The Staging of Gastric Cancer: Nothing Novel but Perhaps Better

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.

Ratio of metastatic to resected lymph nodes for prediction of survival in patients with inadequately staged gastric cancer

Background

Staging is inadequate in up to 70 per cent of patients with gastric cancer in Western countries owing to the small number of lymph nodes dissected during surgery. The aim was to determine whether using the ratio of metastatic to resected lymph nodes (LNR) might improve accuracy.

Methods

Data were analysed from patients with gastric cancer who had gastrectomy in several centres between 1986 and 1998, with dissection of 15 or fewer lymph nodes. LNRs and other prognostic factors were evaluated.

Results

From a total of 738 patients, the median number of resected nodes was 8 (range 1–15) and median LNR was 42·8 per cent. The number of metastatic nodes significantly affected survival only in univariable analysis. In a Cox proportional hazards model, patient age, depth of tumour infiltration, tumour location, and LNR were identified as independent prognostic factors. Compared with node-negative patients, the hazard ratio for an LNR of 0·1–40·0 per cent was 1·85 (P < 0·001), increasing to 2·93 (P < 0·001) when the LNR exceeded 40·0 per cent.

Conclusion

The LNR cannot be used as a substitute for staging with adequate lymphadenectomy. It may help to stratify patients in terms of prognosis when the number of resected lymph nodes is limited.

Prognostic impact of metastatic lymph node ratio in advanced gastric cancer from cardia and fundus

AIM: To investigate the prognostic impact of the metastatic lymph node ratio (MLR) in advanced gastric cancer from the cardia and fundus.

METHODS: Two hundred and thirty-six patients with gastric cancer from the cardia and fundus who underwent D2 curative resection were analyzed retrospectively. The correlations between MLR and the total lymph nodes, positive nodes and the total lymph nodes were analyzed respectively. The influence of MLR on the survival time of patients was determined with univariate Kaplan-Meier survival analysis and multivariate Cox proportional hazard model analysis. And the multiple linear regression was used to identify the relation between MLR and the 5-year survival rate of the patients.

RESULTS: The MLR did not correlate with the total lymph nodes resected (r = -0.093, P = 0.057). The 5-year overall survival rate of the whole cohort was 37.5%. Kaplan-Meier survival analysis identified that the following eight factors influenced the survival time of the patients postoperatively: gender (χ² = 4.26, P = 0.0389), tumor size (χ² = 18.48, P < 0.001), Borrmann type (χ² = 7.41, P = 0.0065), histological grade (χ² = 5.07, P = 0.0243), pT category (χ² = 49.42, P < 0.001), pN category (χ² = 87.7, P < 0.001), total number of retrieved lymph nodes (χ² = 8.22, P = 0.0042) and MLR (χ² = 34.3, P < 0.001). Cox proportional hazard model showed that tumor size (χ² = 7.985, P = 0.018), pT category (χ² = 30.82, P < 0.001) and MLR (χ² = 69.39, P < 0.001) independently influenced the prognosis. A linear correlation between MLR and the 5-year survival was statistically significant based on the multiple linear regression (β = -0.63, P < 0.001). Hypothetically, the 5-year survival would surpass 50% when MLR was lower than 10%.

CONCLUSION: The MLR is an independent prognostic factor for patients with advanced gastric cancer from the cardia and fundus. The decrease of MLR due to adequate number of total resected lymph nodes can improve the survival.