The impact of N-ratio in minimizing stage migration phenomenon in gastric cancer patients with insufficient number or level of lymph node retrieved: results from a Chinese mono-institutional study in 2159 patients

Lymph node ratio as a novel and simple prognostic factor in advanced gastric cancer

TNM staging is no doubt the most critical prognostic factors, representing tumor (T)/lymph node metastasis (N)/distant metastasis (M) in gastric cancer. Lymph node ratio-based N system (Nr) has been repeatedly reported to be of prognostic relevance in advanced gastric cancer independent of stage in the multivariate analysis world-wide, and proposed as more sophisticated than N with regard to predicting accurate prognosis. As a result, proposed TNrM system may predict survival more accurately than the present TNM staging system for patients undergoing limited lymph node analysis. It could adjust stage migration when the lymph node number was used as staging factor. Although correlation of the number of metastatic lymph nodes and lymph node ratio is obvious, biological characteristics other than that could also have been reflected on. It may indicate how successful the operation of lymph node dissection was, or it may be revealing the potential of the patient's lymph node immune-reaction. Recently, high lymph node ratio is closely associated with EGFR expression in advanced gastric cancer. When efficiency of applying lymph node ratio as a biomarker is verified and confirmed in an expansive research, and when cancer causing molecules are identified, as well as the competence as a treatment target is studied, the new biomarker, namely, lymph node ratio, could find itself in a limelight in gastric cancer treatment in the future.

A clinical prognostic scoring system for resectable gastric cancer to predict survival and benefit from paclitaxel- or oxaliplatin-based adjuvant chemotherapy

Background

Gastrectomy with D2 lymphadenectomy is a standard procedure of curative resection for gastric cancer (GC). The aim of this study was to develop a simple and reliable prognostic scoring system for GC treated with D2 gastrectomy combined with adjuvant chemotherapy.

Methods

A prognostic scoring system was established based on clinical and laboratory data from 579 patients with localized GC without distant metastasis treated with D2 gastrectomy and adjuvant chemotherapy.

Results

From the multivariate model for overall survival (OS), five factors were selected for the scoring system: ≥50% metastatic lymph node rate, positive lymphovascular invasion, pathologic TNM Stage II or III, ≥5 ng/mL preoperative carcinoembryonic antigen level, and <110 g/L preoperative hemoglobin. Two models were derived using different methods. Model A identified low- and high-risk patients for OS (P<0.001), while Model B differentiated low-, intermediate-, and high-risk patients for OS (P<0.001). Stage III patients in the low-risk group had higher survival probabilities than Stage II patients. Both Model A (area under the curve [AUC]: 0.74, 95% confidence interval [CI]: 0.69–0.78) and Model B (AUC: 0.79, 95% CI: 0.72–0.83) were better predictors compared with the pathologic TNM classification (AUC: 0.62, 95% CI: 0.59–0.71, P<0.001). Adjuvant paclitaxel- or oxaliplatin-based or triple chemotherapy showed significantly better outcomes in patients classified as high risk, but not in those with low and intermediate risk.

Conclusion

A clinical three-tier prognostic risk scoring system was established to predict OS of GC treated with D2 gastrectomy and adjuvant chemotherapy. The potential advantage of this scoring system is that it can identify high-risk patients in Stage II or III who may benefit from paclitaxel- or oxaliplatin-based regimens. Prospective studies are needed to confirm these results before they are applied clinically.

Prognostic Performance of Different Lymph Node Staging Systems After Curative Intent Resection for Gastric Adenocarcinoma

OBJECTIVE

To compare the prognostic performance of American Joint Committee on Cancer/International Union Against Cancer seventh N stage relative to lymph node ratio (LNR), log odds of metastatic lymph nodes (LODDS), and N score in gastric adenocarcinoma.

BACKGROUND

Metastatic disease to the regional LN basin is a strong predictor of worse long-term outcome following curative intent resection of gastric adenocarcinoma.

METHODS

A total of 804 patients who underwent surgical resection of gastric adenocarcinoma were identified from a multi-institutional database. The relative discriminative abilities of the different LN staging/scoring systems were assessed using the Akaike's Information Criterion (AIC) and the Harrell's concordance index (c statistic).

RESULTS

Of the 804 patients, 333 (41.4%) had no lymph node metastasis, whereas 471 (58.6%) had lymph node metastasis. Patients with ≥N1 disease had an increased risk of death (hazards ratio = 2.09, 95% confidence interval: 1.68-2.61; P < 0.001]. When assessed using categorical cutoff values, LNR had a somewhat better prognostic performance (C index: 0.630; AIC: 4321.9) than the American Joint Committee on Cancer seventh edition (C index: 0.615; AIC: 4341.9), LODDS (C index: 0.615; AIC: 4323.4), or N score (C index: 0.620; AIC: 4324.6). When LN status was modeled as a continuous variable, the LODDS staging system (C index: 0.636; AIC: 4304.0) outperformed other staging/scoring systems including the N score (C index: 0.632; AIC: 4308.4) and LNR (C index: 0.631; AIC: 4225.8). Among patients with LNR scores of 0 or 1, there was a residual heterogeneity of outcomes that was better stratified and characterized by the LODDS.

CONCLUSIONS

When assessed as a categorical variable, LNR was the most powerful manner to stratify patients on the basis of LN status. LODDS was a better predicator of survival when LN status was modeled as a continuous variable, especially among those patients with either very low or high LNR.

Impact of Lymph Node Ratio on Oncologic Outcomes in ypStage III Rectal Cancer Patients Treated with Neoadjuvant Chemoradiotherapy followed by Total Mesorectal Excision, and Postoperative Adjuvant Chemotherapy

PURPOSE

To evaluate the prognostic impact of the lymph node ratio (LNR) in ypStage III rectal cancer patients who were treated with neoadjuvant chemoradiotherapy (NCRT).

MATERIALS AND METHODS

We retrospectively reviewed the data of 638 consecutive patients who underwent NCRT followed by total mesorectal excision, and postoperative adjuvant chemotherapy for rectal cancer from 2004 to 2011. Of these, 125 patients were positive for lymph node (LN) metastasis and were analyzed in this study.

RESULTS

The median numbers of examined and metastatic LNs were 17 and 2, respectively, and the median LNR was 0.143 (range, 0.02-1). Median follow-up time was 55 months. In multivariate analyses, LNR was an independent prognostic factor for overall survival (OS) (hazard ratio [HR] 2.17, p = 0.041), disease-free survival (DFS) (HR 2.28, p = 0.005), and distant metastasis-free survival (DMFS) (HR 2.30, p = 0.010). When ypN1 patients were divided into low (low LNR ypN1 group) and high LNR (high LNR ypN1 group) according to a cut-off value of 0.152, the high LNR ypN1 group had poorer OS (p = 0.043) and DFS (p = 0.056) compared with the low LNR ypN1 group. And there were no differences between the high LNR ypN1 group and the ypN2 group in terms of the OS (p = 0.703) and DFS (p = 0.831).

CONCLUSIONS

For ypN-positive rectal cancer patients, the LNR was a more effective prognostic marker than the ypN stage, circumferential resection margin, or tumor regression grade after NCRT, and could be used to discern the high-risk group among ypN1 patients.

