A comprehensive analysis comparing the eighth AJCC gastric cancer pathological classification to the seventh, sixth, and fifth editions

Revisiting the 8th AJCC system for gastric cancer: A review on validations, nomograms, lymph nodes impact, and proposed modifications

Gastric cancer is the fifth most frequently diagnosed cancer worldwide, behind breast, lung, colorectal, and prostate cancers. In gastric cancer, multimodality treatment shows prospective benefits and also improves survival. Surgery, however, is the mainstay of curative treatment. The staging of gastric cancer patients is critical for harmonization of care. Accurate stages assure that informed clinical decisions are timely made. The American Joint Committee on Cancer (AJCC) staging system is the most widely applied system in to determine the disease's prognosis and survival prediction. The recently adopted 8th AJCC TNM staging system has been revised to enhance its survival predictive power. Subsequent studies have established the validity of the current edition, demonstrating improved stage stratification, discriminatory power, and survival prediction. However, other studies have cast doubt on the superiority of the new edition. Innovations aimed at further improving its prognosis have resulted in developing of novel models. Advances in our understanding of the tumor microenvironment and molecular categorization of cancer have resulted in proposals for their inclusion in TNM staging as potential complementary factors that enhance survival prediction and prognostic assessment ability. The purpose of this study is to conduct a review of the published literature regarding the validity of the 8th AJCC TNM staging system, proposed modifications, and nomograms.

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The 8th AJCC is valid in prognostic stratification of gastric cancer, however, revisions are still required.

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The yPT staging requires some modifications and inclusion of stages that currently don't exist in the 8th AJCC.

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High lymph nodes count and anatomical localization improve the prediction ability of the current AJCC.

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Nomograms comprising of individual prognostic factors are crucial to the current AJCC.

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Molecular markers positively influence survival prediction of gastric cancer.

A novel 8-genome instability-associated lncRNAs signature predicting prognosis and drug sensitivity in gastric cancer

BACKGROUND

Genome instability lncRNA (GILnc) is prevalently related with gastric cancer (GC) pathophysiology. However, the study on the relationship GILnc and prognosis and drug sensitivity of GC remains scarce.

METHOD

We extracted expression data of 375 GC patients from TCGA cohort and 205 GC patients from GSE26942 cohort. Then, lncRNA was separated from expression data, and systematically characterized the 8 marker lncRNAs using the LASSO method. Next, we constructed a GILnc model (GILnc score) to quantify the GILnc index of each GC patient. Finally, we analyzed the relationship between GILnc score and clinical traits including survival outcomes, TP53, and drug sensitivity of GC.

RESULTS

Based on a computational frame, 205 GILncs in GC has been identified. Then, a 8 GILncs was successfully established to predict overall survival in GC patients based on LASSO analysis, divided GC samples into high GILnc score and low GILnc score groups with significantly different outcome and was validated in multiple independent patient cohorts. Furthermore, GILnc model is better than the prediction performance of two recently published lncRNA signatures, and the high GILnc score group was more sensitive to mitomycin. Besides, the GILnc score has greater prognostic significance than TP53 mutation status alone and is capable of identifying intermediate subtype group existing with partial TP53 functionality in TP53 wild-type patients. Finally, GILnc signature as verified in GSE26942.

CONCLUSION

We applied bioinformatics approaches to suggest that a 8 GILnc signature could serve as prognostic biomarkers, and provide a novel direction to explore the pathogenesis of GC.

Challenges surrounding postoperative adjuvant chemotherapy for T2N0 gastric cancer

Determining the requirement for adjuvant chemotherapy in patients with stage IB gastric cancer (GC), and particularly for those with stage T2N0 (muscularis propria) disease, remains challenging. Patients with stage II/III disease benefit from postoperative adjuvant therapy; however, the randomized trials examining whether such therapy affords any survival benefit to patients with T2N0 disease are not sufficient. Current evidence suggests that not all patients with T2N0 disease should undergo such treatment, but only those with a high risk. To date, a number of retrospective studies have attempted to identify factors that are predictive of increased risk in an effort to guide adjuvant therapy-related clinical decision making. The National Comprehensive Cancer Network and the Chinese Society of Clinical Oncology have published guidelines regarding factors associated with increased patient risk. As a result, treatment decisions for patients with stage T2N0 disease are currently determined on an individualized basis, in light of risk factors and the potential benefits of treatment. The present review surveyed current evidence related to the treatment of patients with high-risk GC and highlighted the potential avenues for future investigated.

