Racial Variations in Curative Surgery Survival for Stage II/III Gastric Cancer

New research revealed variations in overall survival (OS) associated with race and ethnicity among patients with stage II or III gastric adenocarcinoma undergoing a curative surgical procedure.

These findings were published in JAMA Network Open and are based on a retrospective cohort study utilizing the National Cancer Database (NCDB) from the American College of Surgeons. The researchers excluded cases of gastric cardia tumors, and procedures had to occur between January 2006 and December 2019.

Gastric cancer | Image credit: Crystal light – stock.adobe.com

Numerous multimodality treatment approaches are available for gastric adenocarcinoma, including neoadjuvant or adjuvant chemotherapy, radiation, or a combination of these. In the United States, neoadjuvant therapy is advised for individuals with locally advanced gastric cancer. Despite this recommendation, the potential influence of race and ethnicity on the outcomes of neoadjuvant therapy remains uncertain.

To assess variations in outcomes based on race and ethnicity and compare those who receive neoadjuvant therapy with those who do not, researchers included 6938 patients in the cohort, with 4266 (61.4%) being male and a mean (SD) age of 65.9 (12.8) years. Of the cohort, 15.8% of patients were Asian, 17.8% were Hispanic, 24.3% were Black, and 53.6% were White.

One finding was that compared with other races and ethnicities, White patients were significantly more likely to be 65 years or older with more comorbidities, and more frequently underwent surgical resection procedures alone without neoadjuvant or adjuvant therapy. Additionally, Asian and Black patients had the highest proportion of being downstaged or achieving pathological complete response following neoadjuvant therapy.

Overall, multivariate models demonstrated an association between perioperative chemotherapy and improved OS (HR, 0.79; 95% CI, 0.69-0.90), while the number of positive lymph nodes and surgical margins were associated with the largest decreases in OS. Among the 4 racial groups assessed in this study, Asian (HR, 0.64; 95% CI, 0.58-0.72) and Hispanic (HR, 0.77; 95% CI, 0.69-0.85) patients had significantly improved OS compared with Black and White patients following surgery. Further, Black patients had improved OS compared with White patients when receiving neoadjuvant therapy specifically (HR, 0.78; 95% CI, 0.67-0.90).

This NCDB retrospective cohort study revealed an independent association between race and ethnicity and outcomes in gastric cancer, even after adjusting for sociodemographic and clinical factors, and the improved outcomes among Asian and Hispanic patients has been seen in prior research as well.

“Various factors may drive this difference, such as differences in tumor response to chemotherapy or lymph node metastasis rate,” the researchers said. “Multiple studies have shown that Asian patients have a significantly reduced frequency of lymph node metastases, which is a significant factor for survival as demonstrated in our multivariate analysis when compared with White or Black patients. Our study, however, did not find that Asian and Hispanic patients had higher lymph node metastasis compared with Black and White patients with clinical stage II or III gastric cancer.”

Several studies—including research using the SEER database and the California Cancer Registry—have indicated that Asian patients, who tend to undergo sufficient lymphadenectomy, exhibit improved survival outcomes. In the current study, both Asian and Hispanic patients displayed a higher count of regional lymph nodes examined. Despite this, the enhanced outcomes observed in diverse racial and ethnic groups cannot be solely attributed to lymphadenectomy.

The research identified a correlation between improved OS outcomes and the administration of neoadjuvant therapy, especially perioperative chemotherapy, in patients with stage II or III gastric adenocarcinoma. According to the researchers, this finding is consistent with the results of a meta-analysis of randomized clinical trials.

“Fortunately, we are seeing an increasing proportion of patients receiving some form of neoadjuvant therapy over time and declining use of postoperative chemoradiotherapy, indicating appropriate adoption of treatment standards established by clinical trials over time,” they said. “However, disparities in receipt of multimodality therapy in the United States have been shown.”

Despite the advantages of this study, such as a large and diverse sample size representing various US populations, it also has limitations. The reliance on data from Commission on Cancer–accredited facilities, which cover only around 70% of cancer diagnoses, may impact the generalizability of the findings. There is also the risk of potential misclassification of certain groups and the unaccounted status of patients belonging to multiple racial or ethnic categories, as well as the possibility of unaddressed racial disparities arising from differences in access to Commission on Cancer–accredited hospitals. Due to data constraints, only a postoperative comparison of clinical and pathological stages was feasible, introducing the potential for misclassification of staging groups, but no evidence suggested differential misclassifications based on race or ethnicity.

“Our findings suggest the importance of future research toward investigating the biological differences in tumor behavior across races that have yet to be elucidated, including consideration of clinical trial design in gastric cancer as well as genomic studies to include stratification on factors of race and ethnicity,” the researchers wrote.

Reference

Wu SP, Keshavjee SH, Yoon SS, Kwon S. Survival outcomes and patterns of care for stage II or III resected gastric cancer by race and ethnicity. JAMA Netw Open. 2023;6(12):e2349026. doi:10.1001/jamanetworkopen.2023.49026