are markers of the quality of surgical excision. The number of lymph nodes obtained and examined is dependent in great part on the diligence of the pathologist finding them in the mesenteric adipose tissue. There are grades for budding and response to prior chemoradiation therapy. The location of vascular invasion (extramural vs. intramural) may predict aggressive behavior. Pathologists proactively are to choose sections of tumor for molecular testing. Meticulous macro- and microscopic evaluation of specimens for rectal carcinoma by pathologist is needed to determine an accurate assessment of staging and other prognostic factors. The modern pathologists play a pivotal part in the care and management of patients suffering from rectal adenocarcinoma. That role goes from the initial histological diagnosis to the gross and microscopic examination of the excised specimens. Based on that examination pathologists issue statements that not only evaluate the quality of the surgical procedure, but also through the application of molecular tests they give light on prognostic factors and information for therapeutic purposes.

Emergency surgery for colorectal cancer does not affect nodal harvest comparing elective procedures: a propensity score-matched analysis

PURPOSE

About 30% of colorectal cancers (CRCs) present with acute symptoms. The adequacy of oncologic resections is a matter of concern since few authors reported that emergency surgery in these patients results in a lower lymph node harvest (LNH). In addition, emergency resections have been reported with a longer hospital stay and higher morbidity rate. We thus conducted a propensity score-matched analysis with the aim of investigating LNH in emergency specimens comparing with elective ones. Secondary aim was the comparison of morbidity and hospital stay.

METHODS

Eighty-seven consecutive R0 emergency surgical procedures were matched with elective CRCs using the propensity score method and the following covariates: age, sex, stage, and localization. Groups were compared using univariate and multivariate analyses. Outcome measures were LNH, nodal ratio, Clavien's morbidity grades, and hospital stay.

RESULTS

Emergency patients presented more metastatic nodes compared with elective ones (p 0.017); however, both presented a comparable mean LNH. Multivariate analysis documented that a T stage ≥3 was the only variable correlated with a nodal positivity (OR 6.3). On univariate analysis, emergency CRCs had a longer mean hospital stay compared with elective resections (p 0.006) and a higher rate of Clavien ≥4 events (p 0.0173). Finally, emergency resection and an age >66 years were variables independently correlated with a mean hospital stay >10 days (OR, respectively, 3.7 and 3.5).

CONCLUSIONS

Emergency CRC resections were equivalent to the elective procedures with respect to LNH. However, emergency surgery correlated with a longer mean hospital stay. Graphical abstract Emergency and Elective resections for CRC provide similar LNH.

The positive impact of surgical quality control on adequate lymph node harvest by standardized laparoscopic surgery and national quality assessment program in colorectal cancer

PURPOSE

We aimed to present the factors associated with lymph node harvest (LNH) and seek whether surgical quality control measures can improve LNH.

METHODS

From a prospectively collected data at a single institution, 874 CRC patients who underwent curative surgery between 2004 and 2013 were included. Factor and survival analyses were performed regarding LNH. Subgroup analysis was performed according to LNH group (LNH ≥ 12 vs LNH < 12) and year of surgery (2004-2008, 2009-2011, and 2012-2013 group).

RESULTS

In the multivariate analysis, tumor location (OR 0.6, p < 0.001), stage (OR 1.95, p < 0.001), and year of surgery (OR 3.86, p < 0.001) showed an association with adequate LNH. In the subgroup analysis categorized by the year of surgery, surgical quality control measures by standardized laparoscopic surgery (OR 52.91, p < 0.001) showed notable association with adequate LNH. Comparing the 2009-2011 and 2012-2013 group, the national quality assessment program additionally improved adequate LNH percentage (83.9 vs 94.3%). In the survival analysis, disease-free survival (DFS) differed according to year of surgery, standardized laparoscopic surgery with high vascular ligation, and adequate LNH by stage. In the overall survival (OS) analysis, the LNH-related factors did not show significant difference.

CONCLUSIONS

Through standardized laparoscopic surgery with high vascular ligation and national quality assessment program, surgical quality control had a positive impact on the increase of adequate LNH. Improving the modifiable LNH factors resulted in the enhancement of adequate LNH and related DFS.

