Lymph nodes after preoperative chemoradiotherapy for rectal carcinoma: number, status, and impact on survival. Am J Surg Pathol. 2008;32:45-50. [PMID: 18162769 DOI: 10.1097/pas.0b013e3180dc92ab]

Lymph node retrieval after preoperative chemoradiotherapy for rectal cancer

BACKGROUND

Current guidelines recommend the assessment of at least 12 lymph nodes for rectal cancer staging. Preoperative chemoradiotherapy may affect lymph node yield in this malignancy. This study investigated the impact of neoadjuvant chemoradiotherapy on the number of lymph nodes retrieved from rectal cancer patients.

METHODS

An analysis of 162 rectal cancer patients who underwent curative surgery between 2005 and 2010. Seventy-one patients with stage II or III tumors received preoperative chemoradiotherapy. Using multivariate analysis, we assessed the correlation between clinicopathologic variables and number of retrieved lymph nodes. We also evaluated the association between survival and number of lymph nodes obtained.

RESULTS

On multivariate analysis, preoperative chemoradiotherapy was the only variable to independently affect the number of lymph nodes obtained. The mean number of lymph nodes was 14.2 in patients treated with preoperative chemoradiotherapy and 19.4 in those not treated (P < 0.001). In the chemoradiotherapy group, 29.6 % of patients had fewer than 12 lymph nodes obtained compared with 9.9 % in the primary surgery group (P = 0.003). After chemoradiation, the number of retrieved lymph nodes was inversely correlated with tumor regression grade. Results showed that 5-year overall and disease-free survival were similar whether the patient had 12 or more nodes retrieved or not.

CONCLUSIONS

Preoperative chemoradiotherapy reduces the lymph node yield in rectal cancer. The number of retrieved lymph nodes is affected by degree of histopathologic response of the tumor to chemoradiation. Thus, number of lymph nodes should not be used as a surrogate for oncologic adequacy of resection after neoadjuvant chemoradiotherapy for rectal cancer.

Importance of and adherence to lymph node staging standards in gastrointestinal cancer

In gastrointestinal oncology, one of the most important factors influencing cancer-specific survival is the presence of positive lymph nodes. Although it remains controversial, adequate lymph node examination is required for accurate staging such that patients can receive appropriate adjuvant treatments and for stratification in clinical trials. Nevertheless, wide variation exists in the quality of lymph node examination in the United States, and many centers are not meeting guideline treatment recommendations.

Shifting concepts in rectal cancer management: a review of contemporary primary rectal cancer treatment strategies

The management of rectal cancer has transformed over the last 3 decades and continues to evolve. Some of these changes parallel progress made with other cancers: refinement of surgical technique to improve organ preservation, selective use of neoadjuvant (and adjuvant) therapy, and emergence of criteria suggesting a role for individually tailored therapy. Other changes are driven by fairly unique issues including functional considerations, rectal anatomic features, and surgical technical issues. Further complexity is due to the variety of staging modalities (each with its own limitations), neoadjuvant treatment alternatives, and competing strategies for sequencing multimodal treatment even for nonmetastatic disease. Importantly, observations of tumor response made in the era of neoadjuvant therapy are reshaping some traditionally held concepts about tumor behavior. Frameworks for prioritizing and integrating complex data can help to formulate treatment plans for patients.

Is step section necessary for determination of complete pathological response in rectal cancer patients treated with preoperative chemoradiotherapy?

AIMS

To assess the efficacy of the step section for determination of pathological complete response (pCR) in rectal cancer treated with preoperative chemoradiotherapy (CRT).

METHODS AND RESULTS

Of 709 patients with rectal cancer who received preoperative CRT, 88 were initially diagnosed as having pCR. These 88 patients were re-evaluated after two-level step sections of the entire tumour by using Dworak's regression grade. Additional serial step sections revealed residual tumour cells in seven of 88 patients (7.95%), all of whom were upgraded to regression grade 3 (near total regression) from regression grade 4 (total regression). Of these seven patients, one (14.3%) showed tumour recurrence, compared with 11 of 81 (13.6%) patients with a final regression grade of 4. Neither recurrence rate nor disease-free survival rate differed significantly between these two groups (P > 0.5). Calcification was significantly more frequent in grade 3 than in grade four patients (71.4% versus 32.1%; P = 0.037), and acellular mucin pools were associated with better disease-free survival (P = 0.022).

CONCLUSIONS

Stratifying patient outcome by final regression grade after step section did not yield different outcomes in patients with initial pCR. If residual tumour cells are not identified on initial meticulous examination, further processing of step sections is not necessary.

Optimal lymph node harvest in rectal cancer (UICC stages II and III) after preoperative 5-FU-based radiochemotherapy. Acetone compression is a new and highly efficient method

INTRODUCTION

Preoperative 5-fluorouracil-based radiochemotherapy (RCT), followed by total mesorectal excision, is accepted as standard therapy in rectal cancers (UICC stages II and III). The accurate evaluation of ypN status after RCT with valuable lymph node (LN) harvest is essential for postoperative risk-adapted treatment decisions. Actual numbers of assessed LNs and validity of ypN status vary extensively depending on the methods used.

MATERIAL AND METHODS

This prospective study validates the acetone compression (AC), whole mesorectal compartment embedding (WME), and fat clearance (FC) methods for LN retrieval in n=257 rectal cancer specimens obtained from 2 high-volume surgical centers. For optimal LN retrieval, the AC method (n=161 specimens: 52 cases with RCT, 109 cases without RCT) was compared with the WME (n=64 cases, with RCT) and FC methods (n=32 cases: 17 cases with RCT, 15 cases without RCT). The efficacy of LN retrieval, costs involved, and molecular diagnostics were measured.

