Nonpalpable breast cancer in women aged 40-49 years: a surgeon's view of benefits from screening mammography.

While mammography screening among women aged 50 years or older has proven to reduce breast cancer mortality, screening in younger women has been repeatedly scrutinized. To test the effect of screening among younger women, we examined 84 consecutive patients aged 40-49 at the time of breast cancer diagnosis: 27 (32.1%) were diagnosed solely by mammography, and 57 (67.9%) had a palpable mass. The mean tumor sizes were 1.3 cm and 3.6 cm for the two groups respectively. While 68.8% nonpalpable invasive tumors were classified as Stage I cancer, only 34% of patients with palpable breast cancer had Stage I disease. None of the patients with nonpalpable breast cancer had disease beyond Stage II. In contrast, 28.3% of the patients with palpable invasive breast cancer presented with advanced disease. In addition, 6.3% versus 41.5% of patients with nonpalpable and palpable breast cancer respectively had nodal metastases. The five-year survival rates for the two groups were 100% and 73% respectively, favoring breast cancer detected mammographically. Screening of women aged 40-49 also resulted in more breast-conserving surgery and less chemotherapy. We conclude that screening in this age group should be continued, although individual assessment is needed.