Qualitative and quantitative issues of lymph nodes as prognostic factor in colon cancer

Randomized controlled trials and alternative study designs in surgical oncology

Surgery is central to the cure of most solid cancers and an integral part of modern multimodal cancer management for early and advanced stage cancers. Decisions made by surgeons and multidisciplinary team members are based on best available knowledge for the defined clinical situation at hand. While surgery is both an art and a science, good decision-making requires data that are robust, valid, representative and, applicable to most if not all patients with a specific cancer. Such data largely comes from clinical observations and registries, and more preferably from trials conducted with the specific purpose of arriving at new answers. As part of the ESSO core curriculum development an increased focus has been put on the need to enhance research literacy among surgical candidates. As an expansion of the curriculum catalogue list and to enhance the educational value, we here present a set of principles and emerging concepts which applies to surgical oncologist for reading, understanding, planning and contributing to future surgeon-led cancer trials.

A Deep Neural Network-Based Decision Support Tool for the Detection of Lymph Node Metastases in Colorectal Cancer Specimens

The identification of lymph node metastases in colorectal cancer (CRC) specimens is crucial for the planning of postoperative treatment and can be a time-consuming task for pathologists. In this study, we developed a deep neural network (DNN) algorithm for the detection of metastatic CRC in digitized histologic sections of lymph nodes and evaluated its performance as a diagnostic support tool. First, the DNN algorithm was trained using pixel-level annotations of cancerous areas on 758 whole slide images (360 with cancerous areas). The algorithm's performance was evaluated on 74 whole slide images (43 with cancerous areas). Second, the algorithm was evaluated as a decision support tool on 288 whole slide images covering 1517 lymph node sections, randomized in 16 batches. Two senior pathologists (C.K. and C.O.) assessed each batch with and without the help of the algorithm in a 2 × 2 crossover design, with a washout period of 1 month in between. The time needed for the evaluation of each node section was recorded. The DNN algorithm achieved a median pixel-level accuracy of 0.952 on slides with cancerous areas and 0.996 on slides with benign samples. N+ disease (metastases, micrometastases, or tumor deposits) was present in 103 of the 1517 sections. The algorithm highlighted cancerous areas in 102 of these sections, with a sensitivity of 0.990. Assisted by the algorithm, the median time needed for evaluation was significantly shortened for both pathologists (median time for pathologist 1, 26 vs 14 seconds; P < .001; 95% CI, 11.0-12.0; median time for pathologist 2, 25 vs 23 seconds; P < .001; 95% CI, 2.0-4.0). Our DNN showed high accuracy for detecting metastatic CRC in digitized histologic sections of lymph nodes. This decision support tool has the potential to improve the diagnostic workflow by shortening the time needed for the evaluation of lymph nodes in CRC specimens without impairing diagnostic accuracy.

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 Impact of Lymph Node Ratio in Patients Undergoing Preoperative Chemoradiotherapy Followed by Curative Resection for Locally Advanced Rectal Cancer

BACKGROUND/AIM

To analyze the prognostic significance of nodal status in patients undergoing preoperative chemoradiotherapy (CRT) followed by curative resection for locally advanced rectal cancer.

PATIENTS AND METHODS

Between 2000 and 2015, 80 consecutive patients with rectal cancer underwent preoperative CRT followed by curative resection. The lymph node ratio (LNR) was defined as the number of positive lymph nodes (LNs) divided by the examined LNs, and log odds of positive lymph nodes (LODDS) was the log of the ratio between positive and negative LNs. The prognostic value of these indicators was evaluated in terms of overall (OS) and disease-free (DFS) survival.

RESULTS

The median follow-up period for patients overall was 59 months (range=11-190 months). The median number of examined LNs and number of positive LNs were 10 (range=1-29) and 2 (range=1-27), respectively, and the median LNR and LODDS values were 0.0 (range=0.0-0.96) and -1.0 (range=-1.7-1.3), respectively. The 5-year OS and DFS were 83% and 64%, respectively. In multivariate analysis, LNR was an independent prognostic factor in terms OS (p=0.041) but not for DFS (p=0.075). LODDS was not significantly associated with OS or DFS. In patients with clinical stage III rectal cancer, LNR was significantly associated with OS and DFS when the number of evaluated LNs was greater than 12 (p=0.038 for OS, p=0.006 for DFS).