RESULTS

Using the AC method, 41 LNs (mean; range 14 to 86 LNs) were detectable in total mesorectal excision specimens after RCT and 44 LNs (mean; range 9 to 78 LNs) in cases without RCT. The LN yield after RCT obtained by using the AC method was equivalent to that of the WME method (mean 32 LNs/specimen; range 12 to 81 LNs) but demonstrated a better time and cost-efficacy. In addition, the AC method facilitated assessment of any tumor deposits, including perineural invasion, and did not hamper molecular analyses. The AC method increased LN retrieval 4- to-6-fold as compared with the literature and 2-fold compared with manual dissection after the FC method.

DISCUSSION

The AC method is the method of choice for accurate LN staging in locally advanced rectal cancer, especially after preoperative RCT, and is well suited for routine gastrointestinal pathology workup.

Number of lymph nodes after neoadjuvant therapy for rectal cancer: How many are needed?

Dear readers,

In the February 2012 issue of the World J Gastrointest Surg (4(2):32-35) Scabini and Ferrando published an editorial entitled “Number of lymph nodes after neoadjuvant therapy for rectal cancer: how many are needed?”.It has been brought to our attention that segments of the editorial are identical or closely resemble the essential parts of the discussion of the original article “Preoperative chemoradiotherapy does not necessarily reduce lymph node retrieval in rectal cancer specimens ¨C Results from a prospective evaluation with extensive pathological work-up” that was published in the Journal of Gastrointestinal Surgery in 2009. Given the striking similarities of the two works, the World J Gastrointest Surg has decided to retract the editorial by Scabini and Ferrando.

Timothy M. Pawlik, MD, MPH, PhD

Editor-in-Chief, World Journal of Gastrointestinal Surgery

Distribution of lymph node metastases is an independent predictor of survival for sigmoid colon and rectal cancer

OBJECTIVE

This study evaluated the prognostic significance of the distribution of lymph node metastases (LND) in patients with colorectal cancer.

BACKGROUND

The impact of the LND on survival in colorectal cancer is unknown.

METHODS

A total of 1205 consecutive patients who underwent potentially curative surgery for sigmoid colon or rectal cancer with high ligation of the inferior mesenteric artery (IMA) from January 1997 to February 2008 were assigned to 4 groups based on LND: LND0, no lymph node metastases-615 patients (51.0%); LND1, metastases in the pericolic nodes-324 patients (26.9%); LND2, metastases in the intermediate nodes-172 patients (14.3%); and LND3, node metastases at the origin of the IMA-94 patients (7.8%).

RESULTS

The 5-year overall survival rates of patients with LND0, LND1, LND2, and LND3 were 83%, 63%, 52%, and 28%, respectively (P < 0.001). The 5-year disease-free survival rates of patients with LND0, LND1, LND2, and LND3 were 83%, 54%, 43%, and 21%, respectively (P < 0.001). On multivariate analysis, LND was an independent prognostic factor for both overall survival and disease-free survival. However, the 5-year local recurrence-free survival rate was not inversely related to the LND. On a subset analysis that compared stage III disease with stage IV disease, the 5-year overall survival and disease-free survival rates were 45% and 31% for the patients with stage IV disease compared with 40% and 32% for the patients with stage III, LND3 disease, respectively (P = 0.761 and 0.704). For the patients with pN1 tumors, the overall survival and disease-free survival did not differ significantly according to the LND (P = 0.471 and 0.347, respectively). However, for patients with pN2 tumors, the overall survival and disease-free survival curves among the LND groups significantly differed (P < 0.001 and <0.001, respectively).

CONCLUSION

LND is an independent predictor of survival for colorectal cancer patients, but it does not predict local recurrence. The N categorization including LND may enhance the prognostic value of the TNM staging system for patients with node-positive sigmoid colon or rectal cancer.

Lymph node harvest in colon and rectal cancer: Current considerations

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

Challenging the feasibility and clinical significance of current guidelines on lymph node examination in rectal cancer in the era of neoadjuvant therapy

PURPOSE

We sought to examine the feasibility and clinical significance of current guidelines on nodal assessment in patients with rectal cancer (RC) treated with neoadjuvant radiation.

METHODS

All patients with RC treated with curative surgery from 1991 to 2003 were included. Number of lymph nodes (LNs) assessed was compared between patients who received neoadjuvant therapy and surgery (NEO) and patients who underwent surgery alone (SURG). Impact of node retrieval on node positivity and disease-specific survival (DSS) in NEO patients was assessed.

RESULTS

In total, 708 patients were identified, of whom 429 (61%) were in the NEO group. These patients had significantly fewer nodes assessed than SURG patients (unadjusted mean, 10.8 v 15.5; adjusted mean difference, -5.0 nodes; P < .001). In the NEO group, 63% of patients had fewer than 12 nodes retrieved (P < .001 v SURG). The proportion of patients diagnosed with node-positive disease in the NEO group was significantly and monotonically associated with the number of lymph nodes retrieved, with no plateau in the relationship. Fewer nodes retrieved was not associated with inferior DSS.

CONCLUSION

In a tertiary cancer center, the 12-LN threshold was not relevant and often not achievable in patients with RC treated with neoadjuvant therapy. Lower LN count after neoadjuvant treatment was not associated with understaging or inferior survival. Although we support the critical importance of careful pathologic examination and adequate nodal staging, we challenge the relevance of LN count both in clinical practice and as a quality indicator in RC.

