Management of mammographic indeterminate lesions

The positive predictive value of mammography in nonpalpable malignancy, only 20 to 25 per cent, could be improved with better mammographic criteria for lesions not requiring biopsy. The outcomes of 89 patients with indeterminate lesions were reviewed to determine whether these lesions could be managed safely by observation rather than biopsy. Indeterminate lesions were defined as 1) tightly clustered, nonlinear calcifications (>5 within 1 cm of tissue); 2) dominant, well-circumscribed soft-tissue masses (≤1 cm²); or 3) asymmetric density. Lesions not immediately undergoing biopsy were followed with frequent-interval mammography. Twenty-two lesions (26%) underwent immediate biopsy, and 2 of these demonstrated carcinoma in situ with microinvasion. Sixty-seven lesions (74%) were observed (median follow- up, 34 months), and 2 (2.5%) proved to be malignant, for an overall malignancy rate of 4.5 per cent. All malignancies were stage I, and the patients remain alive with no evidence of disease (average follow-up, 24 months). Sixty patients were spared unnecessary biopsy, decreasing potential wire-directed biopsies by 25 per cent. The positive predictive value of mammography increased from 21 to 32 per cent over the period. Indeterminate lesions can be safely followed with frequent ipsilateral mammography, reserving biopsy for lesions that progress. Management schemes such as this one can be used to decrease the number of negative wire-directed biopsies.