Sigmoid resection for diverticulitis is more difficult than for malignancies

PURPOSE

Sigmoid resection for diverticulitis is usually the first procedure performed when starting the learning process for laparoscopic colorectal surgery. The aim of this study is to evaluate the difficulty of laparoscopic sigmoid resection for diverticulitis in comparison to sigmoid malignancy in order to assess its role in the residents training program.

METHODS

A cohort of patients was selected who suffered either from malignancy or recurrent diverticulitis in the sigmoid colon. Laparoscopic sigmoid resection was performed. The degree of difficulty was assessed by intraoperative complications and intraoperative technical challenges. Furthermore, take-overs from assistant to surgeon, surgeon to surgeon, and conversion were reported.

RESULTS

A total of 224 patients were included, 119 (53.1%) men and 105 (46.9%) women. Patients suffering from diverticulitis had significantly less co-morbidities than those with malignancies. In the diverticulitis group, there were significantly more technical challenges. There was a higher rate in take-overs from residents (p = 0.02) as well as surgeon to surgeon (p = 0.04). The rate of conversions was also significantly higher in the diverticulitis group (p = 0.03) when compared to the malignancy group.

CONCLUSIONS

The outcomes of our study show that diverticulitis may not be the ideal condition to start the learning process for laparoscopic colorectal surgery.

Lymph node evaluation for colon cancer in routine clinical practice: a population-based study

BACKGROUND

Guidelines recommend that 12 or more lymph nodes (lns) be evaluated during surgical resection of colon cancer. Here, we report ln yield and its association with survival in routine practice.

METHODS

Electronic records of treatment were linked to the population-based Ontario Cancer Registry to identify all patients with colon cancer treated during 2002-2008. The study population (n = 5508) included a 25% random sample of patients with stage ii or iii disease. Modified Poisson regression was used to identify factors associated with ln yield; Cox models were used to explore the association between ln yield and overall (os) and cancer-specific survival (css).

RESULTS

During 2002-2008, median ln yield increased to 17 from 11 nodes (p < 0.001), and the proportion of patients with 12 or more nodes evaluated increased to 86% from 45% (p < 0.001). Lymph node positivity did not change over time (to 53% from 54%, p = 0.357). Greater ln yield was associated with younger age (p < 0.001), less comorbidity (p = 0.004), higher socioeconomic status (p = 0.001), right-sided tumours (p < 0.001), and higher hospital volume (p < 0.001). In adjusted analyses, a ln yield of less than 12 nodes was associated with inferior os and css for stages ii and iii disease [stage ii os hazard ratio (hr): 1.36; 95% confidence interval (ci): 1.19 to 1.56; stage ii css hr: 1.52; 95% ci: 1.26 to 1.83; and stage iii os hr: 1.45; 95% ci: 1.30 to 1.61; stage iii css hr: 1.54; 95% ci: 1.36 to 1.75].

CONCLUSIONS

Despite a temporal increase in ln yield, the proportion of cases with ln positivity has not changed. Lymph node yield is associated with survival in patients with stages ii and iii colon cancer. The association between ln yield and survival is unlikely to be a result of stage migration.

Surgeon-, pathologist-, and hospital-level variation in suboptimal lymph node examination after colectomy: Compartmentalizing quality improvement strategies

BACKGROUND

The goals of this study were to characterize the variation in suboptimal lymph node examination for patients with colon cancer across individual surgeons, pathologists, and hospitals and to examine if this variation affects 5-year, disease-specific survival.

METHODS

A retrospective cohort study was conducted by merging the New York State Cancer Registry with the Statewide Planning & Research Cooperative System, Medicaid, and Medicare claims to identify resections for stages I-III colon cancer from 2004-2011. Multilevel logistic regression models characterized variation in suboptimal lymph node examination (<12 lymph nodes). Multilevel competing-risks Cox models were used for survival analyses.

RESULTS

The overall rate of suboptimal lymph node examination was 32% in 12,332 patients treated by 1,503 surgeons and 814 pathologists at 187 hospitals. Patient-level predictors of suboptimal lymph node examination were older age, male sex, nonscheduled admission, lesser stage, and left colectomy procedure. Hospital-level predictors of suboptimal lymph node examination were a nonacademic status, a rural setting, and a low annual number of resections for colon cancer. The percent of the total clustering variance attributed to surgeons, pathologists, and hospitals was 8%, 23%, and 70%, respectively. Increasing the pathologist and hospital-specific rates of suboptimal lymph node examination were associated with worse 5-year, disease-specific survival.