[Locally advanced rectal cancer management: which role for the pathologist in 2011?]

Locally advanced rectal cancers mainly correspond to lieberkünhien adenocarcinomas and are defined by T3-T4 lesions with or without regional metastatic lymph nodes. Such tumors benefit from neoadjuvant treatment combining chemotherapy and radiotherapy, followed by surgery with total mesorectum excision. Such a strategy can decrease the rate of local relapse and lead to an easier complementary surgery. The pathologist plays an important role in the management of locally advanced rectal cancer. Indeed, he is involved in the gross examination of the mesorectum excision quality and in the exhaustive sampling of the most informative areas. He also has to perform a precise histopathological analysis, including the determination of the circumferential margin or clearance and the evaluation of tumor regression. All these parameters are major prognostic factors which have to be clearly included in the pathology report. Moreover, the next challenge for the pathologist will be to determine and validate new prognostic and predictive markers, notably by using pre-therapeutic biopsies. The goal of this mini-review is to emphasize the pathologist's role in the different steps of the management of locally advanced rectal cancers and to underline its implication in the determination of potential biomarkers of aggressiveness and response.

Perspectives on current tumor-node-metastasis (TNM) staging of cancers of the colon and rectum

Improvements in classifications of cancers based on discovery and validation of important histopathological parameters and new molecular markers continue unabated. Though still not perfect, recent updates of classification schemes in gastrointestinal oncology by the American Joint Commission on Cancer (tumor-node-metastasis [TNM] staging) and the World Health Organization further stratify patients and guide optimization of treatment strategies and better predict patient outcomes. These updates recognize the heterogeneity of patient populations with significant subgrouping of each tumor stage and use of tumor deposits to significantly "up-stage" some cancers; change staging parameters for subsets of IIIB and IIIC cancers; and introduce of several new subtypes of colon carcinomas. By the nature of the process, recent discoveries that are important to improving even routine standards of patient care, especially new advances in molecular medicine, are not incorporated into these systems. Nonetheless, these classifications significantly advance clinical standards and are welcome enhancements to our current methods of cancer reporting.

Clinical impact of lymph node status in rectal cancer

Lymph node status at the time of diagnosis remains one of the principal indicators of prognosis in patients with rectal cancer. Involvement of loco-regional lymph nodes is relevant to surgical and clinical oncologists and continues to impact significantly upon local and systemic management strategies, in both neo-adjuvant and adjuvant settings. In this review, the clinical impact of lymph node status in the surgical management of rectal cancer is considered, with particular reference to the significance of lymphadenectomy and the potential implications for rectal tumours amenable to trans-anal excision. Current standards of care are reviewed and the extent to which the determination of lymph node status influences oncological decisions regarding neo-adjuvant and adjuvant therapies are discussed with areas of controversy highlighted.

Number of lymph nodes examined and prognosis among pathologically lymph node-negative patients after preoperative chemoradiation therapy for rectal adenocarcinoma

BACKGROUND

Preoperative chemoradiation for rectal cancer can decrease the number of evaluable lymph nodes. Hence, the prognostic role of lymph node evaluation in patients with rectal cancer who receive preoperative chemoradiation is unclear. The authors of this report evaluated the prognostic impact of the number of lymph nodes examined in patients with rectal cancer who had negative lymph nodes based on the pathologic extent of disease (ypN0) after they received preoperative chemoradiation.

METHODS

Between 1990 and 2004, 372 patients with nonmetastatic rectal adenocarcinoma received preoperative chemoradiation followed by mesorectal excision and had ypN0 disease. The median radiation dose was 45 gray, and 68% of patients received adjuvant chemotherapy.

RESULTS

Patients had a median of 7 lymph nodes examined after preoperative chemoradiation. Compared with patients who had ≤7 lymph nodes examined, patients who had >7 lymph nodes had higher 5-year rates of freedom from relapse (86% vs 72%; log-rank P = .005) and cancer-specific survival (95% vs 86%; log-rank P = .0004), but no significant difference was observed in the overall survival rate (87% vs 81%; log-rank P = .07). Multivariate Cox proportional models demonstrated that patients who had >7 lymph nodes examined had a significantly lower risk of relapse (hazard ratio [HR], 0.39; P = .003) and death from rectal cancer (HR, 0.45; P = .04) but a similar risk of all-cause mortality (HR, 0.75; 95% CI, 0.46-1.20; P = .23) compared with patients who had ≤7 lymph nodes examined.

CONCLUSIONS

The number of lymph nodes examined was associated independently with disease relapse and cancer-specific survival in patients with rectal cancer who had ypN0 disease after receiving preoperative chemoradiation. Hence, the authors concluded that the number of negative lymph nodes examined may be a prognostic factor in patients with rectal cancer who receive preoperative chemoradiation.

Predictive factors for pulmonary metastases after curative resection of rectal cancer without preoperative chemoradiotherapy

OBJECTIVE

The aim of this study was to clarify the actuarial incidence of pulmonary metastases and risk factors for pulmonary metastases after curative resection of rectal cancer without preoperative chemoradiotherapy.

DESIGN

This study was a retrospective review.

PATIENTS

Data for 314 patients who underwent R0 resection for rectal cancer without preoperative chemoradiotherapy from 2000 to 2006 were reviewed. The mean duration of follow-up was 57.0 months.