The Prognostic Ability of Log Odds of Positive Lymph Nodes in Oral Cavity Squamous Cell Carcinoma

Recently, log odds of positive lymph nodes (LODDS) was proven a better prediction of outcomes than other methods in gastric cancer, pancreatic cancer, and colon cancer. However, the validity is not yet tested in oral cavity squamous cell carcinoma (OSCC). We conducted a retrospective study to compare the predictive ability of LODDS, traditional pN classification and lymph node ratio (rN) in OSCC patients.In total, 347 OSCC patients receiving surgery with or without adjuvant therapy at the time of diagnosis between 2004 and 2013 were identified from the cancer registry database of the Dalin Tzu Chi Hospital. Cox proportional hazards models were used to compare the disease-specific survival (DSS) rates for pN, rN, and LODDS after adjusting for possible confounding risk factors. The discriminatory ability of different classification systems was evaluated using the adjusted hazard ratio and Akaike information criterion (AIC) by multivariate regression model. The prediction accuracy of the model was assessed by Harrell's c-statistic.The 347 OSCC patients had a mean age of 57 years old. Among them, 322 patients (92.8%) were male and 189 patients (54.5%) were in stages III to IV. LODDS showed better discriminatory ability for patients with <5 pathological cervical metastatic nodes and those with rN < 0.2. The hypothetical T-LODDS-M staging system had higher linear trend Chi-square, lower AIC, and higher prediction accuracy compared with the American Joint Committee on Cancer (AJCC) TNM, or hypothetical T-rN-M system. After adjusting for other factors, the LODDS unfavorable group had the highest adjusted hazard ratio (HR, 5.42; 95% confidence interval [CI], 3.19-9.12) and LODDS-based model lowest AIC of 704, comparing with pN and rN-based model. The LODDS-based system had the highest prediction accuracy for 3-year DSS (Harrell's c-statistic, 0.803).In our series, LODDS shows great promise as a prognostic tool for OSCC. Compared with the AJCC pN classification and the rN classification, LODDS can stratify OSCC patients and help to identify high-risk patients missed by the other systems.

Can lymph node ratio replace pn categories in the tumor-node-metastasis classification system for esophageal cancer?

BACKGROUND

We evaluated the prognostic value of lymph node ratio (LNR) in esophageal squamous cell carcinoma (ESCC) patients after tri-incisional esophagectomy by making comparisons with pN categories in the UICC/AJCC (International Union Against Cancer/American Joint Committee on Cancer) classification system (seventh edition).

METHODS

Seven hundred ESCC patients underwent tri-incisional esophagectomy at our center (1988-2008) without neoadjuvant therapy. The adjusted X-tile cutoff values for LNR of 0 and 0.25 were compared with those in UICC/AJCC pN categories.

RESULTS

Univariate and multivariate analyses identified LNR as a significant prognostic factor regardless of the number of retrieved LNs. Spearman's correlation analysis showed close linear correlations between the number of examined and metastatic LNs (r = 0.205, p < 0.001), but not between the number of examined LNs and LNR (r = 0.058, p = 0.123). Significant prognostic differences were seen among LNR categories in all pT categories (p < 0.05), but not in pN categories stratified by tumor status (except T3: p < 0.001). Significant prognostic difference was seen among LNR categories in all pN categories (p < 0.05), but not between pN categories in all LNR categories (p > 0.05). Significant differences in 5-year cancer-specific survival rates were found among retrieved-node groups in the same pN category (except N2+3: p = 0.733), but not within the same LNR category (except N0: p < 0.001).

CONCLUSIONS

LNR is an independent prognostic factor after tri-incisional esophagectomy, regardless of the number of retrieved LNs. In ESCC, LNR might reduce stage migration, have more potential for predicting patient outcomes, and compensate for deficiencies in UICC/AJCC pN categories.

Inverse association between visceral obesity and lymph node metastasis in gastric cancer

BACKGROUND

The relationship between fat distribution and lymph node metastasis has not been well studied. The goal of this study was to determine the impact of visceral obesity on lymph node metastasis in gastric cancer.

MATERIALS AND METHODS

Metastatic lymph node ratio (MLR) was defined as the number of involved nodes by tumor divided by the total number of resected lymph nodes. Visceral (VFA) and subcutaneous fat areas (SFA) were determined by measuring abdominal fat volume distribution via CT scan, and visceral obesity was defined as a VFA to total fat area ratio (V/T) >0.29.

RESULTS

With lymph node metastasis as a dependent variable, the following factors were significant in multivariate analysis among 495 patients: pathologic T stage (P < 0.001), lympho-vascular invasion (P < 0.001), and V/T (hazard ratio (HR) = 0.455, 95 % confidence interval (CI) = 0.263-0.786, P = 0.005). Similarly, when MLR was the dependent variable in multivariate analysis, MLR was significantly associated with lympho-vascular invasion (HR = 2.222, 95 % CI = 1.149-4.296, P = 0.018), and V/T (HR = 0.247, 95 % CI = 0.133-0.458, P < 0.001).

CONCLUSIONS

Visceral obesity defined by higher visceral to total fat area ratio was significantly associated with decreased MLR.

Is retrieval of at least 15 lymph nodes sufficient recommendation in early gastric cancer?

Purpose

The evaluation and extent of lymph node (LN) retrieval is clinically relevant for staging because lymphatic invasion is the most common mechanism leading to up-staging of carcinoma. However, the optimal number of LN retrievals for early gastric cancer (EGC) is unclear. With the aim of clarification, we analyzed our database to investigate the optimal number of retrieved LNs in EGC.

Methods

Three hundred twenty-six gastric cancer patients who underwent curative gastrectomy with D2 LN dissection at Ewha Womans University Hospital (Dongdaemun and Mokdong) were analyzed according to sex, age, tumor location, size of tumor, macroscopic type, histological classification, depth of invasion, LNs metastasis, TNM stage and type of surgery.

Results

In LN negative cases, patients with 15-25 retrieved LNs had a 5- and 10-year survival rate of 88% and 54%, respectively, whereas retrieval of ≥26 LNs was associated with 5- and 10-year survival rate of 90% and 75%, respectively (P = 0.105). In LN positive cases, the 5- and 10-year survival rate was 50% and 30% for the 15-25 group, and 77% and 67% for the ≥26 group, respectively (P = 0.044).

Conclusion

LN metastasis is an independent factor of survival and the number of retrieved LNs significantly relate to the long-term survival benefit in node metastatic EGC. Also, our data suggest that the retrieval of at least 15 LNs may not be sufficient to warrant recommendation for more curative surgery, and that qualified LN dissection should be considered if LN metastasis is in doubt, even in EGC.

Evaluation of N-ratio in selecting patients for adjuvant chemoradiotherapy after d2-gastrectomy

CONTEXT

Whether adjuvant chemoradiotherapy may contribute to improve survival outcomes after D2-gastrectomy remains controversial.

OBJECTIVE

To explore the clinical utility of N-Ratio in selecting gastric cancer patients for adjuvant chemoradiotherapy after D2-gastrectomy.

METHODS

A retrospective cohort study was carried out on gastric cancer patients who underwent D2-gastrectomy alone or D2-gastrectomy plus adjuvant chemoradiotherapy (INT-0116 protocol) at the Hospital A. C. Camargo from September 1998 to December 2008. Statistical analysis were performed using multiple conventional methods, such as c-statistic, adjusted Cox's regression and stratified survival analysis.

RESULTS

Our analysis involved 128 patients. According to c-statistic, the N-Ratio (i.e., as a continuous variable) presented "area under ROC curve" (AUC) of 0.713, while the number of metastatic nodes presented AUC of 0.705. After categorization, the cut-offs provide by Marchet et al. displayed the highest discriminating power - AUC value of 0.702. This N-Ratio categorization was confirmed as an independent predictor of survival using multivariate analyses. There also was a trend of better survival by adding of adjuvant chemoradiotherapy only for patients with milder degrees of lymphatic spread - 5-year survival of 23.1% vs 66.9%, respectively (HR = 0.426, 95% CI 0.150-1.202; P = 0.092).

CONCLUSIONS

This study confirms the N-Ratio as a tool to improve the lymph node metastasis staging in gastric cancer and suggests the cut-offs provided by Marchet et al. as the best way for its categorization after a D2-gastrectomy. In these settings, the N-Ratio appears a useful tool to select patients for adjuvant chemoradiotherapy, and the benefit of adding this type of adjuvancy to D2-gastrectomy is suggested to be limited to patients with milder degrees of lymphatic spread (i.e., NR2, 10%-25%).

