Clinically important aspects of lymph node assessment in colon cancer

Improved Accuracy of Lymph Node Staging and Long-Term Survival Benefit in Colorectal Cancer With Ex Vivo Arterial Methylene Blue Infiltration

Introduction:Ex vivo methylene blue (MB) injection into the main supplying arteries of the colorectal specimen after surgical removal is an uncomplicated technique to support lymph node harvest during pathological evaluation. The primary aim of this randomized, interventional, bicentric trial was to evaluate the impact of MB injection on lymph node yield, with secondary aims assessing the accuracy of lymph node staging and the effect on 5-year overall survival for patients undergoing resection of colorectal cancer.

Methods: In the study period between December 2013 and August 2015, 200 colorectal resections were performed at two independent onco-surgery centers of Hungary. Following surgical resection, each specimen was randomly assigned either to the control (standard pathological work-up) or to the MB staining group before formaldehyde fixation. Patient-level surgical and clinical data were retrieved from routinely collected clinical datasets. Survival status data were obtained from the National Health Insurance Fund of Hungary.

Results: A total of 162 specimens, 82 in the control and 80 in the MB groups, were included for analysis. Baseline characteristics were equally distributed among study groups, except for specimen length. Both the median of total number of lymph nodes retrieved (control 11 ± 8 [0–33] nodes vs. MB 14 ± 6 [0–42] nodes; p < 0.01), and the ratio of cases with at least 12 removed lymph nodes (36/82, 43.9% vs. 53/80, 66.3%; p < 0.01) were higher in the MB group. The rate of accurate lymph node staging was non-significantly improved. As for rectal cancer, nodal staging accuracy (16/31, 51.6% vs. 23/30, 76.7%; p = 0.04) and the proportion with minimum 12 lymph node retrieval (7/31, 22.6%, vs. 18/30, 60%; p < 0.01) was improved by MB injection. In Mantel–Cox regression, a statistically significant survival benefit with methylene blue injection at 5 years post-surgery was proven (51.2% vs. 68.8%; p = 0.04).

Conclusion: In our experience, postoperative ex vivo arterial methylene blue injection appears to be an uncomplicated technique, improving lymph node yield and decreasing the chance of insufficient nodal staging. The technique might also associate with a 5-year overall survival benefit.

Role of one-step nucleic acid amplification in colorectal cancer lymph node metastases detection

Current histopathological staging procedures in colorectal cancer (CRC) depend on midline division of the lymph nodes (LNs) with one section of hematoxylin and eosin staining. Cancer cells outside this transection line may be missed, which could lead to understaging of Union for International Cancer Control Stage II high-risk patients. The one-step nucleic acid amplification (OSNA) assay has emerged as a rapid molecular diagnostic tool for LN metastases detection. It is a molecular technique that can analyze the entire LN tissue using a reverse-transcriptase loop-mediated isothermal amplification reaction to detect tumor-specific cytokeratin 19 mRNA. Our findings suggest that the OSNA assay has a high diagnostic accuracy in detecting metastatic LNs in CRC and a high negative predictive value. OSNA is a standardized, observer-independent technique, which may lead to more accurate staging. It has been suggested that in stage II CRC, the upstaging can reach 25% and these patients can access postoperative adjuvant chemotherapy. Moreover, intraoperative OSNA sentinel node evaluation may allow early CRC to be treated with organ-preserving surgery, while in more advanced-stage disease, a tailored lymphadenectomy can be performed considering the presence of aberrant lymphatic drainage and skip metastases.

Survival effects of primary and metastatic surgical treatment in metastatic small intestinal tumors: A propensity score–matching study

Objective

To analyze the effects of primary tumor resection and metastatic lesion resection on the survival of metastatic small intestinal tumors.

Methods

The research subjects were patients with metastatic small bowel tumors identified from 2004 to 2016 in the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching and Kaplan–Meier analyses were performed to analyze the effect of surgery on the prognosis.

Results

A total of 4,034 patients from the SEER database were analyzed. Both before and after the propensity score–matching analysis, the prognosis of patients who underwent primary tumor surgery and metastatic surgery was better than that of patients who did not undergo surgery; all were patients with metastatic small bowel adenocarcinoma (mSIA) or metastatic small intestinal neuroendocrine tumors (mSI-NETs) (all p < .005). Patients with mSIA and adequate lymph node dissection had a longer prognosis than mSIA patients with inadequate lymph node dissection, but this survival benefit was not present in mSI-NET patients. It made no difference in the prognosis of mSIA and mSI-NETs whether localized surgery or intestine-ectomy was performed. Patients with mSIA who underwent primary and metastatic excision plus chemotherapy had the best overall survival and cancer-specific survival rates, whereas mSI-NET patients who underwent primary and metastatic excision had the best overall survival and cancer-specific survival rates (all p < .001).

Conclusion

In these carefully selected patients, primary tumor resection and/or metastatic lesion resection significantly improved the survival rates for patients with mSIA and mSI-NETs. The mSIA patients with resectable primary tumors seemed to require a sufficient number of lymph node dissections more than the patients with well-differentiated mSI-NETs.

Comparative effectiveness of pathologic techniques to improve lymph node yield from colorectal cancer specimens. A systematic review and network meta-analysis

BACKGROUND

A number of randomized controlled trials (RCT) have compared different techniques to improve lymph node yield (LNY) in colorectal cancer specimens but data on comparative effectiveness are sparse. Our aim was to compare the relative effectiveness and rank all available techniques.

METHODS

A systematic search of Embase, Cochrane, PubMed and Scopus was performed for randomized trials. Pairwise meta-analysis performed if more than two homogeneous studies were available for each comparison. Network meta-analysis was used to rank and compare all available techniques.

RESULTS

Fifteen studies fulfilled the inclusion criteria. Techniques that were compared included methylene blue (MB), GEWF, Carnoy solution (CS), patent blue (PB), formalin, fat clearing (FC) and their combinations. The overall quality of studies was found to be fair. In pairwise meta-analysis MB had a higher lymph node yield weighted mean difference [WMD] 13.67 [4.83-22.51], P<0.01, lower number of specimens with less than 12 lymph nodes log Odds Ratio= -1.88(-2.8, -0.91), P<0.01 and higher LNY in patients with prior chemoradiotherapy (WMD 9.11 [3.15,15.08], p=0.02) as compared to formalin. Evaluation of the network plot revealed a well-connected network. In network meta-analysis MBFC had a higher LNY with [Mean Difference (MD) 13 and 95% credible interval (CI) (2.09- 23.91)] as compared to formalin. MBFC probability of being the best technique for LNY was 91.4%. In network meta-analysis MB did not have a statistically significant difference when compared to formalin.

CONCLUSIONS

MBFCS seems to be the most effective technique for LNY. Further studies are required to make safe conclusions for outcomes such positive lymph nodes and upstaging.

