Abstract A69: Epidemiologic, clinical-pathologic, and therapeutic characterization and its correlation with ethnic ancestry in patients with colorectal cancer of the Barretos Cancer Hospital
Authors: Duraes Ronilson Oliveira , Reis Rui M. V. , Guimaraes Denise P. , Berardinelli Gustavo N. , Oliveira Marco A. , Neto Cristovam S. 
Published: May 2019

Introduction: Colorectal cancer is the third most frequent neoplasm in the world population, with a wide geographical heterogeneity, being more frequent in developed countries than in developing countries. In Brazil, this neoplasm also ranks third in incidence, but has been increasing in recent years due to multiple factors such as diet, lifestyle, and aging populations. Most colorectal neoplasms are sporadic (85% of cases); the others are related to inherited susceptibility factors. Surgery is the main treatment modality in the initial stages (stages I to III). In stages IV, treatment will depend on the extent and location of metastases. Among several prognostic factors, the main ones are clinicopathologic, with special emphasis on staging. The ethnic structure of the population has been gaining prominence as another potential prognostic factor, and this becomes more pressing in the Brazilian population due to its great miscegenation. In Brazil, few studies have evaluated and characterized comprehensively the population of patients diagnosed with colorectal cancer.

Objectives: In this study we intend to characterize the epidemiologic-clinical-pathologic and therapeutic aspects of a convenience series of about 1013 patients with colorectal cancer treated at the Hospital de Cancer de Barretos. We also intend to determine their genetic ancestry and correlate the ethnic structure of the patients with the remaining epidemiologic and clinical-pathologic data, in order to identify potential ancestral markers with clinical relevance.

Materials and Methods: This is a retrospective cohort study of 1013 patients with colorectal cancer, admitted for treatment and follow-up at our institution between 2000 and 2014, where we performed an epidemiologic-clinical-pathologic and therapeutic characterization correlating with supposed prognostic factors such as the location of the primary tumor divided into right and left colon and genetically assessed ancestry.

Results: The main characteristics were slightly male predominance, with the age group between 50 and 75 years being more frequent and EC II as the most representative (37.1%); the left/rectum was highlighted with 75% of the cases. No differences were observed in cancer-specific survival between the location of primary tumors. Tumor location on the left side was associated with the following characteristics: male, age less than 50 years, low-grade tumors, T1 and T2 tumors, and absence of synchronous tumors. We found that the main prognostic factors were staging, emergency surgery, angiolymphatic invasion, and primary tumor localization in the left colon. With regard to ancestral diseases, we observed that European ancestry was associated with patients who did not present synchronic tumors, presence of recurrence, while African ancestry was associated with young patients. However, we cannot confirm ancestry as a prognostic factor for cancer-specific survival.

Conclusion: We performed one of the most complete characterizations of the main epidemiologic-clinical-pathologic factors and treatment in Brazilian patients with colorectal cancer, correlating with the genetically determined ancestry profile. We concluded that neither the location of the primary tumor nor the genetic ancestry was determinant as to the prognosis of our sample.

Citation Format: Ronilson Oliveira Duraes, Rui M. V. Reis, Denise P. Guimaraes, Gustavo N. Berardinelli, Marco A. Oliveira, Cristovam S. Neto. Epidemiologic, clinical-pathologic, and therapeutic characterization and its correlation with ethnic ancestry in patients with colorectal cancer of the Barretos Cancer Hospital [abstract]. In: Proceedings of the AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine; May 4-6, 2017; São Paulo, Brazil. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(1_Suppl):Abstract nr A69.