MAMMOGRAPHIC APPEARANCE OF CANCER IN THE OPPOSITE BREAST - COMPARISONWITH THE FIRST CANCER

OBJECTIVE. Patients who have had cancer in one breast are at high risk for cancer in the contralateral breast,These bilateral cancers may be synchronous or metachronous. If the manifestations on mammography wer e similar in both breasts, an aggressive search for the mammographic f indings of the first breast cancer might lead to early detection of th e contralateral cancer. The purpose of this study was to evaluate mamm ograms for patients with bilateral cancers to determine whether the ma mmographic appearance of the contralateral cancer is likely to be the same as that of the first cancer. MATERIALS AND METHODS. We retrospect ively reviewed the pathologic and mammographic records of 69 patients with surgically proven bilateral primary breast cancer. Thirty four of 69 (49%) had synchronous cancer, and 35 (51%) had metachronous cancer , Mammographic appearances were classified as microcalcifications, spi culated mass, nonspiculated mass (whether circumscribed or poorly defi ned), asymmetric or developing density, architectural distortion, and normal. Multiple findings were subclassified as major and minor findin gs. All findings were compared between both breast cancers, and statis tical significance was determined by the two-sample Z test. RESULTS, F orty six (67%) of 69 patients had different major mammographic finding s in the contralateral cancer. Of 30 patients whose first cancers had microcalcifications, 20 (67%) had microcalcifications in the contralat eral cancer. Of 39 patients whose first cancers lacked microcalcificat ions, 17 (44%) had microcalcifications in the contralateral cancer. Th is difference was statistically significant (p = .02). Of 26 patients whose first cancers had spiculated masses, 9 (35%) had a contralateral spiculated mass. Of 43 patients whose first cancers lacked spiculated masses, 12 (28%) had a contralateral spiculated mass. This difference was not statistically significant (p = .22). CONCLUSION. Our results show that contralateral tumors usually have major mammographic finding s different from those of the first cancer, and the mammographic signs of the first cancer do not indicate the most likely appearance of can cer in the contralateral breast. Evaluation of a contralateral mammogr am should be performed without regard for the mammographic findings fo r the first cancer.