Because radiation therapy is both safe and effective, it can be used on breast cancers at all stages, from Stage 0 to Stage IV. Also, radiation therapy can be used on women who have had either a lumpectomy or a mastectomy.
Doctors recommend radiation therapy to most women who have undergone breast-conserving surgeries, like a lumpectomy. Radiation after lumpectomy is commonly used to reduce the risk of recurrence (i.e., re-occurrence) of disease if:
The cancer is in an early stage.
The tumor is less than 4 centimeters.
The tumor is located in one area of the breast and can be removed without disrupting too much of the surrounding tissue.
About 30% of women who have a mastectomy also have radiation therapy. Most of these women are those who are a high risk of recurrence of breast cancer. When it is less clear whether or not a patient is a likely candidate for recurrent breast cancer, she may opt to have radiation therapy just to have greater peace of mind.
Doctors will recommend radiation after mastectomy if:
The tumor is larger than 5 centimeters.
The tumor has a positive margin of resection, meaning that there are cancer cells present in the tissue beyond the edge of the tumor.
At least 4 lymph nodes were involved.
The cancer was multi-centered, meaning that it occurred in multiple areas in the breast.