Does the new TNM classification (1997) improve prognostic stratification in gastric cancer submitted to R0 surgery?

Evaluation of the 7th AJCC TNM Staging System in Point of Lymph Node Classification

PURPOSE

The 7th AJCC tumor node metastasis (TNM) staging system modified the classification of the lymph node metastasis widely compared to the 6th edition. To evaluate the prognostic predictability of the new TNM staging system, we analyzed the survival rate of the gastric cancer patients assessed by the 7th staging system.

MATERIALS AND METHODS

Among 2,083 patients who underwent resection for gastric cancer at the department of surgery, Hanyang Medical Center from July 1992 to December 2009, This study retrospectively reviewed 5-year survival rate (5YSR) of 624 patients (TanyN3M0: 464 patients, TanyNanyM1: 160 patients) focusing on the number of metastatic lymph node and distant metastasis. We evaluated the applicability of the new staging system.

RESULTS

There were no significant differences in 5YSR between stage IIIC with more than 29 metastatic lymph nodes and stage IV (P=0.053). No significant differences were observed between stage IIIB with more than 28 metastatic lymph nodes and stage IV (P=0.093). Distinct survival differences were present between patients who were categorized as TanyN3M0 with 7 to 32 metastatic lymph nodes and stage IV. But patients with more than 33 metastatic lymph nodes did not show any significant differences compared to stage IV (P=0.055). Among patients with TanyN3M0, statistical significances were seen between patients with 7 to 30 metastatic lymph nodes and those with more than 31 metastatic lymph nodes.

CONCLUSIONS

In the new staging system, modifications of N classification is mandatory to improve prognostic prediction. Further study involving a greater number of cases is required to demonstrate the most appropriate cutoffs for N classification.

Classification of Lymph Node Metastases from Gastric Cancer: Comparison between N-Site and N-Number Systems. Our Experience and Review of the Literature

The tumor, node, metastasis (TNM) system has become the principal method for assessing the extent of disease, determining prognosis in gastric cancer patients, and affecting the therapy strategies. The extent of lymph node metastasis is the most important prognostic factor. The aim of this study was to compare the N-classifications of the 4th and the 5th-6th TNM editions and to evaluate retrospectively the prognostic value of the 2002 TNM edition. We evaluated 344 patients who underwent curative total or subtotal gastrectomy. Nodal involvement was detected in 221 (64%) patients. Median follow-up period was 76 months. Thirty per cent of the old N1 patients were reclassified as pN2 (18.5%) and pN3 (11.3%). Eighty-eight per cent of the old N2 patients were reclassified as pN1 (75%) and pN3 (13.7%). In reclassifying the patients, statistically significant changes were reported between 1987 and 2002 TNM stage grouping, mainly in stage IIIB and IV. The 5-year survival rate per stage group did not statistically differ between the 4th and the 5th–6th editions, although a diminutive trend was registered in the IIIA stage. pTNM stage, nodal numerical stage, nodal topographical stage, and depth of tumor invasion resulted in significantly independent prognostic factors. Our data confirm the simplicity and easy application of the new stadiation and the better prognostic stratification of the N-stage. The pN3 group showed a worse prognosis independent of location. On the other hand, prognostic value of pN1 and pN2 stage is lower, probably depending on lymph node location. In multivariate analysis, the difference between old and new TNM staging is low. Hence, we suggest comparing lymph node location and number in larger series. In our series, in pT1 tumors, neither pN2 nor pN3 involvement was found. Hence, in our opinion, for correct N-staging, 10 lymph nodes in early gastric cancer and at least 16 in the other pT-stages seem sufficient for a real pN0 stadiation.

Comparison of old and new TNM systems for nodal staging in adenocarcinoma of the gastro-oesophageal junction

Background

Adenocarcinoma of the gastro-oesophageal junction is considered a distinct clinical entity, although the current pathological tumour node metastasis (pTNM) classification does not consider this tumour specifically. A prospective study was undertaken to determine the prognostic importance of lymph node involvement in adenocarcinoma of the gastro-oesophageal junction, analysing both a number- and site-based classification, in order to develop a clinically useful nodal staging system.

Methods

Two classification systems were analysed in 116 patients who underwent resection for adenocarcinoma of the gastro-oesophageal junction from January 1988 to August 2001. The Cox regression model was used to evaluate the prognostic significance of the site and number of positive nodes.

Results

The number- and site-based staging systems coincided only in 42 (56 per cent) of 75 patients; in particular, the old pN1 classification was upstaged in 13 of 41 patients and the old pN2 was downstaged in 13 of 34 patients. Lymph node involvement was the most important prognostic factor in both classifications (P < 0·001). The risk of death was significantly influenced by the site of nodal metastasis among patients with a similar number of involved nodes (relative risk with respect to pN0: 2·18 for pN1 with one to six nodes; 6·53 for pN2 with one to six nodes; 7·53 for pN1 with more than six nodes; 39·13 for pN2 with more than six nodes).

Conclusion

Adenocarcinoma of the gastro-oesophageal junction requires a specific lymph node classification which should take into account both the number and site of nodal metastases.