Log odds of positive lymph nodes (LODDS): what are their role in the prognostic assessment of gastric adenocarcinoma?

BACKGROUND

Nodal status is an important prognostic factor for patients with gastric cancer. Log odds of positive nodes (LODDS) (log of the ratio between the number of positive nodes and the number of negative nodes) are a new effective indicator of prognosis. The aim of the study is to evaluate if LODDS are superior to N stage and lymph nodal ratio (LNR).

METHODS

Prognostic efficacy of pN, nodal ratio, and LODDS was analyzed and compared in a group of 177 patients with gastric adenocarcinoma who underwent curative gastrectomy.

RESULTS

pT, pN, LNR, and LODDS were all significantly correlated with 5-year survival. Multivariate analyses showed significant values as prognostic factor for pN, LNR, and LODDS. A Pearson test demonstrated no significant correlation between LODDS and retrieved nodes. In patients with less than 15 examined nodes, LODDS classification and pN were significantly correlated with survival, whereas LNR classification was not significantly related.

CONCLUSIONS

LODDS are not correlated with the extension of the lymphadenectomy and are able to predict survival even if less than 15 nodes are examined. They permit an effective prognostic stratification of patients with a nodal ratio approaching 0 and 1. Further studies are needed to clarify their role and if they are capable of guaranteeing some advantages over pN and LNR.

Does the retrieval of at least 15 lymph nodes confer an improved survival in patients with advanced gastric cancer?

PURPOSE

The standard surgical procedure recommended to treat gastric cancer in advanced cases is dissection of D2 lymph nodes (LNs). However, the optimum number of LNs that should be retrieved in advanced gastric cancer (AGC) remains debatable. Therefore, this study aimed to investigate the optimum number of retrieved LNs and determine the clinical implications of retrieved LN numbers on the treatment of AGC.

MATERIALS AND METHODS

Of 575 AGC patients reviewed, 369 who underwent open curative gastrectomy with D2 or more extensive LN dissection at our institution were analyzed according to their clinicopathologic characteristics and number of LNs retrieved.

RESULTS

Multivariate regression analysis revealed that tumor size (P=0.006), depth of invasion (P=0.000), LN metastasis (P=0.000), and stage (P=0.000) were independent variables with predictive value. The 5-year survival rates were differed significantly according to the numbers of LNs retrieved ([1] 15~25 vs. >25 and [2] 15~39 vs. ≥40) in patients with differentiated carcinoma.

CONCLUSIONS

Tumor size, depth of invasion, LN metastasis, and stage were independent predictive factors for survival. The number of retrieved LNs was significantly associated with a long-term survival benefit in patients with differentiated carcinoma. Therefore, our data suggest that the retrieval of a minimum of 15 LNs may not be sufficient to warrant a recommendation for further curative surgery and that extensive LN dissection should be considered in advanced carcinoma of the differentiated type.

Prognostic impact of lymph node retrieval and ratio in gastric cancer: a U.S. single center experience

INTRODUCTION

Increased lymph node (LN) retrieval for gastric cancer has been associated with improved overall survival (OS). This study examines the impact of number of examined LN (eLN) and lymph node ratio.

METHODS

Patients referred for surgical care of gastric cancer were stratified by number of eLN, positive LNs (LN+), and lymph node ratio (LN+/eLN). Clinicopathologic factors were compared; OS and disease-free survival (DFS) were the primary endpoints.

RESULTS

From 1997 to 2012, 222 patients, median age 67 (range, 17-92) years, were analyzed. Of 220 (99 %) explored, 164 (74 %) underwent resection. Median OS was 22 (range, 0.3-140) months. Perineural and lymphovascular invasion and poor differentiation adversely affected OS, p < 0.05. A median 14 eLN (range, 0-45), with median 1 LN+ (range, 0-31), was observed. There were no OS or DFS differences when comparing the eLN groups. Both OS and DFS were impacted by LN+. Lymph node ratio demonstrated worse median OS with increasing ratio: 49 months (0) to 37 months (0.01-0.2), 27 months (0.21-0.5), and 12 months (>0.5), p < 0.0001. DFS was similar: 35 months (0), decreasing to 22 months (0.01-0.2), 13 months (0.21-0.5), and 7 months (>0.5), p < 0.0001.

CONCLUSION

Number of eLN did not impact survival, while LN+ adversely affected survival. Lymph node ratio may predict prognosis better than number of eLN or LN+ in gastric cancer.

A comparison of five competing lymph node staging schemes in a cohort of resectable gastric cancer patients

BACKGROUND

New classifications for lymph node (LN) staging have recently been proposed to improve upon the UICC/AJCC N category staging convention. Ratio-based systems and logarithmic odds (LODDS) scores are two families of novel competing staging systems. We compared UICC/AJCC staging with 5 ratio and LODDS systems in predicting overall survival (OS) in patients with resected gastric cancer.

METHODS

Using a large population-based dataset, we identified 12,184 nonmetastatic resectable gastric cancer patients between 1988 and 2004. We compared each subject's UICC/AJCC N stage with five novel staging schemes. We analyzed the OS for each method. Our comparison metric was the log-rank Chi squared statistic; larger Chi squared statistics indicate improvements in N stage discrimination.

RESULTS

Median OS was 2.1 years (95 % CI 2.0-2.2 years), while median patient follow-up for surviving patients was 8.3 years (range, 1 month-22 years). Although all 5 staging systems were either comparable or superior to the UICC/AJCC convention, a LN ratio method outperformed others in N stage discrimination based on log-rank tests for OS. This trend was independent of the number of LNs examined.

CONCLUSIONS

Novel LN staging methods have a higher degree of discrimination utility than the UICC/AJCC N convention. These methods may have a role in reducing the prognostic impact of LN count variability. Of the systems assessed, the LN ratio system that assigns greater risk attribution to cases with <16 LNs was the best classification method to predict OS in patients with resectable gastric cancer.

The evaluation of metastatic lymph node ratio staging system in gastric cancer

BACKGROUND

To evaluate the prognostic value and staging accuracy of the metastatic lymph node ratio (rN) staging system for gastric cancer.

METHODS

A total of 1,075 patients with gastric cancer who underwent curative surgery between 2000 and 2009 at our institute were analyzed. Lymph node status was assigned according to the American Joint Committee on Cancer (AJCC) pN system and rN system. Patients with >15 (group 1, n = 691) and ≤15 lymph nodes (group 2, n = 384) retrieved were analyzed separately.

RESULTS

The rN staging system was generated using 0.2 and 0.5 as the cutoff values of lymph node ratio and then compared with AJCC pN stages. A linear regression model revealed that the number of retrieved lymph nodes was related to the number of metastatic lymph nodes, but not with rN. After a median follow-up of 47.66 months, the 5-year survival rates of N0, N1, N2, and N3 patients of group 1 were significantly better than group 2, whereas the differences were not obvious in the rN classification.

CONCLUSIONS

The rN category is a better prognostic tool than the AJCC pN category for gastric cancer patients after curative surgery regardless of the number of lymph node examined.

A comparison between the seventh and sixth editions of the American Joint Committee on Cancer/International Union Against classification of gastric cancer

OBJECTIVE

To evaluate the prognostic significance of the seventh edition TNM staging classification for gastric cancer.

BACKGROUND

The seventh edition TNM staging system for gastric cancer was adopted by the American Joint Committee on Cancer/International Union Against Cancer on January 1, 2010, and included major revisions.

METHODS

The authors analyzed data retrospectively collected on patients with gastric cancer who underwent surgery at the Affiliated Hospital of Qingdao University Medical College between 2000 and 2008. A total of 964 patients with gastric cancer who underwent R0 surgical resection were included.

