P2-14-09: Comparison between Spanish and Peruvian Patients with Early Breast Cancer.
Authors: Castaneda CA , Gomez HL , Vallejos C , Cortes-Funes H , Castellano D , Andrés E , Cruz W , Ciruelos EM 
Published: June 2012

Abstract
Purpose : Breast Cancer (BC) is a genetic, heterogeneous disease and has a remarkable variability according to racial factors. Hypothetic explanations for these disparities include differences in tumor biology. The present study was designed to compare clinical and pathological features between Peruvian Latinas and Spanish women with BC; interest of this analysis increases if we take into account the relationship among historic ancestries of both ethnic groups (Incas emporium and Spanish conquers).
Methods : Information was retrospectively reviewed from patients files and pathologic reports from Instituto Nacional de Enfermedades Neoplasicas (INEN) in Lima- Peru, and Hospital Universitario 12 de Octubre in Madrid- Spain. In order to produce comparative information and avoid subjective clinical measurements we selected only non-metastatic and non-bilateral invasive BC cases that underwent surgery as initial therapy. BC cases were classified as molecular subtypes: Luminal A [RE+ and/or RP+, HER2−], Lum B [RE+ and/or RP+, HER2+], triple negative (TN) [RE-, RP-, HER2−] and HER2 [RE-, RP-, HER2+]. Variables were compared with the X2 test and survival curves were evaluated with Kaplan-Meier method. Results: The study included 3765 BC cases. The Spanish cohort involved 1539 (40.9%) women consecutively diagnosed between 1997 and 2007 (median follow-up of 7.9 years). The Peruvian cohort involved 2226 (59.1%) women consecutively diagnosed between 2000 and 2006 (median follow-up of 6.3 years).
In terms of pathological features, grade I tumors were more frequent in Spanish (16.2%) than Peruvian women (9.6%) (p&lt;0.001). Higher rates of lobular histology were also found in Spanish (12.5%) than Peruvian (6.0%) women (p&lt;0.001). Spanish cases presented at earlier stages when evaluated by lymph node status (N0 in 58.9% vs 47.1%) (p&lt;0.001) or by tumor size (T1 in 37.9% vs 17-2%). Conservative surgery were more frequent among Spanish cases (50.6% vs 16.8%) (p&lt;0.001). TN molecular subtype were more frequent among Peruvian cases (22.5% vs 12.4%) (p&lt;0.001).
Brain (10.4% vs5.3%), and skin and subcutaneous (7.1% vs 2.4%) metastases were more frequently found in Peruvian patients. On the other hand, contralateral breast cancer was more frequent among Spanish patients (12.2% vs 2.8%).
And when evaluated by molecular subtypes, bone metastases in TN were more frequent among Spanish (25.4%) than Peruvian (18.5%) cases.

Disease-free survival rates at 7 years were similar between Spanish and Peruvian patients (80,3% vs 79,6%, p=0.197). However, overall survival at 7 years was better in Spanish women (90.4% vs 82.6%, p&lt;0.001).
Conclusion : Epidemiologic differences in terms of histological features, clinical stage at diagnosis, molecular subtypes distribution, recurrence patterns and prognosis were found among Spanish and Peruvian BC patients in this retrospective analysis.
Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-14-09.