The comparative value of mammographic screening for women 40-49 years old versus women 50-64 years old

The purpose of our study was to compare the major prognostic factors (tumor size, axillary lymph node status, and tumor stage) of breast cancers detected at mammographic screening in women ages 40-49 years old with those in women ages 50-64 years old.

Study subjects were women ages 40-64 years old who participated in our mobile van mammographic screening program from April 1985 to June 1994. We retrospectively reviewed the clinical and pathology records of women in whom breast cancer was detected at mammographic screening. All examinations were performed with dedicated equipment using screen-film technique.

A total of 44,301 screening examinations were done during the study period. Seventy-five cancers were detected in women ages 40-49 years old, and 128 cancers were detected in women ages 50-64 years old. The cancer detection rate was 3.0 per 1000 examinations in the younger age group compared with 5.5 per 1000 examinations in the older age group. The median size of breast cancers was 10 mm for women ages 40-49 versus 11 mm for women ages 50-64. Eighty-eight percent of the patients in both age groups had no evidence of metastasis to axillary lymph nodes. Nineteen percent of women in the younger age group had advanced breast cancer (stage II or higher) compared with 26% of women ages 50-64 (p = .25). No statistically significant differences were noted between the two age groups in the size, lymph node status, or stage of breast cancers detected at mammographic screening. However, the cancers found in younger women had slightly more favorable prognoses.

The major prognostic factors of cancers detected with modern mammographic equipment appear to be at least as favorable for women ages 40-49 years old as for women ages 50-64 years old. As mammographic screening has already been shown to be beneficial for women ages 50-64 years old, screening should also be beneficial for women ages 40-49 years old.