What is the predictive value for malignancy of radiological classification for indeterminate microcalcification seen on mammography?

Objective

The aim of this study is to measure the predictive value for invasive/non-invasive cancer for indeterminate microcalcification (M2, M3 and M4) seen on mammography.

Methods

Four-hundred and thirteen cases of indeterminate calcification were prospectively classified as M2 (benign), M3 (probably benign) or M4 (suspicious for malignancy) and underwent prone 14G stereotactic biopsy. The predictive value for each category was measured by recording the outcome for all cases (no surgery, surgery benign, DCIS, invasive cancer).

Results

Of 41 cases classified as M2, one case had a final outcome of DCIS and none had an outcome of invasive cancer (positive predictive value = 2.4%). Of 184 cases classified as M3 there were 10 cases of invasive cancer and 28 cases of DCIS (positive predictive value of 20.6% overall for malignancy). Of 188 cases classified as M4 there were 70 cases of DCIS, three cases of LCIS and 12 cases of invasive cancer (positive predictive value overall of 45.2% for malignancy).

Conclusion

Sub-classification of microcalcification based on a full radiological work-up including magnification views is useful prior to stereotactic biopsy.

Examples illustrating radiological and pathological correlation will be used.