Determining prognosis in patients with pancreatic endocrine neoplasms: Can the WHO classification system be simplified?

Abstract

Purpose: 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. Patients and 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 < 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. Conclusion: Accurate prognostic information can be obtained by combining tumor size and metastases with simple grading information based on necrosis and mitotic rate. © 2007 by American Society of Clinical Oncology.