The effect of delays in treatment for breast cancer metastasis on survival

It is generally accepted that delay in receiving treatment for breast cancer results in adverse outcomes. The purpose of this study was to evaluate the impact of delay in treatment after the diagnosis of metastatic disease on survival measured from metastatic breast cancer diagnosis and from first treatment while controlling for immortal time effect among patients with metastatic breast cancer. A total of 553 patients with breast cancer metastasis diagnosis from one large urban practice have been followed between January 1, 1999 and June 30, 2008. Prognostic factors and outcomes of these patients were analyzed using log-rank test and Cox regression model. Backward stepwise selection of covariates was conducted to assess the association of treatment delay with survival. The median survival was 40 months (range 1-114 months), with 265 (47.9%) women alive and 288 (52.1%) having died at the end of the follow-up period. Treatment delays of more than 12 weeks had impact on poor survival from first treatment than the delays of 4-12 weeks with borderline significance level (HR 1.76, 95% CI 0.99-3.13, P = 0.056) in multivariate analysis, adjusted by BMI, history of hypertension, ER/PR status, HER2 status, number of metastatic sites, and liver metastasis. Moreover, the interval of 12-24 weeks, compared to the interval of 4-12 weeks was associated with greater risk of death from first treatment (HR 2.39, 95% CI 1.19-4.77, P = 0.014). The treatment delay interval of > 12 weeks was not related with survival since metastatic breast cancer diagnosis, compared to the 4-12 weeks of treatment delays. This study demonstrated that delays of over 12 weeks in receiving treatment for metastatic breast cancer were related to adverse survival outcomes measured from initiation of first treatment. The findings of this study support targeted efforts to ensure prompt treatment initiation in patients diagnosed with metastatic breast cancer.