How many lymph nodes are necessary to stage early and advanced adenocarcinoma of the sigmoid colon and upper rectum?

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.

CUSUM charts in the quality control of colon cancer lymph node analysis: a population-registry study

Background

The most important determinant of survival in patients with colon cancer is the presence or absence of regional lymph node metastases. This factor is consistently associated with long-term and disease-specific survival. Cumulative summation of differences (CUSUM) charts can help to discriminate abnormalities that cannot be explained by the general variability of a process. We used CUSUM charts to analyse the quality of nodal analysis in colon cancer and to use a population-registry cancer database to estimate the optimal number of lymph nodes for adequate prognostic analysis.

Methods

This was a multicentre population-registry cancer study from January 2004 to December 2007. We used these data to produce the different CUSUM curves, focusing on the main variables. To calculate survival, we used the Kaplan–Meier method.

Results

In this study, we examined 548 patients. The CUSUM curves were calculated for overall mortality, specific mortality, and recurrence according to (1) the number of lymph nodes analysed and affected and (2) compared the ratio of the number of lymph nodes affected to the number analysed. Finally, the lymph node ratio was compared to the overall survival CUSUM curve.

Discussion

This CUSUM control chart analysis reinforces the unquestionable importance of analysing at least 12 lymph nodes in patients with colon cancer in order to accurately estimate their prognosis. However, our findings indicate that the analysis of at least 20 lymph nodes is a more appropriate cutoff point for accomplishing the demanding objective of diagnosing a high-quality prognosis in colon cancer patients.

Variability in the lymph node retrieval after resection of colon cancer: Influence of operative period and process

The purpose of this study was to evaluate variations in the number of retrieved lymph nodes (LNs) over time and to determine the factors that influence the retrieval of <12 LNs during colon cancer resection.Patients with colon cancer who were surgically treated between 1997 and 2013 were identified from our institutional tumor registry. Patient, tumor, and pathologic variables were evaluated. Factors that influenced the retrieval of <12 LNs were evaluated using multivariate logistic regression modeling, including time effects.In total, 6967 patients were identified. The median patient age was 61 years (interquartile range [IQR] = 45-79 years) and 58.4% of these patients were male. The median number of LNs retrieved was 21 (IQR = 14-29), which increased from 14 (IQR = 11-27) in 1997 to 26 (IQR = 19-34) in 2013. The proportion of patients with ≥12 retrieved LNs increased from 72% in 1997 to 98.8% in 2013 (P < 0.00001). This corresponded to the more recent emphasis on a multidisciplinary approach to adequate LN evaluation. The number of retrieved LNs was also found to be associated with age, sex, tumor location, T stage, and operative year. Tumor location and T stage influenced the number of retrieved LNs, irrespective of the operative year (P < 0.05). Factors including a tumor location in the sigmoid/left colon, old age, open resection, earlier operative year, and early T stage were more likely to be associated with <12 recovered LNs (P < 0.5; chi-squared test) (P < 0.001).The total number of retrieved LNs may be influenced by tumor location and T stage of a colon cancer, irrespective of the year of surgery. LN retrieval after colon cancer resection has increased in recent years due to a better awareness of its importance and the use of multidisciplinary approaches.

Factors affecting number of lymph nodes harvested and the impact of examining a minimum of 12 lymph nodes in stage I-III colorectal cancer patients: a retrospective single institution cohort study of 1167 consecutive patients

BACKGROUND

To identify factors affecting the harvest of lymph nodes (LNs) and to investigate the association between examining a minimum of 12 LNs and clinical outcomes in stage I-III colorectal cancer (CRC) patients.

METHODS

The clinicopathologic features and the number of examined LNs for 1167 stage I-III CRC patients were analyzed to identify factors affecting the number of LNs harvested and the correlations between clinical outcomes and high harvests (≧12 LNs) and low harvests (<12 LNs).

RESULTS

A multivariate analysis showed that age (P = 0.007), tumor size (P = 0.030), and higher T stage (P = 0.001) were independent factors affecting the examinations of LNs in colon cancer and that tumor size (P = 0.015) was the only independent factor in rectal cancer. Patients with low harvests had poorer overall survival with stage II and stage III CRC (stage II: P < 0.0001; III: P = 0.001) and poorer disease-free survival for stages I-III (stage I: P = 0.023; II: P < 0.0001; III: P = 0.001).

CONCLUSIONS

The factors influencing nodal harvest are multifactorial, and an adequate number of examined LNs (≧12) is associated with a survival benefit. Removal of at least 12 LNs will determine the lymph node status reliably.

The effect of neoadjuvant therapy on the size, number, and distribution of mesorectal lymph nodes

The current therapeutic approach to patients with locally advanced rectal cancer is neoadjuvant radiotherapy or chemoradiotherapy followed by total mesorectal excision. We aimed to investigate the number, size, and distribution of metastatic and nonmetastatic lymph nodes within the mesorectum; whether neoadjuvant therapy has any impact on the number and size of the lymph nodes; and the impact of metastatic lymph node localization on overall and disease-free survival. Specimens from 50 consecutive patients with stage II/III rectal cancer receiving either neoadjuvant radiotherapy or chemoradiotherapy were investigated. Lymph node dissection was carried out by careful visual inspection and palpation. The localization of the each lymph node within the mesorectum and the relation with the tumor site were noted. The size and the number of lymph nodes retrieved decreased significantly with neoadjuvant therapy. Majority of the metastatic and nonmetastatic lymph nodes were located at or proximally to the tumor level and posterior side of the mesorectum. No relation was observed between the overall and disease-free survival, and the localization of the metastatic lymph nodes. Presence of lymph node metastases proximal to the tumor level has no impact on survival compared with the presence of lymph node metastasis only in the peritumoral region of the mesorectum. Although neoadjuvant therapy decreases the size and the number of lymph nodes, reaching an ideal number of lymph nodes for accurate staging is still possible with careful naked eye examination and dissection of perirectal fat. As the majority of metastatic and nonmetastatic lymph nodes are located in peritumoral and proximal compartment, and posterior side of the mesorectum, these regions should be the major interest of dissection.

The diagnostic value of one-step nucleic acid amplification (OSNA) for sentinel lymph nodes in colon cancer patients

BACKGROUND

Lymph node status in colon cancer is critical for prognosis estimation and treatment allocation. The purpose of this study was to compare the performance of one-step nucleic acid amplification (OSNA) through detection of cytokeratin 19 mRNA levels with routine pathological examination (RP) and multilevel fine pathological examination (FP) in sentinel lymph nodes (SLN), detected using the ex vivo SLN mapping (SLNM) procedure, in presurgically defined nonmetastatic colon cancer patients.

METHODS

In this prospective study, 325 SLNs of 128 patients from the Jeroen Bosch Hospital in 's-Hertogenbosch and the Leiden University Medical Center were investigated by RP (H&E), FP (H&E and Keratin Pan immunohistochemical staining), and OSNA. The SLNs were harvested by the SLNM procedure, using Patent blue or Indocyanine green. SLNs were divided and separate parts were used for RP, FP, and the OSNA assay.

