Prognostic value of lymph node evaluation in small bowel adenocarcinoma: analysis of the surveillance, epidemiology, and end results database.

Abstract

The presence of distant metastases and the completeness of resection are important prognostic factors in patients with small bowel adenocarcinoma (SBA); however, the influence of lymph node metastasis on patient outcome has not been well characterized. The objective of the current study was to evaluate the impact of the number of positive and negative lymph nodes on survival after curative resection. Patients who had SBA diagnosed between 1988 and 2005 were identified from the Surveillance, Epidemiology, and End Results (SEER) registry. Cox proportional hazards regression analyses were performed after adjusting for age, sex, race, tumor stage, tumor grade, and primary site. Five-year disease-specific survival (DSS) was determined, all patients were categorized according to the total lymph nodes (TLNs) assessed, and patients with stage III disease also were categorized according to the number of positive lymph nodes (PLNs) and the PLN-to-TLN ratio (the lymph node ratio [LNR]). In total, 1991 patients (n=1216 with stage I/II SBA and n=775 with stage III SBA) were analyzed. Survival depended on the TLNs assessed. The 5-year DSS rate for patients with stage II disease was associated with the TLNs assessed (44%, 69%, and 83% for 0 TLNs, 1-7 TLNs, and>7 TLNs, respectively). The 5-year DSS for patients with stage III disease was associated with the number of PLNs (58% and 37% for <3 PLNs and ≥3 PLNs, respectively). Among patients with stage III disease, the LNR was even more predictive of survival than stratification by the number of PLNs. Survival after surgical resection for stage I, II, and III SBA was associated with the TLNs assessed. Stratifying patients with stage III disease into those with <3 PLNs and ≥3 PLNs significantly improved prognostication.