Preoperative prediction of regional lymph node metastasis of colorectal cancer based on 18F-FDG PET/CT and machine learning

PURPOSE

To establish and validate a regional lymph node (LN) metastasis prediction model of colorectal cancer (CRC) based on 18F-FDG PET/CT and radiomic features using machine-learning methods.

METHODS

A total of 199 colorectal cancer patients underwent pre-therapy diagnostic 18F-FDG PET/CT scans and CRC radical surgery. The Chang-Gung Image Texture Analysis toolbox (CGITA) was used to extract 70 PET radiomic features reflecting 18F-FDG uptake heterogeneity of tumors. The least absolute shrinkage and selection operator (LASSO) algorithm was used to select radiomic features and develop a radiomic signature score (Rad-score). The training set was used to establish five machine-learning prediction models and the test set was used to test the efficacy of the models. The effectiveness of the models was compared by ROC analysis.

RESULTS

The CRC patients were divided into a training set (n = 144) and a test set (n = 55). Two radiomic features were selected to build the Rad-score. Five machine-learning algorithms including logistic regression, support vector machine (SVM), random forest, neural network and eXtreme gradient boosting (XGBoost) were used to established models. Among the five machine-learning models, logistic regression (AUC 0.866, 95% CI 0.808-0.925) and XGBoost (AUC 0.903, 95% CI 0.855-0.951) models performed the best. In the training set, the AUC of these two models were significantly higher than that of the LN metastasis status reported by 18F-FDG PET/CT for differentiating positive and negative regional LN metastases in CRC (all p < 0.05). Good efficacy of the above two models was also achieved in the test set. We created a nomogram based on the logistic regression model that visualized the results and provided an easy-to-use method for predicting regional LN metastasis in patients with CRC.

CONCLUSION

In this study, five machine-learning models for preoperative prediction of regional LN metastasis of CRC based on 18F-FDG PET/CT and PET-based radiomic features were successfully developed and validated. Among them, the logistic regression and XGBoost models performed the best, with higher efficacy than 18F-FDG PET/CT in both the training and test sets.

Using the Fat-Clearing Technique to Improve Lymph Node Retrieval in Colorectal Cancer

College of American Pathologists recommended that at least 12 lymph nodes should be harvested for adequate staging of colorectal carcinoma. Lymph node harvesting is routinely performed by a manual technique of inspection and palpation, which is laborious and time-consuming. The study assessed the influence of the improved fat-clearing technique on the number of lymph nodes retrieved from colorectal cancer specimens and the clinical efficacy. Seventy colorectal cancer resection specimens were examined and assessed by 4 pathology residents. Thirty-five specimens were handled with the conventional manual technique by inspection and palpation, and the other 35 specimens with the improved fat-clearing technique to retrieve lymph nodes. As a result, compared with the conventional manual technique, the numbers of lymph nodes retrieved with the improved fat-clearing technique were significantly increased from 14.7 ± 6.2 lymph nodes to 20.8 ± 9.0 lymph nodes per specimen (P < .05). Besides, the percentage of cases with at least 12 lymph nodes retrieved increased from 80% to 91%. The result of this study pointed out that using the improved fat-clearing technique to process colorectal specimens could increase the lymph node yield effectively, and was effective, practical, and suitable for routine gross examination.

Optical molecular imaging can differentiate metastatic from benign lymph nodes in head and neck cancer

Identification of lymph node (LN) metastasis is essential for staging of solid tumors, and as a result, surgeons focus on harvesting significant numbers of LNs during ablative procedures for pathological evaluation. Isolating those LNs most likely to harbor metastatic disease can allow for a more rigorous evaluation of fewer LNs. Here we evaluate the impact of a systemically injected, near-infrared fluorescently-labeled, tumor-targeting contrast agent, panitumumab-IRDye800CW, to facilitate the identification of metastatic LNs in the ex vivo setting for head and neck cancer patients. Molecular imaging demonstrates a significantly higher mean fluorescence signal in metastatic LNs compared to benign LNs in head and neck cancer patients undergoing an elective neck dissection. Molecular imaging to preselect at-risk LNs may thus allow a more rigorous examination of LNs and subsequently lead to improved prognostication than regular neck dissection.

Effect of activated carbon nanoparticles on lymph node harvest in patients with colorectal cancer

AIM

The aim was to examine the effect of activated carbon nanoparticles (ACNs) on lymph node retrieval in colorectal cancer (CRC) patients.

METHODS

This prospective randomized study of 80 subjects was performed between March 2016 and December 2016. Eighty patients with CRC were randomly divided into two groups, the ACN group and a control group. The patients in the ACN group were subjected to 1 ml of ACN injection in the subserosa around the tumour before colectomy and D3 lymphadenectomy. The patients in the control group received the same procedure without the injection of ACNs. After surgery, lymph nodes were isolated, and the greatest dimensions were measured by the same pathologist.

RESULTS

The average number of lymph nodes harvested from each patient was markedly more in the ACN group (31.3 ± 8.1) than in the control group (21.9 ± 5.3; P < 0.001), and the average number of lymph nodes less than 5 mm in greatest dimension was significantly more in the ACN group (11.9 ± 4.9) than in the control group (4.1 ± 2.4; P < 0.001). The ACN group (15/40) had a higher rate of Stage III patients compared to the control group (6/39; P = 0.026). Besides, the greatest dimension of 32.8% metastatic lymph nodes was less than 5 mm.

CONCLUSION

There is significant upstaging following the use of ACNs, which could find more involved nodes. Therefore, ACNs can be used as a tracer to harvest more lymph nodes in CRC patients, with improvement in the accuracy of pathological staging.

Complete Mesocolic Excision With Central Vascular Ligation in Comparison With Conventional Surgery for Patients With Colon Cancer - The Experiences at Two Centers

Purpose

Revolutions have occurred over the last 3 decades in the management of patients with colorectal cancer. Most advances were in rectal cancer surgery, especially after the introduction of the total mesorectal excision (TME) by Heald. However, no parallel advances regarding colon cancer surgeries have occurred. In 2009, Hohenberger introduced a new concept trying to translate the survival advantages of TME to patients with colon cancer. This relatively new concept of a complete mesocolic excision (CME) with central vascular ligation (CVL) in the management of patients with colon cancer represents an evolution in operative technique. We performed a comparative study between CME with CVL and conventional surgery for patients with colon cancer at Italian and Egyptian cancer centers, considering surgical quality and clinical outcome.

Methods

Seventy-nine Egyptian patients underwent conventional surgery (non-CME group) while 52 Italian patients underwent CME with sharp dissection between the embryological planes and CVL of the supplying vessels (CME group).

Results

Significantly better results were observed in terms of lymph node yield (CME group: 22.5 vs. non-CME group: 12; P < 0.0001) and lymph node ratio (CME group: 0.03 vs. non-CME group: 0.22; P < 0.0001). Regarding surgical morbidity, no significant difference was noted (CME group: 2 vs. non-CME group: 5; P < 0.702).

