Lymph node evaluation in stage IIA colorectal cancer and its impact on patient prognosis: a population-based study

Rectal Cancer: Are 12 Lymph Nodes the Limit?

Lymph node dissection is a crucial element of oncologic rectal surgery. Many guidelines regard the removal of at least 12 lymph nodes as the quality criterion in rectal cancer. However, this recommendation remains controversial. This study examines the factors influencing the lymph node yield and the validity of the 12-lymph node limit. Patients with rectal cancer who underwent low anterior resection or abdominoperineal amputation between 2000 and 2010 were analyzed. In total, 20,966 patients from 381 hospitals were included. Less than 12 lymph nodes were found in 20.53% of men and 19.31% of women (p = 0.03). The number of lymph nodes yielded increased significantly from 2000, 2005 and 2010 within the quality assurance program for all procedures. The univariate analysis indicated a significant (p < 0.001) correlation between lymph node yield and gender, age, pre-therapeutic T-stage, risk factors and neoadjuvant therapy. The multivariate analyses found T3 stage, female sex, the presence of at least one risk factor and neoadjuvant therapy to have a significant influence on yield. The probability of finding a positive lymph node was proportional to the number of examined nodes with no plateau. There is a proportional relationship between the number of examined lymph nodes and the probability of finding an infiltrated node. Optimal surgical technique and pathological evaluation of the specimen cannot be replaced by a numeric cut-off value.

Tumor enhancement ratio on preoperative abdominal contrast-enhanced CT scan for predicting recurrence risk in stage II colon cancer

PURPOSE

The identification of high recurrence risk stage II colon cancer patients was critical to adjuvant chemotherapy decision. However, current definition of high-risk features remains inadequate. This study aimed to construct a model for predicting recurrence risk based on tumor enhancement ratio (TER) on abdominal contrast-enhanced CT scan.

METHOD

282 stage II colon cancer patients were included and randomly divided into training and validation sets in the ratio of 7:3. TER was calculated using maximum tumor attenuation value in contrast-enhanced CT scan divided by the minimum. Kaplan-Meier survival analyses were adopted to evaluate the prognostic value of variables. A model based on TER was built to predict recurrence risk through the LASSO Cox model. The recurrence risk score of patients was calculated based on this model.

RESULTS

The optimal cut-off value of TER was 1.83 derived from the time-dependent ROC (tdROC) curve. Patients with high-TER showed increasingly poorer disease-free survival (DFS) in both training (p < 0.001) and validation (p < 0.001) sets. A model was built based on TER demonstrated satisfactory performance to recurrence risk prediction (C-index: 0.784 in the training set and 0.725 in the validation set). Patients were regrouped into modified high-risk and non-high risk according to recurrence risk score (cut-off value: 1.75) and a significant DFS difference was observed (training set: p < 0.001; validation set: p < 0.001).

CONCLUSION

TER can serve as a high-risk feature of stage II colon cancer. And a model based on TER provided a new approach to assess recurrence risk of stage II disease.

Stage II colon cancer staging using the number of retrieved lymph nodes may be superior to current TNM staging for prognosis stratification: the Japanese study group for postoperative follow-up of colorectal cancer

PURPOSE

The purpose of the study was to compare staging of stage II colon cancer using the number of retrieved lymph nodes (RN) to current TNM staging for stratification of prognosis.

METHODS

The subjects were 6307 patients with stage II colon cancer who underwent curative resection at 24 Japanese institutions. The cutoff for the number of RN was established using Akaike information criterion (AIC) values for relapse-free survival (RFS) and overall survival (OS). Comparison of survival using TNM and T + RN (TRN) staging was performed using a Cox proportional hazards regression model.

