Ductal Carcinoma
This is breast cancer which occurs in the ducts of the breast, which are the tubes that transport milk to the nipple.
 
Lobular Carcinoma
This is breast cancer which occurs in the lobules where the milk is made.
 
Ductal Carcinoma-In-Situ
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
Invasive cancer 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 will be determined by results of tests including examination of the tissues such as the lymph nodes under the arm and other tests your doctor may obtain such as: CAT scans, bone scans and ultrasound.

The type, size and spread of cancer are important information to help a doctor determine a course of treatment. Whatever the stage of the tumor at the time of diagnosis there are aggressive, effective therapies available.

Doctors describe breast cancer as:

• Local: Cancer is 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.

Breast Cancer stages are based on the type, size and spread of cancer. The stages range from 0 to 4 (increasing 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.