Identification of unknown primary tumors in patients with neuroendocrine liver metastases.
BACKGROUND
For patients with neuroendocrine tumor (NET) liver metastases, resection of the primary tumor may prevent local complications (obstruction, ischemia, and bleeding) and improve survival. Despite preoperative evaluation, the primary tumor location may remain unknown.


METHODS
Retrospective cohort analysis of pathology database from January 1, 1993, to August 15, 2008.


METHODS
Academic medical center.


METHODS
One hundred twenty-three patients with NET liver metastases.


METHODS
Successful identification and resection of the primary tumor.


RESULTS
Fifteen patients underwent surgical exploration. The primary tumor was located in 13 patients (86.7%) in the small intestine and resected in 12 patients. Primary tumors in the small intestine found during surgical exploration were significantly smaller than those identified preoperatively (1.38 vs 1.91 cm, P = .03) and were often multifocal (54.2% [n = 15]). Computed tomography (34.6% [n = 78]) and somatostatin receptor scintigraphy (26.2% [n = 42]) were not sensitive in locating a primary NET in the gastrointestinal tract. Colonoscopy was sensitive in detecting colonic NETs (86.7% [n = 15]).


CONCLUSIONS
For patients with NET liver metastases and unknown primary tumor, surgical exploration effectively identifies and resects occult primary tumors that are often located in the small intestine. Primary tumors are usually small and multifocal, so careful palpation of the small intestine is essential. Before patients are considered for surgery, a multidisciplinary team assessment and evaluation consisting of computed tomography, somatostatin receptor scintigraphy, and upper and lower endoscopy should be done.
Department of Surgery, Division of Surgical Oncology, University of California-San Francisco, 1600 Divisadero Street, San Francisco, CA 94143-1932, USA.
Sam C
SC
Wang
Justin R
JR
Parekh
Marlene B
MB
Zuraek
Alan P
AP
Venook
Emily K
EK
Bergsland
Robert S
RS
Warren
Eric K
EK
Nakakura
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003949:Diagnostic Techniques, Surgical; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000556:secondary* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009382:Neoplasms, Unknown Primary / Q000175:diagnosis*; D018358:Neuroendocrine Tumors / Q000175:diagnosis* / Q000556:secondary* / Q000601:surgery; D012189:Retrospective Studies; D055815:Young Adult