Lack of National Adoption of Evidence-Based Treatment for Resectable Gastric Adenocarcinoma

Prognostic prediction and treatment options for gastric signet ring cell carcinoma: a SEER database analysis

Background

In recent years, the overall incidence of gastric cancer has decreased. However, the incidence of gastric signet ring cell carcinoma (SRCC) is still increasing year by year. Compared with other subtypes (non-SRCC) such as adenocarcinoma, SRCC usually exhibits a more aggressive biological behavior. Therefore, studying the prognostic differences and factors associated with SRCC is essential to improve the accuracy of diagnosis and prognosis. The purpose of this study was to investigate the prognostic factors influencing the prognosis of patients with SRCC and to develop personalized treatments for different subgroups of patients.

Methods

The data on gastric SRCC patients and gastric adenocarcinoma (AC) patients from 1992 to 2020 was obtained from the Surveillance, Epidemiology, and End Results (SEER) database. The data of gastric SRCC as the external validation group was reviewed from the First Affiliated Hospital of Soochow University. The overall survival (OS) and cancer specific survival (CSS) at 1 and 2 years were predicted for SRCC patients by constructing prognostic nomograms. A series of validation methods, including Akaike information criterion (AIC), decision curve analysis (DCA), calibration curve analysis, the concordance index (C-index) and the area under the receiver operating characteristic (AUC) curve, were used to verify the accuracy and reliability of the models.

Results

In all, 549 patients with SRCC were included after propensity score matching (PSM). Multivariate Cox regression analysis showed that T stage, N stage, M stage and surgical approach were independent risk factors affecting the prognosis of SRCC patients. A prognostic nomogram was constructed and validated as an accurate model for SRCC patients after scoring by receiver operating characteristic curve (ROC) curves and calibration plots. The patients were further divided into high-risk and low-risk groups, and the Kaplan-Meier curves showed that SRCC patients in the low-risk group could receive only surgery without chemotherapy, while chemotherapy plus surgery was a better option for SRCC patients in the high-risk group.

Conclusion

The prognosis for SRCC was less favorable than that of AC in terms of CSS. The nomograms were developed and validated to predict OS and CSS in patients with SRCC, helping in developing appropriate individualized treatment schedules.

Black race is independently associated with underutilization of preoperative chemotherapy in clinical stage T2 or higher gastric adenocarcinoma

BACKGROUND

Consensus guidelines recommend for perioperative chemotherapy and surgery for patients with clinical stage (cT) T2 or greater gastric adenocarcinoma. We compared adherence to guidelines in these patients stratified by race.

METHODS

Non-Hispanic White and Black patients with resected ≥cT2 gastric adenocarcinoma were identified within the National Cancer Database (2008-2017). We compared administration of preoperative chemotherapy by race, adjusting for clinicodemographic variables. We performed marginal standardization of logistic regression to calculate adjusted probabilities of administration of preoperative chemotherapy in patients under the age of 80 years with insurance.

RESULTS

A total of 13,850 patients were identified (White = 12,161; Black = 1,689). Black race was associated with lower likelihood of receiving preoperative chemotherapy than White race (odds ratio = 0.46, 95% confidence interval: 0.39-0.54). Other factors associated with lower likelihood of preoperative chemotherapy included age ≥70 years, female sex, treatment at community facilities, non-private or no health insurance, and cT4 disease. Factors associated with higher likelihood of preoperative chemotherapy included treatment at high-volume facilities, longer distance to facility, higher education and income levels, cT3 disease, and cN+ disease. In patients <80 years with insurance, marginal standardization models demonstrated that Black race was associated with a lower adjusted probability of receiving preoperative chemotherapy regardless of age, insurance payor, facility type/volume, distance to facility, cT stage, cN stage, sex, and education/income levels.

CONCLUSION

Black race was associated with underutilization of preoperative chemotherapy for cT2 or greater gastric cancer, in discordance to published guidelines. The etiology of these disparities is multifactorial, and correcting the root causes represents a critical area for improvement.