INTERVAL CHANGES IN NONPALPABLE BREAST-LESIONS AS AN INDICATION OF MALIGNANCY

OBJECTIVE: To determine whether the patterns of interval changes in no npalpable breast lesions can be used to determine malignancy. PATIENTS AND METHODS: The authors reviewed the records for 128 nonpalpable bre ast lesions detected by mammography between March 1990 and May 1992 fo r which previous imaging studies were available. Changes in size, dens ity and contour of the 59 masses and changes in size, number, configur ation and pattern for the 69 cases involving microcalcifications were determined from comparison of the current mammograms with the earlier imaging studies, obtained 6 to 42 months previously. These findings we re correlated with the pathological diagnosis based on needle localiza tion and excisional biopsy. RESULTS: Twelve (55%) of the 22 new masses and 15 (48%) of the 31 masses that changed were malignant, but none o f the 6 masses that did not change were malignant (chi2 test, p < 0.01 ). All of the 31 masses that changed increased in size (and of these, 15 [48%] were malignant). In addition, 14 (45%) of the masses that cha nged exhibited increased density (and of these 9 [64%] were malignant) , and 11 (35%) became irregular (and all of these were malignant). Eig ht (47%) of the 17 cases of new calcifications, 18 (43%) of the 42 cas es of calcifications that changed and none of the 10 cases of unchange d calcifications were malignant (chi2 test, p < 0.01). Twelve (44%) of the 27 calcifications that changed in area and 14 (40%) of the 35 tha t changed in number were malignant. Fifteen (60%) of the 25 calcificat ions that changed from scattered to grouped and 8 (53%) of the 15 that changed from punctate to linear were malignant. CONCLUSION: A change in the density or contour of a mass is a fairly definite sign of malig nancy. The authors conclude that interval observation is a good method of detecting malignancy in breast masses but is less reliable for det ecting malignancy in calcifications.