The concept of minimal breast cancer and the pathologist's role in the diagnosis of "early carcinoma".

Minimal breast cancer has been variously defined as a lesion 1 cm or less, or even 5 mm or less. Some authorities consider intraductal cancer and lobular carcinoma in situ as minimal, but we believe that these should be excluded from consideration. Minimal cancer is not early cancer inasmuch as a 1 cm lesion represents 30 doubling times, and a certain percentage of these small cancers have already disseminated. The pathologist's responsibility in diagnosing minimal cancer has become more difficult. His problem is in three major areas: Is this proliferative cystic lesion cancer? Is this lobular or intraductal proliferative lesion in situ carcinoma? And if so, he must be concerned also with the treatment as well as the diagnosis. In any screening program, these minimal cancers, either invasive or in situ, should be evaluated by a group of experts in order that the program be entirely accurate.