Mammographic tumour features can reliably predict the long-term outcome of women with 1–14 mm invasive breast cancer: suggestions for revision of current therapeutic practice and the TNM classification system

We studied the 24-year survival of 714 women with 1–14 mm invasive breast cancer according to mammographic features, including appearance of calcifications and masses. The most common mammographic feature was a stellate lesion with no associated calcifications (420 cases, 59%). Patients with stellate lesions had excellent long-term survival (95%). Casting-type calcifications were observed in 52 (7%) cases and were significantly associated with a positive lymph node status, poorer histological grade, and increased risk of breast cancer death (hazard ratio = 9.19, 95% confidence interval = 4.18–20.17). Except for tumours with casting type calcifications, all tumours less than 10 mm had excellent survival, regardless of node status, histological grade or treatment. For those with casting-type calcifications, survival was poorer even with 1–9 mm tumours (72% at 20 years). For 10–14 mm tumours, 20-year survival was 52% for those with casting calcifications, and 86–100% otherwise. Small invasive cancers accompanied by casting-type calcifications have unexpectedly poor prognosis for their size. Neoductgenesis offers a possible explanation for the unexpectedly poor outcome. There is a need to develop treatment protocols for this group. After exclusion of tumours with casting-type calcifications, the remainder have extremely good prognosis when treated with surgery and no adjuvant therapy.