RESULTS

The diagnostic value of OSNA was 82.1 and 100 % for both FP and combined method (OSNA and FP) compared with RP. An upstaging rate of 20.2 % was obtained with the use of OSNA only and 36.4 % with the use of FP only. An upstaging rate of 46.5 % was obtained by combining the two methods together.

CONCLUSIONS

OSNA and FP appeared to be promising tools for the detection of lymph node micro- and macrometastases in SLNs after SLNM. The performances of OSNA and FP in this study were superior to RP. Because OSNA allows analysis of the whole lymph node, sampling bias can be avoided. OSNA therefore may improve tumor staging.

Total number of lymph nodes harvested is associated with better survival in stages II and III colorectal cancer

BACKGROUND

Lymph node status is important in staging colorectal cancer (CRC). Presence of metastatic nodes differentiates stage III from stage II. The role of adjuvant therapy is still unclear in stage II CRC. Inadequate node sampling may result in inaccurate staging.

METHOD

Records of 131 patients with stages II and III CRC who underwent curative resection, having five or more lymph nodes harvested from the specimen, were prospectively followed up and analyzed. The Kaplan-Meier method was used to analyze survival, based on groups of serially ascending values of lymph nodes harvested. Regression analysis was performed by Cox proportional hazards ratio model with right-censored CRC survival data at a 10 % significance level. The effect of nodal harvest on survival was adjusted for age, sex, preoperative carcinoembryonic antigen (CEA) level, neoadjuvant chemoradiation, pathological tumor stage, histological type, differentiation, margin positivity, angioinvasion, perineural invasion, and lymphovascular infiltration.

RESULTS

The total population showed improved survival with 14 or more nodes harvested (p= 0.005). For both rectal (n= 83; p= 0.03) and colon cancers (n= 46; p= 0.08), most significant survival benefits were seen with over 14 nodes harvested, irrespective of the stage. With multiple regression analysis, advanced age (p= 0.003), male sex (p= 0.017), lymphovascular infiltration (p= 0.015), and preoperative CEA levels (p= 0.096) were found to be other significant factors. The lymph node effect remained significant (HR = 0.19, p= 0.004) after adjusting for the above factors.

CONCLUSION

A lymph node harvest of 14 or more resulted in better survival outcome from CRC in this population. Staging of the disease could be accurate with increased nodal harvesting.

The impact of the lymph node ratio is greater than traditional lymph node status in stage III colorectal cancer patients

BACKGROUND

The prognostic value of nodal status in colorectal cancer (CRC) patients may be influenced by the total number of lymph nodes (LNs) harvested. This study evaluates the impact of LN ratio (LNR) on CRC patients' outcome.

METHODS

A total of 612 stage III CRC patients who underwent curative-intent surgery between 2004 and 2008 were enrolled. The measured end point was postoperative disease-free survival (DFS) and overall survival (OS).

RESULTS

The metastatic LN numbers were significantly higher in patients with more than 12 LN harvested (4.6 ± 5.81 vs. 2.7 ± 1.97, P < 0.001). The mean LNR was 22.9 ± 20 % (range = 2-100 %, median = 16.7 %). As the cutoff value of LNR was set above 17 %, the impact of the LNR on 5-year DFS became statistically significant. In univariate analysis, the 5-year DFS and OS for patients with high-LNR tumors was 54.4 and 57.3 %, respectively, significantly lower than those for patients with low-LNR tumors (72.8 and 76.4 %; P < 0.001). In multivariate analysis, the independent factors affecting the 5-year DFS and OS were tumor depth, carcinoembryonic antigen level, and LNR.

CONCLUSION

The LNR, set at the median value or 17 %, could be an independent prognostic factor for stage III CRC patients.

The impact of the lymph node ratio is greater than traditional lymph node status in stage III colorectal cancer patients

BACKGROUND

The prognostic value of nodal status in colorectal cancer (CRC) patients may be influenced by the total number of lymph nodes (LNs) harvested. This study evaluates the impact of LN ratio (LNR) on CRC patients' outcome.

METHODS

A total of 612 stage III CRC patients who underwent curative-intent surgery between 2004 and 2008 were enrolled. The measured end point was postoperative disease-free survival (DFS) and overall survival (OS).

RESULTS

The metastatic LN numbers were significantly higher in patients with more than 12 LN harvested (4.6 ± 5.81 vs. 2.7 ± 1.97, P < 0.001). The mean LNR was 22.9 ± 20 % (range = 2-100 %, median = 16.7 %). As the cutoff value of LNR was set above 17 %, the impact of the LNR on 5-year DFS became statistically significant. In univariate analysis, the 5-year DFS and OS for patients with high-LNR tumors was 54.4 and 57.3 %, respectively, significantly lower than those for patients with low-LNR tumors (72.8 and 76.4 %; P < 0.001). In multivariate analysis, the independent factors affecting the 5-year DFS and OS were tumor depth, carcinoembryonic antigen level, and LNR.

CONCLUSION

The LNR, set at the median value or 17 %, could be an independent prognostic factor for stage III CRC patients.

Early stage colon cancer

Evidence has now accumulated that colonoscopy and removal of polyps, especially during screening and surveillance programs, is effective in overall risk reduction for colon cancer. After resection of malignant pedunculated colon polyps or early stage colon cancers, long-term repeated surveillance programs can also lead to detection and removal of asymptomatic high risk advanced adenomas and new early stage metachronous cancers. Early stage colon cancer can be defined as disease that appears to have been completely resected with no subsequent evidence of involvement of adjacent organs, lymph nodes or distant sites. This differs from the clinical setting of an apparent “curative” resection later pathologically upstaged following detection of malignant cells extending into adjacent organs, peritoneum, lymph nodes or other distant sites, including liver. This highly selected early stage colon cancer group remains at high risk for subsequent colon polyps and metachronous colon cancer. Precise staging is important, not only for assessing the need for adjuvant chemotherapy, but also for patient selection for continued surveillance. With advanced stages of colon cancer and a more guarded outlook, repeated surveillance should be limited. In future, novel imaging technologies (e.g., confocal endomicroscopy), coupled with increased pathological recognition of high risk markers for lymph node involvement (e.g., “tumor budding”) should lead to improved staging and clinical care.

