Stage I breast cancer
Stage I breast cancer is the earliest stage of invasive breast cancer. At this stage, the cancer cells have spread beyond the original location and into the surrounding breast tissue.
Because a stage I tumor is small, it may be difficult to detect. However, breast self-exams and routine screening are always important and can often lead to early diagnosis, when the cancer is most treatable.
Types of stage I breast cancer
Stage I is divided into two categories:
- Stage IA: The tumor measures 2 cm or smaller (about the size of a pea or shelled peanut), and has not spread outside the breast.
- Stage IB: Small clusters of cancer cells measuring no more than 2 mm, are found in the lymph nodes, and either there is no tumor inside the breast, or the tumor is small, measuring 2 cm or less.
The survival rate for stage IA breast cancer may be slightly higher than for stage IB. However, all women with stage I breast cancer are considered to have a good prognosis.
At stage I, TNM designations help describe the extent of the disease. For example, there may or may not be cancer cells in the lymph nodes, and the size of the tumor may range from 1 - 2 cm. Most commonly, stage I breast cancer is described as:
- T: T1, T2, T3 or T4, depending on the size and/or extent of the primary tumor.
- N0: Usually, cancer has not spread to the lymph nodes
- M0: The disease has not spread to other sites in the body