Non-Cancerous Breast Conditions

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How non-cancerous breast conditions affect breast cancer risk

As noted earlier, some types of non-cancerous or benign breast conditions are linked to higher breast cancer risk, while others are not. Doctors often divide benign breast conditions into 3 general groups, based on whether the cells are multiplying (proliferative) and whether there are abnormal cells or patterns of cells (atypia):

  • Non-proliferative lesions do not seem to affect cancer risk
  • Proliferative lesions without atypia slightly increase cancer risk
  • Proliferative lesions with atypia raise the risk of cancer
  • benign breast conditions are divided into these groups in this section. Details on each of the specific conditions listed can be found in the section called “Types of non-cancerous breast conditions.”

Non-proliferative lesions

These conditions are not linked with the overgrowth of breast tissue. They do not seem to affect breast cancer risk, or if they do, the effect is very small. They include:

  • hyperplasia of the usual type
  • (non-sclerosing)
  • tumor (benign)
  • single (solitary) papilloma
  • cell tumor
  • necrosis
  • ectasia
  • lumps or tumors (lipoma, hamartoma, hemangioma, hematoma, neurofibroma, adenomyoepthelioma)
  • and apocrine metaplasia
  • calcifications

Proliferative lesions without atypia

These conditions are linked with the growth of cells in the ducts or lobules of the breast tissue. They seem to raise a woman’s risk of breast cancer slightly (1½ to 2 times the usual risk):

  • or florid ductal hyperplasia of the usual type (without atypia)
  • adenosis
  • papillomas or papillomatosis
  • scars

Proliferative lesions with atypia

These conditions are linked with the excess growth of cells in the ducts or lobules of the breast tissue, and the cells no longer look normal. They can raise breast cancer risk about 3½ to 5 times higher than normal:

  • ductal hyperplasia
  • lobular hyperplasia

Lobular carcinoma in situ

This condition raises breast cancer risk 7 to 11 times that of normal.

Last Medical Review: 01/14/2014
Last Revised: 01/14/2014