Methylene blue-assisted lymph node dissection technique is not associated with an increased detection of lymph node metastases in colorectal cancer

Lymph node staging is of paramount importance for prognosis estimation and therapy stratification in colorectal cancer. A high number of harvested lymph nodes is associated with an improved outcome. Methylene blue-assisted lymph node dissection effectively improves the lymph node harvest and ensures sufficient staging. Now, the effect on node positivity rate and stage-related outcome was investigated. The study cohort with advanced lymph node dissection consisted of 669 colorectal cancer cases of all stages, which were collected between 2007 and 2012. A historical collection of 663 cases investigated with conventional techniques between 2002 and 2004 served as control. Lymph node harvest was dramatically improved in the study group with mean lymph node numbers of 34 ± 17 vs 13 ± 5 (P<0.001) and sufficient staging rates of 98% vs 62% (P<0.001). However, neither the rate of nodal positive cases (37% vs 37%; P = 0.98) nor the rate of N2 cases differed between the two groups (14% vs 13%; P = 0.80). Furthermore, no differences were found concerning the outcome in both groups. The advanced lymph node dissection technique guarantees adequate histopathological lymph node staging in virtually all cases of colorectal cancer and is therefore extremely helpful. The hypothesis that it also provides a higher sensitivity in detecting metastases, however, could be not proved.

Evaluation of preoperative C-reactive protein aids in predicting poor survival in patients with curative colorectal cancer with poor lymph node assessment

Lymph node status is the most significant prognostic factor of colorectal cancer. However, there is a risk of disease understaging if the extent of lymph node assessment is sub-optimal. Preoperative C-reactive protein (CRP) is known to be a useful tool in predicting postoperative outcomes in patients with colorectal cancer. We retrospectively evaluated whether CRP adds to prognosis information in stage I-III colorectal cancer patients with poor lymph node assessment. In stages I-III, multivariate analysis revealed that CRP-positive status and advanced T-stage were factors that independently affected survival. In stage III, univariate analysis revealed that lymph node number retrieval and lymph node ratio were factors that affected survival. However, CRP positivity was the only independent factor for survival. CRP positivity did not predict poor prognosis in stage II or III patients with adequate lymph node retrieval. By contrast, the prognosis of CRP-positive patients was poorer than that of CRP-negative patients in stage II and III, with inadequate lymph node retrieval. CRP is an independent prognostic marker in patients with stage I-III, II or III colorectal cancer. The evaluation of CRP may provide useful information on prognosis in curative patients with an inadequate examination of lymph nodes.

Impact of age on the quality of lymphadenectomy for colorectal cancer

The aim of this study was to evaluate the impact of patient age on the number of lymph nodes dissected during surgery for colorectal cancer. Clinical and histopathological data of 231 consecutive patients who underwent elective surgery for colorectal cancer were reviewed retrospectively. Patients were divided into those aged ≤70 years and >70 years. Our findings suggest that patient's age influences the number of lymph nodes detected in surgical specimens; this number was lower in patients aged >70 years and decreased with further aging.

[Lymph node staging in gastrointestinal cancer. Combination of methylene blue-assisted lymph node dissection and ex vivo sentinel lymph node mapping]

The histopathological lymph node staging is of crucial importance for the prognosis estimation and therapy stratification in gastrointestinal cancer. However, the recommended numbers of lymph nodes that should be evaluated are often not reached in routine practice. Methylene blue assisted lymph node dissection was introduced as a new, simple and efficient technique to improve lymph node harvest in gastrointestinal cancer. This method is inexpensive, causes no delay and needs no toxic substances. All studies performed revealed a highly significantly improved lymph node harvest in comparison to the conventional technique. Moreover, this technique can be combined with a new ex vivo sentinel lymph node mapping that for the first time is based on histological sentinel lymph node detection. The success rate of this method is similar to conventional techniques and it enables an efficient application of extended investigation methods, such as immunohistochemistry or the polymerase chain reaction.

The clinical significance of lymph node size in colon cancer

To date, the clinical value of lymph node size in colon cancer has been investigated only in a few studies. Only in radiological diagnosis is lymph node size routinely recognized, and nodes ≥10 mm in diameter are considered pathologic. However, the few studies regarding this topic suggest that lymph node size is not a reliable indicator of metastatic disease. Moreover, we hypothesized that increasing lymph node size is associated with favorable outcome. By performing a morphometric study, we investigated the clinical significance of lymph node size in colon cancer in terms of metastatic disease and prognosis. A cohort of 237 cases with excellent lymph node harvest (mean lymph node count: 33±17) was used. The size distribution in node-positive and -negative cases was almost identical. In all, 151 out of the 305 metastases detected (49.5%) were found in lymph nodes with diameters ≤5 mm. Only 25% of lymph nodes >10 mm showed metastases. Minute lymph nodes ≤1 mm were involved only very rarely (2 of 81 cases). In 67% of the cases, the largest positive lymph node was <10 mm. The prognostic relevance of lymph node size was investigated in a subset of 115 stage I/II cases. The occurrence of ≥7 lymph nodes that were >5 mm in diameter was significantly associated with better overall survival. Our data show that lymph node size is not a suitable factor for preoperative lymph node staging. Minute lymph nodes have virtually no role in correct histopathological lymph node staging. Finally, large lymph nodes in stage I/II disease might indicate a favorable outcome.

Number of lymph nodes retrieved is an important determinant of survival of patients with stage II and stage III colorectal cancer

OBJECTIVE

The number of lymph nodes retrieved is recognized to be a prognostic factor of Stage II colorectal cancer. However, the prognostic significance of the number of lymph nodes retrieved in Stage III colorectal cancer remains controversial.

METHODS

The relationship between the number of lymph nodes retrieved and clinical and pathological factors, and significance of the number of lymph nodes retrieved for prognosis of Stage II and III colorectal cancer were investigated. A total of 16 865 patients with T3/T4 colorectal cancer who had R0 resection were analysed.

RESULTS

The arithmetic mean of the number of lymph nodes retrieved of all cases was 20.0. The number of lymph nodes retrieved were varied according to several clinical and pathological variables with significant difference, and the greater difference was observed in scope of nodal dissection. Survival of Stages II and III was significantly associated with the number of lymph nodes retrieved. Five-year overall survival of the patients with ≤ 9 of the number of lymph nodes retrieved and those with >27 differed by 6.4% for Stage II colon cancer, 8.8% for Stage III colon cancer, 12.5% for Stage II rectal cancer and 10.6% for Stage III rectal cancer. With one increase in the number of lymph nodes retrieved, the mortality risk was decreased by 2.1% for Stage II and by 0.8% for Stage III, respectively. The cut-off point of the number of lymph nodes retrieved was not obtained.

CONCLUSIONS

The number of lymph nodes retrieved was shown to be an important prognostic variable not only in Stage II but also in Stage III colorectal cancer, and it was most prominently determined by the scope of nodal dissection. A cut-off value for the number of lymph nodes retrieved was not found, and it is necessary to carry out appropriate nodal dissection and examine as many lymph nodes as possible.