CONCLUSION

Our study suggests that LNR is a more effective prognostic factor than LODDS in terms of predicting survival. LNR was a significant predictor for survival for patients with clinical stage III rectal cancer with >12 harvested LNs.

Anastomotic leak after surgery for colon cancer and effect on long-term survival

AIM

An anastomotic leak after surgery for colon cancer is a recognized complication but how it may adversely affect long-term survival is less clear because data are scarce. The aim of the study was to investigate the long-term impact of Grade C anastomotic leak in a large, population-based cohort.

METHOD

Data on patients undergoing resection for Stage I-III colon cancer between 2008 and 2012 were collected from the Swedish, Norwegian and Danish Colorectal Cancer Registries. Overall relative survival and conditional 5-year relative survival, under the condition of surviving 1 year, were calculated for all patients and stratified by stage of disease.

RESULTS

A total of 22 985 patients were analysed. Anastomotic leak occurred in 849 patients (3.7%). Five-year relative survival in patients with anastomotic leak was 64.7% compared with 87.0% for patients with no leak (P < 0.001). Five-year relative survival among the patients who survived the first year was 88.6% vs 81.3% (P = 0.003). Stratification by cancer stage showed that anastomotic leak was significantly associated with decreased relative survival in patients with Stage III disease (P = 0.001), but not in patients with Stage I or II (P = 0.950 and 0.247, respectively).

CONCLUSION

Anastomotic leak after surgery for Stage III colon cancer was associated with significantly decreased long-term relative survival.

Superior prognosis stratification for stage III colon cancer using log odds of positive lymph nodes (LODDS) compared to TNM stage classification: the Japanese study group for postoperative follow-up of colorectal cancer

OBJECTIVES

The aim of this study is to examine whether prognosis stratification in staging of Stage III colon cancer using T factor and log odds of positive lymph nodes (LODDS) categories is superior to that of the TNM staging system.

MATERIALS AND METHODS

The subjects were 5,919 patients with Stage III colon cancer who underwent curative resection at 24 Japanese institutions. Univariate analysis of LODDS categories and clinicopathologic factors was conducted using a Cox proportional hazards regression model for cancer-specific survival (CSS). Independent prognostic factors for CSS were extracted in multivariate analysis using factors with significance in univariate analysis. Effect sizes of risk factors for CSS were compared using the LogWorth statistic. Combinations of T factor and LODDS categories were used to create L-stage subgroups A, B and C. Stratification of prognosis with L-stage and TNM was compared using the Akaike information criterion (AIC).

RESULTS

In multivariate analysis, LODDS was identified as an independent prognostic factor, together with age, maximum tumor diameter, histopathological grade, L, V, pT, and pN. The LogWorth of LODDS was 17.149, which was the second highest after pT (31.562), and that of pN was 7.434. The 5-year CSS was 96.5%, 88.5%, and 66.6% in TNM stages IIIA, IIIB, and IIIC, respectively, and 96.0%, 87.6%, and 59.3% in L-stage A, B, and C, respectively (p < 0.0001). AICs for TNM and L-stage were 14,795.5 and 14,707.8, respectively.

CONCLUSIONS

Prognosis stratification of the stage classification for Stage III colon cancer was superior with L-stage compared to TNM stage classification.

Log odds of positive lymph nodes is prognostically equivalent to lymph node ratio in non-metastatic colon cancer

BACKGROUND

Globally, colorectal cancer (CRC) is the third and second leading cancer in men and women respectively with 600,000 deaths per year. Traditionally, clinicians have relied solely on nodal disease involvement, and measurements such as lymph node ratio (LNR; the ratio of metastatic/positive lymph nodes to total number of lymph nodes examined), when determining patient prognosis in CRC. The log odds of positive lymph nodes (LODDS) is a logistic transformation formula that uses pathologic lymph node data to stratify survival differences among patients within a single stage of disease. This formula allows clinicians to identify whether patients with clinically aggressive tumours fall into higher-risk groups regardless of nodal positivity and can potentially guide adjuvant treatment modalities. The aim of this study was to investigate whether LODDS in colon cancer provides better prognostication compared to LNR.