RESULTS

The relative risk (RR) for the seventh edition T classification was found to increase steadily and reasonably compared with the sixth edition. However, the RR for the sixth edition N classification was found to increase steadily and reasonably compared with the seventh edition classification. Cox regression multivariate analysis showed that the sixth edition N classification was superior to the seventh edition N classification as an independent prognostic factor. In survival analysis, the seventh edition TNM classification provided a more detailed classification; however, some subgroups of the seventh edition TNM classification did not demonstrate significantly different survival rates. The combination of the seventh edition T classification and the sixth edition N classification, with ideal RR results, showed significantly different survival rates except for IA and IB.

CONCLUSIONS

The combination of the seventh edition T classification and the sixth edition N classification seems to provide the optimal prognosis.

Prognostic assessment of different metastatic lymph node staging methods for gastric cancer after D2 resection

AIM

To compare the prognostic assessment of lymph node ratio and absolute number based staging system for gastric cancer after D2 resection.

METHODS

The clinical, pathologic, and long-term follow-up data of 427 patients with gastric cancer that underwent D2 curative gastrectomy were retrospectively analyzed. The relationships between the metastatic lymph node ratio (MLR), log odds of positive lymph nodes (LODDS), and positive lymph nodes (pN) staging methods and the long-term prognoses of the patients were compared. In addition, the survival curves, accuracy, and homogeneity were compared with stratification to evaluate the prognostic assessment of the 3 methods when the number of tested lymph nodes was insufficient (< 10 and 10-15).

RESULTS

MLR [hazard ratio (HR) = 1.401, P = 0.012], LODDS (HR = 1.012, P = 0.034), and pN (HR = 1.376, P = 0.005) were independent risk factors for gastric cancer patients. The receiver operating characteristic (ROC) curves showed that the prognostic accuracy of the 3 methods was comparable (P > 0.05). Spearman correlation analysis confirmed that MLR, LODDS, and pN were all positively correlated with the total number of tested lymph nodes. When the number of tested lymph node was < 10, the value of survival curves staged by MLR and LODDS was superior to those of pN staging. However, the difference in survival curves between adjacent stages was not significant. In addition, the survival rate of stage 4 patients using the MLR and LODDS staging methods was 26.7% and 27.3% with < 10 lymph node, respectively which were significantly higher than the survival rate of patients with > 15 tested lymph nodes (< 4%). The ROC curve showed that the accuracy of the prognostic assessment of MLR, LODDS, and pN staging methods was comparable (P > 0.05), and the area under the ROC curve of all 3 methods were increased progressively with the enhanced levels of examined lymph nodes. In addition, the homogeneity of the 3 methods in patients with ≤ 15 tested lymph nodes also showed no significant difference.

CONCLUSION

Neither MLR or LODDS could reduce the staging bias. A sufficient number of tested lymph nodes is key to ensure an accurate prognosis for patients underwent D2 radical gastrectomy.

Comparison of three lymph node staging schemes for predicting outcome in patients with gastric cancer

BACKGROUND

Several node staging schemes have been proposed for gastric cancer. The optimal system remains controversial.

METHODS

Patients with gastric cancer were identified from the Surveillance, Epidemiology, and End Results (SEER) database, and a Chinese patient cohort was used for independent validation. The prognostic performance of three node staging schemes was compared, involving a number-based scheme (pN), ratio-based scheme (rN) and log odds of positive lymph nodes scheme (LODDS).

RESULTS

There were 12 443 patients in the SEER database and 866 in the Chinese cohort. LODDS provided better discriminatory capacity and higher predictive accuracy than either pN or rN, for patients with gastric cancer in both the SEER database and the Chinese cohort. The multivariable model using the LODDS classification was significantly more predictive than the pN classification. LODDS suffered much less from stage migration and was able efficiently to discriminate the heterogeneity for patients with no nodes involved or all nodes involved, whereas the pN and rN schemes could not.

CONCLUSION

LODDS showed a clear prognostic superiority over both pN and rN schemes. It could serve as an important reference for the tumour node metastasis (TNM) node classification.

The role of perioperative radiotherapy in gastric cancer

Gastric cancer is one of the most common neoplasms and a main cause of cancer-related mortality worldwide. Surgery remains the mainstay for cure and is considered for all patients with potentially curable disease. However, despite the fact that surgery alone usually leads to favorable outcomes in early stage disease, late diagnosis usually means a poor prognosis. In these settings, multimodal therapy has become the established treatment for locally advanced tumors, while the high risk of locoregional relapse has favored the inclusion of radiotherapy in the comprehensive therapeutic strategy. We provide a critical, non-systematic review of gastric cancer and discuss the role of perioperative radiation therapy in its treatment.

The evaluation of metastatic lymph node ratio staging system in gastric cancer

BACKGROUND

To evaluate the prognostic value and staging accuracy of the metastatic lymph node ratio (rN) staging system for gastric cancer.

METHODS

A total of 1,075 patients with gastric cancer who underwent curative surgery between 2000 and 2009 at our institute were analyzed. Lymph node status was assigned according to the American Joint Committee on Cancer (AJCC) pN system and rN system. Patients with >15 (group 1, n = 691) and ≤15 lymph nodes (group 2, n = 384) retrieved were analyzed separately.

RESULTS

The rN staging system was generated using 0.2 and 0.5 as the cutoff values of lymph node ratio and then compared with AJCC pN stages. A linear regression model revealed that the number of retrieved lymph nodes was related to the number of metastatic lymph nodes, but not with rN. After a median follow-up of 47.66 months, the 5-year survival rates of N0, N1, N2, and N3 patients of group 1 were significantly better than group 2, whereas the differences were not obvious in the rN classification.

CONCLUSIONS

The rN category is a better prognostic tool than the AJCC pN category for gastric cancer patients after curative surgery regardless of the number of lymph node examined.

Metastatic lymph node ratio versus number of metastatic lymph nodes as a prognostic factor in gastric cancer

OBJECTIVE

Knowledge of prognostic factors in gastric cancer is essential to decide on single patient management. We aim to establish the value of lymph node ratio compared to lymph node involvement in the prediction of gastric cancer survival and treatment approach.

METHODS

Charts of ninety-six consecutive patients undergoing gastrectomy for resectable gastric cancer were reviewed between January 1996 and December 2005. Receiver operating characteristic (ROC) curves were plotted to verify the accuracy of metastatic lymph node ratio (MLNR) and number of metastatic lymph node (NMLN) cut-off values for survival prediction. Patients were divided into two groups according to ROC curve cut-offs and accuracy in prognosis was reviewed.

RESULTS

ROC curves showed that 5 metastatic nodes and a node ratio value of 20% had the best survival prognostic correlation. The median survival of patients with MLNR and NMLN were similar according to cut-off determinations (≤ 5/> 5 metastatic nodes and ≤20/>20% lymph node ratio). Five-year survival rates were 70.9% vs 17.1% and 72.4% vs 15.6%, respectively (p < 0.001). Positive correlation coefficient was found between the number of excised nodes and the number of metastatic nodes.

CONCLUSION

Number of metastatic lymph nodes showed greater accuracy than lymph node ratio for survival prediction in gastric cancer.

Prognostic significance of tumor deposits in gastric cancer patients who underwent radical surgery

BACKGROUND

To investigate the prognostic significance of tumor deposits (TDs) in gastric cancers patients who underwent radical surgery.

METHODS

Clinicopathologic and prognostic data from 2998 gastric cancer patients who underwent R0 surgery with D2/D3 lymphadenectomy were retrospectively reviewed. A TD was defined as discrete foci of tumor found in the perigastric fat or in adjacent ligament away from the leading edge of the tumor and showing no evidence of residual lymph node tissue, but within the lymph drainage area of the primary carcinoma.