Challenges in the management of stage II colon cancer

Approximately one third of patients diagnosed with early-stage colon cancer will present with lymph node involvement (stage III) and about one quarter with transmural bowel wall invasion but negative lymph nodes (stage II). Adjuvant chemotherapy targets micrometastatic disease to improve disease-free (DFS) and overall survival (OS). While beneficial for stage III patients, the role of adjuvant chemotherapy is unestablished in stage II disease. This likely relates to the improved outcome of these patients, and the difficulties in developing studies with sufficient power to document benefit in this patient population. However, recent investigation also suggests that molecular differences may exist between stage II and III cancers and within stage II patients. Validated pathologic prognostic markers are useful at identifying stage II patients at high risk for recurrence for whom the benefit from adjuvant chemotherapy may be greater. Such high-risk features include higher T stage (T4 v T3), suboptimal lymph node retrieval, presence of lymphovascular invasion, bowel obstruction, or bowel perforation, and poorly differentiated histology. However, for the majority of patients who do not carry any of these adverse features and are classified as "average-risk" stage II patients, the benefit of adjuvant chemotherapy remains unproven. Emerging understanding of the underlying biology of stage II colon cancer has identified molecular markers that may change this paradigm and improve our risk assessment and treatment choices for stage II disease. Assessment of microsatellite stability (MSI), which serves as a marker for DNA mismatch repair (MMR) system function, has emerged as a useful tool for risk stratification of patients with stage II colon cancer. Patients with high frequency of MSI have been shown to have increased OS and limited benefit from 5-fluorouracil (5-FU)-based chemotherapy. Additional research is necessary to clearly define the most appropriate way to use this marker and others in routine clinical practice.

Lymph node harvest in colorectal adenocarcinoma specimens: the impact of improved fixation and examination procedures

A review of 1050 pathology reports from colorectal adenocarcinoma specimens examined at the Department of Pathology, Sørlandet sykehus HF, Kristiansand, Norway during the period 1995-2006 revealed a poor performance of most doctors concerning lymph node harvest. A mean of 8.1 nodes per specimen (range 12.3-2.1) and a mean proportion of 22.3% of specimens with ≥12 lymph nodes (range 47.1-0%) were found. A small pilot study was undertaken in 2007 to evaluate the effect of prolonged formalin fixation and the use of a special lymph node fixative [glacial acetic acid, ethanol, water and formaldehyde (GEWF) solution] with regard to the number of retrieved nodes. This showed that one extra day formalin fixation and the use of GEWF solution considerably enhanced the detection of lymph nodes, particularly those of smaller size. Based on these findings, our routines concerning handling of colorectal cancer specimens were changed during 2007. After this time all specimens have been fixed in a mixture of GEWF solution and formalin for at least 48 h and the doctors have been encouraged to find as many lymph nodes as possible. In cases revealing <12 nodes after microscopical examination, the specimens have been re-examined and searched for additional nodes. A review of lymph node retrieval in 423 cases of colorectal cancer during the period 2008-2010 showed that the mean number of nodes per specimen had increased to 16.8 (range 29.0-13.3) and the proportion of specimens with ≥12 nodes to 78.0% (range 96.8-63.6%). Thus, these changes of routines which were easy to implement without significant extra costs have considerably improved lymph node harvest at our department. The use of a special lymph node fixative (e.g. GEWF solution) is highly recommended not only for detection of nodes in colorectal specimens, but also for retrieval of lymph nodes embedded in fat tissue generally.

Clinicopathologic factors associated with lymph node retrieval in resectable colon cancer: a Veterans' Affairs Central Cancer Registry (VACCR) database analysis

BACKGROUND

A long-term determinant of survival in resectable colon cancer is the involvement of regional lymph nodes. We evaluated the clinicopathologic factors associated with lymph node retrieval.

METHODS

We conducted a retrospective analysis of patients with resected stage I-III colon cancer in the Veteran's Affairs Central Cancer Registry between 1995 and 2008. One-way ANOVA compared the differences between various groups. Multivariate logistic regression analysis was performed to determine the factors associated with the harvest of 12 or more lymph nodes for pathologic examination.

RESULTS

There were 19,240 patients with resectable colon cancer included in our analysis. Mean number of lymph nodes retrieved increased with later year of diagnosis, higher overall stage, higher T descriptor, age <65 years, poorer differentiation and right-sided tumors (P < 0.01 for all covariates). These aforementioned factors are also associated with an increased probability of retrieving 12 or more lymph nodes after surgical resection (P < 0.01 for all covariates).

CONCLUSIONS

Later year of diagnosis, younger patients, right-sided tumors, poorer differentiation, higher T descriptor and overall stage are associated with increased number of lymph nodes retrieved. These may indicate the presence of an immunological response of tumor versus host affecting lymph node retrieval.

Lymph node harvest in colon cancer specimens depends on tumour factors, patients and doctors, but foremost on specimen handling

There are good indications that the number of lymph nodes found in the specimen after resections for colon cancer somehow has a bearing on prognosis. Many factors have been reported in the literature to influence lymph node retrieval. We wanted to assess these closer with special focus on the pathology handling process in our own practice. A range of international literature was reviewed to study what has been found to influence lymph node harvest. A questionnaire was sent to 13 renowned national and international institutions to explore their handling of the colon cancer specimens to obtain a histological diagnosis. A retrospective, hospital audit was undertaken to examine if the number of lymph nodes and staging after examinations of the specimens varied between individual pathologists. In the literature, tumour and patient characteristics, as well as the surgeon and the pathologist, are found to be influential, but it is difficult to ascertain which ones are truly essential. Fat solvents were found by several to increase the lymph node yield, although some also opposed this finding. Our questionnaire showed some variations in the routines of each Department. A junior pathologist was more likely to inspect the specimen first hand and not more than half employed specific lymph node detection strategies while three of 13 did not seek a minimum number of lymph nodes. Still every department had implemented a standard procedure for such examinations. The internal audit showed without doubt that the devotion of the pathologist secured significantly more lymph nodes from the specimen and this may also have detected more stage III cancers. Several tumour and individual patient characteristics, surgical approach and specimen handling may influence lymph node yield and theoretically, TNM staging. Our investigation specifically suggests that tissue handling by pathologists may be a prominent factor in lymph node harvest from colon cancer specimens.

Predictive factors affecting survival in stage II colorectal cancer: is lymph node harvesting relevant?

PURPOSE

Lymph node status is important in colorectal cancer. Multiple studies indicate a relationship between the number of nodes harvested and survival. This is important in patients with stage II disease where the role of adjuvant therapy is unclear. This study sought to analyze the impact of lymph node harvest on survival in patients with stage II colorectal cancer.

METHODS

The data of our hospital's colorectal tumor registry from 1997 to 2008 was reviewed. The records of 3534 patients of all stages were analyzed; of these patients, 913 patients with stage II colorectal cancer underwent curative resection. A univariate analysis estimated 5-year survival by Kaplan-Meier analysis based on various lymph node groupings. Patients were further analyzed with respect to sex, age, tumor grade, and tumor location. Multivariate linear regression analysis by the Cox proportional hazards model was performed using these variables to analyze survival relative to lymph node harvesting.

RESULTS

Of 913 stage II patients, the mean age was 71 years and 48% were male. Univariate analysis of the number of lymph nodes harvested found that ≥24 nodes removed was a significant and independent factor for improved survival in stage II (P = .009) and ≥36 nodes in stage III cancers (P = .008). Cox proportional hazards ratios found male sex (P < .03) and poorly differentiated tumors (P < .015) to be negative independent risk factors for survival. Tumor location in the sigmoid was associated with improved survival (P < .02).

