Predictors of lymph node metastasis in patients with gastrointestinal stromal tumors (GISTs).

BACKGROUND: Lymph node metastasis is not common among patients with gastrointestinal stromal tumors (GISTs) and its prognostic value is controversial. The purposes of this study are to identify predictors of lymph node metastasis and determine its prognostic associations.

METHODS: A retrospective analysis of the surveillance, epidemiology and end results (SEER) database was performed. Patients with GISTs that underwent surgery and pathologic nodal staging were identified. Logistic regression and Cox regression were performed to identify independent predictors and prognostic factors, respectively.

RESULTS: Of 1430 patients (age: 61.5 ± 14.5 years, 52% males), 140 (9.8%) had lymph node metastasis. On multivariable analysis, distant metastasis was the only independent predictor of lymph node metastasis (OR 4.95, 95% CI: 2.43-10.08, p < 0.001). In the entire cohort, lymph node metastasis did not reflect a worse overall survival (OS, HR 1.12, 95% CI: 0.49-2.58, p = 0.794) or disease-specific survival (DSS, HR 0.95, 95% CI: 0.31-2.88, p = 0.924), but was an independent predictor of worse OS in 51 patients (25.4% of 201 patients) who presented with both lymph node metastasis and synchronous distant metastasis (HR 2, 95% CI: 1.25-3.21, p = 0.004). Lymph node metastasis was also independently associated with worse survival among patients with small intestinal (OS: HR 1.88, 95% CI: 1.15-3.1, p = 0.013) and colorectal tumors (OS: HR 3.41, 95% CI: 1.56-7.46, p = 0.002, DSS: HR 3.58, 95% CI: 1.27-10.06, p = 0.016).

CONCLUSIONS: Metastatic disease is an independent predictor of lymph node metastasis in patients with GISTs. Lymph node metastasis is also associated with worse overall survival in patients with metastatic GISTs.