RESULTS

Pulmonary metastases developed in 41 patients. Mean duration from rectal surgery to identification of pulmonary metastases was 21.1 months. Surgery for pulmonary metastases was performed first for 19 patients (46.3%), and all patients achieved R0 surgery. Multivariate analysis revealed that tumor depth (T3 to T4), lymph node ratio (>0.091), and tumor location (anal canal) were significant independent risk factors for pulmonary metastases. Five-year actuarial incidence of pulmonary metastasis increased significantly with increased numbers of risk factors (0 factors, 1.1%; 1 factor, 13.2%; ≥2 factors, 40.1%). In terms of lateral pelvic lymph node involvement, the number of lateral pelvic lymph node involvements (≥4) and the distribution of lateral pelvic lymph node metastases (bilateral) were significant risk factors for pulmonary metastases.

CONCLUSIONS

The present study clearly demonstrated predictive factors for pulmonary metastases after R0 resection of rectal cancer without preoperative chemoradiotherapy. Actuarial incidence of pulmonary metastases was significantly related to the number of risk factors present. The data from the present study should facilitate the establishment of novel algorithms for predicting pulmonary metastases after resection of rectal cancer, which may lead to the appropriate surveillance strategies after rectal surgery.

[Pathological work-up of rectal cancer following partial/total mesorectal excision]

Total mesorectal excision (TME) refers to the anatomically accurate surgical resection of the rectum from its surrounding fascias and has become the gold standard for treating rectal cancer. The pathologist plays a key role in the assessment of these specimens and good pathological reporting of rectal cancer is essential to achieving the optimum possible results for patients with rectal cancer. In experienced hands, these techniques result in a dramatic improvement in cancer-related cure rates from 45% to 75% and a reduction in pelvic recurrences from 40% to 5%-10%. Moreover, preservation of sexual and urinary functions is possible in the majority of cases. This article reviews the pathological assessment of the TME specimen in detail with regards to current international guidelines and describes its anatomical background. In addition, particular issues relating to margins, lymph node dissection and effects of neoadjuvant therapy are discussed.

Lymph node counts as an indicator of quality at the hospital level in colorectal surgery

BACKGROUND

Substantial evidence suggests that the number of lymph nodes examined in colorectal cancer (CRC) is a powerful predictor of outcomes. However, the lymph node count as a benchmark of quality in CRC is controversial. We sought to examine the impact of lymph node counts on disease-specific survival (DSS) of CRC patients at the hospital level.

STUDY DESIGN

This study used data obtained between 1994 and 2003 from Region 5 of the California Cancer Registry. Hospitals in Region 5 of the California Cancer Registry were stratified according to the median number of nodes examined and grouped according to the median number of nodes examined, <7, 7 to 9, and ≥10. These hospital groups were then evaluated for the frequency of meeting the 12-node threshold, frequency of positive lymph nodes, and DSS at the hospital level.

RESULTS

Median number of nodes examined in group A was 4 (mean 5.6, SD 5.9), in group B was 8 (mean 9.7, SD 8.5), and in group C was 10 (mean 11.3, SD 9.2). In group A, 13.7%, in group B 32.8%, and in group C, 42.8% met the 12-node threshold. The frequency of N1 and N2 disease for group A was 20.7% and 9.1%, 19. 7% and 11.1% for group B, and 20.1% and 11.3% for group C (p = 0.12). Five-year DSS was 72.7% for group A, 73.7% for group B, and 76.7% for group C (p = 0.002). DSS survival of N0 patients for group A was 78.6%, 81.5% for group B, and 85.1% for group C (p < 0.0001). There was no statistically significant difference in DSS for N1 (p = 0.18) or N2 (p = 0.90) between the 3 groups.

CONCLUSIONS

Lymph node counts can have value as a benchmark of surgical/pathologic quality in node-negative CRC. These results question the value of lymph node counts as a benchmark of surgical/pathologic quality for node-positive CRC.

Recurrence rates and prognostic factors in ypN0 rectal cancer after neoadjuvant chemoradiation and total mesorectal excision

BACKGROUND

Neoadjuvant chemoradiation followed by surgery and adjuvant chemotherapy is typically recommended for patients with locally advanced rectal cancer. Patients with pathologically node-negative tumors have an improved prognosis, but recurrence patterns and independent prognostic factors in these patients have been incompletely characterized.

METHODS

Using a retrospective cohort study design, we included all rectal cancer patients treated with neoadjuvant chemoradiation and curative surgery from 1993 through 2003, who had ypN0 tumors. We characterized recurrence rates and patterns in patients not treated with adjuvant chemotherapy. Secondarily, we compared them to patients who did receive adjuvant treatment and assessed for independent prognostic factors, using univariate and multivariable survival analyses.

RESULTS

Overall, 324 ypN0 patients (ypT0: n = 73; ypT1-2: n = 130; ypT3-4: n = 120) were followed for a median of 5.8 years. The risk of recurrence was associated with pathologic stage-2.7% ypT0, 12.3% ypT1-2, 24.2%ypT3-4. Five-year recurrence-free survival in patients who did not receive adjuvant treatment was 100% (ypT0), 84.4% (ypT1-2) and 75% (ypT3-4). There was no significant difference in 5-year recurrence-free survival between patients who did and did not receive adjuvant treatment. In multivariable analysis, pathologic stage was the factor most strongly associated with recurrence (hazard ratio 3.6 for ypT3-4 vs. ypT0-2, 95% confidence interval 1.9-6.7, P < 0.0001).

CONCLUSIONS

The recurrence rates for selected patients with ypT0-2N0 rectal cancer after neoadjuvant chemoradiation and total mesorectal excision are low. Although standard practice remains completion of planned postoperative adjuvant chemotherapy for all patients undergoing chemoradiation, these data suggest prospective trials may be warranted to measure the benefit of adjuvant chemotherapy in favorable subgroups, such as ypT0-2N0.

