Clinicopathologic analysis of pancreatic adenocarcinoma in African Americans and Caucasians.
BACKGROUND
African Americans have a higher incidence of pancreatic adenocarcinoma than do Caucasians for unknown reasons. Whether other clinicopathologic differences exist between these two groups is not known. This study was undertaken to compare the clinical, pathologic, and biologic findings for a group of patients with a histologic diagnosis of pancreatic ductal adenocarcinoma of the usual type in a single institution.


METHODS
We studied 410 patients (166 African Americans and 244 Caucasians) with a histologic diagnosis of pancreatic ductal adenocarcinoma of the usual type and analyzed (a) the clinicopathologic characteristics of the tumors, (b) the immunohistochemical expression of biomarkers implicated in pancreatic carcinogenesis (Fas, Fas ligand, HER2, p21/waf-1, p27, and p53), and (c) the presence and types of K- mutations at codon 12 as determined by polymerase chain reaction-mediated amplification. All elements of data were not available for all patients.


RESULTS
African Americans had significantly higher rates of K-ras mutations to valine than did Caucasians (58% versus 22%, respectively; p = 0.015) and were less likely to have received chemotherapy (45% versus 70%, respectively; p = 0.001) or radiation therapy (34% versus 57%, respectively; p = 0.003). African Americans also had more frequent positive surgical margins than did Caucasians (56% versus 25%, respectively; p = 0.001), although mean tumor size was similar between the two groups (African Americans, 3.4 cm; Caucasians, 3.5 cm). Other clinicopathologic variables were similar between the two groups, including median survival (African Americans, 8.5 months; Caucasians, 10.1 months), 5-year survival (African Americans, 3%; Caucasians, 6%), and stage at presentation. Differences in biomarker immunoreactivity included less frequent Fas expression (4% versus 24%, respectively; p = 0.048) and a trend toward more frequent strong HER2 expression (39% versus 18%, respectively p = 0.11) in African Americans than in Caucasians.


CONCLUSIONS
Although African American and Caucasian patients had similar survival rates associated with usual type pancreatic ductal adenocarcinoma, there were differences in management and expression of biologic markers between these two groups. African Americans were significantly less likely to receive radiation therapy or chemotherapy than were Caucasians, which may assume more importance as treatment improves. At the molecular level, African Americans had more frequent K- mutations to valine than did Caucasians.
Pernick
Nat L
NL
Department of Pathology, Barbara Ann Karmanos Cancer Institute and Wayne State University School of Medicine, Detroit, USA.
Sarkar
Fazlul H
FH
Philip
Philip A
PA
Arlauskas
Patricia
P
Shields
Anthony F
AF
Vaitkevicius
Vainutis K
VK
Dugan
Michael C
MC
Adsay
N Volkan
NV
D000368:Aged; D044383:Black People; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis* / Q000208:ethnology* / Q000473:pathology; D003710:Demography; D005260:Female; D011905:Genes, ras; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000208:ethnology* / Q000473:pathology; D016019:Survival Analysis; D044465:White People; D001741:Black or African American