Purpose: To investigate the relationship between the tumor size of breast cancer by palpation and the sensitivity of mammography (MMG) and ultrasonography (US), and which modality can detect nonpalpable breast cancer in women aged 30 to 39 years.
Methods: We retrospectively evaluated the tumor size by palpation, breast density, and the sensitivity of MMG and US in 165 patients aged 30 to 39 years. Palpation, US, and MMG were performed with prior knowledge of the results of other modalities. The tumor size on palpation were classified into Tnp; nonpalpable, T1p; 2 cm or less, T2p; more than 2 cm, but not more than 5 cm, and T3p; more than 5 cm.
Results: Of 165 patients, 147 patients (89%) showed mammographically dense breasts. Of 165 cancers, 14 (8%) were Tnp, 40 (24%) were T1p, 82 (50%) were T2p, and 29 (18%) were T3p. The sensitivity of MMG was 57% (8 of 14) for Tnp, 78% (31 of 40) for T1p, 90% (74 of 82) for T2p, and 97% (28 of 29) for T3p. The sensitivity of US was 43% (6 of 14) for Tnp and 100% for palpable cancers. Of 14 nonpalpable cancers, 4 (29%), 4 (29%), and 2 (14%) could be detected by only MMG, bloody nipple discharge, and US.
Conclusions: The sensitivity of MMG depends on the tumor size on palpation in this age range. MMG fails to detect relatively large palpable cancers. On the other hand, US can detect all palpable cancers. However, the sensitivity of US declines for nonpalpable cancers. For the detection of nonpalpable cancers, MMG, US, and nipple discharge are complementary modalities.