RESULTS

TDs were detected in 17.8% of patients. TDs were more frequently observed in cancers of larger size, of Borrmann type 4, with lymphovascular invasion, deeper in depth of invasion, and with extended lymph node metastasis. Multivariate analysis confirmed the presence of TDs as 1 of independent factors predicting a poorer outcome. When stratified by pN category, significant differences in survival were observed between patients with and without TDs for those in pN0/pT1-3, pN1/pT3, pN2/pT1-3 and pN3/pT2-3 category, but not for those in pT4a and pT4b category. Moreover, for cancers in each pN category, the prognosis for patients with TDs in pT1-4a category was similar with that of those without TDs in pT4a category, but significantly better than that of those with or without TDs in pT4b category. A revised pT category and a revised pTNM system were proposed, in which all the cancers with TDs in pT1-4a category were incorporated into those without TDs in pT4a category according to the pN category. Further analysis revealed the revised pT category and the revised pTNM system had better homogeneity, discriminatory ability, and monotonicity of gradients than the American Joint Committee on Cancer (AJCC) pT category and the AJCC pTNM system, respectively, representing optimum prognostic stratification.

CONCLUSION

TDs significantly correlated with gastric cancer patients' survival. It might be more suitable for TDs to be treated as a form of serosal invasion. Consequently, en bloc resection of the primary carcinoma is crucially important, and adjuvant chemotherapy should always be considered if TDs have been detected.

The tumor-log odds of positive lymph nodes-metastasis staging system, a promising new staging system for gastric cancer after D2 resection in China

Background

In this study, we established a hypothetical tumor-lodds-metastasis (TLM) and tumor-ratio-metastasis (TRM) staging system. Moreover, we compared them with the 7^th edition of American Joint Committee on Cancer tumor-nodes-metastasis (AJCC TNM) staging system in gastric cancer patients after D2 resection.

Methods

A total of 1000 gastric carcinoma patients receiving treatment in our center were selected for the analysis. Finally, 730 patients who received D2 resection were retrospectively studied. Patients were staged using the TLM, TRM and the 7^th edition AJCC TNM system. Survival analysis was performed with a Cox regression model. We used two parameters to compare the TNM, TRM and TLM staging system, the −2log likelihood and the hazard ratio.

Results

The cut points of lymph node ratio (LNR) were set as 0, 0–0.3, 0.3–0.6, 0.6–1.0. And for the log odds of positive lymph nodes (LODDS), the cut points were established as≤−0.5, −0.5-0, 0-0.5, >0.5. There were significant differences in survival among patients in different LODDS classifications for each pN or LNR groups. When stratified by the LODDS classifications, the prognosis was highly homologous between those in the according pN or LNR classifications. Multivariate analysis showed that TLM staging system was better than the TRM or TNM system for the prognostic evaluation.

Conclusions

The TLM system was superior to the TRM or TNM system for prognostic assessment of gastric adenocarcinoma patients after D2 resection.

Evaluation of the seventh edition of American Joint Committee on Cancer TNM staging system for gastric cancer: results from a Chinese monoinstitutional study

BACKGROUND

To investigate the validity of the 7th edition of American Joint Committee on Cancer (AJCC) TNM staging system for gastric cancer with special attention paid to pT2/pT3, pN1/pN2, and pN3a/pN3b category.

MATERIALS AND METHODS

Clinicopathologic data of 1998 patients underwent R0 surgery for histologically proven gastric cancers with >15 lymph nodes retrieved were retrospectively reviewed.

RESULTS

Prognoses were significantly different between pT2 and pT3 categories, between pN1 and pN2 categories, or between pN3a and pN3b categories. Each stage in the 6th edition was divided into the 7th edition stage with different survival rates. Moreover, stage IIIA, IIIB, and IIIC in the 7th edition system was divided into the 6th edition stage with different survival rates. Prognoses for patients in 7th edition T4aN1M0/T3N2M0/T2N3aM0, T4bN0-1M0/T4aN2M0/T3N3aM0, and T4aN3aM0/T4bN2M0 were similar to that of patients in T1N3bM0, T2N3bM0, and T3N3bM0, respectively, but significantly better than that of patients in T2N3bM0, T3N3bM0, and T4aN3bM0, respectively. However, no significant difference could be observed among patients in T4bN3aM0, T4aN3bM0, T4bN3bM0, and stage IV. A revised TNM system was proposed, in which T1N3bM0 was incorporated into stage IIIA, T2N3bM0 into stage IIIB, T3N3bM0 into stage IIIC, T4bN3aM0/T4aN3bM0/T4bN3bM0 into stage IV. Further analyses revealed the revised TNM system had better homogeneity, discriminatory ability, and monotonicity of gradients than the 6th and the 7th edition system.

CONCLUSIONS

It is reasonable to subclassify the 6th edition pT2 category and pN1 category into the 7th edition pT2/pT3 category and pN1/pN2 category, respectively. However, for better prognostic stratification, it might be more suitable for pN3a and pN3b categories to be considered individual determinants of the 7th edition TNM staging system.

Prognostic significance of lymph node station 7 for patients with gastric cancers underwent radical surgery

BACKGROUND

To investigate the validity of gastric cancers with nodes metastasis at Level II stations limited to No. 7 being classified as level-based n1 stage disease and the impact of this revision on lymph node staging.

METHODS

Clinicopathologic features and prognosis of 1,606 node positive gastric cancers were retrospectively reviewed. Four patient groups were classified according to the status of node involvement: Group A, 734 patients with node metastasis at Level I stations; Group B, 317 patients with nodes metastasis at Level II stations limited to No. 7; Group C, 501 patients with nodes metastasis at Level II stations besides No. 7; and Group D, 54 patients with nodes metastasis at Level III stations.

RESULTS

Although the extent of node metastasis for patients in Group B was more severe than that for patients in Group A, clinicopathologic features (especially pT stage) were not significantly different. Although overall survival for patients in Group B was significantly worse than that for patients in Group A, no significant differences in prognosis could be observed when stratified by pN or rN category. A revised level-based n category was established by considering cancers in Group B as level-based n1 stage disease. Multivariate analysis confirmed rN category and the revised level-based n category independently predicted patients' survival. A novel N category was established by combining rN category and the revised level-based n category. Further analysis revealed the novel N category had better homogeneity, discriminatory ability, and monotonicity of gradients than the other node categories, indicating the novel N system might be the most valuable node staging system for prognostic assessment.

CONCLUSION

It might be more suitable for cancers in Group B being classified as level-based n1 stage disease. And we recommend the anatomical location of metastatic lymph nodes also being considered in the categorization of lymph node metastasis.

Assessment of the nodal status in ampullary carcinoma: the number of positive lymph nodes versus the lymph node ratio

BACKGROUND

This study was intended to compare the prognostic power of the number of positive lymph nodes with that of the lymph node ratio in patients with ampullary carcinoma.

METHODS

A retrospective analysis was conducted of the medical records of 71 consecutive patients with ampullary carcinoma who underwent pancreaticoduodenectomy with regional lymph node dissection. A total of 2151 lymph nodes were dissected (median: 28 nodes per patient) and examined histologically. Cutoff points were determined for both the number of positive nodes and the lymph node ratio using χ(2) scores calculated with the Cox proportional hazards regression model.

RESULTS

Lymph node metastasis was found in 34 patients. The best cutoff point for the number of positive nodes was identified as three nodes, and that for the lymph node ratio was identified as 10%. Univariate analysis revealed both the number of positive nodes (0, 1-3, or ≥ 4; P < 0.0001) and the lymph node ratio (0%, 0-10%, or >10%; P < 0.0001) as significant prognostic factors. Multivariate analysis identified the number of positive nodes as an independent prognostic factor (P < 0.001), whereas the lymph node ratio failed to remain as an independent variable. The cumulative 5-year survival rates were 85% for patients with 0 positive nodes, 63% for patients with 1-3 positive nodes, and 0% for patients with ≥ 4 positive nodes (P < 0.0001).