CONCLUSION

Patients with stage II disease had an improved survival when ≥24 lymph nodes were harvested, and patients with stage III disease had improved survival with up to a 36 node harvest. Male sex and poorly differentiated tumors had a worse prognosis, and tumors located in the sigmoid were associated with improved survival in stage II cancers. An increased lymph node harvest is recommended to improve survival in these stages.

One step nucleic acid amplification (OSNA) - a new method for lymph node staging in colorectal carcinomas

Background

Accurate histopathological evaluation of resected lymph nodes (LN) is essential for the reliable staging of colorectal carcinomas (CRC). With conventional sectioning and staining techniques usually only parts of the LN are examined which might lead to incorrect tumor staging. A molecular method called OSNA (One Step Nucleic Acid Amplification) may be suitable to determine the metastatic status of the complete LN and therefore improve staging.

Methods

OSNA is based on a short homogenisation step and subsequent automated amplification of cytokeratin 19 (CK19) mRNA directly from the sample lysate, with result available in 30-40 minutes. In this study 184 frozen LN from 184 patients with CRC were investigated by both OSNA and histology (Haematoxylin & Eosin staining and CK19 immunohistochemistry), with half of the LN used for each method. Samples with discordant results were further analysed by RT-PCR for CK19 and carcinoembryonic antigen (CEA).

Results

The concordance rate between histology and OSNA was 95.7%. Three LN were histology+/OSNA- and 5 LN histology-/OSNA+. RT-PCR supported the OSNA result in 3 discordant cases, suggesting that metastases were exclusively located in either the tissue analysed by OSNA or the tissue used for histology. If these samples were excluded the concordance was 97.2%, the sensitivity 94.9%, and the specificity 97.9%. Three patients (3%) staged as UICC I or II by routine histopathology were upstaged as LN positive by OSNA. One of these patients developed distant metastases (DMS) during follow up.

Conclusion

OSNA is a new and reliable method for molecular staging of lymphatic metastases in CRC and enables the examination of whole LN. It can be applied as a rapid diagnostic tool to estimate tumour involvement in LN during the staging of CRC.

[Acetone compression. A fast, standardized method to investigate gastrointestinal lymph nodes]

Lymph node staging is the most important prognostic parameter in malignant gastrointestinal tumors. Manual dissection of adipose tissue is time-consuming and also depends on the experience of the individual examiner. By combining elution with acetone and mechanical compression using simple equipment it was possible to completely embed adipose tissue from 404 surgical specimens (colon 348, stomach 28, greater omentum 14, other location 14) without manual dissection. As a result of the procedure, the weight of the adipose tissue could be reduced by 90%-95%, making full histological examination possible. The colon specimens included an average of 43.8 lymph nodes (14-109) in 14 embedding cassettes (1-38) with a native fat weight of 234.7 g (42.8-820 g). The quality of histological staining, including immunohistochemical and molecular investigations, is of comparable quality to routine work-up. Elution with acetone enables the prompt, standardized and full histological work-up of adipose tissue without manual dissection. Moreover, additional costs are low. The number of lymph nodes required by medical associations was attained in all cases and often exceeded. This method was successfully used in other organs (greater omentum, breast).

Meeting the 12 lymph node (LN) benchmark in colon cancer

BACKGROUND

Examining >or=12 LN in colon cancer has been suggested as a quality metric. The purpose of this study was to determine whether the 12 LN benchmark is achieved at NCCN centers compared to a US population-based sample.

METHODS

Patients with stage I-III disease resected at NCCN centers were identified from a prospective database (n = 718) and were compared to 12,845 stage I-III patients diagnosed in a SEER region. Age, gender, location, stage, number of positive nodes were compared for NCCN and SEER data in regards to number of nodes evaluated. Multivariate logistic regression models were developed to identify factors associated with evaluating 12 LNs.

RESULTS

92% of NCCN and 58% of SEER patients had >or=12 LN evaluated. For patients treated at NCCN centers, factors associated with not meeting the 12 LN target were left-sided tumors, stage I disease and BMI >30.

CONCLUSIONS

>or=12 LN are almost always evaluated in NCCN patients. In contrast, this target is achieved in 58% of SEER patients. With longer follow-up of the NCCN cohort we will be able to link this quality metric to patterns of recurrence and survival and thereby better understand whether increasing the number of nodes evaluated is a priority for cancer control.

Fewer than 12 lymph nodes can be expected in a surgical specimen after high-dose chemoradiation therapy for rectal cancer

PURPOSE

Lymph node harvest of >or=12 has been adopted as a marker for adequacy of resection for colorectal cancer. We have noted a paucity of lymph nodes in rectal cancer specimens after neoadjuvant therapy, positing that the number of lymph nodes depends on the response to radiation and may not be an appropriate benchmark. Our purpose was to determine whether the number of lymph nodes harvested after neoadjuvant therapy is a useful quality indicator.

METHODS

A database of rectal cancer patients was queried to identify patients undergoing total mesorectal excision after neoadjuvant chemoradiation between January 1997 and August 2007. We compared patients with <12 lymph nodes to those with >or=12 lymph nodes relative to multiple patient and treatment factors.

RESULTS

One hundred seventy-six patients were identified (119 men; mean age, 60.4 y (range, 22-87)). Mean lymph node harvest was 10.1 (range, 1-38). Only 28% had >or=12 lymph nodes and 32% had <6 lymph nodes. There was no statistically significant difference in lymph node harvest relative to radiation dosage, age, tumor response, or type of surgery. There was no correlation between the number of lymph nodes harvested and the number of nodes positive for cancer.

CONCLUSIONS

With a standardized surgical technique and pathologic evaluation, the number of lymph nodes present after neoadjuvant chemoradiation and total mesorectal excision for rectal cancer varies greatly.

Lymph node retrieval in colorectal cancer resection specimens: national standards are achievable, and low numbers are associated with reduced survival

OBJECTIVES

The current guidelines identify the retrieval of at least 12 lymph nodes as crucial for accurate staging of colorectal cancer. We set out to review our figures from a single centre to see whether this standard has been met, and to examine for factors which may influence the number of lymph nodes retrieved. The influence of a low lymph node harvest on survival in patients with Dukes' A and B cancers was specifically investigated.

METHOD

Data were collected from all patients with colorectal cancer undergoing resectional surgery from our prospectively compiled database between June 1998 and May 2007. A multivariate analysis was performed to identify factors resulting in low lymph node yields in those patients undergoing formal resection. Survival analyses were performed in patients with Dukes' A and B cancers to assess whether a low lymph node yield negatively impacted on survival.

