MULTIVARIATE-ANALYSIS OF ROENTGENOLOGIC CHARACTERISTICS AND RISK-FACTORS FOR NONPALPABLE CARCINOMA OF THE BREAST

Screening mammography improves carcinoma of the breast survival throug h early detection and treatment of nonpalpable, often noninvasive, car cinomas. Consideration of the roentgenologic characteristics of mammog raphic masses and calcifications in combination with risk factors of p atients may improve the yield of spot localization breast biopsy. Risk factors solicited by questionnaire were correlated with the roentgeno logic appearance and histopathologic factors of 482 specimens from spo t localization breast biopsies (39 percent malignant). Masses with irr egular contour (p<0.001) and high density (p<0.005) were associated wi th malignant tumors. Packed, coarse and round calcifications were asso ciated with benignity (p<0.001), whereas scattered, fine and mixed cal cifications were associated with malignant tumors (p<0.05). Malignant masses with smooth contour were significantly more likely to be associ ated with noninvasive histology. Patients found to have malignant tumo rs were significantly older than patients with benign lesions (58 vers us 52 years, p<0.001). Stepwise logistic regression was used to evalua te the relative usefulness of demographics and roentgenologic features in predicting benign and malignant pathology among masses and calcifi cations. Age and irregular contour were independent significant predic tors of malignancy for masses. Age, round, coarse, packed or scattered calcifications were significant independent predictors of benignity a mong calcifications. The radiologist correctly predicted malignant pat hology in 60 percent of the patients and benign pathology in 78 percen t. Parity, age at menarche, age at first pregnancy, age at menopause, history of benign breast disease, history of carcinoma of the breast, family history of carcinoma of the breast, birth control pill exposure and smoking were not significantly associated with the diagnosis of m alignant tumor. These results suggest that risk factors for carcinoma of the breast are insignificant for nonpalpable lesions because patien ts referred for needle localization are already selected for high risk . Roentgenologic patterns of masses are useful for predicting which le sions are invasive.