<prompt> The most impoant prognostic factor in carcinoma breast isSize of tumourSkin involvementInvolvement of musclesAxillary gland involvement  <response>: The Nottingham prognostic index NPI is used to determine prognosis following surgery for breast cancer. Its value is calculated using three pathological criteria: the size of the lesion; the number of involved lymph nodes; and the grade of a tumour.Size of lesion is least impoant.The extent of axillary lymph node involvement by breast cancer--is the most established and reliable prognostic factor for subsequent metastatic disease and survivalDevita principles of oncology 10th edition, Bailey and love 26th edition. 