Types and Stages of Breast Cancer

According to the American Cancer Society, more than 260,000 women in the U.S. will be diagnosed with invasive breast cancer each year, with more than 40,000 American women dying from the disease. Breast cancer is the most common form of cancer among women in this country other than skin cancer, and is the second leading cause of cancer death in the nation, following lung cancer.

Knowing the type, size and spread of cancer is vital to helping a doctor determine a course of treatment. No matter the stage of the tumor at the time of diagnosis, there are aggressive, effective therapies available. Doctors describe breast cancer as either:

  • Local: The cancer is found only in the breast.
  • Regional: The cancer has spread to the axillary nodes under the arm.
  • Distant: The cancer has metastasized or spread to other parts of the body.

For more information, contact the St. Mary's Regional Medical Center Cancer Center at 580-249-5504.

Types of Breast Cancer

  • Ductal Carcinoma – occurs in the ducts of the breast, which are the tubes that transport milk to the nipple.
  • Lobular Carcinoma – occurs in the lobules where the milk is made.
  • Ductal Carcinoma-In-Situ – refers to the earliest type of breast cancer where cells that have the characteristics of cancer are found confined in the breast ducts. Because these cells have not broken through the membrane and they are confined, they do not have the potential to spread.
  • Invasive Cancers – refers to those ductal or lobular cancers that have broken through the membrane around the ducts or lobules. Invasive cancer does not necessarily mean the cancer has metastasized or spread to other parts of the body. That is determined by tests including examination of the tissues such as the lymph nodes under the arm and CT scans, bone scans and ultrasounds.

Stages of Breast Cancer

Breast cancer is classified by stages ranging from 0 to 4. The stages increase in severity with the number.

  • Stage 0 involves only a small cluster of cancer cells in the duct or lobule
  • Stage 1 is a tumor smaller than 2 cm
  • Stage 2 is a tumor up to 5 cm that has not spread to the axillary lymph nodes
  • Stage 3 is a tumor of any size that may have spread to the axillary lymph nodes
  • Stage 4 is a tumor of any size that has metastasized and has gone to other tissues besides the breast and lymph nodes