Conclusion

CME appears to be a safe procedure when performed by experienced hands through proper embryological planes. It also provides a superior specimen, with a higher lymph node yield, which consequently affects the lymph node ratio. Eventually, CME with CVL should be increasingly adopted and studied more deeply.

Prognostic value of total number of lymph nodes retrieved differs between left-sided colon cancer and right-sided colon cancer in stage III patients with colon cancer

Background

The consensus is that a minimum of 12 lymph nodes should be analyzed at colectomy for colon cancer. However, right colon cancer and left colon cancer have different characteristics, and this threshold value for total number of lymph nodes retrieved may not be universally applicable.

Methods

The data of 63,243 patients with colon cancer treated between 2004 and 2012 were retrieved from the National Cancer Institute’s Surveillance, Epidemiology, and End Results database. Multivariate Cox regression analysis was used to determine the predictive value of total number of lymph nodes for survival after adjusting for lymph nodes ratio. The predictive value in left-sided colon cancer and right-sided colon cancer was compared. The optimal total number of lymph nodes cutoff value for prediction of overall survival was identified using the online tool Cutoff Finder. Survival of patients with high total number of lymph nodes (≥12) and low total number of lymph nodes (< 12) was compared by Kaplan–Meier analysis.

Results

After stratifying by lymph nodes ratio status, total number of lymph nodes≥12 remained an independent predictor of survival in the whole cohort and in right-sided colon cancer, but not in left-sided colon cancer. The optimal cutoff value for total number of lymph nodes was determined to be 11. Low total number of lymph nodes (< 11) was associated with significantly poorer survival after adjusting for lymph nodes ratio in all subgroups except in the subgroup with high lymph nodes ratio (0.5–1.0).

Conclusions

Previous reports of the prognostic significance of total number of lymph nodes on node-positive colon cancer were confounded by lymph nodes ratio. The 12-node standard for total number of lymph nodes may not be equally applicable in right-sided colon cancer and left-sided colon cancer.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4431-5) contains supplementary material, which is available to authorized users.

Is it time for one-step nucleic acid amplification (OSNA) in colorectal cancer? A systematic review and meta-analysis

BACKGROUND

Lymph node metastasis (LNM) is prognostic in colorectal cancer (CRC). However, evaluation by routine haematoxylin and eosin histology (HE) limits nodal examination and is subjective. Missed LNMs from tissue allocation bias (TAB) might under-stage disease, leading to under-treatment. One-step nucleic acid amplification (OSNA) for CK19 messenger ribonucleic acid (mRNA), a marker of LNM, analyses the whole node. The aim of the present systematic review and meta-analysis was to assess recent studies on OSNA versus HE and its implications for CRC staging and treatment.

METHODS

Databases including OVID, Medline and Google Scholar were searched for OSNA, LNM and CRC. Study results were pooled using a random-effects model. Summary receiver operator curves (SROC) assessed OSNA's performance in detecting LNM when compared to routine HE histology.

RESULTS

Five case-control studies analysing 4080 nodes from 622 patients were included. The summary estimates of pooled results for OSNA were sensitivity 0.90 [95% confidence interval (CI) 0.86-0.93], specificity 0.94 (95% CI 0.93-0.95) and diagnostic odds ratio 179.5 (CI 58.35-552.2, p < 0.0001). The SROC curve indicated a maximum joint sensitivity and specificity of 0.88 and area under the curve of 0.94, p < 0.0001. On average, 5.4% HE-negative nodes were upstaged by OSNA.

CONCLUSIONS

OSNA is as good as routine HE. It may avoid TAB and offer a more objective and standardised assay of LNM. However, for upstaging, its usefulness as an adjunct to HE or superiority to HE requires further assessment of the benefits, if any, of adjuvant therapy in patients upstaged by OSNA.

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.

A report of the frequency of colorectal carcinoma and involved lymph nodes in South-West Iran

Context:

The colorectal cancer (CRC) is the most common malignancy between men and women. CRC has considerable morbidity and mortality, with more than 1000,000 new cases and 500,000 annual deaths. Regional lymph nodes are most common sites of metastasis from colon cancer. Lymph node involvement is an essential factor in enabling the accurate evaluation of prognosis in CRC patients.

Aims:

In this study, we focused on the frequency of CRC and involved lymph nodes and adequacy of lymph node dissection in patients who referred to the Oncology and Radiotherapy Department of Golestan Hospital in Ahvaz City located in South-West Iran.

Setting and Design:

We conducted a retrospective study among patients receiving surgical treatment for CRC in the Department of Oncology and Radiotherapy of Golestan Hospital in Ahvaz City located in South-West Iran between 2001 and 2010.

Methods and Materials:

All patients who underwent resection for CRC by open or laparoscopic approaches were included in the study. Data were collected from patients’ medical records.

Statistical Analysis Used:

Statistical data were analyzed using SPSS 21.

Results:

A total of 585 cases with CRC aged from16 to 89 years with mean age of 53-year-old were studied. Average number of dissected nodes was 8 lymph nodes, and lymph nodes were not found in pathology specimen of 61 cases (10.4%). In 199 patients (34.01%), number of dissected lymph nodes was 12 or more and in 386 patients (65.98%), number of dissected lymph nodes was <12.

Conclusion:

This study revealed a large amount of patients that had been under over treatment with radiotherapy and the following inability. Lack of removal of sufficient tissue by the surgeon during surgery or an inadequate sample check by a pathologist might lead to an inability to correct staging of the disease as well as the inability to determine the treatment program of the patients and over treatment with radiotherapy and chemotherapy.

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.

Which Lymph Nodes Contain Metastases in Colon Cancer Patients? A Retrospective Histopathological Evaluation of 156 Patients

Background. We hypothesized that a reliable N0 status can be established by sampling and evaluating the largest lymph nodes in the resected large-bowel specimen of patients with colon cancer. Patients and methods. This was a retrospective analysis of all surgical colon cancer patients treated between 2008 and 2010, excluding those who had received neoadjuvant treatment. We analyzed the relationship between lymph node size and the presence of metastasis. Furthermore, we examined other prognostic factors for a histopathological N+ status. Results. Our patient group consisted of 156 patients with a median age of 73 years (range = 29-91 years). A total of 2044 lymph nodes (a median of 12 per patient, range = 2-47 nodes) were harvested, 1803 (88.2%) without and 241 (11.8%) with tumor spread. Using a unique ranking model, we found that in 58 out of the 59 N+ patients (98.3%, 95% confidence interval = 90.9% to 99.9%), the largest tumor-positive node was among the 5 largest lymph nodes in the specimen. The examination of ≥10 lymph nodes had no effect on the chance of finding a positive lymph node compared with examination of <10 nodes ( P = .46). Conclusion. In our study, the N-stage was determined by the 5 largest nodes in almost all specimens. The chance of finding a small tumor-positive node when the larger ones were clean was very small.

