Prognostic value of preoperative serum lactate dehydrogenase levels for resectable gastric cancer and prognostic nomograms

The present study aimed to evaluate the prognostic significance of preoperative serum lactate dehydrogenase (SLDH) levels for resected gastric cancer and construct prognostic nomograms for risk prediction. The study cohort consisted of 619 patients with D2-resected gastric cancer. The relationship of SLDH levels with clinicopathological features and clinical outcomes was evaluated. Prognostic nomograms were created using identified prognosticators to predict 3-year overall survival (OS) and 3-year disease-free survival (DFS), and bootstrap validation was performed. High SLDH levels were correlated with old age but not depth of invasion or lymph node metastasis. When assessed as a continuous variable, high SLDH levels were independently associated with poor OS and DFS. Internal validation of the developed nomograms revealed good predictive accuracy (bootstrap-corrected concordance indices: 0.77 and 0.75, respectively for prediction of OS and DFS). The preoperative SLDH levels, an identified unfavorable prognosticator, were incorporated into nomograms along with other clinicopathological features to refine the prediction of clinical outcomes for patients with D2-resected gastric cancer.

Comparison of prognostic nomograms based on different nodal staging systems in patients with resected gastric cancer

Purpose: Previous studies addressing the optimal nodal staging system in patients with resected gastric cancer have shown inconsistent results, and the optimal system for development of prognostic nomograms remains unclear. In this study, we compared prognostic nomograms based on the metastatic lymph node (MLN) count, lymph node ratio (LNR), and log odds of metastatic lymph nodes (LODDS) to predict the 5-year overall survival in patients with resected gastric cancer. Methods: We analysed 15,320 patients with resected gastric cancer in the Surveillance, Epidemiology, and End Results (SEER) database between 1988 and 2010. Missing data were handled using multiple imputation. When assessed as a continuous covariate with restricted cubic splines, each MLN, LNR, and LODDS variable was incorporated into a nomogram with other significant prognosticators to predict the 5-year overall survival. A two-centre Chinese dataset (1,595 cases) was used as external validation data. Results: The discriminatory abilities of the MLN-, LNR-, and LODDS-based nomograms were comparable (concordance indices: 0.744, 0.741, and 0.744, respectively, in the SEER set, P > 0.152 for all pairwise comparisons; 0.715, 0.712, and 0.713, respectively, in the Chinese set, P > 0.445 for all pairwise comparisons). The discriminatory abilities of the three nomograms were all superior to the American Joint Committee on Cancer (AJCC) TNM classification (concordance indices: 0.713, P < 0.001 for all in the SEER set; and 0.693, P < 0.001 for all in the Chinese set). The discriminatory abilities of the nomograms were comparable regardless of the number of nodes examined. Moreover, decision curve analyses indicated similar net benefits of using the nomograms. Conclusion: MLN-, LNR-, and LODDS should be considered equally in the development of multivariate prognostic models and nomograms to refine the prediction of survival among patients with resected 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.

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 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.

Stage migration effect on survival in gastric cancer surgery with extended lymphadenectomy: the reappraisal of positive lymph node ratio as a proper N-staging

OBJECTIVE

The purpose of this study is to analyze the relationship between the number of examined lymph nodes (NexLN) and survival in gastric cancer and to determine whether the metastatic/examined lymph node ratio (LN ratio) system can compensate for the shortcomings of the UICC/AJCC staging.

METHODS

Prospective data of 8949 primary T1-T4a gastric cancer patients who underwent curative surgery were reviewed. The patients were stratified by T-stage and grouped according to NexLN; 1 to 14 exLN denoted the first group and every subsequent 10 LNs thereafter. Numbers of LN and 5-year survival rates were analyzed according to NexLN. "The NR-staging system" was generated using 0.2 and 0.5 as the cut-off values of LN ratio and then compared with UICC/AJCC stages.

RESULTS

The proportion of advanced N-stage increased with NexLN. Survival and the LN ratio were constant regardless of NexLN when combining all N0-N3b patients, however, T2/3 and T4a patients showed an increasing tendency toward survival in N1/2 and N3a as NexLN increased, mainly due to a stage migration effect. The LN ratio system showed better patterns of distribution of the LN stage and survival graph. The power of the differential staging of the LN ratio system was fortified with higher NexLN.

CONCLUSION

The relationship between NexLN and survival is probably affected by stage migration in a high-volume gastric cancer center. The LN ratio system could be a better option to compensate for this effect, and the value of the prognosis prediction in this system increases with a higher NexLN.

Long-term results of tailored D(2) lymph node dissection after R(0) surgery for gastric cancer

Implementation of extended lymph node dissection for gastric cancer in western non-specialized centers through tailoring its extent upon disease stage and patient comorbidities was suggested as a wise policy to reduce morbidity and mortality rates, albeit with a potential for undertreatment in elderly and/or comorbid patients. Current definition of R(0) resection for gastric cancer lacks consideration of treatment-related variables such as extended lymph node dissection. Few studies to date have tried to fill this gap in such a clinical context. A retrospective evaluation of factors influencing long-term results after R(0) surgery was done in a prospective series of a non-specialized western surgical unit during the implementation of D(2) lymphadenectomy. Univariate and multivariate analysis of 22 variables were performed on a prospective database of 233 consecutive R(0) resections performed by ten different surgeons in 10 years. Endpoint was disease-free survival calculated at 5 and at 10 years. Disease-free survival rates were independently influenced by age, American Society of Anesthesiologists (ASA) status and lymph node ratio. Subset analysis of the status at censor stratified for age and ASA status failed to identify any significant difference in disease recurrence rates. Lymph node ratio was the only treatment-related independent prognostic factor for long-term results after R(0) surgery for gastric cancer in the setting of a non-specialized western unit, where the extent of lymph node dissection needs to be tailored on the presence of comorbidities (ASA status).

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.