RESULTS

AIC was lowest for 14 retrieved lymph nodes for RFS and OS. This number was used as the cutoff. In multivariate analysis, age (≥ 69), male gender, V1, CEA (> 5), pT (T4a, T4b), and RN-L were independent factors associated with RFS and OS. Six combinations of pT and RN categories were used to establish three subgroups: TRN stages IIA, IIB, and IIC. The 5-year RFS was 83.9%, 72.3%, and 71.8% in TNM stages IIA, IIB, and IIC; and 86.0%, 76.9%, and 60.3% in TRN stages IIA, IIB, and IIC. The 5-year OS was 90.0%, 81.3%, and 82.6% for the TNM stages; and 91.6%, 85.0%, and 71.9% for the TRN stages. The AIC for RFS was lower for TRN (22,318.2) than for TNM (22,390.6), and that for OS was also lower for TRN (16,285.3) than for TNM (16,355.1).

CONCLUSION

Stage II colon cancer staging using the number of retrieved lymph nodes may be superior to current TNM staging for prognosis stratification.

Neoadjuvant chemotherapy in locally advanced colon cancer: a systematic review

BACKGROUND

Preoperative or neoadjuvant chemotherapy (NAC) has emerged as a novel alternative to treat locally advanced colon cancer (LACC), as in other gastrointestinal malignancies. However, evidence of its efficacy and safety has not yet been gathered in the literature. The aim of the present study was to perform an extensive review of the scientific evidence for NAC in patients with LACC.

METHODS

PubMed, EMBASE, MEDLINE and Cochrane Library were searched for a systematic review of the literature from 2010 to 2019. Six eligible studies were included, with a total of 27,937 patients, 1232 of them (4.4%) treated with NAC. There were only one randomized controlled trial, three phase II non-randomized single arm studies and two retrospective studies.

RESULTS

The baseline computed tomography scan showed that most of patients had a T3 tumor. The completion rate of the planned neoadjuvant treatment ranged from 52.5 to 93.8%. Between 97.2 and 100% of patients had the scheduled surgery. The median tumor volume reduction after NAC ranged from 62.5 to 63.7%. The anastomotic leak rate in the NAC group ranged from 0 to 7%, with no cases of postoperative mortality. There was major pathological tumor regression in 4-34.7% of cases. Between 84 and 100% of NAC patients had R0-surgery. Survival after NAC seems to be encouraging although significant improvement has only been proven in T4b tumours.

CONCLUSIONS

According to our systematic review, the NAC may be a safe and effective emerging therapeutic alternative for treating LACC. This approach, which is still being tested, increases the reliance on accurate radiological staging.

Increasing negative lymph node count predicts favorable OS and DSS in breast cancer with different lymph node-positive subgroups

Adequate lymph node evaluation is recommended for optimal staging in patients with malignant neoplasms including breast cancer. However, the role of negative lymph nodes (LNs) remains unclear in breast cancer according to N substage (N1, N2, and N3). In this study, for the first time, we analyzed the prognostic significance of negative LNs in breast cancer patients. A critical relationship was observed between negative LN count and survival, independent of patient characteristics and other related molecular variables including estrogen receptor (PR) status, progesterone receptor (ER) status, human epidermal growth factor receptor 2 (HER2) status, depth of tumor invasion and degree of differentiation. This research is of great importance in providing more information about the prognosis of breast cancer by statistical analysis of negative lymph nodes and can serve as a useful supplement to the current pathological system.

Assessing the adequacy of lymph node yield for different tumor stages of colon cancer by nodal staging scores

Background

According to the current official guidelines, at least 12 lymph nodes (LNs) are qualified as an adequate sampling for colon cancer patients. However, patients evaluated with less nodes were still common in the United States, and the prevalence of positive nodal disease may be under-estimated because of the false-negative assessment. In this study, we present a statistical model that allows preoperative determination of the minimum number of lymph nodes needed to confirm a node-negative disease with certain confidence.

Methods

Adenocarcinoma colon cancer patients with stage T1-T3, diagnosed between 2004 and 2013, who did not receive neoadjuvant therapies and had at least one lymph node pathologically examined, were extracted from the Surveillance, Epidemiology and End Results (SEER) database. A beta binomial distribution was used to estimate the probability of an occult nodal disease is truly node-negative as a function of total number of LNs examined and T stage.