Adequate lymphadenectomy for colorectal cancer: a comparative analysis between open and laparoscopic surgery

Background

In the surgical treatment of colorectal cancer, a lymphadenectomy is considered adequate when at least 12 lymph nodes are removed.

Aim

To evaluate whether videolaparoscopic surgery positively affects the rates of adequate lymphadenectomy.

Methods

An observational study was conducted with patients undergoing either open or videolaparoscopic surgery for colorectal cancer between 2008 and 2013. The following variables were collected: gender, age, tumor site, histology, degree of differentiation, tumor stage, number of lymph nodes removed, and number of lymph nodes affected by the disease.

Results

A total of 62 patients with colorectal cancer were included; 42 (67.7%) received open surgery, and 20 (32.3%) laparoscopic surgery. Regarding lymphadenectomy, a mean of 13 lymph nodes (95% CI: 10-16) were removed in the group that received open surgery, while 19 lymph nodes were removed (95% CI: 14-24) in the laparoscopic surgery group (p=0.021). Adequate lymphadenectomy (removal of at least 12 lymph nodes) was achieved in 58.1% of the total cases, in 50.0% of the patients who received open surgery, and in 75% of those who received laparoscopic surgery. Non-elderly patients and those with an advanced disease stage were more likely to receive an adequate lymphadenectomy (p=0.004 and p=0.035, respectively).

Conclusion

Disease stage and patient age were the factors that had the greatest influence on achieving an adequate lymphadenectomy. The type of surgery did not affect the number of lymph nodes removed.

Clinico-pathological factors influencing lymph node yield in colorectal cancer and impact on survival: analysis of New Zealand Cancer Registry data

BACKGROUND

Lymph node yield (LNY) and lymph node ratio (LNR) are recognized as independent prognostic factors in colorectal cancer (CRC).

OBJECTIVES

To examine the relationship between LNY and other clinico-pathological variables, and the prognostic value of LNY and LNR on patient survival in CRC.

METHODS

The clinico-pathological and survival data for patients diagnosed from January 2000 to July 2012 were retrieved from the New Zealand Cancer Registry. Multiple linear regression was used to identify clinico-pathological factors influencing LNY, and Cox regression was used to determine the association between LNY and LNR and patient survival.

RESULTS

14,646 patients were included in the study (mean age 70.3 years, 50.1% male). Mean LNY was 17.4. Younger age, right-sided disease, higher T stage, female sex and no neoadjuvant radiotherapy (rectal cancer) were all associated with higher LNY (P ≤ 0.001). Overall survival in Stage I-III disease increased with higher LNY (for LNY ≥ 12, HR = 0.67, 95% CI 0.64-0.72; P < 0.001). Survival in Stage III-IV disease was inversely related to LNR (HR = 0.56, 95% CI 0.51-0.62; P < 0.001).

CONCLUSION

LNY is influenced by patient age, site of disease and T stage. LNY (Stage I-II) and LNR (Stage III-IV) have independent prognostic value in 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.

Total number of lymph nodes in oncologic resections, is there more to be found?

Pathologic staging of oncologic specimens includes the identification of the accurate lymph node status. Retrieving more lymph nodes leads to a more reliable N0 status in the TNM classification. The aim of this prospective study was to evaluate whether more lymph nodes can be retrieved from oncologic resection specimens when more time is invested in the search and if this contributes to a more reliable N-status in the individual patient. A total of 67 gastrointestinal oncologic specimens were reexamined for additional lymph nodes. The mean number of lymph nodes collected in the prospective group was compared against two retrospective groups, one before minima for lymph node counts were set (retrospective group 1) and one after (retrospective group 2). More lymph nodes were dissected per specimen in the prospective group (24.1 lymph nodes), compared to the retrospective group (14.3 lymph nodes, P = <0.001). During the study period, more patients were diagnosed as pN+ compared to the two retrospective groups (62.7 vs. 47.8 % respectively, P = 0.082). Significantly more lymph nodes can be found in oncologic specimens when more time is invested in the search. This will result in more accurate staging of the tumor.

Intra-arterial methylene blue injection into ex vivo colorectal cancer specimens improves lymph node staging accuracy: a randomized controlled trial

AIM

A randomized controlled trial was carried out to study the effect of a recently proposed technique of ex vivo intra-arterial methylene blue injection of the surgical specimen removed for colorectal cancer on lymph node harvest and staging.

METHOD

Between May 2012 and February 2013, 100 consecutive colorectal cancer resection specimens in a single institution were randomly assigned to intervention (methylene blue injection) and control (standard manual palpation technique) groups before formalin fixation. The specimen was then examined by the histopathologist for lymph nodes.

RESULTS

Both groups were similar for age, sex, site of tumour, operation and tumour stage. In the intervention group, a higher number of nodes was found [median 23 (5-92) vs. 15 (5-37), P < 0.001], with only one specimen not achieving the recommended minimum standard of 12 nodes [1/50 (2%) vs. 8/50 (16%), P = 0.014]. However, there was no upstaging effect in the intervention group [23/50 (46.0%) vs. 20/50 (40.0%); P = 0.686]. With a significantly lower number of nodes harvested in rectal cancer, the positive effect of the intervention was particularly observed in the patients who underwent preoperative neoadjuvant radiotherapy [median 30 nodes (12-57) vs. 11 (7-15); P = 0.011; proportion of cases with < 12 nodes 0/5 vs. 5/8 (62.5%), P = 0.024].

CONCLUSION

Ex vivo intra-arterial methylene blue injection increases lymph node yield and can help to reduce the number of cases with a lower-than-recommended number of nodes, particularly in patients with rectal cancer having neoadjuvant treatment. The technique is easy to perform, cheap and saves time.

Effects of newly developed chemotherapy regimens, comorbidities, chemotherapy-related toxicities on the changing patterns of the leading causes of death in elderly patients with colorectal cancer

BACKGROUND

Abundant evidences have shown that newly developed chemotherapy regimens improved 5-year survival rate of colorectal cancer (CRC) patients over the past two decades. However, their impact on risk of death from leading causes among elderly patients is still poorly understood.

PATIENTS AND METHODS

A retrospective cohort study of 69 718 elderly CRC patients with their first primary tumors in 1992-2009, identified from the 12 areas of Surveillance, Epidemiology, and End Results-Medicare linked database with their Medicare claims up to 2010. Multivariate Cox regression models were used to assess the effect of newly developed chemotherapy regimens, comorbidities, and chemotherapy related toxicities on cause-specific death and their temporal patterns among elderly CRC patients.