Prognostic impact of the lymph node ratio in rectal cancer patients who underwent preoperative chemoradiation

AIM

The purpose of this study was to investigate the prognostic impact of the lymph node ratio (LNR) in ypN-positive rectal cancer patients who received preoperative chemoradiation (preop-CRT).

METHODS

A total of 75 patients diagnosed as node-positive after undergoing preop-CRT followed by curative resection were enrolled. Patients were categorized into two groups based on their median LNR, 0.143.

RESULTS

The median metastatic and retrieved lymph node numbers were 2.0 (range: 1-79) and 18.0 (range: 5-80). Abdominoperineal resection, circumferential resection margin involvement and higher LNR were proven to be independent adverse prognostic factors affecting survival in the multivariate analysis including LNR as a covariate. Of the 47 patients with ypN1, 35 (74.5%) showed a lower LNR (N1G1) and 12 (25.5%) showed a higher LNR (N1G2). The N1G1 group showed better overall survival than the N1G2 group (P = 0.018). There was no difference between the survival rates of the N1G2 group and the ypN2 group (P = 0.987).

CONCLUSIONS

LNR is an independent prognostic factor after preop-CRT for rectal cancer. LNR showed better prognosis stratification than the ypN stage. Therefore, LNR should be considered as an additional prognostic factor in node-positive rectal cancer after preop-CRT.

The prognostic value of lymph node ratio after neoadjuvant chemoradiation and rectal cancer surgery

BACKGROUND

Neoadjuvant chemotherapy decreases total lymph nodes harvested and possibly affects lymph node staging after total mesorectal excision in patients with rectal cancer.

OBJECTIVE

This study aimed to compare staging by lymph node ratio with staging by absolute number of positive lymph nodes.

DESIGN

This study is a retrospective cohort review.

SETTING

: A tertiary care referral center was the setting for this investigation.

PATIENTS

A total of 281 consecutive patients who underwent neoadjuvant chemoradiation and total mesorectal excision after histologically confirmed rectal cancer between January 1, 1998 and December 31, 2008 were included in this study.

MAIN OUTCOME MEASURES

Lymph node ratio is the number of positive lymph nodes divided by the total number of lymph nodes within one sample. Risk categories of low (0 to < 0.09); medium (0.09 to < 0.36); and high (≥ 0.36) for lymph node ratio were chosen by significance with the use of Cox proportional hazards models. These categories were then used in a reclassification table and compared with positive lymph node stage: low (0 positive nodes), medium (1-3 nodes), and high (> 3) by 5-year mortality rates.

RESULTS

The majority (87%) of patients were concordant in risk assessment. Thirty patients were downstaged to lower risk lymph node ratio categories without showing actual lower mortality rates. Seven patients were upstaged to a high-risk lymph node ratio category with a supporting higher 5-year mortality rate. When limiting the analysis to those with fewer than 12 nodes, 136 (95%) patients were concordant in risk assessment; all 30 incorrectly downstaged patients were removed, but the 7 correctly upstaged patients remained.

CONCLUSIONS

Patients who undergo neoadjuvant chemoradiation before rectal cancer surgery frequently have fewer than 12 lymph nodes harvested despite maintaining vigorous surgical standards. Lymph node ratios may provide excellent prognostic value and are possibly a better independent staging method than absolute positive lymph node counts when less than 12 lymph nodes are harvested after neoadjuvant treatment.

Comparison of positive lymph node ratio with an inflammation-based prognostic score in colorectal cancer

BACKGROUND

Two prognostic scoring systems have been proposed in colorectal cancer: the pathologically based positive lymph node ratio (pLNR) and the inflammation-based modified Glasgow Prognostic Score (mGPS). This study compared these two scores with the tumour node metastasis (TNM) staging system in terms of cancer survival.

METHODS

Between 2003 and 2005, 206 patients, of mean(s.d.) age 69·9(10·6) (range 40-95) years, underwent curative resection for colorectal cancer in two centres. Age, sex, primary tumour site and whether radio/chemotherapy was given were recorded in addition to the three scores (TNM stage, pLNR and mGPS). Univariable and multivariable analyses of overall survival were performed.

RESULTS

Age, rectal cancer, TNM stage, pLNR and mGPS were significant factors in univariable analysis. On multivariable analysis, N category and tumour stage (I-III) were removed from the model, leaving pLNR and mGPS as independent predictors of overall survival: hazard ratio 1·51 (95 per cent confidence interval 1·24 to 1·84; P < 0·001) and 1·56 (1·18 to 2·08; P = 0·020) respectively. C-statistic analysis, used to compare pLNR and mGPS directly, found only pLNR to be significant (P < 0·001)

CONCLUSION

This study found pLNR to be the superior prognostic scoring system in determining long-term survival in patients undergoing resection for colorectal cancer.

Quantitative lymph node evaluation as an independent marker of long-term prognosis in stage III rectal cancer

BACKGROUND

The prognostic significance of lymph node evaluation is not well described for rectal cancer due to a lack of reproducibility in nodal counts and variable use of adjuvant and neoadjuvant therapy. The aim of this study was to examine the role of quantitative lymph node evaluation as an independent marker of prognosis in stage III rectal cancer.

