Determining prognosis in patients with pancreatic endocrine neoplasms: can the WHO classification system be simplified?
OBJECTIVE
The WHO classification for well-differentiated pancreatic endocrine neoplasms (PENs) incorporates both stage and grade. This study compares the prognostic value of a simplified staging and grading system with the WHO system in a large single-institution study.


METHODS
A prospective database (1982 to 2005) identified 183 patients who underwent operative treatment for PENs. Tumors were staged (< 2 cm primary, >/= 2 cm primary, or metastases) and graded (low grade: no necrosis and < two mitoses/50 high-powered fields [HPF]; or intermediate grade: necrosis and/or >/= two mitoses/50 HPF) with a simplified schema. Influence of stage and grade on recurrence and disease-specific survival (DSS) was determined. Prognostic strength was assessed with the concordance index (CI).


RESULTS
Median age of the 183 patients was 56 years, and 53% were women. Median follow-up time was 44 months (range, 1 to 226 months). Classification identified 28 patients (15%) with WHO 1.1 disease, 74 (41%) with 1.2 disease, and 81 (44%) with 2.0 disease. Classification by stage identified 35 patients (19%) with tumors less than 2 cm, 96 (52%) with tumors >/= 2 cm, and 52 (29%) with nodal or distant metastases. Tumors were low grade in 102 patients (56%). Earlier stage tumors were more likely to be low grade (< 2 cm, 83%; >/= 2 cm, 61%; metastases, 28%; P < .001). The WHO classification, tumor stage, and grade were associated with 5-year DSS (P < .001). Tumors >/= 2 cm or metastases are stratified by grade (5-year DSS rate for low v intermediate grade: >/= 2 cm, 97% v 80%, respectively; P < .001; metastases, 93% v 62%, respectively; P = .05). The CI was 0.72 for WHO, 0.71 for stage, 0.66 for grade, and 0.76 for stage combined with grade.


CONCLUSIONS
Accurate prognostic information can be obtained by combining tumor size and metastases with simple grading information based on necrosis and mitotic rate.
Department of Surgery, Memorial Sloan-Kettering Cancer Center, Howard 1223, 1275 York Ave, New York, NY 10021, USA.
Cristina R
CR
Ferrone
Laura H
LH
Tang
James
J
Tomlinson
Mithat
M
Gonen
Steven N
SN
Hochwald
Murray F
MF
Brennan
David S
DS
Klimstra
Peter J
PJ
Allen
D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000473:pathology*; D011379:Prognosis; D014944:World Health Organization