RESULTS

The leading causes of death among CRC patients were CRC, circulation disorders, and secondary cancers, which accounted for 51.4%, 25%, and 4.6% of all-cause death, respectively. Patients diagnosed in more recent diagnostic time periods were significantly less likely to die of CRC [period 2: 5-year hazard ratio = 0.94, 95% confidence interval (CI) 0.90-0.97; period 3: 0.86, 0.83-0.90], circulation disorders (period 2: 0.94, 0.88-1.00; period 3: 0.80, 0.75-0.87), and more likely to die of secondary cancer (period 3: 1.42, 1.20-1.68) compared with those diagnosed in period 1. Charlson comorbidities index and the selected pre-existing comorbidities were significantly associated with increased 5-year risk of death from all three leading causes. Both hematological and gastric toxicity were associated with reduced risk of death from CRC and circulation disorders. The association between diagnostic time period and risk reduction in death from CRC depended on chemotherapy treatment (P < 0.0001). Subgroup analyses showed that the chemotherapy-dependent significant risk reduction was seen in patients with stage II-III CRC, patients without comorbidities, and patients without toxicities (P < 0.0001 for all).

CONCLUSION

The newly developed chemotherapy regimens were associated with the decreased risk of mortality from CRC.

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.

Colorectal cancer lymph node staining by activated carbon nanoparticles suspension in vivo or methylene blue in vitro

AIM: To investigate whether activated carbon nanoparticles suspension (ACNS) or methylene blue (MB) can increase the detected number of lymph nodes in colorectal cancer.

METHODS: Sixty-seven of 72 colorectal cancer patients treated at our hospital fulfilled the inclusion criteria of the study which was conducted from December 2010 to February 2012. Seven patients refused to participate. Eventually, 60 patients were included, and randomly assigned to three groups (20 in each group): ACNS group (group A), MB group (group B) and non-stained conventional surgical group (group C). In group A, patients received subserosal injection of 1 mL ACNS in a 4-quadrant region around the mass. In group B, the main artery of specimen was identified and isolated after the specimen was removed, and 2 mL MB was slowly injected into the isolated, stretched and fixed vessel. In group C, no ACNS and MB were injected. All the mesentery lymph nodes were isolated and removed systematically by visually inspecting and palpating the adipose tissue.

RESULTS: No difference was observed among the three groups in age, gender, tumor location, tumor diameter, T-stage, degree of differentiation, postoperative complications and peritoneal drainage retention time. The total number of detected lymph nodes was 535, 476 and 223 in the three groups, respectively. The mean number of detected lymph nodes per patient was significantly higher in group A than in group C (26.8 ± 8.4 vs 12.2 ± 3.2, P < 0.001). Similarly, there were significantly more lymph nodes detected in group B than in group C (23.8 ± 6.9 vs 12.2 ± 3.2, P < 0.001). However, there was no significant difference between group A and group B. There were 50, 46 and 32 metastatic lymph nodes dissected in 13 patients of group A, 10 patients of group B and 11 patients of group C, without significant differences among the three groups. Eleven of the 60 patients had insufficient number of detected lymph nodes (< 12). Only one patient with T_4a rectal cancer had 10 lymph nodes detected in group B, the other 10 patients were all from group C. Based on the different diameter categories, the number of detected lymph nodes in groups A and B was significantly higher than in group C. However, there was no statistically significant difference between group A and group B. The metastatic lymph nodes were not significant different among the three groups. Similarly, tumor location, T stage and tumor differentiation did not affect the staining results. Body mass index was a minor influencing factor in the two different staining methods. The stained lymph nodes can easily be identified from the mesenteric adipose tissues, and the staining time for lymph nodes was not significantly different compared with unstained group. None of the patients in groups A and B had drug-related complications.

CONCLUSION: Both activated carbon nanoparticles suspension in vivo and methylene blue in vitro can be used as tracers to increase the detected number of lymph nodes in colorectal cancer.

Effects of being uninsured or underinsured and living in extremely poor neighborhoods on colon cancer care and survival in California: historical cohort analysis, 1996-2011

Background

We examined the mediating effects of health insurance on poverty-colon cancer care and survival relationships and the moderating effects of poverty on health insurance-colon cancer care and survival relationships among women and men in California.

Methods

We analyzed registry data for 3,291 women and 3,009 men diagnosed with colon cancer between 1996 and 2000 and followed until 2011 on lymph node investigation, stage at diagnosis, surgery, chemotherapy, wait times and survival. We obtained socioeconomic data for individual residences from the 2000 census to categorize the following neighborhoods: high poverty (30% or more poor), middle poverty (5-29% poor) and low poverty (less than 5% poor). Primary health insurers were Medicaid, Medicare, private or none.

Results

Evidence of mediation was observed for women, but not for men. For women, the apparent effect of poverty disappeared in the presence of payer, and the effects of all forms of health insurance seemed strengthened. All were advantaged on 6-year survival compared to the uninsured: Medicaid (RR = 1.83), Medicare (RR = 1.92) and private (RR = 1.83). Evidence of moderation was also only observed for women. The effects of all forms of health insurance were stronger for women in low poverty neighborhoods: Medicaid (RR = 2.90), Medicare (RR = 2.91) and private (RR = 2.60). For men, only main effects of poverty and payers were observed, the advantaging effect of private insurance being largest. Across colon cancer care processes, Medicare seemed most instrumental for women, private payers for men.

Conclusions

Health insurance substantially mediates the quality of colon cancer care and poverty seems to make the effects of being uninsured or underinsured even worse, especially among women in the United States. These findings are consistent with the theory that more facilitative social and economic capital is available in more affluent neighborhoods, where women with colon cancer may be better able to absorb the indirect and direct, but uncovered, costs of care.

Outcomes of laparoscopic colon cancer surgery in a population-based cohort in British Columbia: are they as good as the clinical trials?

BACKGROUND

Randomized controlled trials have shown equivalent outcomes for laparoscopic-assisted colectomy (LAC) and open colectomy (OC) when performed by well-trained surgeons experienced in both techniques. Our goal was to evaluate the outcomes of LAC at a population level.

METHODS

Using the prospectively collected Gastrointestinal Cancer Outcomes Unit database from the British Columbia Cancer Agency, short- and long-term outcomes in patients with colon cancer treated with LAC and OC were compared from 2003 to 2008 inclusive.

RESULTS

There was a statistically significant increase in the proportion of LAC from 2003 to 2008 (P < .001). LAC was more likely to be performed in the elective setting (P < .001) and for smaller tumors (P < .001). A similar proportion of patients had a minimum of 12 lymph nodes identified by pathology (58% vs 60%, P = not significant). Disease-free survival was similar for the 2 groups after adjusting for stage, emergency presentation, and adjuvant chemotherapy. There was no difference in overall survival.

CONCLUSIONS

The introduction of LAC for colon cancer in British Columbia outside of optimized clinical trial conditions appears to be effective and safe.

