10-Year Breast Cancer Survival: A Cohort Study Which Analyzes Patients Treated in an Oncologic Brazilian Hospital in Relation to Seer Women

Abstract

INTRODUCTION: Brazil is a developing country and its cientific literature is limited in evaluating the survival of patients with breast cancer. There is no study comparing survival in relation to developed countries, especially for long period of follow-up. PATIENTS AND METHODS: A retrospective cohort study, approved by the Ethics Committee 451/2011, evaluating the characteristics of patients with invasive breast cancer without previous treatment, diagnosed from 1998 to 2001 at Barretos Cancer Hospital (BCH) in relation to patients with the same characteristics from SEER database. We analyzed the characteristics related to the diagnosis of tumors, overall survival (OS) and cancer-specific survival (SS) with 10 years of follow- up. For categorical variables we used the Chi-square test and for continuous variable the Student T test. The Kaplan Meier method and log rank test were used to evaluate the survival. RESULTS: We evaluated 47, 250 out of 603, 839 SEER patients and 834 out of 10, 045 BCH patients, representing 48, 084 and 7. 83% of the total women with breast cancer. Compared with the clinical stage at diagnosis BCH showed lower rate of early tumors (10. 2 x 50. 1%) and higher rate of metastatic disease (14. 3 x 2. 2%) (p <0. 001). The follow-up was higher in the SEER, but when mortality is deleted, it was similar between the groups. The OS and SS were higher in patients in the SEER (p <0. 001), with a difference of 16. 3% and 19% in OS and 19. 6% and 26. 3% in the SS at 5 and 10 years respectively. The OS according to clinical staging was similar in stage I, II and III, but in BCH patients there was higher OS in clinical stage IV (p=0. 014), with 12. 2% and 2. 7% difference at 5 and 10 years respectively. The SS was higher in the SEER for stages I (p = 0. 001), representing 3. 6% and 13. 0% at 5 and 10 years, and at stage II (p = 0. 001), representing 4. 7% and 6. 6% at 5 and 10 years respectively. DISCUSSION: This study represents the largest Brazilian series evaluating OS and SS for a long period of time and copared with the U. S. population. Although survival differences among specific groups, OS was similar in stages I, II and III. The high rate of advanced disease at diagnosis, determines worse impact on OS and SS. CONCLUSION: This study enhances the need for improvement of the Brazilian Health System, since the change of the paradigm of Brazilian breast cancer mortality will only be achieved when we increase the rates of early breast cancer diagnosis.