The impact of a national program to provide free mammograms to low-income, uninsured women on breast cancer mortality rates.

Background: The National Breast and Cervical Cancer Early Detection Program (NBCCEDP) provides free or low-cost breast and cervical cancer screening to low-income, uninsured or underinsured women. The authors analyzed the impact of the NBCCEDP on breast cancer mortality rates.

Methods: The data consisted of observations for each state and year for the period from 1990 through 2004. The outcome variable was the breast cancer mortality rate for women ages 40 to 64 years. Independent variables included the proportion of women ages 40 to 64 years screened under NBCCEDP. The impact of screening intensity was estimated using least-squares regression with state and year fixed effects.

Results: In 2004, 1.2% of women ages 40 to 64 years were screened under NBCCEDP. The NBCCEDP screening rate was related significantly and negatively to breast cancer mortality in the same year. Results indicate that, for every 1000 women screened, there were 0.6 fewer deaths because of breast cancer among women ages 40 to 64 years. Changes in screening rates were unrelated to breast cancer mortality≥2 years in the future.

Conclusions: In the current study, there was some evidence suggesting that the NBCCEDP led to a reduction in breast cancer mortality rates. However, the failure to detect an impact of screening on mortality rates in subsequent years suggests that caution is needed in interpreting these results as strong evidence in favor of the effectiveness of the NBCCEDP in reducing breast cancer mortality.