Analysis of sentinel lymph node biopsy results in colon cancer in regard of the anthropometric features of the population and body composition assessment formulas

Purpose

The aim of the study was to assess sentinel lymph node biopsy (SLNB) results in colon cancer (CC) regarding basic anthropometric features of the studied population and their derivatives calculated using mathematical formulas.

Methods

One hundred three SLNBs in CC have been analysed. Various indicators were calculated for every patient using mathematical formulas: BMI, Roher’s index, lean body weight, body fat percentage and body weight/ideal body weight for a given height ratios using the following formulas: Broca’s, Broca’s ideal weight, Broca–Brugsch, Lorenz’s, Potton’s, Devine’s, Robinson’s, Miller’s and Hamwi. The results were compared with accuracy, sensitivity and false negative results percentage by means of ROC curves and the test for structure indicators (for determined cut-off points).

Results

No statistically significant relationship between the results and patients' sex or age were found. ROC curve analysis did not reveal statistically significant relationships between the obtained results and indicators calculated on the basis of growth and weigh (all p > 0.05). The analyses of sensitivity and accuracy with determined cut-off point, in spite of differences amounting to 19 % (analysis of lean body weight/weight ratio), showed no statistical significance for any of the relationships (all p > 0.05).

Conclusions

No indicator with high diagnostic and prognostic value has been found. The problem of qualifying patients for SLNB in CC in regard of the anthropometric features of the population and body composition assessment formulas remains open and requires further analysis on larger populations.

Right Hemicolectomy is not Routinely Indicated in Pseudomyxoma Peritonei

Pseudomyxoma peritonei (PMP) is primarily the result of a ruptured mucinous appendix neoplasm (MAN). Often MAN is lumped with but biologically distinct from intestinal appendiceal adenocarcinoma. Nodal and systemic dissemination are rare with the peritoneal cavity being the primary site of recurrence. Routine performance of right hemicolectomy (RHC) for PMP/MAN has been extensively debated without consensus. Our objective was to ascertain whether RHC has a survival advantage over appendectomy. We hypothesize if RHC is mandatory, then increased tumor recurrence and mortality should be observed in appendectomy only. Retrospective chart review was carried out in patients with tumors that met the Ronnett classification for PMP/MAN. Demographics, tumor grade, extent, recurrence, and progression were recorded. We report the rate of nodal involvement/recurrence in patients treated with RHC versus appendectomy as well as the rate of systemic and peritoneal recurrence and survival. Multivariate logistic regression was done to identify factors that impact survival. Of 120 patients, 48 had appendectomy and 72 had RHC. Seven per cent of patients undergoing RHC had positive lymph nodes and no nodal failures (0%) in patients undergoing appendectomy. Appendectomy versus RHC recurrence rates (21 vs. 28%, P = 0.12) and death resulting from disease (8 vs. 22%, P = 0.27) were similar. Logistic regression revealed that the type of surgery had no impact on recurrence and mortality, only optimal resection score and performance status. There was no difference in tumor recurrence or survival based on treatment by appendectomy or RHC. Performance status and complete cytoreduction are the only factors associated with survival. Lymph node involvement is rare and selective RHC is safe in PMP/MAN.

Lymph node harvest in colon and rectal cancer: Current considerations

The prognostic significance of identifying lymph node (LN) metastases following surgical resection for colon and rectal cancer is well recognized and is reflected in accurate staging of the disease. An established body of evidence exists, demonstrating an association between a higher total LN count and improved survival, particularly for node negative colon cancer. In node positive disease, however, the lymph node ratios may represent a better prognostic indicator, although the impact of this on clinical treatment has yet to be universally established. By extension, strategies to increase surgical node harvest and/or laboratory methods to increase LN yield seem logical and might improve cancer staging. However, debate prevails as to whether or not these extrapolations are clinically relevant, particularly when very high LN counts are sought. Current guidelines recommend a minimum of 12 nodes harvested as the standard of care, yet the evidence for such is questionable as it is unclear whether an increasing the LN count results in improved survival. Findings from modern treatments, including down-staging in rectal cancer using pre-operative chemoradiotherapy, paradoxically suggest that lower LN count, or indeed complete absence of LNs, are associated with improved survival; implying that using a specific number of LNs harvested as a measure of surgical quality is not always appropriate. The pursuit of a sufficient LN harvest represents good clinical practice; however, recent evidence shows that the exhaustive searching for very high LN yields may be unnecessary and has little influence on modern approaches to treatment.

Fluorescence diagnosis of metastatic lymph nodes using 5-aminolevulinic acid (5-ALA) in a mouse model of colon cancer

BACKGROUND

Lymph node metastasis is one of the most critical prognostic factors in patients with colorectal cancer. Although regional lymph nodes should be surgically resected and pathologically examined, techniques for the intraoperative diagnosis of lymph node metastasis remain to be well established. Fluorescence diagnosis using 5-aminolevulinic acid (5-ALA) is a promising technique for evaluating various malignancies. After exogenous administration of 5-ALA, protoporphyrin IX (PPIX) accumulates in malignant cells and can be detected as red fluorescence. In this study, we investigated the usefulness of fluorescence diagnosis using 5-ALA for the detection of lymph node metastasis in a mouse model of colon cancer.

MATERIALS AND METHODS

An orthotopic colon cancer model was prepared by inoculating the cecal wall of nude mice with HCA7, a human colon adenocarcinoma cell line. After 3 wk, 40 mg/kg of 5-ALA was administered intraperitoneally (IP) or orally (PO). Fluorescence diagnosis with a D-Light System (Karl Storz) was then performed after 3 or 6 h.

RESULTS

In the IP group, PPIX fluorescence was detected in metastatic lymph nodes as well as in other malignant lesions, including primary tumors and abdominal implantations, while non-metastatic nodes were fluorescence-negative. In contrast, no obvious fluorescence was detected in cancerous tissues in the PO group.

CONCLUSIONS

PPIX fluorescence induced by intraperitoneal injection of 5-ALA allows metastatic lymph nodes to be accurately diagnosed in this mouse model. This technique may facilitate the intraoperative diagnosis of lymph node metastases from colon cancer in a clinical setting.

Extended resections for colorectal cancer - indications for supraradical lymphadenectomy

The laparoscopic approach to standard resections in colorectal cancer has proven that it may provide equal rates of R0 resections and adequate retrieval of lymph nodes as open procedures if performed by experienced hands. There might be difficulties in more advanced tumors or those with lymphatic spread beyond typical drainage areas and more extensive operations might be required. An atypical pattern of lymphatic spread often is associated with other adverse factors such as multifocality of primary cancers and adverse tumorbiological factors such as grade. Such patient subgroups may be defined beforehand and include particularly patients with underlying ulcerative colitis. Repetitively, extended lymph node dissection approaches have been advocated, however neither in randomised trails nor in meta-analysis has a more favourable outcome of patients undergoing such extended lymphatic dissections been demonstrated. Sticking to the rules of classical dissection of lymphatic drainage basins with removal of adequate lymph node numbers is one corner stone for successful treatment of colorectal cancer. The other one refers to a detailed description of the procedure performed in order to make the surgical procedure trackable.