CONCLUSION

There was a large variation in suboptimal lymph node examination between surgeons, pathologists, and hospitals. Collaborative efforts that promote optimal examination of lymph nodes may improve prognosis for colon cancer patients. Given that 93% of the variation was attributable to pathologists and hospitals, endeavors in quality improvement should focus on these 2 settings.

Exploration of the Optimal Minimum Lymph Node Count after Colon Cancer Resection for Patients Aged 80 Years and Older

The elderly colon cancer (CC) patients are increasing and represent a heterogeneous patient group. The objectives of this study were to identify the features of lymph node examination and to explore the optimal minimum lymph node count after CC resection for patients aged ≥80. Using the Surveillance, Epidemiology, and End Results (SEER) database, we identified 65719 CC patients in stage I-III between 2004 and 2012, 26.0% of patients were aged ≥80. The median node count decreased with increasing age, which were 25.5, 20.2, 17.8 and 16.9 for patients aged 20–39, 40–59, 60–79, and ≥80. The rate of ≥12 nodes and the rate of node positivity for patients aged ≥80 were obviously lower than younger patients. Using X-tile analysis, we determined 9 nodes as the optimal node count for patients aged ≥80. Then, we compared the 5-year cancer specific survival (CSS) between patients with ≥9 nodes and <9 nodes. The results showed the 5-year CSSs were improved for patients with ≥9 nodes. Furthermore, the rate of node positivity and survival under the 9-node measure were equal to 12-node measure. Therefore, the lymph node examination should be discriminately evaluated for elder patients, and 9-node measure was available for patients aged ≥80.

Colorectal cancer: Quality of surgical care in Michigan

OBJECTIVE

Surgery remains the cornerstone therapy for colorectal cancer (CRC). This study assesses CRC quality measures for surgical cases in Michigan.

METHODS

In this retrospective cohort study, processes of care and outcomes for CRC resection cases were abstracted in 30 hospitals in the Michigan Surgical Quality Collaborative (2014-2015). Measures were case-mix and reliability adjusted, using logistic regression models.

RESULTS

For 871 cases (640 colon cancer, 231 rectal cancer), adjusted morbidity (27.4%) and mortality rates (1.5%) were low. Adjusted process measures showed gaps in quality of care. Mesorectal excision was documented in 59.4% of rectal cancer (RC) cases, 65% of RC cases had sphincter preserving surgery, 18.7% of cases had < 12 lymph nodes examined, 7.9% had a positive margin, 52.1% of stage II/III RC cases had neoadjuvant therapy, and 36% of ostomy cases had site marking.

CONCLUSION

This study finds gaps in quality of care measures for CRC, suggesting opportunity for regional quality improvement.

A high lymph node yield in colon cancer is associated with age, tumour stage, tumour sub-site and priority of surgery. Results from a prospective national cohort study

AIM

To determine the relation between patient-related and histopathological factors, as well as the influence of national programs for diagnosing and treatment of colon cancer and a lymph node yield (LNY) ≥ 12.

METHOD

An analysis was carried out of the LNY in a nationwide Danish cohort treated by curative resection of stage I-III colon cancer in the period 2003-2011. The association between a LNY ≥ 12 and age, sex, body mass index, open vs. laparoscopic surgery, acute vs. elective surgery, pT stage, tumour sub-site and year of diagnosis was analysed.

RESULTS

A total of 13,766 patients were eligible for the analysis. In total, 71.4 % of the patients had a LNY ≥ 12. In multivariate analysis, age, pT stage, tumour sub-site and priority of surgery were independently associated with the probability of a LNY ≥ 12. Odds ratios (ORs) were as follows: age <65 1, 65-75 0.685 (confidence interval (CI) 0.586-0.800), >75 0.517 (CI 0.439-0.609); T1 1, T2 2.750 (CI 2.168-3.487), T3 6.016 (CI 4.879-7.418), T4 6.317 (CI 4.950-8.063); right colon 1, left colon 0.568 (0.511-0.633); elective surgery 1, acute surgery 0.748 (CI 0.625-0.894). Moreover, year of diagnosis was associated with the probability of a LNY ≥ 12: OR 1.480 (CI 1.445-1.516) for each increasing year in the study period.

