Stages of Breast Cancer

Institutes & Services > TriHealth Cancer Institute > About Your Cancer > Breast Cancer > Stages of Breast Cancer

Every woman experiences this complicated disease in her own way. Treatment decisions revolve around factors such as:

  • The size of the tumor
  • Whether or how far the cancer has spread
  • The stage of the cancer

Staging is simply a way of describing the current condition of the cancer in five basic stages, from 0 to IV. It’s important to remember that staging is not the only factor that affects your breast cancer diagnosis. Other factors include:

  • The type of cancer you have
  • How quickly it is growing
  • Your general health and age
  • Whether you have had breast cancer previously
  • Presence of female hormones or other factors such as the HER2 oncogene that affect the speed of cancer growth

What are the Stages of Breast Cancer?

Stage O Breast Cancer

The disease is confined to the milk ducts (ductal carcinoma in situ).

Stage I Breast Cancer

The tumor is less than 2 cm across and has not spread.

Stage II Breast Cancer

Stage II Breast Cancer is one of the following:

  • IIA: The tumor is smaller than 2 cm across but has spread to the lymph nodes underneath your arm
  • IIB: The tumor is between 2 and 5 cm, with or without spread to lymph nodes
  • IIB: The tumor is larger than 5 cm and has not spread to the lymph nodes

Stage III Breast Cancer (Also Called “Locally Advanced Breast Cancer”)

The tumor is any size, with cancerous lymph nodes that stick either to one another or to surrounding tissue (IIIA).

  • IIIB: The tumor is any size and has spread to the skin, chest wall or lymph nodes beneath the breast.

Stage IV Breast Cancer

The tumor, regardless of size, has spread to other areas beyond the breast, such as lungs, liver, bones or brain.

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