RESULTS

A total of 2449 patients underwent formal resection and were included in the analysis. The median lymph node retrieval was 13 nodes (range 0-136). On multivariate analysis, preoperative chemo-radiotherapy, operation type, specimen length and patient age all independently influenced lymph node retrieval. Patient gender, ethnicity, operative mode, operative team and consultant presence had no influence. Survival in patients with Dukes' A and B cancers was significantly reduced if <12 nodes were sampled.

CONCLUSIONS

As a unit, we are achieving the national standard for lymph node harvest. This standard was maintained whether the surgeon performing the surgery was a consultant or a trainee, and also when the surgery was performed in the emergency setting. These data support the concept of 12 nodes being required for accurate staging.

Impact of metastatic lymph node ratio in node-positive colorectal cancer

Colorectal cancer (CRC) is one of the most common malignant diseases in the world. Presently, the most widely used staging system for CRC is the tumor nodes metastasis classification system, which classifies patients into prognostic groups according to the depth of the primary tumor, presence of regional lymph node (LN) metastases, and evidence of distant metastatic spread. The number of LNs with confirmed metastasis is related to the severity of the disease, but this number depends on the number of LNs retrieved, which varies depending on patient age, tumor grade, surgical extent, and tumor site. Numerous studies and a recent structured review have demonstrated associated improvements in the survival of CRC patients with increasing numbers of LNs retrieved for examination. Hence, the impact of lymph node ratio (LNR), defined as the number of metastatic LNs divided by the number of LNs retrieved, has been investigated in various malignancies, including CRC. In this editorial, we review the literature demonstrating the clinicopathological significance of LNR in CRC patients. Some reports have indicated the advantage of considering the LNR compared to the number of LNs retrieved and/or LN status. When the LNR is taken into consideration for survival analysis, the number of LNs retrieved and/or the LN status is not always found to be a prognostic factor. The cut-off points for LNRs were proposed in numerous studies. However, optimal thresholds for LNRs have not yet received consensus. It is still unclear whether the LNR has more prognostic validity than N stage. For all these reasons, the potential advantages of LNRs in the staging system should be investigated in large prospective data sets.

Revised TN categorization for colon cancer based on national survival outcomes data

PURPOSE

The sixth edition of American Joint Committee on Cancer (AJCC) Cancer Staging Manual for colon cancer subdivided stage II into IIA (T3N0) and IIB (T4N0) and stage III into IIIA (T1-2N1M0), IIIB (T3-4N1M0), and IIIC (anyTN2M0). Subsequent analyses supported revised substaging of stage III because of improved survival for T1-2N2 versus T3-4N2 and T4N1 survival was more similar to T3-4N2 than to T3N1. The AJCC Hindgut Taskforce sought population-based validation that depth of invasion and nodal status interact to affect survival.

PATIENTS AND METHODS

Surveillance, Epidemiology, and End Results (SEER) population-based data from January 1992 to December 2004 for 109,953 colon cancer patients were compared with National Cancer Data Base (NCDB) data on 134,206 patients. T4N0 cancers were stratified by tumors that perforate visceral peritoneum (T4a) versus tumors that invade or are adherent to adjacent organs or structures (T4b). N1 and N2 were stratified by number of involved positive lymph nodes (N+): N1a/N1b (1 v 2-3), N2a/N2b (4 to 6 v > or = 7). Five-year observed and relative survival data were obtained for each TN category.

RESULTS

SEER rectal cancer analyses confirm that T1-2N2 cancers have better prognosis than T3-4N2,T4bN1 have similar prognosis to T4N2, T1-2N1 have similar prognosis to T2N0/T3N0, and T1-2N2ahave similar prognosis to T2N0/T3N0 (T1N2a) or T4aN0 (T2N2a). Prognosis for T4a lesions is betterthan T4b by N category. The number of positive nodes affects prognosis.

CONCLUSION

This SEER population-based colon cancer analysis is highly consistent with rectal cancer pooled analysis and SEER rectal cancer analyses, supporting the shift of T1-2N2 lesions from IIIC to IIIA/IIIB, shifting T4bN1 from IIIB to IIIC, subdividing T4/N1/N2, and revising substaging of stages II/III. Survival outcomes by TN category for colon and rectal cancer are strikingly similar.

An evaluation of the relationship between lymph node number and staging in pT3 colon cancer using population-based data

PURPOSE

The number of lymph nodes examined has been proposed as a quality benchmark for colon cancer surgery, although it is unknown whether this strategy reduces understaging.

METHODS

We identified 11,044 patients who underwent surgery for colon cancer with pT3 wall penetration between 1988 and 2003 from the Surveillance, Epidemiology and End Results cancer registry. We determined the proportion of patients who were node positive for each node count. We used logistic regression to predict the odds of being node positive by node count after adjusting for confounders. We used joinpoint analysis to determine whether there was a consistent relationship between node count and the odds of being node positive.

RESULTS

The proportion of patients found to be node positive increased with node count at low counts (<or=5-6 nodes), but patients with 7 nodes identified were as likely to be node positive as patients with 30 or more nodes (odds ratio = 0.97; 95% CI = 0.90-1.05). Joinpoint analysis demonstrated a dramatic increase in odds of node positivity with increasing node count to 5 nodes (slope = 0.2; P < .0001). Between 6 and 13 nodes there was a marginal increase in odds of positive nodes (slope = 0.03; P = .006), but when more nodes were evaluated, odds of node positivity actually declined (slope = -0.01; P = .04).

CONCLUSIONS

Staging of pT3 colon cancer improves with increasing node count, but only when the node count is low (<5-7 nodes). At higher counts, an increased node count has marginal effects on staging.

Nodal stage of stage III colon cancer: the impact of metastatic lymph node ratio

PURPOSE

We assessed which classification of lymph node metastasis better predicted outcomes in patients with colorectal carcinoma.

METHODS

We identified 318 patients (176 men) with stage III colon cancer who underwent curative resection. The number of LNs dissected, LNR, and disease-free survival time, were analyzed. Lymph node disease was stratified by the American Joint Committee on Cancer staging and LNR, with the latter categorized into groups with LNR <0.059 (n = 67), 0.059-0.23 (n = 171), and >0.23 (n = 80). Median follow-up time was 37 (range, 1-122) months.

RESULTS

LNR significantly increased with the number of metastatic LNs (P < 0.0001). Three-year disease-free survival (DFS) rates differed significantly in the three LNR groups. Within each TNM stage, 3-year DFS rates differed according to LNR, but, within each LNR subgroup, 3-year DFS did not differ according to TNM stage. When both TNM stage and LNR subgroup were considered, 3-year DFS was stratified into four groups, which differed significantly (P < 0.0001). Considering number of retrieved lymph nodes, this stratification was not found when <12 lymph nodes retrieved.

CONCLUSIONS

Re-stratified lymph node staging, reflecting both LNR and TNM stage, can predict survival in patients with LN-positive colon cancer, especially when more than 12 lymph nodes harvested.

Number of lymph nodes examined and associated clinicopathologic factors in colorectal carcinoma

CONTEXT

Nodal metastasis is one of the most important prognostic factors in colorectal carcinoma. The number of lymph nodes recovered and examined in resection specimens has been recently shown to be critical for proper staging and is associated with survival.