Prognostic implications of the eighth edition of the union for international cancer control - classification for gastric cancer patients from specialized treatment centers in Germany and Korea: A STOBE-Compliant large-scale cohort study

The validity of the 8th edition of the Union for International Cancer Control (UICC) staging system for gastric cancer has been evaluated only in Asian cohorts and not in European cohorts. The aim of this study was to evaluate the prognostic performance of the 8th edition of the UICC staging system in German and Korean cohorts independently and compare it with that of the 7th edition.A total of 6121 patients (526 from Germany and 5595 from Korea) who underwent upfront surgery for gastric cancer were retrospectively reclassified according to the 8th edition. Survival according to the UICC stages was estimated by the Kaplan-Meier method and compared by log-rank tests. A Cox proportional hazards model was fitted after adjusting for clinicopathological factors, and receiver operating characteristics analysis was conducted.The 8th edition showed significant differences in survival between each adjacent stage in the Korean cohort but not in the German cohort. Multivariate analyses revealed that the 8th edition staging was an independent prognostic factor, and its C-statistics were >0.76 in both German and Korean patients. The results were comparable to those observed with the UICC seventh edition (C-statistics was 0.768 vs 0.767 in the German cohort and 0.789 vs 0.785 in the Korean cohort for the 7th vs the 8th edition).The 8th edition showed prognostic value in predicting the survival of gastric cancer patients in both German and Korean cohorts. However, the predictive ability of the 8th and 7th edition was similar.

Longer Operating Time During Gastrectomy Has Adverse Effects on Short-Term Surgical Outcomes

BACKGROUND

Gastric cancer continues to be one of the malignant tumor types with high morbidity and mortality worldwide. Although remarkable improvements have been made to combat gastric cancer, surgery is still the first choice of treatment for gastric cancer.

METHODS

This was a single-center and retrospective study. A total of 110 patients who underwent radical gastrectomy with D2 lymph node dissection between 2014 and 2017 were included in this study, and all patients were treated by the same medical staff. Based on the median operating time, patients were grouped into a long-time group (>180 min) and a short-time group (≤180 min). Influences of operating time on outcomes of patients in the short-term and long-term groups were analyzed.

RESULTS

The long-time group showed a higher incidence of postoperative complications compared with the short time group (P < 0.01) with a significant decrease in serum albumin and the prognostic nutritional index value. Moreover, a long operating time was often caused by the operating start time (P < 0.001), excision difficulty caused by lager tumor size (P < 0.001), worse tumor differentiation, and deeper tumor invasion (P < 0.05). However, length of operating time did not significantly influence overall survival of patients who underwent radical gastrectomy.

CONCLUSIONS

The results suggested that operating time might be an indicator of the incidence of postoperative complication and that several important variables, such as prognostic nutritional index, serum albumin, operating start time, and excision time, could be intervened in the perioperative period to help patients gain a better outcome after gastrectomy.

Mutations Defining Patient Cohorts With Elevated PD-L1 Expression in Gastric Cancer

The immunotherapy agent pembrolizumab has been approved for gastric cancer (GC) patients with recurrent or advanced disease who are PD-L1 positive. Mutations in the primary lesion may drive the expression of immune targets thereby priming the tumor to therapeutic sensitivity. In this study, we aimed to uncover mutations associated with elevated PD-L1 expression in GC patients. Data from 410 GC patients were available, including the mutational spectrum of 39,916 genes and expression values of 20,500 genes. PD-L1 gene expression was compared to the mutational status of each gene separately by using a Mann-Whitney U-test and a Receiver Operating Characteristic test. Only mutations with a prevalence over 5% were considered. Significance was accepted in cases of p < 1E-05 and a fold change over 1.44. Mutations in 209 genes were associated with increased PD-L1 expression. These mutations were enriched in genes related to microtubule-based movement (p = 3.4E-4), cell adhesion (p = 4.9E-4), response to DNA-damage (p = 6.9E-4), and double-strand break-repair (p = 1.6E-3). Mutations in TTK (p = 8.8E-10, AUC = 0.77), COL7A1 (p = 2.0E-9, AUC = 0.74), KIF15 (p = 2.5E-9, AUC = 0.75), and BDP1 (p = 3.3E-9, AUC = 0.74) had the strongest link to elevated PD-L1 expression. Finally, we established a decision tree based on mutations in PIK3CA, MEF2C, SLC11A1, and KIF15 capable to separate patient sub-cohorts with elevated PD-L1 expression. In summary, we identified mutations associated with elevated PD-L1 expression that facilitate the development of better prognostic biomarkers for GC, and might offer insight into the underlying tumor biology.