METHODS

New Zealand Cancer Registry data were retrieved for consecutive patients with rectal cancer from January 1995 to July 2003. Cases with node-negative tumours, distant metastases, death within 30 days of surgery and incomplete data fields were excluded. Three nodal stratification systems were investigated - Total Number of Nodes examined (TNN), Absolute number of Positive Nodes (APN) and Lymph Node Ratio (LNR). Univariate and Cox regression analyses were performed with 5-year all-cause mortality as the primary end point.

RESULTS

The study identified 895 stage III rectal cancer cases. The mean APN and LNR were significantly higher in patients who died within 5 years. An increasing APN or LNR was associated with a significant increase in 5-year mortality. The APN and LNR were also powerful predictors of 5-year mortality after correcting for other factors using Cox regression. The TNN was of no prognostic significance.

CONCLUSIONS

Both the APN and LNR are highly effective at independently predicting and stratifying 5-year mortality in stage III rectal cancer. The significant predictive value of the LNR is likely to be a reflection of the APN rather than one functioning in autonomy, given that the TNN was of no prognostic significance.

Lymph node yield following colorectal cancer surgery

BACKGROUND

Lymph node yield (LNY) is a measure of quality of care and a strong prognostic factor for outcome from colorectal cancer (CRC). The main aims of this study were to determine LNY across multiple Australian centres and the clinico-pathologic factors that influence yield.

METHODS

Analysis of data from prospective CRC databases at 11 Australian centres between January 1988 and May 2008 was undertaken utilizing the linkage and analysis resources of BioGrid Australia. The LNY depending on different clinico-pathologic patient characteristics was evaluated.

RESULTS

In total, 10,082 cases (54.1% men, 45.9% women) were identified. Median LNY was 12 (range 0-174). LNY increased significantly (P < 0.001) over time, from a mean of 8.5 in 1988 to 13 in 2008. LNY also varied significantly between surgical centres. Female gender, younger age, right-sided disease, higher T and N stage, specific operation types and absence of preoperative radiotherapy were all significantly associated with higher LNY.

CONCLUSIONS

While varying across centres, the median LNYs in Australia are acceptable and have improved significantly over recent years. Multiple clinico-pathologic factors significantly influence the number of nodes retrieved.

The effect of neoadjuvant chemoradiation therapy on the prognostic value of lymph nodes after rectal cancer surgery

BACKGROUND

Neoadjuvant therapy may affect the prognostic impact of total lymph node harvests and lymph node positivity after surgery for rectal cancer.

METHODS

We performed a retrospective review of 390 consecutive patients with histologically confirmed rectal cancer. Postoperative follow-up evaluation and survival were confirmed via medical record review. The impacts of lymph node positivity and total lymph node harvest on survival and recurrence are reflected as proportional hazard ratios (HRs).

RESULTS

A total of 221 patients underwent neoadjuvant therapy, of whom 75 had positive nodes. Node-positive patients showed a significantly shorter survival time (HR, 2.89; P = .002) and time to local recurrence (HR, 6.36; P = .031) compared with patients without positive nodes. Survival and recurrence were not significantly different between patients with a total harvest of fewer than 12 nodes and patients with a higher lymph node harvest.

CONCLUSIONS

After neoadjuvant treatment and total mesorectal excision, lymph node positivity is associated with significantly shorter survival and time to local recurrence in rectal cancer patients, whereas absolute total lymph node harvests likely have little impact on prognosis.

Influence of preoperative chemoradiotherapy on the number of lymph nodes retrieved in rectal cancer

OBJECTIVE

To evaluate the relation of preoperative chemoradiotherapy to the number of lymph nodes retrieved in curative intent surgery for rectal cancer.

SUMMARY BACKGROUND DATA

Current guidelines recommend evaluation of least 12 to 14 lymph nodes in rectal cancer. It is well known that lymph nodes retrieval is affected by many factors.

METHODS

This was a retrospective study of 615 patients who underwent curative intent surgery for primary rectal cancer. Preoperative chemoradiotherapy involving 50.4 Gy fractionated radiotherapy and concurrent chemotherapy was performed in patients with locally advanced rectal cancer (clinically T3 or T4). We explored associations between the number of lymph nodes retrieved in the pathologic specimen and patient demographics (age, gender, body mass index [BMI]), treatment (surgeon, sphincter-saving, preoperative chemoradiotherapy), and tumor-related variables (location, stage, histology). After adjustment for other factors, we compared the mean number of obtained lymph nodes between patients treated with preoperative chemoradiotherapy and those treated without preoperative chemoradiotherapy.

RESULTS

Univariate analysis demonstrated that age, BMI, preoperative chemoradiotherapy, location, and stage significantly related the number of lymph nodes retrieved. Multivariate analysis revealed age, BMI, preoperative chemoradiotherapy, and stage as independent factors influencing the number of lymph nodes retrieved. The mean number of lymph nodes adjusted for age, BMI, and stage was significantly lower in patients treated with preoperative chemoradiotherapy than in those treated without preoperative chemoradiotherapy (14.5 vs. 21.5, P < 0.001). The reduction rate by preoperative chemoradiotherapy was 32.6% (7/21.5). In patients who underwent preoperative chemoradiotherapy, advanced age (P < 0.001) and high BMI (P = 0.037) were associated with decreased number of retrieved lymph nodes.

CONCLUSIONS

Preoperative chemoradiotherapy significantly decreased the number of retrieved lymph nodes by approximately 33%. Therefore, the recommended number of retrieved lymph nodes should be adjusted when rectal cancer is treated with preoperative chemoradiotherapy.

Can adequate lymphadenectomy be obtained by laparoscopic resection in rectal cancer? Results of a case-control study in 200 patients

AIM

The aim of this study is to compare pathological findings in rectal cancer specimens obtained by laparoscopy or laparotomy.