Results

A total of 125,306 patients met study criteria; and 47,788 of those were node-positive. The probability of falsely identifying a patient as node-negative decreased with an increasing number of nodes examined for each stage, and was estimated to be 72% for T1 and T2 patients with a single node examined and 57% for T3 patients with a single node examined. To confirm an occult nodal disease with 90% confidence, 3, 8, and 24 nodes need to be examined for patients from stage T1, T2, and T3, respectively.

Conclusions

The false-negative rate of diagnosed node negative, together with the minimum number of examined nodes for adequate staging, depend preoperatively on the clinical T stage. Predictive tools can recommend a threshold on the minimum number of examined nodes regarding to the favored level of confidence for each T stage.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3491-2) contains supplementary material, which is available to authorized users.

Mid-term oncologic outcome of a novel approach for locally advanced colon cancer with neoadjuvant chemotherapy and surgery

PURPOSE

Neoadjuvant chemotherapy is being actively tested as an emerging alternative for the treatment of locally advanced colon cancer (LACC) patients, resembling its use in other gastrointestinal tumors. This study assesses the mid-term oncologic outcome of LACC patients treated with oxaliplatin and fluoropyrimidines-based preoperative chemotherapy followed by surgery.

METHODS AND PATIENTS

Patients with radiologically resectable LACC treated with neoadjuvant therapy between 2009 and 2014 were retrospectively analyzed. Radiological, metabolic, and pathological tumor response was assessed. Both postoperative complications, relapse-free survival (RFS), and overall survival (OS) were studied.

RESULTS

Sixty-five LACC patients who received treatment were included. Planned treatment was completed by 93.8 % of patients. All patients underwent surgery without delay. The median time between the start of chemotherapy and surgery was 71 days (65-82). No progressive disease was observed during preoperative treatment. A statistically significant tumor volume reduction of 62.5 % was achieved by CT scan (39.8-79.8) (p < 0.001). It was also observed a median reduction of 40.5 % (24.2-63.7 %) (p < 0.005) of SUV_max (Standard Uptake Value) by PET-CT scan. Complete pathologic response was achieved in 4.6 % of patients. Postoperative complications were observed in 15.4 % of patients, with no cases of mortality. After a median follow-up of 40.1 months, (p ₂₅-p ₇₅: 27.3-57.8) 3-5 year actuarial RFS was 88.9-85.6 %, respectively. Five-year actuarial OS was 95.3 %.

CONCLUSION

Preoperative chemotherapy in LACC patients is safe and able to induce major tumor regression. Survival times are encouraging, and further research seems warranted.

Histologic prognostic markers in stage IIA colorectal cancer: a comparative study

OBJECTIVE

pTNM stage IIA colorectal cancer (CRC) is not currently submitted to any adjuvant treatment due to its good prognosis. Nevertheless, a percentage of cases unexpectedly recur. The aim of this study was to assess and compare the prognostic value and inter-observer agreement of a novel histological grading system based on the counting of poorly differentiated clusters (PDC) of cancer cells and that of conventional histological grade, lymphatic, venous and perineural invasion (LVI, VI, PNI), tumour budding (TB) and tumor border configuration in stage IIA CRC.

MATERIALS AND METHODS

the afore mentioned histological parameters were assessed in 82 stage IIA CRCs. Inter-observer agreement and correlation with tumour relapse were analyzed by using Fleiss-Cohen's weighted K statistics, Fisher exact test and Chi-squared test. The Mantel-Cox log-rank test was applied to assess the strength of association with disease-free interval (DFI).