Proposal and validation of a modified staging system to improve the prognosis predictive performance of the 8th AJCC/UICC pTNM staging system for gastric adenocarcinoma: a multicenter study with external validation

Background

The 8th edition of the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) pathological tumor-node-metastasis (pTNM) staging system may have increased accuracy in predicting prognosis of gastric cancer due to its important modifications from previous editions. However, the homogeneity in prognosis within each subgroup classified according to the 8th edition may still exist. This study aimed to compare and analyze the prognosis prediction abilities of the 8th and 7th editions of AJCC/UICC pTNM staging system for gastric cancer and propose a modified pTNM staging system with external validation.

Methods

In total, clinical data of 7911 patients from three high-capacity institutions in China and 10,208 cases from the Surveillance, Epidemiology, and End Results (SEER) Program Registry were analyzed. The homogeneity, discriminatory ability, and monotonicity of the gradient assessments of the 8th and 7th editions of AJCC/UICC pTNM staging system were compared using log-rank χ², linear-trend χ², likelihood-ratio χ² statistics and Akaike information criterion (AIC) calculations, on which a modified pTNM classification with external validation using the SEER database was proposed.

Results

Considerable stage migration, mainly for stage III, between the 8th and 7th editions was observed in both cohorts. The survival rates of subgroups of patients within stage IIIA, IIIB, or IIIC classified according to both editions were significantly different, demonstrating poor homogeneity for patient stratification. A modified pTNM staging system using data from the Chinese cohort was then formulated and demonstrated an improved homogeneity in these abovementioned subgroups. This staging system was further validated using data from the SEER cohort, and similar promising results were obtained. Compared with the 8th and 7th editions, the modified pTNM staging system displayed the highest log-rank χ², linear-trend χ², likelihood-ratio χ², and lowest AIC values, indicating its superior discriminatory ability, monotonicity, homogeneity and prognosis prediction ability in both populations.

Conclusions

The 8th edition of AJCC/UICC pTNM staging system is superior to the 7th edition, but still results in homogeneity in prognosis prediction. Our modified pTNM staging system demonstrated the optimal stratification and prognosis prediction ability in two large cohorts of different gastric cancer populations.

A comprehensive analysis comparing the eighth AJCC gastric cancer pathological classification to the seventh, sixth, and fifth editions

To perform a comprehensive analysis comparing the prognostic and discriminative ability of the eighth AJCC gastric cancer (GC) pathological classification to that of the seventh, sixth and fifth editions, and secondly to assess their long‐term significance. Patients who had undergone R0 gastrectomy were identified and restaged accordingly. To evaluate and confirm any difference in prognostic ability between the competing editions, the Akaike information criterion (AIC) and Bayesian information criterion (BIC) were computed and compared since both have different analytic strengths. The area under the curve (AUC) with 95% CI based on the time‐dependent receiver‐operating characteristics analyses were also calculated to assess any change in prognostic rankings from the first to tenth postoperative year. The rankings calculated by both statistical methods showed similar results, in which the seventh edition was identified as possessing the best prognostic ability. Additionally, these ranks were found to remain consistent over the ten postoperative years, but demonstrated no clinical significance as their respective 95% CIs calculated by the AIC, BIC, and AUC were found to overlap. However, the more detailed staging classifications of the eighth edition was shown to display the best prognostic demarcation for stratifying patients with higher‐staged disease. This study thereby identified the eighth AJCC GC edition to possess similar long‐term prognostic ability as to its previous three editions but contrastingly demonstrated the best distinctive ability for stratifying overall survival and can thus be considered as being clinically more reliable.