A new study has found that newer drug therapies available since the 1990s, in particular aromatase inhibitors, improve the survival of women with metastatic breast cancer in the general population.
The study was conducted by a team of researchers led by Dr. Stephen Chia at the University of British Columbia in Vancouver.
As part of the study, researchers compared outcomes of 2150 women diagnosed with metastatic breast cancer in the Canadian province of British Columbia between 1991 and 2001 and evaluate whether new hormonal and chemotherapeutic drugs approved for public use actually had an impact on survival outside the clinical trial setting.
Researchers were able to make inferences about drug efficacy versus no treatment because not all patients in the general population received any palliative systemic therapy.
The study found that new drugs had a significant positive effect on survival for women with metastatic disease in the latter half of the 1990s. Median survival remained unchanged between the 1991-1992 and 1994-1995 groups, at only 438 days in the first and 450 days in the second time period.
Researchers noted that survival improved by approximately 30 percent as systemic therapy, in particular aromatase inhibitors, became more widely used.
"Our population-based study of a large cohort of women with a recent diagnosis of metastatic breast cancer is the first to demonstrate a significant improvement in survival over time. While the study does not definitively attribute these improvements to a single therapy, the greatest differences in survival were associated with the introduction of the aromatase inhibitors, docetaxel and trastuzumab in the later two cohorts," researchers said.
The findings of the study will be published in the September issue of CANCER.