RESULTS

inter-observer agreement was very good/good in the assessment of PDC presence and grade, while it was moderate at best in the evaluation of the other parameters. The presence of PDC, high PDC grade, LVI and TB were significantly associated with disease progression (p < 0.0001; p = 0.0012; p = 0.0308; p = 0.0002) and shorter DFI (p = 0.0001; p < 0.0001; p = 0.0129; p = 0.0008). PDC presence (p < 0.0001) and TB (p = 0.012) were independent prognostic factors in multivariate analysis.

CONCLUSIONS

our findings suggest that the assessment of PDC may be useful to stratify patients with stage IIA CRC for recurrence risk, and to identify high risk patients who could benefit from adjuvant chemotherapy.

Lymph node hypoplasia is associated with adverse outcomes in node-negative colon cancer using advanced lymph node dissection methods

PURPOSE

Lymph node size as a prognostic parameter has not been investigated well in the past. Recent data, however, have indicated that this parameter could be even more important than the lymph node count.

METHODS

Based on the results of earlier studies, we analyzed the lymph node size and number of node-negative colon cancer patients with regard to survival. Data from 115 node-negative cases of colon cancer were analyzed. Lymph nodes with diameters ≤5 mm were defined as small, and all other lymph nodes were classified as intermediate/large in size and labeled LN5. All of the cases were categorized according to the number of LN5s. The LN5 very low (LN5vl) group included cases with less than two LN5s. All of the other cases were assigned to the LN5 low/high (LN5l/h) group.

RESULTS

The overall survival analysis revealed significantly worse outcomes for the LN5vl group, with a mean survival of 34 months compared to the LN5l/h group, with a mean survival of 40 months (P = 0.022). After adjusting for the pT1/2 and pT3/4 stages, we still found a significant outcome difference (P = 0.012). Multivariate analysis identified LN5vl and T-stage as being independently correlated with the outcome. The vast majority of LN5vl cases (91 %) were located in the left colon. The location itself, however, was not prognostic (P = 0.478).

CONCLUSION

LN5 count, as a marker of immune response, could be shown as being prognostic in node-negative colon cancer. Patients with low LN5 counts showed poor outcomes. These patients could perhaps profit from adjuvant chemotherapy.

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

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

Optimal Time Intervals between Pre-Operative Radiotherapy or Chemoradiotherapy and Surgery in Rectal Cancer?

BACKGROUND

In rectal cancer therapy, radiotherapy or chemoradiotherapy (RT/CRT) is extensively used pre-operatively to (i) decrease local recurrence risks, (ii) allow radical surgery in non-resectable tumors, and (iii) increase the chances of sphincter-saving surgery or (iv) organ-preservation. There is a growing interest among clinicians and scientists to prolong the interval from the RT/CRT to surgery to achieve maximal tumor regression and to diminish complications during surgery.

METHODS

The pros and cons of delaying surgery depending upon the aim of the pre-operative RT/CRT are critically evaluated.

RESULTS

Depending upon the clinical situation, the need for a time interval prior to surgery to allow tumor regression varies. In the first and most common situation (i), no regression is needed and any delay beyond what is needed for the acute radiation reaction in surrounding tissues to wash out can potentially only be deleterious. After short-course RT (5Gyx5) with immediate surgery, the ideal time between the last radiation fraction is 2-5 days, since a slightly longer interval appears to increase surgical complications. A delay beyond 4 weeks appears safe; it results in tumor regression including pathologic complete responses, but is not yet fully evaluated concerning oncologic outcome. Surgical complications do not appear to be influenced by the CRT-surgery interval within reasonable limits (about 4-12 weeks), but this has not been sufficiently explored. Maximum tumor regression may not be seen in rectal adenocarcinomas until after several months; thus, a longer than usual delay may be of benefit in well responding tumors if limited or no surgery is planned, as in (iii) or (iv), otherwise not.

CONCLUSION

A longer time interval after CRT is undoubtedly of benefit in some clinical situations but may be counterproductive in most situations. After short-course RT, long-term results from the clinical trials are not yet available to routinely recommend an interval longer than 2-5 days, unless the tumor is non-resectable at diagnosis.