METHODS

A retrospective study of patients on the prospectively maintained Cabrini Monash University Department of Surgery colorectal neoplasia database, incorporating data from hospitals in Melbourne Australia, identified patients entered between January 2010 and March 2016. Association of LODDS and LNR with clinical variables were analysed. Disease-free (DFS) and overall (OS) survival were investigated with Cox regression and Kaplan-Meier survival analyses.

RESULTS

There were 862 treatment episodes identified in the database (402 male, 47%). The median patient age was 73 (range 22-100 years). There were 799 colonic cancers and 63 rectosigmoid cancers. The lymph node yield (LNY) was suboptimal (< 12) in 168 patients (19.5%) (p = 0.05). The 5-year OS for the different LNR groups were 86, 91 and 61% (p < 0.001) for LNR₀ (655 episodes), LNR₁ (128 episodes) and LNR₂ (78 episodes), respectively. For LODDS, they were 85, 91 and 61% (p < 0.001) in LODDS₀ (569 episodes), LODDS₁ (217 episodes) and LODDS₂ (75 episodes) groups (p < 0.001). Overall survival rates were comparable between the LNR and LODDS group and for LNY < 12 and stage III patients when each were sub-grouped by LODDS and LNR.

CONCLUSION

This study has shown for that the prognostic impact of LODDS is comparable to LNR for colon cancer patients. Accordingly, LNR is recommended for prognostication given its ease of calculation.

The Prognostic Relevance of Sentinel Lymph Node Metastases Assessed by PHGR1 mRNA Quantification in Stage I to III Colon Cancer

BACKGROUND: Regional lymph node (LN) metastasis is a strong and well-established prognostic factor in colon cancer, and recent data suggest a prognostic value of detecting micrometastases and isolated tumor cells in regional LNs. The aim of the study was to investigate the clinical relevance of detecting sentinel lymph node (SLN) metastases in colon cancer patients by measuring the novel metastasis marker PHGR1 mRNA. METHODS: Using quantitative reverse-transcription polymerase chain reaction, we measured PHGR1 mRNA levels in SLNs and primary tumors from 206 patients surgically treated for stage I to III colon cancer and 52 normal LNs from patients undergoing surgery for benign colon diseases. The prognostic impact of these findings was evaluated by Kaplan-Meier analysis and Cox proportional-hazards regression. RESULTS: Compared to normal LNs, elevated PHGR1 mRNA levels were detected in SLNs from 56 (89%) of the 63 patients with pN+ disease. Furthermore, 68 (48%) of the 143 node-negative (pN0) patients had elevated PHGR1 mRNA levels in SLNs, suggesting occult metastases. With a median follow-up of 7.2 years, a significantly shorter recurrence-free (P=.005) and disease-specific (P=.02) survival was observed in patients with elevated PHGR1 mRNA levels in SLNs. Multivariable modeling showed that the SLN PHGR1 mRNA level was an independent prognostic factor. However, when the survival analyses were restricted to pN0 patients, no significant prognostic information was found. CONCLUSION: Measuring PHGR1 mRNA in SLNs provided independent prognostic information on operable colon cancer patients but not in the pN0 subgroup.

Prognostic relevance of an epigenetic biomarker panel in sentinel lymph nodes from colon cancer patients

BACKGROUND

Patients with early colorectal cancer (stages I-II) generally have a good prognosis, but a subgroup of 15-20% experiences relapse and eventually die of disease. Occult metastases have been suggested as a marker for increased risk of recurrence in patients with node-negative disease. Using a previously identified, highly accurate epigenetic biomarker panel for early detection of colorectal tumors, we aimed at evaluating the prognostic value of occult metastases in sentinel lymph nodes of colon cancer patients.

