Performance of a nomogram predicting disease-specific survival after an R0 resection for gastric cancer in patients receiving postoperative chemoradiation therapy

Development and External Validation of a Nomogram to Predict Recurrence-Free Survival After R0 Resection for Stage II/III Gastric Cancer: An International Multicenter Study

Background: The benefit of adjuvant chemotherapy varies widely among patients with stage II/III gastric cancer (GC), and tools predicting outcomes for this patient subset are lacking. We aimed to develop and validate a nomogram to predict recurrence-free survival (RFS) and the benefits of adjuvant chemotherapy after radical resection in patients with stage II/III GC.

Methods: Data on patients with stage II/III GC who underwent R0 resection from January 2010 to August 2014 at Fujian Medical University Union Hospital (FMUUH) (n = 1,240; training cohort) were analyzed by Cox regression to identify independent prognostic factors for RFS. A nomogram including these factors was internally and externally validated in FMUUH (n = 306) and a US cohort (n = 111), respectively.

Results: The multivariable analysis identified age, differentiation, tumor size, number of examined lymph nodes, pT stage, pN stage, and adjuvant chemotherapy as associated with RFS. A nomogram including the above 7 factors was significantly more accurate in predicting RFS compared with the 8^th AJCC-TNM staging system for patients in the training cohort. The risk of peritoneal metastasis was higher and survival after recurrence was significantly worse among patients calculated by the nomogram to be at high risk than those at low risk. The nomogram's predictive performance was confirmed in both the internal and external validation cohorts.

Conclusion: A novel nomogram is available as a web-based tool and accurately predicts long-term RFS for GC after radical resection. The tool can also be used to determine the benefit of adjuvant chemotherapy by comparing scores with and without this intervention.

Evaluating TNM stage prognostic ability in a population-based cohort of gastric adenocarcinoma patients in a low-incidence country

OBJECTIVES

TNM stage is the preeminent cancer staging system and a fundamental determinant of disease prognosis. Our goal was to evaluate the predictive power of TNM stage for gastric adenocarcinoma (GAC), in a low-incidence country.

METHODS

A province-wide chart review of GAC patients diagnosed from April 1, 2005 to March 31, 2008 was conducted in Ontario and linked to routinely collected vital status data with a follow-up on March 31, 2012. TNM staging was classified using the sixth and seventh Union International for Cancer Control/American Joint Committee on Cancer editions. Kaplan-Meier and log-rank tests compared stage-stratified survival estimates. Discrimination was evaluated using Harrell's C statistic.

RESULTS

The cohort included 2366 patients. One- and 5-year survival was 43% and 17%. Using the sixth edition, 9% of patients had stage I disease, 5.4% stage II, 7.3% stage III, and 64% stage IV; 15% were not staged. Using the seventh edition, 9% were stage I, 7.7% stage II, 16% stage III, and 54% stage IV; 14% were not staged. Stage-stratified 5-year survival ranged from 68% to 7% with the sixth edition and from 70% to 4% with the seventh edition. Harrell's C statistic was 0.64 (0.63-0.65) for the broad sixth edition staging categories and 0.68 (0.67-0.69) for the broad seventh edition. Discriminative power was similar for the refined stage categories and across multiple subgroup analyses; it was best in non-metastatic patients.

CONCLUSION

Existing staging systems for GAC used in North America predict individualized prognosis poorly. The creation of a more complex prediction tool is necessary to provide accurate and precise prognostication information to oncologists, patients, and their families.

Validation of the Memorial Sloan Kettering Cancer Center nomogram to predict disease-specific survival in a Chinese gastric cancer population receiving postoperative chemoradiotherapy after an R0 resection

The widely validated Memorial Sloan Kettering Cancer Center (MSKCC) nomogram for gastric carcinoma (GC) was developed based on patients who received R0 resection only. The purpose of the current study was to assess the performance of this nomogram in Chinese patients who received postoperative chemoradiotherapy (CRT) after an R0 resection for GC. From 2006 to 2015, the clinical data of 150 eligible patients were retrospectively collected from the Fudan University Shanghai Cancer Center (FUSCC) and used for external validation. The nomogram was validated by means of the concordance index (CI) and a calibration plot. The CI for the nomogram was 0.657, which was lower than the CI of the nomogram for patients who received surgery alone (0.80). In the calibration plot, the gap between the observed and the predicted survival gradually increased as the predicted 5-year disease-specific survival (DSS) decreased. Thus the MSKCC nomogram for GC significantly underestimated the survival of patients in the FUSCC cohort, especially the survival of patients whose predicted 5-year DSS was less than 50%. The current study indicates the potential for the nomogram to be developed as an ideal tool to identify target patients for postoperative CRT.