CONCLUSION

A LNY ≥ 12 is significantly associated with age, pT stage, tumour sub-site and priority of surgery. A significant increase in the LNY over the period of the study was observed, probably reflecting the effect of national programmes initiated by the Danish Colorectal Cancer Group.

Non-surgical factors influencing lymph node yield in colon cancer

There are numerous factors which can affect the lymph node (LN) yield in colon cancer specimens. The aim of this paper was to identify both modifiable and non-modifiable factors that have been demonstrated to affect colonic resection specimen LN yield and to summarise the pertinent literature on these topics. A literature review of PubMed was performed to identify the potential factors which may influence the LN yield in colon cancer resection specimens. The terms used for the search were: LN, lymphadenectomy, LN yield, LN harvest, LN number, colon cancer and colorectal cancer. Both non-modifiable and modifiable factors were identified. The review identified fifteen non-surgical factors: (13 non-modifiable, 2 modifiable) which may influence LN yield. LN yield is frequently reduced in older, obese patients and those with male sex and increased in patients with right sided, large, and poorly differentiated tumours. Patient ethnicity and lower socioeconomic class may negatively influence LN yield. Pre-operative tumour tattooing appears to increase LN yield. There are many factors that potentially influence the LN yield, although the strength of the association between the two varies greatly. Perfecting oncological resection and pathological analysis remain the cornerstones to achieving good quality and quantity LN yields in patients with colon cancer.

Prior Abdominal Surgery Jeopardizes Quality of Resection in Colorectal Cancer

BACKGROUND

Prior abdominal surgery increases complexity of abdominal operations. Effort to prevent injury during adhesiolysis might result in less extensive bowel resection in colorectal cancer surgery. The aim of this study was to evaluate the effect of prior abdominal surgery on the outcome of colorectal cancer surgery.

METHODS

A nationwide prospective database of patients with primary colorectal cancer resection in The Netherlands between 2010 and 2012 was reviewed for histopathology, morbidity and mortality in patients with compared to patients without prior abdominal surgery.

RESULTS

9042 patients with and 17,679 without prior abdominal surgery were analyzed. After prior abdominal surgery 20.7 % had less than 10 lymph nodes in the histopathological specimen compared to 17.8 % without prior abdominal surgery (adjusted OR 1.17, 95 % CI 1.09-1.26). Adjusted ORs for less than 10 and 12 lymph nodes were significant in colon cancer resection and not in rectal cancer resection. Subgroups of patients who had previous hepatobiliary surgery or other abdominal surgery had a higher incidence of inadequate number of harvested lymph nodes. Prior colorectal surgery increased the percentage of positive circumferential rectal resection margin by 64 % (12.5 and 7.6 %; adjusted OR 1.70, 95 % CI 1.21-2.39). For colon cancer morbidity was significantly higher in patients with prior surgery (33.2 and 29.7 %; adjusted OR 1.18, 95 % CI 1.10-1.26), 30-day mortality was comparable (4.7 % prior surgery and 3.8 % without prior surgery; adjusted OR 1.01, 95 % CI 0.88-1.17).

CONCLUSIONS

Prior abdominal surgery compromises the quality of resection and increases postoperative morbidity in patients with primary colorectal cancer.

Stage migration vs immunology: The lymph node count story in colon cancer

Lymph node staging is of crucial importance for the therapy stratification and prognosis estimation in colon cancer. Beside the detection of metastases, the number of harvested lymph nodes itself has prognostic relevance in stage II/III cancers. A stage migration effect caused by missed lymph node metastases has been postulated as most likely explanation for that. In order to avoid false negative node staging reporting of at least 12 lymph nodes is recommended. However, this threshold is met only in a minority of cases in daily practice. Due to quality initiatives the situation has improved in the past. This, however, had no influence on staging in several studies. While the numbers of evaluated lymph nodes increased continuously during the last decades the rate of node positive cases remained relatively constant. This fact together with other indications raised doubts that understaging is indeed the correct explanation for the prognostic impact of lymph node harvest. Several authors assume that immune response could play a major role in this context influencing both the lymph node detectability and the tumor’s behavior. Further studies addressing this issue are need. Based on the findings the recommendations concerning minimal lymph node numbers and adjuvant chemotherapy should be reconsidered.

