Decreased Breast Cancer Size, Stage and Mortality in Rhode Island: An Example of a Well-Screened Population
To determine the impact of a high mammographic screening rate on breast cancer presentation and outcome
Population cohort study
State cancer registry
All incident breast cancers diagnosed in female residents from 1987 to 2001
Main Outcomes Measures:
Mammography rates, in situ (DCIS) and invasive breast cancer incidence, tumor size, extent of nodal metastases, rate of breast conservation surgery (BCS) and mortality
The rate of mammography in all age groups increased, with 84% of all women reporting a mammogram within the prior two years in 1999-2001 (p<0.001). There were 11,301 cases of breast cancer diagnosed from 1987-2001. There was a 129% increase in the incidence of DCIS (p<0.01) with no increase in the incidence of invasive disease. The mean tumor size of invasive cancer decreased from 2.5±1.9 cm to 2.0±1.7 cm (p<0.01) with a decrease in the extent of nodal metastases and significantly fewer Stage III and IV cancers reported in the latter years of the study (p<0.05). There has been an increase in the rate of BCS in women 50-64 years with Stage 0, I, and II tumors and in women age 65 and older with Stage I cancers. Breast cancer mortality decreased 25% from 38.0/100,000 to 28.4/100,000 in 1987-89 and 1998-2000, respectively (p<0.001).
High mammography rates have resulted in smaller breast cancers permitting increased breast conservation surgery and a decrease in mortality.
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