OBJECTIVE

To assess the clinicopathologic factors that may be associated with the number of lymph nodes harvested from surgical resections.

DESIGN

Clinicopathologic factors of 434 consecutive cases of colorectal cancers treated by surgical resection from a single tertiary medical center were retrospectively reviewed and correlated with number of lymph nodes recovered.

RESULTS

Our data show that patient age, tumor location, and length of resected bowel segment were associated with number of lymph nodes harvested in surgical resections of colorectal cancer. The average number of lymph nodes was 18.2 and 17.8 for patients younger than 50 years and aged 50 through 60 years, respectively, whereas it was 14.4, 15.1, and 14.9 for patients aged 61 through 70 years, 71 through 80 years, and 80 years and older, respectively. More lymph nodes were present in resection specimens of cecum/ascending colon and descending colon cancers than in those of transverse colon, sigmoid colon, and rectal cancers. There was a linear increase in number of lymph nodes examined with increasing length of bowel resection specimens. In multivariate regression analysis, the factors that remained independent predictors of removal of 12 or more lymph nodes from resection specimens were tumor location and length of resected bowel segment.

CONCLUSIONS

The number of lymph nodes obtained in resection specimens for colorectal cancer was significantly associated with the length of resected segments of bowel, patient age, and location of the tumor.

Is lymph node count an ideal quality indicator for cancer care?

Although lymph node count has substantial appeal as a quality indicator because of the ease of measurement, the presence of variation in the population, the association with survival for many cancers, and the previous success of quality intervention programs, improvements in patient outcome by increasing lymph node counts have not yet been demonstrated. This article discusses potential pitfalls in the use of lymph node count as a quality indicator.

Are 12 nodes needed to accurately stage T1 and T2 colon cancers?

Evaluation of 12 lymph nodes has been mandated to prevent colon cancer understaging. Given that the probability of node metastases is largely associated with T-stage, are <12 nodes substandard for T1 and T2 lesions? We evaluated if survival for T1 and T2 tumors varies by nodes examined. In SEER, 61,237 patients undergoing colon cancer resection were identified. For each T-stage, 5-year survival rates were compared for node-negative cancers by using stepwise node cut-point comparisons (4 nodes, <4, etc.). Survival impact was determined by log-rank test and hazard regression. For T1 tumors, 4 nodes had 24% lower hazard of death compared to <4. For T2 tumors, 10 nodes had the biggest survival impact, 15% lower hazard of death. In conclusion, the number of nodes to stage T1 and T2 lesions may be <12.

Lymph node evaluation in early-stage colon cancer

Accurate nodal staging is of crucial importance in patients with nonmetastatic colon cancer, because it affects patient prognosis and delivery of adjuvant chemotherapy. In this article, we review the role of 2 controversial aspects of lymph node staging in colon cancer: the number of lymph nodes evaluated and sentinel lymph node (SLN) biopsy. Although it is clear that the number of lymph nodes assessed correlates with patient survival, the underlying mechanisms are far more uncertain, and thus, more research is warranted to determine whether interventions to increase nodal assessment will lead to improved patient outcomes. Sentinel lymph node biopsy does not appear to have the same advantages in the treatment of patients with colon cancer as in the treatment of patients with breast cancer or melanoma. Also, it might not improve colon cancer staging above standard pathology, and should be restricted to use in research settings.

Identifying Stage III Colorectal Cancer Patients: The Influence of the Patient, Surgeon, and Pathologist

Purpose

Nodal yields from resected colorectal cancers vary greatly. This study sought to determine what patient, tumor, and management factors influence the number of nodes retrieved and to determine if the extent of lymphadenectomy affects stage allocation and influences survival.

Patients and Methods

Retrospective study of the nodal yields of 7,062 surgically resected colorectal cancer patients for whom colorectal pathology minimum data sets had been collected. The percentage of patients diagnosed as stage III was compared across nodal yield categories. A threshold for an adequate lymphadenectomy was defined as retrieval of 12 nodes. Binary logistic regression was used to determine factors associated with obtaining an adequate lymphadenectomy.

Results

Median nodal yields increased over the study period from 7 (interquartile range [IQR], 4 to 11) in 1995 to 13 (IQR 8 to 19) in 2003. There was no difference in yield by cancer site or sex, but yields were lower in older patients. Yields increased with increasing local invasion and stage of tumor. The percentage of patients diagnosed as stage III increased as yields increased. Five-year survival was lower in those patients who did not have an adequate lymphadenectomy. Adequate lymphadenectomy was significantly more likely in patients with advanced tumors and when the surgery and pathology was undertaken by a specialist. Older patients were significantly less likely to receive an adequate lymphadenectomy.

Conclusion

Variations in nodal yield are due to idiosyncratic patient and tumor characteristics and differences in the quality of surgery and pathology undertaken. Adequate lymphadenectomy is essential to ensure correct stage allocation and optimal survival.

Potential pathological understaging of pT3 rectal cancer with less than 26 lymph nodes recovered: a prospective study based on a resampling of 50 rectal specimens

The aim of the paper was to establish if the 12 lymph nodes recommended by tumor-node-metastasis (TNM) system are sufficient for a correct staging of rectal cancer. For this purpose, we first compared the mean number of lymph nodes recovered in the same surgical specimen at the routine sampling and at a resampling performed by a second expert gastrointestinal pathologist. The study was performed on 50 cases of pT2N0 and pT3N0 rectal cancers, with a minimum number of 12 lymph nodes recovered at first sampling, histologically negative for metastases. Resampling retrieved a variable number (1 to 24) of nodes missed at first sampling. The final pN0 status was maintained in pT2 patients, whereas in 18.7% of pT3 patients, metastatic lymph nodes were detected if the mean number of lymph nodes increased from 17.8 to 26.8 after the second sampling. Interestingly, all pN1 patients had only a single metastatic lymph node measuring less than 4.9 mm. As we have shown that most (five out of six) missed metastatic lymph nodes were detected in specimens in which a maximum number of 19 lymph nodes had been originally recovered, we strongly suggest a resampling of pT3N0 rectal specimens if less than 20 lymph nodes have been recovered.

Pathology practice patterns affect lymph node evaluation and outcome of colon cancer: a population-based study

BACKGROUND

A large variation in the number of nodes examined between patients, hospitals, and regions has been reported for patients with colon cancer. We studied determinants of this variation and its relation to survival in the south of The Netherlands.

PATIENTS AND METHODS

All patients who underwent resection for stage I-III colon carcinoma diagnosed from 1999 to 2002 in the Eindhoven Cancer Registry area were included (n = 2168). Determinants of lymph node evaluation and their relationship to survival were assessed, including variation between the six departments of pathology.

