Advantages and limitations of physical examination and mammography in breast cancer screening.

Among 167 breast cancers detected on screening by xeromammography and physical examination, the accuracy of each modality was found to depend not only on the size and stage of the tumor itself but also on the structure and composition of the surrounding breast tissue. Overall, 53% (89/167) of cancers were found on physical examination and 78% (131/167) on xeromammography. Mammographic accuracy was greatest for large breasts and fatty breasts but was reduced for small breasts, dense breasts, and retroareolar lesions. The proportion of tumors with negative findings on physical examination was equal among women above and below 50 years of age.