Small bowel adenocarcinoma: understaged and undertreated?

Abstract

Primary small bowel adenocarcinoma (SBA) is a rare, chemoresistant tumor with an aggressive clinical nature. Surgery is the mainstay of therapy, but the extent of lymph node (LN) recovery necessary for optimal care of jejunoileal SBA is unknown. The SEER database was queried to identify patients whose primary jejunoileal SBA was diagnosed between 1995 and 2005. Patients were grouped by AJCC stage and number of LNs recovered from the surgical specimen. Of 1444 patients with primary SBA, 93 (6.4%), 529 (36.6%), 356 (24.7%), and 466 (32.3%) were initially diagnosed with stage I, II, III, and IV disease, respectively. Five-year overall survival (OS) rate was 59.8%, 39.5%, 27.0%, and 3.2% for patients with stage I, II, III, and IV SBA, respectively. When ≥10 nodes were recovered, OS rate increased nonsignificantly in stage I (73.2% vs. 55.6%) and significantly in stage II (61.8% vs. 32.9%, P < .001) but was unchanged in stage III (27.4% vs. 27.3%, P = .13). Recovery of ≥10 nodes occurred in 26.9%, 23.6%, and 42.1% of patients with stage I, II, and III SBA, respectively. Multivariate analysis identified age, AJCC stage, site of primary tumor, recovery of ≥10 LNs, and number of positive nodes as significant for OS. We have found SBA staging is largely inadequate. Our results suggest recovery of ≥10 LNs ensures accurate staging. Improvement in stage II SBA OS after adequate LN may reflect a high degree of understaging in this dataset rather than a therapeutic effect of LAD.