RESULTS

The biomarker panel was analyzed by quantitative methylation-specific PCR in primary tumors and 783 sentinel lymph nodes from 201 patients. The panel status in sentinel lymph nodes showed a strong association with lymph node stage (P = 8.2E-17). Compared with routine lymph node diagnostics, the biomarker panel had a sensitivity of 79% (31/39). Interestingly, among 162 patients with negative lymph nodes from routine diagnostics, 13 (8%) were positive for the biomarker panel. Colon cancer patients with high sentinel lymph node methylation had an inferior prognosis (5-year overall survival P = 3.0E-4; time to recurrence P = 3.1E-4), although not significant. The same trend was observed in multivariate analyses (P = 1.4E-1 and P = 6.7E-2, respectively). Occult sentinel lymph node metastases were not detected in early stage (I-II) colon cancer patients who experienced relapse.

CONCLUSIONS

Colon cancer patients with high sentinel lymph node methylation of the analyzed epigenetic biomarker panel had an inferior prognosis, although not significant in multivariate analyses. Occult metastases in TNM stage II patients that experienced relapse were not detected.

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.

Survival Impact of Primary Tumor Lymph Node Status and Circulating Tumor Cells in Patients with Colorectal Liver Metastases

OBJECTIVE

The aim of this study was to analyse the survival impact of primary tumor nodal status (N0/N+) in patients with resectable colorectal liver metastases (CLM), and to determine the value of circulating and disseminated tumor cells (CTCs/DTCs) in this setting.

METHODS

In this prospective study of patients undergoing resection of CLM from 2008 to 2011, peripheral blood was analyzed for CTCs using the CellSearch System^®, and bone marrow was sampled for DTC analyses just prior to hepatic resection. The presence of one or more tumor cells was scored as CTC/DTC-positive. Following resection of the primary tumor, the lymph nodes (LNs) were examined by routine histopathological examination.

RESULTS

A total of 140 patients were included in this study; 38 patients (27.1%) were negative at the primary colorectal LN examination (N0). CTCs were detected in 12.1% of all patients; 5.3% of patients in the N0 group and 14.7% of patients in the LN-positive (N+) group (p = 0.156), with the LN-positive group (N+) consisting of both N1 and N2 patients. There was a significant difference in recurrence-free survival (RFS) when analysing the N0 group versus the N+ group (p = 0.007) and CTC-positive versus CTC-negative patients (p = 0.029). In multivariate analysis, CTC positivity was also significantly associated with impaired overall survival (OS) [p = 0.05], whereas DTC positivity was not associated with survival.

CONCLUSION

In this cohort of resectable CLM patients, 27% had primary N0 colorectal cancer. Assessment of CTC in addition to nodal status may contribute to improved classification of patients into high- and low-risk groups, which has the potential to guide and improve treatment strategies.

Assessment of clinically related outcomes and biomarker analysis for translational integration in colorectal cancer (ACROBATICC): study protocol for a population-based, consecutive cohort of surgically treated colorectal cancers and resected colorectal liver metastasis

Background

More accurate predictive and prognostic biomarkers for patients with colorectal cancer (CRC) primaries or colorectal liver metastasis (CLM) are needed. Outside clinical trials, the translational integration of emerging pathways and novel techniques should facilitate exploration of biomarkers for improved staging and prognosis.

Methods

An observational study exploring predictive and prognostic biomarkers in a population-based, consecutive cohort of surgically treated colorectal cancers and resected colorectal liver metastases. Long-term outcomes will be cancer-specific survival, recurrence-free survival and overall survival at 5 years from diagnosis. Beyond routine clinicopathological and anthropometric characteristics and laboratory and biochemistry results, the project allows for additional blood samples and fresh-frozen tumour and normal tissue for investigation of circulating tumour cells (CTCs) and novel biomarkers (e.g. immune cells, microRNAs etc.). Tumour specimens will be investigated by immunohistochemistry in full slides. Extracted DNA/RNA will be analysed for genomic markers using specific PCR techniques and next-generation sequencing (NGS) panels. Flow cytometry will be used to characterise biomarkers in blood. Collaboration is open and welcomed, with particular interest in mutual opportunities for validation studies.