CONCLUSIONS

The number of positive lymph nodes better predicts the outcome after resection than the lymph node ratio in patients with ampullary carcinoma.

Superiority of metastatic lymph node ratio to the 7th edition UICC N staging in gastric cancer

AIM: To compare and evaluate the appropriate prognostic indicators of lymph node basic staging in gastric cancer patients who underwent radical resection.

METHODS: A total of 1042 gastric cancer patients who underwent radical resection and D2 lymphadenectomy were staged using the 6th and 7th edition International Union Against Cancer (UICC) N staging methods and the metastatic lymph node ratio (MLNR) staging. Homogeneity, discriminatory ability, and gradient monotonicity of the various staging methods were compared using linear trend χ², likelihood ratio χ² statistics, and Akaike information criterion (AIC) calculations. The area under the curve (AUC) was calculated to compare the predictive ability of the aforementioned three staging methods.

RESULTS: Optimal cut-points of the MLNR were calculated as MLNR0 (0), MLNR1 (0.01-0.30), MLNR2 (0.31-0.50), and MLNR3 (0.51-1.00). In univariate, multivariate, and stratified analyses, MLNR staging was superior to the 6th and 7th edition UICC N staging methods. MLNR staging had a higher AUC, higher linear trend and likelihood ratio χ² scores and lower AIC values than the other two staging methods.

CONCLUSION: MLNR staging predicts survival after gastric cancer more precisely than the 6th and 7th edition UICC N classifications and should be considered as an alternative to current pathological N staging.

Which is the most suitable classification for colorectal cancer, log odds, the number or the ratio of positive lymph nodes?

Objective

The aim of the current study was to investigate which is the most suitable classification for colorectal cancer, log odds of positive lymph nodes (LODDS) classification or the classifications based on the number of positive lymph nodes (pN) and positive lymph node ratio(LNR) in a Chinese single institutional population.

Design

Clinicopathologic and prognostic data of 1297 patients with colorectal cancer were retrospectively studied. The log-rank statistics, Cox's proportional hazards model, the Nagelkerke R² index and a Harrell's C statistic were used.

Results

Univariate and three-step multivariate analyses identified that LNR was a significant prognostic factor and LNR classification was superior to both the pN and LODDS classifications. Moreover, the results of the Nagelkerke R² index (0.130) and a Harrell's C statistic (0.707) of LNR showed that LNR and LODDS classifications were similar and LNR was a little better than the other two classifications. Furthermore, for patients in each LNR classification, prognosis was homologous between those in different pN or LODDS classifications. However, for patients in pN1a, pN1b, LODDS2 and LODDS3 classifications, significant differences in survival were observed among patients in different LNR classifications.

Conclusions

For patients with colorectal cancer, the LNR classification is more suitable than pN and LODDS classifications for prognostic assessment in a Chinese single institutional population.

Splenic hilar lymph node metastasis independently predicts poor survival for patients with gastric cancers in the upper and/or the middle third of the stomach

BACKGROUND

Effectiveness of splenectomy for advanced gastric cancers occupying the upper and/or the middle third of the stomach is still in debate. The aim of the present study is to elucidate the impact of splenectomy on patient survival by investigating the pathological characteristics and prognostic significance of splenic hilar lymph node metastasis.

METHODS

Clinicopathologic and prognostic data of 265 patients with gastric cancer in the upper and/or the middle third of the stomach who underwent the operation of en bloc resection of primary cancer and D2/D3 lymphadenectomy combined with splenectomy were retrospectively reviewed.

RESULTS

Multivariate analysis revealed pT category, pN category, and distant lymph node metastasis independently correlated with the presence of splenic hilar lymph node metastasis. Prognoses of patients with positive splenic hilar lymph nodes were significantly poorer than that of patients with negative splenic hilar lymph nodes for the entire study population and for those who underwent R0 resection, but not for those who underwent R1-2 resection. There was no significant difference in survival between patients who underwent R0 resection with positive splenic hilar lymph nodes and those who underwent R1-2 resection. Splenic hilar lymph node metastasis was one of independent indicators predicting worse prognosis and the presence of distant metastasis after surgery. Subset analysis according to the TNM stage revealed there were significant differences in survival between patients with and without splenic hilar lymph node metastasis.

CONCLUSIONS

Splenic hilar lymph node metastasis should be considered as one of incurable factors. Consequently, the efficiency of splenectomy aiming at prolonging survival for patients with high risk of splenic hilar lymph nodes metastasis should be questioned, although resection of invasive organs form gastric cancers has been recommended if R0 surgery could be achieved.

Does N ratio affect survival in D1 and D2 lymph node dissection for gastric cancer?

AIM: To identify whether there could have been changes in survival if lymph node ratio (N ratio) had been used.

METHODS: We assessed 334 gastric adenocarcinoma cases retrospectively between 2001 and 2009. Two hundred and sixteen patients out of 334 were included in the study. Patients were grouped according to disection1 (D1) or dissection 2 (D2) dissection. We compared the estimated survival and actual survival determined by Pathologic nodes (pN) class and N ratio, and SPSS 15.0 software was used for statistical analysis.

RESULTS: Ninety-six (44.4%) patients underwent D1 dissection and 120 (55.6%) had D2 dissection. When groups were evaluated, 23 (24.0%) patients in D1 and 21 (17.5%) in D2 had stage migration (P = 0.001). When both D1 and D2 groups were evaluated for number of pathological lymph nodes, despite the fact that there was no difference in N ratio between D1 and D2 groups, a statistically significant difference was found between them with regard to pN1 and pN2 groups (P = 0.047, P = 0.044 respectively). In D1, pN0 had the longest survival while pN3 had the shortest. In D2, pN0 had the longest survival whereas pN3 had the shortest survival.

CONCLUSION: N ratio is an accurate staging system for defining prognosis and treatment plan, thus decreasing methodological errors in gastric cancer staging.

Impact of the number of dissected lymph nodes on survival for gastric cancer after distal subtotal gastrectomy

Objectives. To investigate the prognostic impact of the number of dissected lymph nodes (LNs) in gastric cancer after curative distal gastrectomy. Methods. The survival of 634 patients who underwent curative distal gastrectomy from 1995 to 2004 was retrieved. Long-term surgical outcomes and associations between the number of dissected LNs and the 5-year survival rate were investigated. Results. The number of dissected LNs was one of the most important prognostic indicators. Among patients with comparable T category, the larger the number of dissected LNs was, the better the survival would be (P < 0.05). The linear regression showed that a significant survival improvement based on increasing retrieved LNs for stage II, III and IV (P < 0.05). A cut-point analysis yields the greatest variance of survival rate difference at the levels of 15 LNs (stage I), 25 LNs (stage II) and 30 LNs (stage III). Conclusion. The number of dissected LNs is an independent prognostic factor for gastric cancer. To improve the long-term survival of patients with gastric cancer, removing at least 15 LNs for stage I, 25 LNs for stage II, and 30 LNs for stage III patients during curative distal gastrectomy is recommended.

Role of the lymph node ratio in pancreatic ductal adenocarcinoma. Impact on patient stratification and prognosis

BACKGROUND

Survival after resection of pancreatic adenocarcinoma is poor. Several prognostic factors such as the status of the resection margin, lymph node status, or tumor grading have been identified. Aim of the study was to evaluate the prognostic significance of the lymph node ratio (LNR) for resected pancreatic ductal adenocarcinoma.

MATERIALS AND METHODS

Data were collected from 101 patients who had undergone pancreatoduodenectomy for pancreatic ductal adenocarcinoma. Patients were divided into four groups according to the absolute LNR (0, 0-0.199, 0.2-0.399, >0.4). Kaplan-Meier and Cox proportional hazard models were used to evaluate the prognostic effect.