Overall Survival of Stage III Colon Cancer with Only One Lymph Node Metastasis Is Independently Predicted by Preoperative Carcinoembryonic Antigen Level and Lymph Node Sampling Status

Background

This study identified predictors of favorable overall survival (OS) for stage III colon cancer patients who had only one lymph node (LN) metastasis (N1a).

Methods

Variables, including preoperative carcinoembryonic antigen (CEA) level, LN sampling status, and the choices of postoperative adjuvant chemotherapy, were recorded. Prognostic significance was determined using the log-rank test and multivariate Cox regression analysis.

Results

The median 42-month follow-up period included 363 eligible patients. Among them, 230 (63.3%) received only 5-flurouracil (5-FU) adjuvant chemotherapy; 76 (20.9%) underwent oxaliplatin-based regimens; and 57 (15.7%) chose surgery alone. The 5-year survival rate of these evaluated patients was 75%, 63%, and 77%, respectively (P = 0.823). Multivariate analysis revealed that normal preoperative CEA level (≦5 ng/mL) and adequate LN sampling (LN ≧ 12) were significant predictors for higher 5-year OS (P < 0.001; P = 0.007, respectively). However, the use of postoperative adjuvant chemotherapy in these N1a colon cancer patients did not significantly affect their 5-year OS.

Conclusions

A preoperative CEA level of less than or equal to 5 ng/mL, and curative surgery with an adequate lymphadenectomy determined a favorable OS outcome in stage III colon cancer with only one LN metastasis.

The loss in expectation of life after colon cancer: a population-based study

Background

To demonstrate how assessment of life expectancy and loss in expectation of life can be used to address a wide range of research questions of public health interest pertaining to the prognosis of cancer patients.

Methods

We identified 135,092 cases of colon adenocarcinoma diagnosed during 1961–2011 from the population-based Swedish Cancer Register. Flexible parametric survival models for relative survival were used to estimate the life expectancy and the loss in expectation of life.

Results

The loss in expectation of life for males aged 55 at diagnosis was 13.5 years (95 % CI 13.2–13.8) in 1965 and 12.8 (12.4–13.3) in 2005. For males aged 85 the corresponding figures were 3.21 (3.15–3.28) and 2.10 (2.04–2.17). The pattern was similar for females, but slightly greater loss in expectation of life. The loss in expectation of life is reduced given survival up to a certain time point post diagnosis. Among patients diagnosed in 2011, 945 life years could potentially be saved if the colon cancer survival among males could be brought to the same level as for females.

Conclusion

Assessment of loss in expectation of life facilitates the understanding of the impact of cancer, both on individual and population level. Clear improvements in survival among colon cancer patients have led to a gain in life expectancy, partly due to a general increase in survival from all causes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1427-2) contains supplementary material, which is available to authorized users.

Novel Methods of Lymph Node Evaluation for Predicting the Prognosis of Colorectal Cancer Patients with Inadequate Lymph Node Harvest

Purpose

Lymph node metastasis is an important factor for predicting the prognosis of colorectal cancer patients. However, approximately 60% of patients do not receive adequate lymph node evaluation (less than 12 lymph nodes). In this study, we identified a more effective tool for predicting the prognosis of patients who received inadequate lymph node evaluation.

Materials and Methods

The number of metastatic lymph nodes, total number of lymph nodes examined, number of negative metastatic lymph nodes (NL), lymph node ratio (LR), and the number of apical lymph nodes (APL) were examined, and the prognostic impact of these parameters was examined in patients with colorectal cancer who underwent surgery from January 2004 to December 2011. In total, 806 people were analyzed retrospectively.

Results

In comparison of different lymph node analysis methods for rectal cancer patients who did not receive adequate lymph node dissection, the LR showed a significant difference in overall survival (OS) and the APL predicted a significant difference in disease-free survival (DFS). In the case of colon cancer patients who did not receive adequate lymph node dissection, LR predicted a significant difference in DFS and OS, and the APL predicted a significant difference in DFS.