Status and perspectives

The project is ongoing and recruiting at an expected rate of 120–150 patients per year, since January 2013. A project on circulating tumour cells (CTCs) has commenced, with analysis being prepared. Investigating molecular classes beyond the TNM staging is under way, including characteristics of microsatellite instability (MSI) and elevated microsatellite alterations in selected tetranucleotides (EMAST). Hot spot panels for known mutations in CRC are being investigated using NGS. Immune-cell characteristics are being performed by IHC and flow cytometry in tumour and peripheral blood samples. The project has ethical approval (REK Helse Vest, #2012/742), is financially supported with a Ph.D.-Grant (EMAST project; Folke Hermansen Cancer Fund) and a CTC-project (Norwegian Research Council; O. Nordgård). The ACROBATICC clinical and molecular biobank repository will serve as a long-term source for novel exploratory analysis and invite collaborators for mutual validation of promising biomarker results. The project aims to generate results that can help better discern prognostic groups in stage II/III cancers; explore prognostic and predictive biomarkers, and help detail the biology of colorectal liver metastasis for better patient selection and tailored treatment. The project is registered at http://www.ClinicalTrials.gov NCT01762813.

The prognostic yield of biomarkers harvested in chemotherapy-naive stage II colon cancer: can we separate the wheat from the chaff?

The TNM-system fails to accurately predict disease recurrence in a considerate number of patients. While node-negative (stage II) colon cancer is considered to have an overall good prognosis, the 5-year cancer-specific survival is reported at 81-83% in patients who did not have adjuvant chemotherapy. Thus, reliance on node-status alone has lead to under-treatment in a subgroup of stage II patients with an unfavorable prognosis. The search for new and better prognosticators in stage II colon cancer has suggested several proposed biomarkers of better prognostication and prediction. However, few such biomarkers have reached widespread clinical utility. For the clinician swimming in the sea of emerging biomarkers, it may be hard to recognize the true floating aid from the surrounding debris in the search for more precise decision-making. Proposed markers include microsatellite instability (MSI), KRAS mutations and BRAF mutations, but a number of gene panels and consensus molecular subtypes are proposed for clinical prediction and prognostication as well. While several studies suggest such biomarkers or panels to have a prognostic role in subgroups of patients, a number of studies are reported in heterogeneous groups with in part discordant findings, which again distorts the predictive and prognostic ability of each marker. Lack of homogeneous cohorts, underpowered studies in strict subgroups and challenges in analytical and clinical validity may hamper the progress towards widespread clinical utility. The harvest of prognostic biomarkers in colon cancer has yielded a huge number of candidates for which it is now time to separate the wheat from the chaff.

Long-Term Follow-Up and Survivorship After Completing Systematic Surveillance in Stage I-III Colorectal Cancer: Who Is Still at Risk?

PURPOSE

In patients with a high life expectancy at the time of surgery for colorectal cancer (CRC), the long-term outcome may be influenced by factors other than their cancer. We aimed to investigate the long-term outcome and cause of death beyond a 5-year surveillance programme.

METHODS

We evaluated the overall survival (OS) and cancer-specific survival (CSS) of a population-based cohort of stage I-III CRC patients <75 years old who completed a systematic surveillance programme.

RESULTS

In total, 161 patients <75 years old, 111 (69 %) of whom were node negative (pN0), were included. The median follow-up time was 12.1 years. The OS was 54 % at 15 years and differed significantly between the pN0 and pN+ patients (65 vs. 30 %; P < 0.001); CSS (72 %) also differed between the pN0 and pN+ patients (85 vs. 44 %; P < 0.001). For the 5-year survivors (n = 119), 14 (12 %) died of CRC during additional long-term follow-up (7 each for pN0 and pN+), and 6 patients (5 %; all pN0) died of other cancers. Patients aged <65 years exhibited better long-term survival (81 %), but most of the deaths were due to CRC (10/12 deaths). Only two of the 14 cancer-related deaths involved microsatellite instable (MSI) CRC. Females exhibited better OS and CSS beyond 5 years of surveillance.

CONCLUSIONS

The long-term survival beyond 5-year survivorship for stage I-III CRC is very good. Nonetheless, cancer-related deaths are encountered in one-third of patients and occur most frequently in patients who are <65 years old at disease onset-pointing to a still persistent risk several years after surgery.