MATERIALS AND METHODS

Bowel length, distal and circumferential margins, and number of total and positive nodes harvested were prospectively recorded in specimens obtained from 100 consecutive patients who had a laparoscopic total mesorectal excision for cancer. These data were compared with those extracted from a well-matched group of 100 patients who had an open procedure.

RESULTS

The mean length of the specimens was 31.04 cm in the case group and 29.45 cm in the control group (not significant (NS)). All distal margins in both groups were negative. The circumferential margin was positive in four cases in the case group and nine cases in the control group (NS). The mean number of lymph nodes harvested was 13.76 nodes/patient in the case group and 12.74 nodes/patient in the control group (NS). The mean number of involved lymph nodes was 1.18 node/case in the case group and 1.96 node/case in group 2 (NS).

CONCLUSION

There is no difference between laparoscopic or open approaches concerning specimen's length, distal margin, circumferential margin, and total and positive lymph nodes. Laparoscopic rectal resection is not only technically feasible but it seems also oncologically safe.

To count and how to count, that is the question: interobserver and intraobserver variability among pathologists in lymph node counting

Optimal cancer staging requires retrieval of a minimal number of nodes. However, variability among pathologists in counting on a slide has not been studied. To study the differences in node counting among pathologists, 10 pathologists counted nodes on 15 slides on 2 occasions. They also opined on whether selected "structures" represented countable nodes. There was no slide on which all pathologists agreed on all occasions. The greatest variability was on slides on which the number of nodes exceeded 8. There was disagreement on the size of the smallest countable node, on how to count 2 closely related structures, and when the gross disagreed with the microscopic finding. With a mean count of 5.7 nodes per slide, the 95% confidence interval was +/- 2.6, which could be clinically significant when the count approaches the set minimum. Uniform criteria are necessary to allow for meaningful comparisons between studies on minimal nodal counts for cancer lymphadenectomies.

Lymph node yield in rectal cancer surgery: effect of preoperative chemoradiotherapy

AIM

Adequate lymph node resection in rectal cancer is important for staging and local control. This study aims to verify the effect of neoadjuvant chemoradiation, as well as some clinicopathological features, on the yield of lymph nodes in rectal carcinoma.

METHODS

Data on consecutive patients who had total mesorectal excision for rectal adenocarcinoma at a single cancer center between January 2003 and July 2008 were reviewed. No patient had any prior pelvic surgery or radiotherapy. Patients had neoadjuvant chemoradiotherapy if they were stage II or III.

RESULTS

A total of 116 patients were included. The mean age was 53 years (range 29-83). Fifty-nine patients (51%) received neoadjuvant therapy before resection. The mean number of lymph nodes removed was 18 (range 4-67) per specimen. There was less lymph node yield in patients who received neoadjuvant therapy (16 vs. 19, p = 0.008). Only 64% of patients who had preoperative therapy had 12 lymph nodes or more in the specimen as opposed to 88% of those who had surgery upfront (p = 0.003). Other factors associated with lower lymph node yield included: female sex (p = 0.03) and tumour location in the lower rectum (p = 0.002). Age, tumour stage and grade, type of operation and surgical delay did not affect the number of lymph nodes removed.

CONCLUSION

Preoperative chemoradiotherapy for rectal cancer results in reduction in lymph node yield. Female sex and lower rectal tumours are also associated with retrieval of fewer lymph nodes.

The effect of preoperative chemoradiotherapy on lymph node harvest after total mesorectal excision for rectal cancer

PURPOSE

This study was designed to evaluate whether preoperative chemoradiotherapy reduces the number of lymph nodes harvested after total mesorectal excision of rectal cancer.

METHODS

From January 1995 to December 2007, 168 consecutive patients with rectal cancer underwent total mesorectal excision in the Department of Surgical Oncology at the University of Crete. The patients were divided into three groups (Group A, no chemoradiotherapy; Group B, short course of chemoradiotherapy; Group C, long course of chemoradiotherapy). The primary end points were the number of lymph nodes examined and the percentage of patients with fewer than 12 lymph nodes removed.

RESULTS

The overall number of lymph nodes retrieved was not significantly reduced by the use of preoperative chemoradiotherapy. The percentage of patients with fewer than 12 lymph nodes examined, however, was significantly higher in Group C. The leakage rate and the duration of hospital stay were not affected. The rate of wound infections was higher in Group C.

CONCLUSION

Preoperative chemoradiotherapy did not significantly decrease the overall number of lymph nodes retrieved but did increase the percentage of patients with fewer than 12 lymph nodes examined.

The influence of the number of retrieved lymph nodes on staging and survival in patients with stage II and III rectal cancer undergoing tumor-specific mesorectal excision

OBJECTIVE

This study was designed to determine whether the number of lymph nodes retrieved influence staging and survival in patients with stage II and III rectal cancer that undergo tumor-specific mesorectal excision.

SUMMARY BACKGROUND DATA

The prognostic impact of the retrieved nodes has been emphasized in patients with colorectal cancer, but few studies have focused on patients with rectal cancer.

METHODS

A total of 900 patients who underwent tumor-specific mesorectal excision with curative intent and adjuvant chemoradiation therapy for stage II and III rectal cancer from January 1989 to December 2006 were analyzed.