RESULTS

The actuarial 3- and 5-year survival rates were 32 and 17%, respectively. The median survival was 19 months. Patients with LNR 0/0-0.199/0.2-0.399/>0.4 survived 40.2/30.5/18.1, and 13.6 months, respectively (P = 0.001). At the multivariate analysis, lymph node status was not found to be a significant prognostic factor; on the contrary LNR >0.2 (P = 0.007), positive resection margin (P = 0.001), and grading (P = 0.05) were significantly related to survival.

CONCLUSION

LNR is a more powerful predictor of survival than the lymph node status in patients undergoing pancreaticoduodenectomy for ductal adenocarcinoma.

Can lymph node ratio take the place of pN categories in the UICC/AJCC TNM classification system for colorectal cancer?

BACKGROUND

Lymph node ratio (LNR) has been reported to represent a powerful independent prognostic value in some malignancies. The significance of LNR in colorectal cancer is still under debate.

METHODS

A total of 505 patients with stage III colorectal cancer were reviewed. Using running log-rank statistics, we calculated the best cutoff values for LNRs and proposed a novel rN category: rN1, 0% < LNR ≤ 35%; rN2, 35% < LNR ≤ 69%; and rN3, LNR > 69%. A Spearman's correlation coefficient test was used to assess the correlation between the number of retrieved nodes and the number of metastatic nodes, as well as the number of retrieved nodes and the LNRs. Univariate and two-step multivariate analyses were performed, respectively, to identify the significant prognostic clinicopathologic factors.

RESULTS

The 5-year overall survival rate decreased significantly with increasing LNRs: rN(1) = 61% survival rate, rN(2) = 30.3% survival rate, and rN(3) = 11.2% survival rate (P < 0.001). Univariate and two-step multivariate analyses identified the rN category as a significant prognostic factor no matter whether the minimum number of LNs retrieved was met. There was a significant prognostic difference among different rN categories for any pN category, but no apparent prognostic difference was seen between different pN categories in any rN category. Moreover, marked heterogeneity could be seen within III(a-c) substages when survival was compared among rN(1-3) categories but not between pN(1-2) categories.

CONCLUSIONS

rN categories have more potential for predicting patient outcomes and are superior to the UICC/AJCC pN categories. We recommend rN categories for prognostic assessment and rN categories should be reported routinely in histopathological reports.

The extent of lymph node dissection for gastric cancer: a critical appraisal

The extent of lymphadenectomy during therapeutic gastrectomy for gastric cancer remains a protracted and controversial issue. While traditionally extended lymphadenectomy is performed in Eastern Asia, limited lymphadenectomy is advocated by most western surgeons. Two large western randomized trials, meta-analyses and a recent systematic review were unable to demonstrate overall benefit from extended lymphadenectomy. In this review, the currently available data on this topic are critically evaluated, while ongoing studies and future perspective are discussed.

The interaction between N-category and N-ratio as a new tool to improve lymph node metastasis staging in gastric cancer: results of a single cancer center in Brazil

BACKGROUND

Depth of tumor invasion (T-category) and the number of metastatic lymph nodes (N-category) are the most important prognostic factors in patients with gastric cancer. Recently, the ratio between metastatic and dissected lymph nodes (N-ratio) has been established as one. The aim of this study is to evaluate the impact of N-ratio and its interaction with N-category as a prognostic factor in gastric cancer.

METHODS

This was a retrospective study in which we reviewed clinical and pathological data of 165 patients who had undergone curative surgery at our institution through a 9-year period. The exclusion criteria included metastases, gastric stump tumors and gastrectomy with less than 15 lymph nodes dissected.

RESULTS

The median age of the patients was 63 years and most of them were male. Total gastrectomy was the most common procedure and 92.1% of the patients had a D2-lymphadenectomy. Their 5-year overall survival was 57.7%. T-category, N-category, extended gastrectomy, and N-ratio were prognostic factors in overall and disease-free survival in accordance with univariate analysis. In accordance with TNM staging, N1 patients who have had NR1 had 5-year survival in 75.5% whereas in the NR2 group only 33% of the cases had 5-year survival. In the multivariate analysis, the interaction between N-category and N-ratio was an independent prognostic factor.

CONCLUSION

Our findings confirmed the role of N-ratio as prognostic factor of survival in patients with gastric cancer surgically treated with at least 15 lymph nodes dissected. The relationship between N-category and N-ratio is a better predictor than lymph node metastasis staging.

Gastric cancer and the search for a good prognostic classification: a challenge

INTRODUCTION

Gastric cancer is the second most common cancer worldwide. The standard treatment is radical surgical resection, but 60% of patients will present recurrence. TNM classification (6th edition, American Joint Committee on Cancer) recommends the removal of at least 15 regional lymph nodes to carry out an adequate pathological staging. But in our environment, only 20% of cases have the minimum recommended, so it would be very important to have an alternative prognostic. We designed a retrospective study to evaluate different prognostic factors in patients inadequately staged.

MATERIAL AND METHODS

We focused on patients with serosal involvement (pT3). The evaluation included general parameters such as age, sex, tumor site, histological type, type of gastrectomy, histological grade, number of nodes analyzed </≥ 10, lymph node ratio (LNR) with a 20% cutoff value, and adjuvant treatment. The association between clinicopathological variables and recurrence was investigated by univariate and multivariate logistic regression. It was considered statistically significant with P < 0.05.

RESULTS

A total of 92 patients who met the criteria were studied. Median age 65 years; 68% men, 32% women; median follow-up time for the overall population, 44 months (range 15-119 months); number of nodes analyzed, median 7 (range 0-14 nodes); recurrence in 59%; median time to recurrence, 15 months (range 3-48 months); the cumulative risk of relapse at five years, 64%. Multivariate statistical analysis showed that the LNR (P = 0.03) and total number of nodes analyzed </≥ 10 (P = 0.04) were independent predictors for the risk of recurrence.

CONCLUSION

LNR and total number of nodes analyzed with a threshold of 10 (</≥ 10 nodes analyzed) were independent predictors of recurrence in patients with gastric carcinoma pT3 and an insufficient number of nodes examined.

Log odds of positive lymph nodes: a novel prognostic indicator superior to the number-based and the ratio-based N category for gastric cancer patients with R0 resection

BACKGROUND

Log odds of positive lymph nodes (LODDS) is defined as the log of the ratio between the probability of being a positive lymph nodes and the probability of being a negative lymph nodes when one lymph node is retrieved. The value of LODDS staging system on prognostic assessment for gastric cancer patients with R0 resection is still unclear.

METHODS

Clinicopathologic and prognostic data of 2547 gastric cancer patients underwent D2 or D3 lymphadenectomy with R0 surgery were retrospectively studied.

RESULTS

Multivariate analysis indentified LODDS stage was an independent prognostic factor, but not pN classification or rN classification. The scatter plots of the relationship between LODDS and the number, the ratio of nodes metastasis, suggested that the LODDS stage had power to divide patients with the same number or ratio of nodes metastasis into different groups. For patients in each of the pN or rN classifications, significant differences in survival could always be observed among patients in different LODDS stages. However, for patients in each LODDS stage, prognosis was highly homologous between those in different pN or rN classifications. A minimum number of 10, 15, 20, 25, and 10 nodes retrieved should be met for patients in the pN0, pN1, pN2, pN3, and rN0-3 classifications, respectively, unless the hazard risks of death would be underestimated or overestimated. However, LODDS stage could discriminate among 5 groups of patients with highly homologous prognosis, regardless how many nodes retrieved.

CONCLUSIONS

The LODDS system is more reliable than the Union Internationale Contre le Cancer and American Joint Committee on cancer pN system and the rN system for prognostic assessment.