Elevated microsatellite alterations at selected tetranucleotides in early-stage colorectal cancers with and without high-frequency microsatellite instability: same, same but different?

Microsatellite instability (MSI) is associated with better prognosis in colorectal cancer (CRC). Elevated microsatellite alterations at selected tetranucleotides (EMAST) is a less‐understood form of MSI. Here, we aim to investigate the role of EMAST in CRC±MSI related to clinical and tumor‐specific characteristics. A consecutive, population‐based series of stage I–III colorectal cancers were investigated for MSI and EMAST using PCR primers for 10 microsatellite markers. Of 151 patients included, 33 (21.8%) had MSI and 35 (23.2%) were EMAST+, with an overlap of 77% for positivity, (odds ratio [OR] 61; P < 0.001), and 95% for both markers being negative. EMAST was more prevalent in colon versus rectum (86% vs. 14%, P = 0.004). EMAST+ cancers were significantly more frequent in proximal colon (77 vs. 23%, P = 0.004), had advanced t‐stage (T3–4 vs. T1–2 in 94% vs. 6%, respectively; P = 0.008), were larger (≥5 cm vs. <5 cm in 63% and 37%, respectively; P = 0.022) and had poorly differentiated tumor grade (71 vs. 29%, P < 0.01). Furthermore, EMAST+ tumors had a higher median number of harvested lymph nodes than EMAST− (11 vs. 9 nodes; P = 0.03). No significant association was found between EMAST status and age, gender, presence of distant metastases or metastatic lymph nodes, and overall survival. A nonsignificant difference toward worse survival in node‐negative colon cancers needs confirmation in larger cohorts. EMAST+ cancers overlap and share features with MSI+ in CRC. Overall, survival was not influenced by the presence of EMAST, but may be of importance in subgroups such as node‐negative disease of the colon.

The Log Odds of Positive Lymph Nodes Stratifies and Predicts Survival of High-Risk Individuals Among Stage III Rectal Cancer Patients

INTRODUCTION

The log odds of positive lymph nodes (LODDS) is an empiric transform formula that incorporates positive and negative lymph node data into a single ratio for prognostic utility. We sought to determine the value of the log odds ratio as a prognostic indicator compared with established lymph node indices in advanced-stage rectal cancer patients who have undergone curative resection.

METHODS

Retrospective analysis of rectal cancer operations from 1995 to 2013 identified all stage III cancer patients who underwent curative resection. Patients were stratified into three groups according to calculated lymph node ratios (LNRs) and log odds ratios (LODDS). The relationship between LNR, LODDS, and 5-year overall survival (OS) were assessed.

RESULTS

OS for all patients was 81.4%. Both LNR and LODDS stratifications identified differences in 5-year OS. LODDS stratification was significantly associated with OS (p = .04). Additional significant clinicopathologic demographic variables included sex (p = .02), venous invasion (p = .02), tumor location (p < .001), and receipt of adjuvant chemotherapy (p = .047). LODDS separated survival among patients in the low LNR group (LNR1).

CONCLUSION

This study confirms that the measure of lymph node involvement transformed by the log odds ratio is a suitable predictor of 5-year overall survival in stage III rectal cancer. LODDS may be applied to stratify high-risk patients in the management of adjuvant therapy.

IMPLICATIONS FOR PRACTICE

Traditionally, clinicians have relied solely on the total number of positive lymph nodes affected when determining patient prognosis in rectal cancer. However, the current staging strategy does not account for "high-risk," biologically aggressive tumors that fall into the same risk categories as less clinically aggressive tumors. The log odds of positive lymph nodes is a logistic transform formula that uses pathologic lymph node data to stratify survival differences among patients within a single stage of disease. This formula allows clinicians to identify whether patients with clinically aggressive tumors fall into higher-risk groups, providing additional insight into how to better counsel patients and manage postoperative therapies.

Molecular subtypes in stage II-III colon cancer defined by genomic instability: early recurrence-risk associated with a high copy-number variation and loss of RUNX3 and CDKN2A

Objective

We sought to investigate various molecular subtypes defined by genomic instability that may be related to early death and recurrence in colon cancer.

