EVALUATION OF RADIATION THERAPY INDICATION FOR NODE POSITIVE BREAST CANCER RATES TRENDS IN SÃO PAULO, BRASIL (2000-2014)

Introduction: Recent meta-analysis showed an overall survival improvement with radiation therapy in the management of womens breast cancer with lymph node involvement, in both breast conservative surgery and radical mastectomy. Given that esthetical outcomes may influence the indication of radiation therapy, the present study sought to analyze the trend of radiation therapy indication in node-positive breast cancer population in São Paulo (SP), Brazil. Methods: We analyzed data between the years 2000 and 2014 available on the database of Fundação Oncocentro de São Paulo (FOSP), which is an authoritative organ that electronically collects data from the major cancer hospitals from SP. Were analyzed women aged 18 to 80 years, with node-positive breast cancer, time to treatment in up to 365 days and had performed a surgical procedure plus chemotherapy or hormone therapy. It was excluded metastatic or undefined T or N stage patients. Initially, we perform a binary logistic regression to access realization of radiation therapy over time in years. Next, we performed multivariate logistic regression about radiation therapy no realization adjusted for: residence in or out of SP; treatment and diagnostic in or out the same institution; N1 or N2/N3; T1/T2 or T3/T4; time to initiate treatment; age range (18-30, 31-50, 51-70, 7180); year of diagnostic; did or not both hormone and chemotherapy. Results: It was analyzed 25815 women, mean age of 53 years, 71% received radiation therapy and 56% did both chemotherapy and hormone therapy. We observed a trend to decrease in the use of radiation therapy, from 75,1% in 2000 (CI 74,0 – 76,2%) to 67,0% (CI 66,0 – 68,1%) in 2014. The factors protectives against underuse of radiation therapy were residence outside of SP (OR 0,84 p=0,007), time to initiate treatment above 30 days (OR 0,92 p=0,009) and treatment with both hormone and chemotherapy (OR 0,50 p<0,001), while underuse of radiation therapy was associated with T1/T2 (OR 1,23 p<0,001), age 71-80 (versus 18-30 years OR 1,34 p<0,001) and year of diagnoses (OR 1,03/year p<0,001). Conclusion: In striking opposite to current evidence, our data demonstrate a decrease in annual rate of radiation therapy indication in node-positive breast cancer over time. These findings should alert the oncology community of the possible ominous outcomes associated with the underuse of radiotherapy but also that implementation of interventions to increase the indication of radiotherapy are warranted.