Ratio between metastatic and examined lymph nodes (N ratio) may have low clinical utility in gastric cancer patients treated by limited lymphadenectomy: results from a single-center experience of 526 patients

BACKGROUND

The aim of this study was to evaluate the prognostic value of the ratio of metastatic to examined lymph nodes (N ratio) in gastric cancer patients who underwent limited lymphadenectomy and had a small number (< or =15) of analyzed nodes.

METHODS

The prognostic value of the actual AJCC/UICC pN staging system and the N ratio (0%, 1-25%, > 25%) were analyzed by means of univariate and multivariate analyses for 526 patients who underwent R0 resection for gastric adenocarcinoma at the Latvia Oncology Center.

RESULTS

The mean (SD) number of analyzed nodes was 5.6 (2.8). The number of positive nodes significantly increased with the number of analyzed nodes (p < 0.001). No significant differences in survival (p = 0.508) and risk of death (p = 0.224) were observed between pN1 and pN2 subsets. When the N ratio (1-25% vs. > 25%) was taken into account, a significant difference was demonstrated between pNR1 and pNR2 with respect to survival (p = 0.017) and risk of death (p = 0.012). Nonetheless, the joint allocation of the two classifications demonstrated that only a minority of patients (28 cases) belonged to the pNR1 subset and none of these belonged to the AJCC/UICC pN2 subset.

CONCLUSIONS

When a small number of lymph nodes are analyzed, the N ratio can discriminate patients better than TNM classification. However, because a small number of retrieved nodes produced only a small number of pNR1 patients, the N ratio classification cannot be justified for clinical use.

Prognostic impact of metastatic lymph node ratio on gastric cancer after curative distal gastrectomy

AIM: To investigate the prognostic impact of metastatic lymph node ratio (rN) on gastric cancer after curative distal gastrectomy.

METHODS: A total of 634 gastric cancer patients who underwent curative resection (R0) of lymph nodes at distal gastrectomy in 1995-2004. Correlations between positive nodes and retrieved nodes, between rN and retrieved nodes, and between rN and negative lymph node (LN) count were analyzed respectively. Prognostic factors were identified by univariate and multivariate analyses. Staging accuracy of the pN category (5th UICC/TNM system) and the rN category was compared according to the survival rates of patients. A linear regression model was used to identify the relation between rN and 5-year survival rate of the patients.

RESULTS: The number of dissected LNs was related with metastatic LNs but not related with rN. Cox regression analysis showed that depth of invasion, pN and rN category were the independent predictors of survival (P < 0.05). There was a significant difference in survival between LN stages classified by the rN category or by the pN category (P < 0.05). However, no significant difference was found in survival rate between LN stages classified by the pN category or by the rN category (P > 0.05). Linear regression model showed a significant linear correlation between rN and the 5-year survival rate of gastric cancer patients (β = 0.862, P < 0.001). Pearson’s correlation test revealed that negative LN count was negatively correlated with rN (P < 0.001).

CONCLUSION: rN category is a better prognostic tool than the 5th UICC pN category for gastric cancer patients after curative distal gastrectomy. Increased negative LN count can reduce rN and improve the survival rate of gastric cancer patients.

New metastatic lymph node ratio system reduces stage migration in patients undergoing D1 lymphadenectomy for gastric adenocarcinoma

BACKGROUND

The American Joint Committee on Cancer (AJCC)/International Union Against Cancer (UICC) staging system for gastric cancer incorporates the absolute number of metastatic lymph nodes (N status) and is optimally used when >or=15 nodes are examined. The ratio of metastatic to examined nodes (N ratio) is an effective prognostic tool, but has not been examined in Western patients undergoing primarily D1 lymphadenectomy.

METHODS

Two hundred and fifty seven patients with gastric adenocarcinoma who underwent gastric resection between 1995 and 2005 at our institution were examined. Novel N ratio intervals were determined using the best cutoff approach (Nr0: N ratio = 0 and >or=15 nodes examined; Nr1: 0 <or= N ratio <or= 0.3; Nr2: 0.3 < N ratio <or= 0.7; and Nr3: N ratio > 0.7). Overall survival was examined according to N status and N ratio.

RESULTS

83% of patients underwent D1 lymphadenectomy with a median of 14 lymph nodes examined. Overall survival stratified by N status was significantly different in patients with <15 nodes examined compared with those with >or=15 nodes examined. When we stratified by N ratio intervals, there was no significant difference in overall survival in patients with <15 versus >or= 15 nodes examined. On multivariate analysis, N ratio but not N status was retained as an independent prognostic factor.

CONCLUSIONS

The use of N status for staging patients undergoing primarily D1 lymphadenectomy results in significant stage migration due to varying numbers of nodes examined. Use of N ratio reduces stage migration and may be a more reliable method of staging these patients.

Determining of metastatic lymph node ratio in patients who underwent D2 dissection for gastric cancer

The purpose of this study was to determine outcome of the ratio of metastatic lymph nodes to the total number of dissected lymph nodes (MLR) in patients with gastric cancer. We retrospectively analyzed 111 patients who underwent D(2) lymph node dissection. The prognostic factors including UICC/AJCC TNM classification and MLR were evaluated by univariate and multivariate analysis. The MLR was significantly higher in patients with a larger tumor, lymphatic vessel invasion, blood vessel invasion and perineural invasion, and advanced stage. Moreover, the MLR was significantly associated with the depth of invasion and the number of lymph node metastasis. The univariate analysis revealed for overall survival (OS) that stage of disease, lymphatic vessel invasion, blood vessel invasion, perineural invasion, lymph node metastasis (UICC/AJCC pN stage) and MLR were relevant prognostic indicators. Furthermore, both UICC/AJCC pN stage and MLR were detected as prognostic factor by multivariate analysis, as was perineural invasion. Our results indicated that MLR and UICC/AJCC pN staging system were important prognostic factors for OS of patients with D(2) lymph node dissection in gastric cancer in a multivariate analysis. MLR may be useful for evaluating the status of lymph node metastasis in gastric cancer.

Gastric cancer: predictors of recurrence when lymph-node dissection is inadequate

Background

The TNM classification (sixth edition) requires at least 15 lymph nodes to be examined to allow an accurate staging. However, in our environment, only 20% of patients have the recommended minimum of 15 nodes removed.

Purpose

To evaluate clinicopathological predictors of recurrence in patients with gastric cancer undergoing radical resection with an inadequate number of lymph nodes examined.

Methods

101 patients were included in this retrospective cohort. We evaluated age, gender, tumoral location, Borrmann type, Lauren histotype, type of gastrectomy, grade, invasion depth of tumor, lymph node involvement, ratio between metastatic and total number of excised lymph nodes keeping 20% as the cutoff value (LNR) and adjuvant treatment. The association between these variables and recurrence was investigated by using univariate methods and multivariate logistic regression analysis.

Results

Median (range) age was 63 years (44-85). 63% males, 37% females. Median follow-up time for the whole patients population was 36 months (10-104). Median number of lymph nodes retrieved was 6 (0-14). Recurrence: 50 of 101 cases (49,6%); 41 hematogeneus dissemination, 9 locoregional recurrences. The following factors were found to be correlated with the recurrence risk: tumoral location, invasion depth of tumor, lymph node involvement and LNR. A multivariate analysis revealed that depth of invasion [odds ratio (OR) 2.80, 95% confidence interval (CI) 1.03-7.58, P = 0.04] and LNR (OR 2.34, 95% CI 1.05-5.21, P = 0.03) were independent risk factors for recurrences of gastric cancer. Median time to recurrence: 16 months (2-50). 82% of recurrences occurred within the first two years after surgical treatment. The estimated cumulative risk of recurrence at five years: 61% in the whole patients population, with serosal invasion and LNR > and < 20% was 82% and 44%, without serosal invasion 73% and 39% respectively.

Conclusion

Invasion depth of tumor and LNR were independent predictors of recurrence in gastric cancer after potentially curative resection with an inadequate number of lymph nodes examined.