One hundred consecutive cases of sentinel lymph node mapping in colon cancer-the results of prospective, single--centre feasibility study with implementation of immunohistochemical staining

PURPOSE

Although the importance of sentinel node biopsy (SNB) in colon cancer (CC) has not been clearly established, this method is proposed as potentially enabling more appropriate staging by means of immunohistochemistry (IHS). The aim of the study was to evaluate the SNB method used in CC treatment taking into consideration the results of the IHS examination.

MATERIALS AND METHODS

In the period from May 2005 to September 2010 in the 1st Department of Surgical Oncology and General Surgery, Wielkopolska Cancer Centre, 100 SNB in CC were performed. Sentinel nodes (SN) were identified intraoperatively with the use of Patent Blue dye. In the case of negative hematoxylin and eosin staining, the SN material was subjected to immunohistochemical examination. Finally, the histopathological findings of sentinel and non-sentinel lymph nodes were compared with the results of the immunohistochemical staining.

RESULTS

At least one SN was identified in 99 of 100 patients (99%). The SN was the only place of metastases in 12.1% (12/99) of the patients. The accuracy of SNB in determining the regional lymph node status was 93.9% (93/99). The sensitivity of the method was 83.3% (30/36). The false-negative rate amounted to 16.7% (6/36). Upstaging obtained by the implementation of the immunohistochemical method was 10% (7/70).

CONCLUSIONS

The application of the immunohistochemical staining enables upstaging of some patients, potentially benefiting from adjuvant chemotherapy. For full and definitive assessment of SNB in CC, further research is required especially in terms of additional factors determining a patient's eligibility for this procedure.

Surgical and pathological outcomes after right hemicolectomy: case-matched study comparing robotic and open surgery

OBJECTIVE

To compare the surgical and pathological outcomes of patients with right-sided colon cancers operated on by means of open and robotic surgery with extracorporeal anastomosis.

METHODS

Thirty-three consecutive patients who underwent robotic right hemicolectomy due to right-sided colon cancer were retrospectively well matched with 102 patients operated on by the open approach. Data were included in a prospectively maintained database.

RESULTS

Mean operative time was longer in the robotic group (P < 0.001), 191.7 min (134-250) versus 136.2 (45-240) min in the open group. Estimated intraoperative blood loss was less in the robotic group, which presented a mean of 6.1 ml versus 94.8 ml in the open group (P < 0.001). Despite the similar length of the surgical specimen and number of lymph nodes retrieved between both groups, 15 or more lymph nodes were found in the specimen in 90 out of 102 patients (88.2%) operated on by the open technique versus 33 out of 33 patients (100%) who underwent robotic hemicolectomy (P = 0.038). The median length of postoperative hospital stay was shorter in the robotic group, 5 versus 8 days (P < 0.001). No other statistically significant difference was observed in terms of pathological and postoperative results.

CONCLUSIONS

Robotic right hemicolectomy is an oncologically safe and effective procedure. The number of lymph nodes retrieved in the robotic group compared with the open group of our series was more homogeneous, and none of the patients operated on with this technique had a suboptimal lymphadenectomy. Further clinical trials are needed to confirm current evidence and determine whether this can influence the prognosis.

Variation in lymph node assessment after colon cancer resection: patient, surgeon, pathologist, or hospital?

BACKGROUND

Evaluation of ≥ 12 lymph nodes after colon cancer resection has been adopted as a hospital quality measure, but compliance varies considerably. We sought to quantify relative proportions of the variation in lymph node assessment after colon cancer resection occurring at the patient, surgeon, pathologist, and hospital levels.

METHODS

The 1998-2005 Surveillance, Epidemiology, and End Results-Medicare database was used to identify 27,101 patients aged 65 years and older with Medicare parts A and B coverage undergoing colon cancer resection. Multilevel logistic regression was used to model lymph node evaluation as a binary variable (≥ 12 versus <12) while explicitly accounting for clustering of outcomes.

RESULTS

Patients were treated by 4,180 distinct surgeons and 2,656 distinct pathologists at 1,113 distinct hospitals. The overall rate of 12-lymph node (12-LN) evaluation was 48%, with a median of 11 nodes examined per patient, and 33% demonstrated lymph node metastasis on pathological examination. Demographic and tumor-related characteristics such as age, gender, tumor grade, and location each demonstrated significant effects on rate of 12-LN assessment (all P < 0.05). The majority of the variation in 12-LN assessment was related to non-modifiable patient-specific factors (79%). After accounting for all explanatory variables in the full model, 8.2% of the residual provider-level variation was attributable to the surgeon, 19% to the pathologist, and 73% to the hospital.

CONCLUSION

Compliance with the 12-LN standard is poor. Variation between hospitals is larger than that between pathologists or surgeons. However, patient-to-patient variation is the largest determinant of 12-LN evaluation.

[A method for individualising the risk of a negative lymph node classification error in cancer of the colon]

INTRODUCTION

In cancer of the colon, the number of lymph nodes that should be analysed before a patient is classified as free of lymph node involvement has been widely discussed. A mathematical model is proposed which is based on the Bayes Theorem for calculating the probability of error (PE) similar to that normally used to evaluate a diagnostic test, but adapted to a quantitative variable, the lymph node count.

METHODS

The clinical histories of 480 patients routinely operated on in attempt to cure cancer of the colon were reviewed. Cases with any kind of metastasis were excluded. The proposed formula based on the Bayes Theorem was applied with the aim of calculating the PEs for the complete series and for different patient sub-groups (T2, T3, and T4 tumours).

RESULTS

For the probabilities of error of classifying a patient as N negative, which varied between 5% and 1% (near or practically 0), the minimum number of negative lymph nodes required for analysis fluctuated between 7 and 17, respectively, for the complete series. This minimum figure was also variable for the different sub-groups (T2, T3, and T4 tumours) studied. These numbers mainly depended on the case characteristics of a specific study group as regards the prevalence of the N+ cases that they dealt with, and of its historically demonstrated ability to collect and identify positive lymph nodes in those patients that had them.

CONCLUSION

From a mathematical point of view, the minimum number of lymph nodes that have to be analysed in cancer of the colon in order to classify a patient as N negative is not a constant. This depends on the error that is prepared to be assumed for that diagnosis, possibly depending on certain tumour traits, and also may be adapted to the cases of each study group.

Lymph node harvest in colon cancer: influence of microsatellite instability and proximal tumor location

BACKGROUND

At least 12 harvested lymph nodes are recommended for proper staging of colon cancer. The effect of tumor-related factors associated with lymph node harvest is not well understood as data are lacking. We investigated tumor-related factors in relation to the number of lymph nodes harvested.

