Breast. TNM classification of malignant tumours

The breast classification was the first TNM classification proposed by the UICC. It was published in 1954 and received general approval. It was amended in 1972, when it was accepted that the size of the primary tumour was of more prognostic significance than its local extension. It was agreed also that minor skin changes should not affect the classification of T1, T2 or T3 and that extension to the pectoral fascia or muscle should be recorded as a sub-category of these categories. Size determined by mammography is more accurate than measurement by calliper and approximates pathological size. Mammographic size is therefore preferred but for centres without this facility, calliper measurement should be recorded. The classification will remain unchanged until at least 1986