Using a needle, fluid can be removed from a cyst to check if it contains cancerous cells. A solid lump must be analyzed under a microscope. This requires either a needle biopsy or a surgical biopsy to be performed, to remove some or all of the lump.
Cancerous cells can be tested for the presence of estrogen- or progesterone-receptors. Other tests - including a chest X-ray, bone scan, and liver function evaluation - are conducted to help the doctor determine whether the cancer has spread.