METHODS

Patient and tumor characteristics were investigated in relation to harvested lymph nodes (LN >or= 12), number of metastatic nodes, LN ratio (LNR), and prognosis with univariate and multivariate analyses.

RESULTS

An LN harvest >or=12 nodes was achieved in 36% of the patients. Having <12 nodes harvested was not associated with increased risk for locoregional recurrence, distant metastasis, or decreased survival. Tumor size >5 cm, microsatellite instability (MSI), and proximal tumor location predicted a harvest of LN >or= 12. The highest rate (54%) of LN >or= 12 was found for MSI cancers [odds ratio (OR) 2.9, 95% confidence interval (CI) 1.3-6.5; P = 0.011]. Multivariate analysis identified a proximal location as an independent factor of LN >or= 12 (adjusted OR 3.5, 95% CI 1.5-8.2; P = 0.003), with MSI an independent factor in stage II to III colon cancer (adjusted OR 2.6, 95% CI 1.1-6.0; P = 0.026). To determine the best prognosticator, LNR was the only significant factor in the multivariate analysis (Cox proportional hazards) with a hazard ratio (HR) of 2.9 (95% CI 1.1-7.8; P = 0.038) for LNR 0.01-0.17 and an HR of 5.8 (95% CI 2.5-13.1; P < 0.001).

CONCLUSIONS

Proximal tumor location and microsatellite instability are associated with a higher number of lymph nodes harvested, pointing to possible underlying genetic and immunologic mechanisms. The LNR is an independent prognostic variable for colon cancer.

Mismatch repair protein expression is an independent prognostic factor in sporadic colorectal cancer

Abstract Background. Mismatch repair (MMR) status has been reported as a prognostic and predictive factor in sporadic colorectal cancer (CRC). The purpose of this study was to determine the prognostic and predictive value of MMR protein expression in the adjuvant setting. Patients and methods. The MMR status in the primary tumor was retrospectively assessed on paraffin-embedded formalin-fixed samples from 1 006 patients with sporadic CRC (488 stage II and 518 stage III) using immunohistochemical analysis (IHC) of MLH1 and MSH2 expression. The patients were included in adjuvant Nordic trials between 1991 and 1996 randomly assigned to surgery alone or surgery plus adjuvant 5-fluorouracil (5-FU)-based chemotherapy. Data was censored at 120 months after surgery. Results. One hundred fifty-seven patients (15.6%) showed a loss of MMR protein expression (139 MLH1 negative, 15 MSH2 negative and 3 MLH1 and MSH2 negative) and were classified as MMR protein negative. A normal MMR protein expression was found in 849 patients who were defined as MMR protein positive. MMR protein expression was a significant prognostic marker in the entire study group with a better overall survival (OS) among patients with MMR protein negative tumors compared to patients with MMR protein positive tumors (p=0.01). In a multivariate analysis the MMR protein expression was significantly associated with OS, (HR 0.70 [95% CI, 0.40 to 0.99]; p=0.01). The MMR status did not predict survival benefit from adjuvant 5-FU-based chemotherapy. Conclusion. This study reveals that IHC of MLH1 and MSH2 expression can yield important prognostic information but is not a predictive factor for adjuvant 5-FU-based chemotherapy in sporadic CRC.

Large variation between hospitals and pathology laboratories in lymph node evaluation in colon cancer and its impact on survival, a nationwide population-based study in the Netherlands

BACKGROUND

adequate lymph node (LN) evaluation is important for planning treatment in patients with colon cancer. Aims of this study were to identify factors associated with adequate nodal examination and to determine its relationship with stage distribution and survival.

PATIENTS AND METHODS

data from patients with colon carcinoma stages I-III who underwent surgical treatment and diagnosed in the period 2000-2006 were retrieved from the Netherlands Cancer Registry. Multilevel logistic analysis was carried out to examine the influence of relevant factors on the number of evaluated LNs. The relationship with survival was analysed using Cox regression analysis.

RESULTS

the number of examined LN was determined for 30 682 of 33 206 tumours. Median number of evaluated LN was 8, ranging from 4 to 15 between pathology laboratories. Females, younger patients, right-sided pN+ tumours with higher pT stage and patients diagnosed in an academic centre were less likely to have nine or less LN evaluated. Unexplained variation between hospitals and pathology laboratories remained, leading to differences in stage distribution. With increasing number of evaluated LN, the risk of death decreased.

CONCLUSION

there was large diversity in nodal examination among patients with colon cancer, leading to differences in stage distribution and being associated with survival.

Effects of socioeconomic status on colon cancer treatment accessibility and survival in Toronto, Ontario, and San Francisco, California, 1996-2006

OBJECTIVES

We examined the differential effects of socioeconomic status on colon cancer care and survival in Toronto, Ontario, Canada, and San Francisco, California.

METHODS

We analyzed registry data for colon cancer patients from Ontario (n = 930) and California (n = 1014), diagnosed between 1996 and 2000 and followed until 2006, on stage, surgery, adjuvant chemotherapy, and survival. We obtained socioeconomic data for individuals' residences from population censuses.

RESULTS

Income was directly associated with lymph node evaluation, chemotherapy, and survival in San Francisco but not in Toronto. High-income persons had better survival rates in San Francisco than in Toronto. After adjustment for stage, survival was better for low-income residents of Toronto than for those of San Francisco. Middle- to low-income patients were more likely to receive indicated chemotherapy in Toronto than in San Francisco.

CONCLUSIONS

Socioeconomic factors appear to mediate colon cancer care in urban areas of the United States but not in Canada. Improvements are needed in screening, diagnostic investigations, and treatment access among low-income Americans.

Guideline for optimization of colorectal cancer surgery and pathology

BACKGROUND AND OBJECTIVES

There is evidence of gaps in care for colorectal cancer surgery related to obtaining negative resection margins and lymph node assessment. Recommendations on the surgical and pathological management of curable colon and rectal cancer were developed.

METHODS

A systematic review on colorectal resection margins and lymph nodes was conducted. This evidence, combined with evidence from existing guidelines and expert consensus, was used to develop recommendations. The draft guideline was reviewed by an expert panel and was externally reviewed by practitioners in Ontario, Canada.

RESULTS

The search of the recent literature identified 107 articles pertinent to resection margins and lymph node assessment. The majority of the evidence was of poor quality. Of the 63 practitioners who reviewed the guideline, 97% agreed with the draft recommendations and 92% thought that the report should be approved as a practice guideline.

CONCLUSIONS

Achieving optimized performance concerning margin status and lymph node assessment requires the coordinated efforts of surgeons and pathologists, as well as other medical professionals. Focus should be on ensuring that colorectal cancers are resected with negative (R0) margins and that an adequate number of lymph nodes are assessed to allow for accurate decision making relating to prognosis and adjuvant therapy.