Canadian Journal of Surgery 1995; 38: 110-111
Until the late 1960s, breast biopsy was always performed because of a palpable abnormality. Such biopsy specimens almost always revealed a lesion measuring more than 1 cm in dimension. In the United States, the Breast Cancer Detection Demonstration Project was the stimulus for the generalized use of mammography, which resulted in an increase in the diagnosis of nonpalpable cancers. Breast cancer incidence peaked between 1974 and 1976.[2]
In Canada, the National Breast Screening Study, initiated in 1980, was an opportunity for clinicians in screening centres to become familiar with the new challenge of dealing with mammographic abnormalities. According to Sterns' experience, screening mammography was rarely performed in the Kingston, Ont., area before 1988. After that time, the number of referrals for an abnormal mammogram increased rapidly.
Sterns emphasizes that expert clinical examination by the surgeon remains of the utmost importance as the first step in the evaluation of mammographically diagnosed breast lesions. Among 435 patients referred by their physician with an abnormal mammogram and supposedly normal clinical findings, 13% had a clinical abnormality and 3.3% had a palpable breast cancer. It confirms the observation of the National Breast Screening Study[3] that experienced surgeons performing physical examination of the breast have better sensitivity and positive predictive value than other health professionals.
When a lump is palpable, the surgeon must decide on the need for a surgical biopsy. When the mammogram in abnormal, the surgeon must decide if localization and surgical biopsy will be performed after an opinion given by a radiologist.
Sterns' study illustrates the importance of a second opinion from an expert radiologist in the assessment of all abnormal mammograms to reduce the number of unnecessary surgical biopsies. Only 34% of abnormal mammograms in fact suggested cancer, and in 73% of these localization and surgical biopsy were ultimately necessary.
Finally, a carcinoma was confirmed in 40 (36.4%) of 110 women who underwent a mammographic localization biopsy. This rate is superior to the rate of 21.3% reported by Bland and Frykberg[4] for 21 centres where 9472 biopsies of mammographically detected nonpalpable breast lesions were performed. To further reduce the number of false-positive mammograms and unnecessary surgical biopsies without missing early breast cancers will be very difficult. One promising avenue is the combined use of stereotactic fine-needle or core biopsy with mammography.
The Karolinska Hospital has reported its experience with 2594 mammographically detected nonpalpable breast lesions.[5] The predictive value of a negative result combining mammography and stereotactic fine-needle biopsy was almost 100%, thus sparing these women surgical biopsies. The same procedure identified 75% of patients with early breast cancer who underwent surgical biopsy.
More than ever, surgeons will be required to work closely with radiologists (before surgery) and pathologists (during surgery) to face the new challenge of the abnormal mammogram.[6]
2. Harris JR, Lipman ME, Veronesi U et al: Breast cancer. N Engl J Med 1992; 327: 319-328
3. Baines CJ, Miller AB, Bassett AA: Physical examination: its role as a single screening modality in the Canadian National Breast Screening Study. Cancer 1989; 63: 1816-1822
4. Bland KI, Frykberg ER: Selective management of in situ carcinoma of the breast. Breast Dis 1992; 3: 11-22
5. Azavedo E, Svane G, Auer G: Stereotactic find-needle biopsy in 2594 mammographically detected nonpalpable lesions. Lancet 1989; 1: 1033-1036
6. Immediate management of mammographically detected breast lesions. Association of Directors of Anatomic and Surgical Pathology. Am J Surg Pathol 1993; 17: 850-851