RESULTS

Cancer-specific survival (CSS) of stage II patients with less than 15 nodes (25th percentile) was not different from stage III patients, but CSS was better in stage II patients with more than 15 nodes. When using cutoff values of the 25th and 50th percentiles (22 and 31 nodes), recurrence-free survival (RFS) was statistically different among subgroups of stage II and III patients. In multivariate analysis, stage II disease with less than 15 nodes retrieved was an adverse factor for CSS and RFS. In Kaplan-Meier survival analysis, using cutoff values, the difference for CSS was not significant with 22 and more nodes and the difference for RFS was not observed with 23 and more nodes.

CONCLUSIONS

The number of lymph nodes retrieved is closely associated with survival and recurrence in patients with stage II rectal cancer and, for more accurate prognostic stratification, at least 22 and 23 nodes seem to be necessary, respectively, for CSS and for RFS.

Metastasis to the sigmoid or sigmoid mesenteric lymph nodes from rectal cancer

OBJECTIVE

We analyzed metastases to the sigmoid and sigmoid mesenteric lymph nodes from rectal cancer.

BACKGROUND

It has been reported that rectal cancer spreads upward and lateral. However, metastasis to the sigmoid mesenteric or sigmoid nodes from rectal cancer has been rarely reported.

METHODS

We enrolled 347 patients who underwent curative resection for rectal cancer with proven lymph node metastases and dissection of the sigmoid and sigmoid mesenteric lymph nodes. Lymph node classification was performed by the colorectal surgeon and the lymph nodes were sent to pathology. Two hundred ninety sigmoid mesenteric and 248 sigmoid lymph node dissections were confirmed by pathologic examination.

RESULTS

There were 185 and 162 patients with extraperitoneal and intraperitoneal rectal cancers, respectively. The T categories were T1 in 4 patients (1.2%), T2 in 25 patients (7.2%), T3 in 252 patients (72.6%), and T4 in 66 patients (18.8%). The N categories were N1 in 216 patients (62.2%) and N2 in 131 patients (37.8%). Metastases to the sigmoid and sigmoid mesenteric lymph nodes occurred in 60 (20.7%) and 28 patients (11.3%), respectively. Metastases to the sigmoid or sigmoid mesenteric lymph nodes, without metastases to the superior rectal and inferior mesenteric lymph nodes, developed in 18 patients (5.2%). Compared with patients without sigmoid mesenteric lymph node metastases, N2 category disease, and poor differentiation, overall recurrence was more common in patients with sigmoid mesenteric lymph node metastases. Patients with sigmoid lymph node metastases were common in the N2 category of disease. However, the number of retrieved lymph nodes, and the overall and local recurrence rates were not significantly different. Seventeen of 18 patients with only sigmoid mesenteric or sigmoid lymph node metastases had N1 category disease; 8 and 10 patients had extraperitoenal and intraperitoneal rectal cancers, respectively. For patients with N1 category disease, there was no difference in the overall and local disease recurrence rates among the patients.

CONCLUSION

Sigmoid mesenteric or sigmoid lymph node metastases developed in 23.2% of patients in the present study. But, there were no differences in the cancer-specific survival, overall and local disease recurrence rates in the patients with sigmoid mesenteric or sigmoid lymph node metastases.

[What do we know about the lymphatic drainage of the rectum?]

Lymph node (LN) involvement is one of the most significant prognostic factors of patients with rectal cancer. However, the distribution of rectal LN is not well known. The rectal LN are mainly located around the rectal arteries. In the mesorectum, the LN are mainly located posteriorly. The number of LN by patient varies considerably. Many reasons can explain this variability. Acquired factors such as infection, inflammation or metastatic involvement facilitate the detection of LN. In contrast, preoperative radiotherapy reduces the number and size of lymph nodes. The procedure of resection affects the number of LN harvested. Extensive lymphadenectomies increase the number of LN harvested. The technique used by pathologist has equally a major influence. The fat clearing method allows detection of a greater number of LN than manual dissection particularly for small LN. Toxicity of these solutions and a time-consuming process explain that fat clearing method is rarely used in clinical practice. Detection of rectal lymph nodes is difficult and tedious but is necessary for an accurate staging of patients with rectal cancer.

The ratio of metastatic to examined lymph nodes is a powerful independent prognostic factor in rectal cancer

OBJECTIVE

The aim of the study was to evaluate the prognostic value of the ratio of metastatic to examined lymph nodes (LNR) in patients with rectal cancer.

SUMMARY BACKGROUND DATA

Lymph nodes ratio (LNR) has been shown to have prognostic value in patients with colon cancer. The impact of LNR on disease-free and overall survival in patients with rectal cancer is unknown.

PATIENTS AND METHODS

From 1998 to 2004, 307 patients underwent rectal resection for adenocarcinoma. The relationships between overall and disease-free survival at 3 years and 15 variables, including the presence or absence of metastatic lymph nodes, the total number of lymph nodes examined, and LNR, were analyzed by multivariate analysis. Patients were then assigned to 4 groups based on LNR: LNR = 0 (N0 patients), LNR = 0.01 to 0.07, LNR >0.07 to 0.2, LNR >0.2.

RESULTS

The mean number of lymph nodes examined was 22 +/- 12. In the multivariate analysis, LNR was a significant prognostic factor for both disease-free (P = 0.006) and overall survival (P = 0.0003), whereas the presence or absence of metastatic lymph nodes was not. LNR remained a significant prognostic factor in the 59 patients in whom fewer than 12 lymph nodes were examined (P = 0.0058). According to LNR values, disease-free and overall survival decreased significantly with increasing LNR (P < 0.001).

CONCLUSIONS

LNR is the most significant prognostic factor for both overall and disease-free survival in patients with rectal cancer, even in patients with fewer than 12 lymph nodes examined.