Methods

We sought to investigate various molecular subtypes defined by instability at microsatellites (MSI), changes in methylation patterns (CpG island methylator phenotype, CIMP) or copy number variation (CNV) in 8 genes. Stage II-III colon cancers (n = 64) were investigated by methylation-specific multiplex ligated probe amplification (MS-MLPA). Correlation of CNV, CIMP and MSI, with mutations in KRAS and BRAFV600E were assessed for overlap in molecular subtypes and early recurrence risk by uni- and multivariate regression.

Results

The CIMP phenotype occurred in 34% (22/64) and MSI in 27% (16/60) of the tumors, with noted CIMP/MSI overlap. Among the molecular subtypes, a high CNV phenotype had an associated odds ratio (OR) for recurrence of 3.2 (95% CI 1.1-9.3; P = 0.026). Losses of CACNA1G (OR of 2.9, 95% CI 1.4-6.0; P = 0.001), IGF2 (OR of 4.3, 95% CI 1.1-15.8; P = 0.007), CDKN2A (p16) (OR of 2.0, 95% CI 1.1-3.6; P = 0.024), and RUNX3 (OR of 3.4, 95% CI 1.3-8.7; P = 0.002) were associated with early recurrence, while MSI, CIMP, KRAS or BRAF V600E mutations were not. The CNV was significantly higher in deceased patients (CNV in 6 of 8) compared to survivors (CNV in 3 of 8). Only stage and loss of RUNX3 and CDKN2A were significant in the multivariable risk-model for early recurrence.

Conclusions

A high copy number variation phenotype is a strong predictor of early recurrence and death, and may indicate a dose-dependent relationship between genetic instability and outcome. Loss of tumor suppressors RUNX3 and CDKN2A were related to recurrence-risk and warrants further investigation.

The prognostic impact of the log odds of positive lymph nodes in colon cancer

AIM

This study aimed to investigate the prognostic impact of the log odds of positive lymph nodes (LODDS) in colon cancer.

METHOD

Four hundred and forty patients with colon cancer were divided into three each groups according to their lymph node ratio (LNR) and LODDS. Survival analysis was performed.

RESULTS

The 5-year overall survival (OS) rate was 70.2%. In univariate analysis age, pT and pN stage, tumour grade, lymphatic, venous and perineural invasion, surgical margin clearance, LNR and LODDS were significantly associated with OS. In multivariate analysis age, surgical margins, perineural invasion and LODDS were found to be independent prognostic factors. In subgroup analysis of patients with an inadequate number of examined lymph nodes (NELN) (n = 76) and node-negative patients (n = 210), LODDS retained its prognostic value, whereas the impact of LNR was not statistically significant (P = 0.063). The overall survival rates of node-negative patients in the LODDS groups 0, 1 and 2 were 81%, 74.2% and 50%, respectively (P = 0.020). LNR and LODDS classifications were both significantly associated with survival in Stage III colon cancer, but only LODDS was an independent prognostic factor.

CONCLUSION

Conventional TNM staging for nodes (pN) and LNR status cannot reliably classify node-negative patients into homogeneous groups. LODDS provides more valuable information than LNR independently of the NELN.

Accuracy of TNM staging in colorectal cancer: a review of current culprits, the modern role of morphology and stepping-stones for improvements in the molecular era

Colorectal cancer (CRC) is the third most common cancer worldwide. Survival is largely stage-dependant, guided by the tumor-node-metastases (TNM) system for TNM assessment. Histopathological evaluation, including assessment of lymph node status, is important for correct TNM staging. However, recent updates in the TNM system have resulted in controversy. A continued debate on definitions resulting in potential up- and downstaging of patients, which may obscure survival data, has led the investigators to investigate other or alternative staging tools. Consequently, additional prognostic factors have been searched for using the regular light microscopy. Among the factors evaluated by histopathology include the evaluation of tumor budding and stromal environment, angiogenesis, as well as involvement of the immune system (including the 'Immunoscore'). We review the current role of histopathology, controversies in TNM-staging and suggested alternatives to better predict outcome for CRC patients in the era of genomic medicine.

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.