The superiority of ratio-based lymph node staging in gastric carcinoma

BACKGROUND

The need for a precise lymph node staging without stage migration is of paramount importance when comparing and evaluating international treatment results.

METHODS

We reviewed 1019 patients who underwent R0 resection at Kansai Medical University between 1980 and 1997. The patients were classified according to the 1997 International Union Against Cancer (UICC)/American Joint Committee on Cancer (AJCC) pN classification or the N staging depending on the ratio between the number of excised and the number of involved lymph nodes (pN1, < or = 25%; pN2, < or = 50%; pN3, >50%).

RESULTS

Among the 1997 UICC/AJCC pN subgroups, prognosis worsened with an increase in lymph node ratio. In contrast, the ratio-based classification showed more homogenous survival according to the number of involved lymph nodes. Multiple stepwise regression analysis showed that the ratio-based classification was the most significant prognostic factor, whereas the 1997 UICC/AJCC classification was not found to be an independent predictor of survival. In addition, the ratio-based classification showed a superiority to the 1997 UICC/AJCC classification with respect to stage migration.

CONCLUSIONS

Ratio-based lymph node staging is simple and gives more precise information for prognosis with fewer problems related to stage migration than the 1997 UICC/AJCC staging system.

Utility of prognostic stratification in adults with community-acquired bacterial meningitis

Prognostic stratification uses baseline clinical features to subdivide patients into subgroups with different risks for a particular outcome. We review the importance of prognostic stratification in internal medicine, in infectious diseases, and in adults with community-acquired bacterial meningitis.

Evaluation of the 5th edition of the TNM classification for gastric cancer: improved prognostic value

The main change in the 5th edition (1997) of the TNM classification for gastric cancer compared to the 4th edition (1987) is the use of the number of involved nodes instead of the location of positive nodes. As a result stage grouping is also altered. A second change is the requirement for the examination of at least 15 nodes to justify the N0 status. Patients with fewer examined negative nodes are unclassifiable (Nx). Data were retrieved from a randomized trial database comparing D1 and D2 dissection and 633 curatively operated patients were included. According to the criteria of the 5th edition, 39% of the node-positive patients had another N stage compared to the 4th: 21% had a lower and 18% had a higher stage. 5-year survival rates according to the 4th edition N0, N1 and N2 groups were respectively 72%, 34% and 27%. According to the 5th edition these percentages were for the N0, N1, N2, N3 and Nx groups respectively 75%, 38%, 19%, 8% and 65%. The former 1987 N1 and N2 group were significantly split into three new N 1997 groups (P = 0.006, respectively P< 0.0005). The Cox's regression analysis showed the N 1997 classification to be the most important prognostic variable, with a higher prognostic value than N 1987. In addition, the new TNM stage was also a better prognosticator. The requirement for examining at least 15 nodes, however, could not be fulfilled in 38% of all node-negative patients and we found that a minimum of 5 consecutive negative lymph nodes is a reliable number for staging purposes. We conclude that the 5th edition of the TNM classification provides a better estimation of prognosis, however, examination of at least 15 negative regional lymph nodes is too high a threshold and 5 gives similar prognostic value.

A prognostic score for gastric cancer

BACKGROUND

Scoring systems are generally used for predicting prognosis in the intensive care unit, but there is no score being used frequently for predicting prognosis in gastric cancer. The aim of this study was to develop a prognostic score for gastric cancer patients.

METHODS

Demographic, clinical, laboratory, radiologic, histopathologic data, and operative findings for 128 patients who had curative or palliative resection for gastric cancer were analyzed for their effect on overall and disease-free survival. Ten variables-invasion depth of tumor, node status (American Joint Committed on Cancer, 1992), metastasis, node status (Union Internationale Contre le Cancer, 1997), metastatic lymph node ratio, resectability, tumor location, extent of lymphadenectomy, Borrmann type, Lauren type-that have independent significant effect or borderline significance on both overall and disease-free survival according to multivariate analysis were chosen. Coefficients were calculated for these variables by using Cox regression analysis, and thus the Prognostic Score for Gastric Cancer (PSGC) was designed. All patients were scored using the PSGC and also staged clinically (AJCC 1992) and histopathologically (AJCC 1992 and UICC 1997).

RESULTS

Patients were grouped according to their scores: group 1, patients with scores 20 to 50 (probability of 5-year overall survival 50% to 95%); group 2, patients with scores 51 to 80 (probability of 5-year overall survival 10% to 50%); and group 3, patients with scores 81 and higher (probability of 5-year overall survival <10%). Overall survival and disease-free survival decreased significantly with increasing scores. The association of PSGC and staging systems with survival was analyzed by stepwise logistic regression and Cox regression analyses. PSGC was proved to have the most significant association with overall and disease-free survival.

CONCLUSIONS

Inclusion of more variables in PSGC seems to make it superior than staging. It is easy to adapt PSGC to different patient populations, which may make it accepted as a practical and useful scoring system in clinical practice.