A novel method for prediction of long-term outcome of women with T1a, T1b, and 10–14 mm invasive breast cancers: a prospective study Original Research Article

Background Women with small mammographically detected breast cancers generally have good long-term outcomes, but a few with T1a (1–5 mm) and T1b (6–10 mm) tumours will eventually die from breast cancer. We investigated whether women at high risk of breast-cancer death could be identified with mammographic criteria and differentiated from women with small cancers of the breast and good outcomes. Methods We prospectively applied mammographic classifications of tumour type to a consecutive series of 343 mammograms of invasive breast cancers of size 1–14 mm. Classifications were: stellate (spiculated) mass with no calcifications; circular or oval lesions with no calcifications; spiculated or circular lesions with non-casting-type calcifications; and casting-type calcifications. Findings 20-year survival for women with 1–14 mm invasive tumours with casting-type calcifications was 55%. 14% of 138 women with 1–9 mm tumours had casting-type calcifications on mammography, which accounted for 73% of all breast-cancer deaths (p<0·001). T1a, T1b, and 10–14 mm tumours with casting-type calcifications behaved as if they were larger lesions, since the rate of death was similar to that for women with advanced high-grade tumours. Most women who died were node-negative. The long-term survival of women who had tumours of 1–9 mm with no casting-type calcifications was about 95%. Interpretation Mammographic classification seemed to reliably predict good and bad long-term outcomes for survival in tumours of 14 mm or smaller, and especially for those smaller than 10 mm. The implications for therapy are substantial.