RESULTS

A median number of six lymph nodes per specimen had been examined. The median number for each department of pathology ranged from three to eight (P < 0.0001). After correction for relevant factors, this variation remained, resulting in differences in the proportion of N+ tumours between departments from 29% to 41% (P < 0.0001). The number of nodes examined was positively associated with survival. Survival for node-negative patients differed between the departments of pathology (up to hazard ratio 1.5; P = 0.02).

CONCLUSION

There was a large variation in lymph node evaluation between the departments of pathology, leading to differences in stage distribution and survival. Intervention strategies should be directed at nodal assessment.

Re-fixation in a lymph node revealing solution is a powerful method for identifying lymph nodes in colorectal resection specimens

AIM

To verify an impact of a lymph node revealing solution (LRS) on the number of lymph nodes (LN) revealed in colorectal resection specimens.

MATERIAL AND METHOD

Fifty-nine cases of rectosigmoid carcinomas divided into two subgroups-stage pT2&3 (20 cases) and ypT2&3 (with pre-operative radiotherapy-39 cases)-were formalin fixed for 42-72 h, serially sectioned and re-fixed in LRS containing ethanol, diethyl ether, glacial acetic acid, and formalin for 24 h. The number of LNs was matched to a control group consisting of 34 cases of colorectal carcinoma, 14 pT2&3 and 20 ypT2&3 rectosigmoid carcinomas examined routinely. Results were statistically tested by Student's t-test.

RESULTS

In the study group the total number of revealed LNs was 869, range 1-48, average 14.7 per specimen, median 15. In the control group the number of LNs was 200, range 0-13, average 5.9 per specimen, median 6. The difference between the study and the control group was statistically significant (P = 0.05).

CONCLUSION

Using LRS leads to a significant increase in the number of revealed LNs in colorectal resection specimens and makes it possible to find more than 12 LNs in a majority of stage pT2 and pT3 adenocarcinomas.

Aktuelle Behandlungsstrategien beim Rektumkarzinom

In the last ten years, considerable progress has been achieved in the treatment of rectal cancer. According to improved interdisciplinary staging, rectal carcinomas can be treated based on a stage-dependent concept: "low-risk" pT1 (G1/G2) carcinomas can be cured by local full wall excision, while "high-risk" pT1 (G3/G4) and pT2 carcinomas require transabdominal resection. In contrast, locally advanced rectal cancers in cUICC-II/-III stages (T3/T4 or N(+)) should receive long-term, 5-FU-based, neoadjuvant chemoradiotherapy according to the excellent results of the CAO/AIO/ARO-94 trial of the German Rectal Cancer Study Group. High-quality resection must be based on radical oncologic principles such as "no-touch" technique, radicular dissection of vessels, and total mesorectal excision. Multimodal treatment is completed with adjuvant 5-FU-based chemotherapy. This therapeutic approach led to a reduction in the 5-year local recurrence rate to 6% and disease-free survival of approximately 68% in advanced rectal cancer (overall survival: 76%).

Lymph Node Evaluation in Colorectal Cancer Patients: A Population-Based Study

BACKGROUND

Adequate lymph node evaluation is required for proper staging of colorectal cancer, and the number of lymph nodes examined is associated with survival. According to current guidelines, the recommended minimum number of lymph nodes examined to ensure adequate sampling is 12. We used data from the National Cancer Institute's Surveillance, Epidemiology, and End Results program to determine the proportion of colorectal cancer patients in the United States who receive adequate lymph node evaluation.

METHODS

For 116,995 adults with colorectal adenocarcinoma, diagnosed from 1988 through 2001, who underwent radical surgery and did not receive neoadjuvant radiation, we evaluated the number of lymph nodes, the likelihood of receiving adequate lymph node evaluation (i.e., at least 12 lymph nodes examined), and the influence of tumor and patient factors on lymph node evaluation. All statistical tests were two-sided.

RESULTS

Among all patients, the median number of lymph nodes examined was nine. Only 37% of all patients received adequate lymph node evaluation. The proportion of patients receiving adequate lymph node evaluation increased from 32% in 1988 to 44% in 2001 (P(trend)<.001, Cochran-Armitage test). Advanced tumor stage was statistically significantly associated with adequate lymph node evaluation (odds ratio [OR] of receiving adequate lymph node evaluation=2.27, 95% confidence interval [CI] = 2.18 to 2.35). Older patients (> or =71 years, OR = 0.45, 95% CI = 0.44 to 0.47) were less likely to receive adequate lymph node evaluation than younger patients, and those with left-sided (OR = 0.45, 95% CI = 0.44 to 0.47) or rectal (OR = 0.52, 95% CI = 0.50 to 0.54) cancers were less likely to receive adequate lymph node evaluation than patients with right-sided cancers. In all analyses, geographic location was an important predictor of adequate lymph node evaluation, which ranged from 33% to 53%, depending on geographic location.

CONCLUSIONS

In 2001, the majority of patients with colorectal cancer still received inadequate lymph node evaluation. The association of demographic variables, particularly patient age and geographic location, with adequate lymph node evaluation indicates that local surgical and pathology practice patterns may affect adequacy of lymph node evaluation.

Tumor micrometastases in mesorectal lymph nodes and their clinical significance in patients with rectal caner

AIM: To investigate the number, size, and status of lymph nodes within the mesorectum and to explore the prognostic significance of lymph node micrometastases in patients with rectal cancer.

METHODS: Thirty-one patients with rectal cancer undergone total mesorectal excision between October 2001 and October 2002 were included. Mesorectal nodes retrieved from the resected specimens were detected with a combination of haematoxylin and eosin (HE) staining and immunohistoch-emistry (IHC). The relations between lymph node metastases, micrometastases and postoperative recurrence were analyzed.

RESULTS: A total of 548 lymph nodes were harvested, with 17.7 ± 8.2 nodes per case. The average number of metastatic nodes in HE-positive patients and micrometastatic nodes in IHC-positive patients was 5.2 ± 5.1 per case and 2.2 ± 1.3 per case, respectively. The mean size of all nodes and metastatic nodes was 4.1 ± 1.8 mm and 5.2 ± 1.7 mm in diameter, respectively. The mean size of micrometastatic nodes was 3.9 ± 1.4 mm in diameter. The size of the majority of mesorectal nodes (66.8%), metastatic nodes (52.6%), and micrometastatic nodes (79.5%) was less than 5 mm in diameter. During a median follow-up period of 24.6 ± 4.7 mo, 5 patients (16.7%) had recurrence, of them 2 died and 3 survived. Another case died of tumor unrelated cause and was excluded. All 5 recurrent cases had 3 or more nodes involved, and one of them developed only lymph node micrometastases. The mean number of both metastatic and micrometastatic nodes per case differed significantly between the recurrent and non-recurrent groups (P < 0.01 and P = 0.01, respectively).

CONCLUSION: The majority of lymph nodes, metastatic, and micrometastatic lymph nodes within the mesorectum are smaller than 5 mm in diameter. The nodal status and the number of lymph nodes involved with tumor metastases and micrometastases are related to the rapid postoperative recurrence.