Results of a National Breast Cancer Program in Chile: 318 Women Treated Under Standardized Clinical Guidelines

Abstract

Multidisciplinary approach is standard in breast cancer (BC) patients. Data on systemic therapies show a 15 yr. absolute reduction in BC mortality of 3-10% mainly with anthracycline based Chemotherapy (CT). Recently, EBCTCG`s meta-analysis on 10,801 pts. showed radiation (RT) reduces LRR at 10 years, by 15.7%, and 15 yr. BC mortality by 3.8%. In Chile, since 2004, BC is part of a national program (GES), guaranteeing access to treatment under national guidelines. This study aims to evaluate OS, BCSS, DFS, LRRFS and DMFS in a historical cohort of patients (pts) treated at a tertiary hospital in Chile under these guidelines. We retrospectively reviewed the records of 318 pts. with no distant metastases, 2005 - 2009, following such guidelines. Adriamycin based CT was indicated in patients with LN+ or if LN- disease when other risk factors (young age or tumors ≥2 cm). Tx was given for 5 yrs. in ER+ pts. RT was indicated in pts. with breast conserving surgery and mastectomy pts. with LN+ disease or skin involvement. Five-year actuarial survival rates of OS, DFS, LRR, and DM were calculated by Kaplan-Meier method and comparisons among groups performed using two-sided log-rank tests. We also evaluated the pCR in pts. treated with neo-adjuvant CT (NCT). Median age was 52 yrs. old (22 – 98), with 58% older than 50 yrs. old. Median tumor size was 25 mm. One-hundred and ninety-four patients were found to have pathological LN+ disease, median 3 positive nodes (1 – 27). Seventy-six percent were ER+. According to AJCC most patients were pathological stage II (53%) and III (33%). Twenty-nine percent of them (95 patients) received neo-adjuvant chemotherapy (NCT) and 223 received adjuvant CT, 95% received RT and 76% HT. Seven percent of those treated with NCT achieved pCR. With a median follow-up of 53 months, 67 pts. died. Fifty-nine were BC deaths and 78% occurred during the first 3 yrs. of follow-up. There were 9 LRR, most frequently in the ipsilateral breast or chest wall and 45 DM, being bone the most frequent site. At 5 years, the results were the following: 76% OS (Fig.1), 79% BCSS, 83% DFS, 97% LRRFS and 85% DMFS. Five year OS was better in the adjuvant than in the NCT group (86% versus 64%, p < 0.0001). The staging clinical-pathological correlation was 48%. When analyzing the accuracy of clinical as compared to pathological staging the former overestimated T stage and N stage in up to 42% and 50% of cases respectively. At 5 yrs. of follow-up, rates of LRR and DM were 3% and 14% respectively, with 83% DFS, 76% OS and 79% BCSS. The pCR was 7% with NCT. Clinicopathological correlation was 52-77% for T stage and 50-64% in N stage, with a tendency to over stage. In conclusion, treating BC patients following national clinical guidelines is feasible in a developing country and their outcomes are similar to what has been published internationally.