Conclusion

If patients did not receive adequate lymph node evaluation, the LR and NL were useful parameters to complement N stage for predicting OS in colon cancer, whereas LR was complementary for rectal cancer. The APL could be used for prediction of DFS in all patients.

Risk factors for colorectal neoplasms based on colonoscopy and pathological diagnoses of Chinese citizens: a multicenter, case-control study

PURPOSE

Since observational data in the urban residents are required to better assess the risk factors of colorectal neoplasm occurrence and the effectiveness of colonoscopy screening and surveillance, we conducted a case-control study at multicenters in China to identify patient characteristics and neoplasm features of colorectal adenoma (CRA) and colorectal carcinoma (CRC).

METHODS

A total of 4089 patients who had undergone a colonoscopy from 19 hospitals were enrolled, of which 1106 had CRA and 466 had CRC. They were compared with controls. The analysis provides features and risk factors of colorectal neoplasm using multivariate logistic regression.

RESULTS

Increasing age, a family history of colorectal cancer or previous cases of colorectal adenoma or hypertension disease, gastrointestinal surgery, regular intake of pickled food (adjusted odds ratio [aOR] 1.42, 95 % confidence interval [CI], 1.048-1.924), consumption of alcohol, and a positive result of fecal occult blood testing (FOBT; aOR 2.509, 95 % CI 1.485-4.237) were associated with an increased risk of CRA. In the CRC group, increasing age, regular intake of pickled foods, and a positive FOBT result were risk factors. In addition, a positive abdominal computed tomography (CT) before a colonoscopy and physical signs of emaciation were also significantly associated with an increasing risk of colorectal carcinoma. Regular intake of vegetables decreased the risk of both CRA and CRC.

CONCLUSIONS

Age, pickled foods, and a positive FOBT are risk factors for colorectal neoplasm. Vegetable intake was associated with a decreased risk of CRA and CRC.

No change in lymph node positivity rate despite increased lymph node yield and improved survival in colon cancer

AIM

To analyse trends over time in the number of lymph nodes evaluated and in the proportion of node positivity and to investigate the impact on survival for patients with colon cancer.

PATIENTS AND METHODS

8616 patients resected for M0 colon cancer diagnosed in the southern Netherlands between 2000 and 2011 were included in this study. Trends in nodal evaluation and node positivity were analysed. Multivariable logistic regressions were used to assess the influence of period of diagnosis on adequate nodal evaluation (P12 lymph nodes) and no depositivity after adjusting for patient and tumour characteristics. Crude 5-year relative survival was used as an estimate for disease-specific survival.

RESULTS

Overall, the proportion adequate nodal evaluation increased from 13% in 2000–2002 to 59% in 2009–2011 (p < 0.0001), whereas the proportion node positivity remained similar across study periods (approximately 35%). Patients diagnosed in later periods were more likely to have received adequate nodal yield (adjusted Odds ratio (OR) 2009–2011 versus 2000–2002 9.8, 95% Confidence interval (CI) 8.3–11.6). However, the adjusted odds of having node positive disease did not differ between periods of diagnosis. Relative excess risk of dying was independently correlated with the number of lymph nodes evaluated (1–8 LNs versus P12 LNs, N0: 2.2, 95% CI 1.7–2.9; N+: 1.7, 95% CI 1.4–2.0) and period of diagnosis (2009–2011 versus 2000–2002, N+ only: 0.8, 95% CI 0.6–1.0).

CONCLUSION

The reason for improved survival with increased nodal yield is different from simple understaging as the proportion of lymph node positivity remained constant.

Alcohol Fat Clearing Increases Lymph Node Yield after Surgery for Colorectal Cancer

Lymph node (LN) yield is associated with oncologic outcome in patients who undergo surgery for colorectal adenocarcinoma (CRC). Standards to maximize LN yield have been initiated to enhance treatment of patients with CRC. This study evaluates the impact of a simple alcohol-based preparation protocol on LN yield. Surgical specimens from patients with CRC were prepared using either the alcohol protocol or standard formalin fixation and LN yield was compared. In total, 80 consecutive patients (n = 40 formalin, n = 40 alcohol) were examined. Overall, median LN yield increased from 17 to 29 ( P < 0.01) with the alcohol fat clearance protocol. For patients with rectal adenocarcinoma who underwent proctectomy after neoadjuvant chemoradiotherapy, LN yield increased from 15 to 23 ( P = 0.02). The frequency of need for additional sampling to achieve a minimum 12 LN count was also reduced. Initiation of a standardized alcohol fat-clearing protocol increased LN yield after surgery for CRC. This simple, cost-effective measure may improve the efficiency of LN assessment and accurate staging, which may impact oncologic outcomes.

