Evaluation of Breast Symptoms
Women with breast symptoms are not candidates for screening because they require a diagnostic evaluation. During a 10-year period, 16% of 2,400 women aged 40 to 69 years sought medical attention for breast symptoms at their health maintenance organization. Women younger than 50 years were twice as likely to seek evaluation. Additional testing was performed in 66% of these women, including invasive procedures performed in 27%. Cancer was diagnosed in 6.2%, most often stage II or III. Of the breast symptoms prompting medical attention, a mass was most likely to lead to a cancer diagnosis (10.7%) and pain was least likely (1.8%) to do so.
Pathologic Diagnosis of Breast Cancer
Breast cancer is most often diagnosed by pathologic review of a fixed specimen of breast tissue. The breast tissue can be obtained from a symptomatic area or from an area identified by an imaging test. A palpable lesion can be biopsied with core needle biopsy or, less often, fine-needle aspiration biopsy or surgical excision; image guidance improves accuracy. Nonpalpable lesions can be sampled by core needle biopsy using stereotactic x-ray or ultrasound guidance or can be surgically excised after image-guided localization. In a retrospective study of 939 patients with 1,042 mammographically detected lesions who underwent core needle biopsy or surgical needle localization under x-ray guidance, sensitivity for malignancy was greater than 95% and the specificity was greater than 90%. Compared with surgical needle localization under x-ray guidance, core needle biopsy resulted in fewer surgical procedures for definitive treatment, with a higher likelihood of clear surgical margins at the initial excision.
Ductal CarcinomaIn Situ
Ductal carcinoma in situ (DCIS) is a noninvasive condition that can evolve to invasive cancer, with variable frequency and time course. Some authors include DCIS with invasive breast cancer statistics, but others argue that the term be replaced by ductal intraepithelial neoplasia, similar to the terminology used for cervical and prostate precursor lesions, and that breast cancer statistics exclude these DCIS cases.
DCIS is most often diagnosed by mammography. In the United States, only 4,900 women were diagnosed with DCIS in 1983, compared with approximately 64,000 women who are expected to be diagnosed in 2013, when mammographic screening has been widely adopted.[3,4,5] The Canadian National Breast Screening Study-2 of women aged 50 to 59 years found a fourfold increase in DCIS cases in women screened by clinical breast examination (CBE) plus mammography compared with those screened by CBE alone, with no difference in breast cancer mortality. (Refer to the PDQ summary on Breast Cancer Treatment for more information.)