Prediction models for patients with esophageal or gastric cancer: A systematic review and meta-analysis

Background

Clinical prediction models are increasingly used to predict outcomes such as survival in cancer patients. The aim of this study was threefold. First, to perform a systematic review to identify available clinical prediction models for patients with esophageal and/or gastric cancer. Second, to evaluate sources of bias in the included studies. Third, to investigate the predictive performance of the prediction models using meta-analysis.

Methods

MEDLINE, EMBASE, PsycINFO, CINAHL, and The Cochrane Library were searched for publications from the year 2000 onwards. Studies describing models predicting survival, adverse events and/or health-related quality of life (HRQoL) for esophageal or gastric cancer patients were included. Potential sources of bias were assessed and a meta-analysis, pooled per prediction model, was performed on the discriminative abilities (c-indices).

Results

A total of 61 studies were included (45 development and 16 validation studies), describing 47 prediction models. Most models predicted survival after a curative resection. Nearly 75% of the studies exhibited bias in at least 3 areas and model calibration was rarely reported. The meta-analysis showed that the averaged c-index of the models is fair (0.75) and ranges from 0.65 to 0.85.

Conclusion

Most available prediction models only focus on survival after a curative resection, which is only relevant to a limited patient population. Few models predicted adverse events after resection, and none focused on patient’s HRQoL, despite its relevance. Generally, the quality of reporting is poor and external model validation is limited. We conclude that there is a need for prediction models that better meet patients’ information needs, and provide information on both the benefits and harms of the various treatment options in terms of survival, adverse events and HRQoL.

Predicting recurrence after curative resection for gastric cancer: External validation of the Italian Research Group for Gastric Cancer (GIRCG) prognostic scoring system

BACKGROUND

Most nomograms for Gastric Cancer (GC) were developed to predict overall survival (OS) after curative resection. The Italian Research Group for Gastric Cancer (GIRCG) prognostic scoring system (PSS) was designed to predict the recurrence risk after curative treatment based on pathologic tumor stage and treatment performed (D1-D2/D3 lymphadenectomy). This study was carried out to externally validate the GIRCG's PSS.

PATIENTS AND METHODS

Adopting the same criteria used by GIRCG to build the PSS, 185 patients with GC operated with curative intention were selected. The median follow-up period was 77.8 months (1.93-150.8) for all patients and 102.5 months (60.9-150.8) for patients free of disease. The NRI (net reclassification improvement) was calculated to estimate the overall improvement in the reclassification of patients using the PSS in place of the TNM stage system.

RESULTS

GC recurrence occurred in 70 (37.8%) patients. The mean time to recurrence was 22.2 (range 1.9-98.1) months. For patients with recurrence, the gain in the proportion of reclassification was 0.257 (p < 0.001), indicating an improvement of 26%. For patients without recurrence, the gain in the proportion of reclassification was -0.122 (p < 0.001), indicating a worsening of 12%. The NRI calculated was 0.135 (p = 0.0527).

CONCLUSION

The GIRCG's PSS, which predicts the likelihood of recurrence after radical surgical treatment for GC, is more accurate than TNM system to predict recurrence mainly for high-risk patients. Yet, the PSS does not have the same effectiveness for low-risk patients, overestimating the chance of recurrence occurs even for disease-free patients.

Validation of a gastric cancer nomogram using a cancer registry

BACKGROUND

A Memorial Sloan Kettering (MSKCC) nomogram predicts disease specific survival (DSS) for gastric adenocarcinoma. The goal of this study is to use a cancer registry to compare nomogram predicted survival with actual survival in the general population.

METHODS

All patients undergoing surgery for gastric adenocarcinoma from the Surveillance, Epidemiology, and End Results (SEER) database (1988-2012) were studied.

RESULTS

6954 patients were identified. Majority of cancers were in the antrum (30.2%), and had intestinal histology (73.7%). Median follow-up was 8.2 years. Five year DSS for nomogram risk groups (0-25%, 26-50%, 51-75%, and 76-100%) was 23%, 48%, 57%, and 81% respectively. Actual DSS was 7-15% lower than nomogram predicted DSS. Relative to patients in the 76-100% 5-year DSS risk group, patients in the 0-25%, 26-50%, and 51-75% groups had significantly higher risks of death with hazard ratios of 6.84 (95%CI 6.12-7.65), 3.30 (95%CI 2.83-3.86), and 2.64 (95%CI 2.30-3.03), respectively (all P < 0.001). The concordance index for 5-year nomogram predicted DSS was 0.68 (95%CI 0.67-0.69).

CONCLUSIONS

The MSKCC gastric cancer nomogram over-estimates DSS from gastric cancer in the general population and has a moderate concordance index. Predictive tools generated at specialized institutions may not perform as well in the general population.