Inaccurate Clinical Stage Is Common for Gastric Adenocarcinoma and Is Associated with Undertreatment and Worse Outcomes.

Background: Accurate clinical staging (CS) of gastric cancer is critical for appropriate treatment selection and prognostication, but CS remains highly imprecise. Our study evaluates factors associated with inaccurate CS, the impact of inaccurate CS on outcomes, and utilization of adjuvant therapy in patients who are understaged.

Methods: We conducted a retrospective review of NCDB patients diagnosed with clinical early stage gastric adenocarcinoma (cT1-2N0M0) between 2004 and 2016. Patients not undergoing upfront gastrectomy or with missing pathologic staging were excluded. Patients were classified as accurately staged, inaccurately staged with receipt of adjuvant therapy (IS+), and inaccurately staged with no receipt of adjuvant therapy (IS-). Logistic regression was utilized to assess the impact of factors on CS accuracy and receipt of adjuvant therapies. Kaplan-Meier and Cox proportional hazard methods were used for survival analysis.

Results: Approximately 40% of patients were inaccurately staged (IS). cT2, moderately/poorly differentiated, and site-overlapping tumors were associated with increased likelihood of being IS. Treatment at an academic facility was associated with decreased likelihood of understaging. Only 54% of patients who were IS received adjuvant therapy.

Conclusion: Accurate CS of gastric cancer remains inadequate. Understaging is associated with detrimental effects on receiving guideline-concordant care and, possibly, patient outcomes. Targeted interventions reducing the proportion of understaged patients and ensuring receipt of appropriate therapy is needed to optimize outcomes. Patients with high-risk disease that are frequently understaged may benefit from selective neoadjuvant therapy. Centralization of gastric cancer care may also be a key strategy in improving receipt of guideline-concordant therapies.