Survival after 2-cm Breast Cancer

Cancers of exactly 2 cm in size occupy a special niche in breast oncology. That size is the one at which breast cancer is most commonly diagnosed (the “modal size”) and 2.0 cm marks the boundary between stage i and ii for node-negative breast cancers and between stage ii and iii for node-positive breast cancers. The size of the primary tumour and the nodal status are the two most useful parameters for predicting prognosis in breast cancer patients and for planning clinical management. In patients who present with localized breast cancer, increasing tumour size is inversely correlated with breast cancer–specific survival1–5. Conventionally, tumour size is measured by the pathologist based on the largest diameter of the resected specimen, estimated to the nearest millimetre. However, size evaluation is inexact, and pathologists tend to round the tumour size to the nearest centimetre or half-centimetre. As a result, many tumours are reported to be 2.0 cm in size, but relatively few are reported to be 1.9 cm or 2.1 cm. Because 2.0-cm breast cancers represent a large proportion of all breast cancer patients, and because 2.0 cm defines the border between stage i and ii breast cancers, a detailed examination of the clinical course of those tumours is of interest. We examined size distribution and tumour characteristics in 4265 unselected breast cancer patients diagnosed at age 50 or younger. We compared the 5and 10-year survival rates and annual mortality rates for young women with cancers whose size was reported to be exactly 2.0 cm and compared those rates with the rates for women with smaller and larger cancers.