[Treatment reality with respect to laparoscopic surgery of colonic cancer in Germany]

BACKGROUND

Prospective randomized studies and meta-analyses have shown that laparoscopic resection for colonic cancer is equivalent to open resection with respect to the oncological results and has short-term advantages in the early postoperative outcome. The aim of this study was to investigate whether laparoscopic colonic resection has become established as the standard in routine treatment.

METHODS

Data from the multicenter observational study "Quality assurance colonic cancer (primary tumor)" from the time period from 1 January 2009 to 21 December 2011 were evaluated with respect to the total proportion of laparoscopic colonic cancer resections and tumor localization and specifically for laparoscopic sigmoid colon cancer resections. A comparison between low and high volume clinics (< 30 versus ≥ 30 colonic cancer resections/year) was carried out.

RESULTS

Laparoscopic colonic cancer resections were carried out in 12 % versus 21.4 % of low and high volume clinics, respectively (p < 0.001) with a significant increase for low volume clinics (from 8.0 % to 15.6 %, p < 0.001) and a constant proportion in high volume clinics (from 21.7 % to 21.1 %, p = 0.905). For sigmoid colon cancer laparoscopic resection was carried out in 49.7 % versus 47.6 % (p = 0.584). Differences were found between low volume and high volume clinics in the conversion rates (17.3 % versus 6.6 %, p < 0.001), the length of the resected portion (Ø 23.6 cm versus 36.0 cm, p < 0.001) and the lymph node yield (Ø n = 15.7 versus 18.2, p = 0.008). There were no differences between the two groups of clinics regarding postoperative morbidity and mortality. The postoperative morbidity and length of stay were significantly lower for laparoscopic sigmoid resection than for conventional sigmoid resection.

CONCLUSION

The laparoscopic access route for colonic cancer resection is not the standard approach in the participating clinics. The laparoscopic access route has the highest proportion for sigmoid colon resection. The differences in the conversion rates, length of the resected portion and the number of lymph nodes investigated between the low volume and high volume clinics must be viewed critically and must be interpreted in connection with the long-term oncological results.

Influence of microsatellite instability and KRAS and BRAF mutations on lymph node harvest in stage I-III colon cancers

Lymph node (LN) harvest is influenced by several factors, including tumor genetics. Microsatellite instability (MSI) is associated with improved node harvest, but the association to other genetic factors is largely unknown. Research methods included a prospective series of stage I-III colon cancer patients undergoing ex vivo sentinel-node sampling. The presence of MSI, KRAS mutations in codons 12 and 13, and BRAF V600E mutations was analyzed. Uni- and multivariate regression models for node sampling were adjusted for clinical, pathological and molecular features. Of 204 patients, 67% had an adequate harvest (≥ 12 nodes). Adequate harvest was highest in patients whose tumors exhibited MSI (79%; odds ratio [OR] 2.5, 95% confidence interval [CI] 1.2-4.9; P = 0.007) or were located in the proximal colon (73%; 2.8, 1.5-5.3; P = 0.002). In multiple linear regression, MSI was a significant predictor of the total LN count (P = 0.02). Total node count was highest for cancers with MSI and no KRAS/BRAF mutations. The independent association between MSI and a high LN count persisted for stage I and II cancers (P = 0.04). Tumor location in the proximal colon was the only significant predictor of an adequate LN harvest (adjusted OR 2.4, 95% CI 1.2-4.9; P = 0.01). An increase in the total number of nodes harvested was not associated with an increase in nodal metastasis. In conclusion, number of nodes harvested is highest for cancers of the proximal colon and with MSI. The nodal harvest associated with MSI is influenced by BRAF and KRAS genotypes, even for cancers of proximal location. Mechanisms behind the molecular diversity and node yield should be further explored.