The widespread use of screening mammograms has increased the number of breast cancers found before they cause any symptoms, but some are still missed.

The most common sign of breast cancer is a new lump or mass. A lump that is painless, hard, and has uneven edges is more likely to be cancer. But some cancers are tender, soft, and rounded. So it's important to have anything unusual checked by a doctor.

Other signs of breast cancer include the following:

  • Swelling of all or part of the breast
  • Skin irritation or dimpling
  • Breast pain
  • Nipple pain or the nipple turning inward
  • Redness, scaliness, or thickening of the nipple or breast skin
  • A nipple discharge other than breast milk

Sometimes breast cancer can spread to lymph nodes under the arm and cause a lump or swelling there, even before the tumor in the breast tissue is large enough to be felt.

If you have any symptoms that might be a sign of breast cancer, be sure to see a doctor as soon as you can. After asking you some questions and doing a complete physical exam (including a clinical breast exam), your doctor may want to do more tests, such as those listed below.

Imaging tests

Mammograms: Although mammograms are mostly used for screening, they can also be used if there is a breast problem. These are called diagnostic mammograms. This kind of mammogram might show that everything is okay and you can go back to having yearly mammograms. Or it might show that a biopsy should be done. Even if the mammogram doesn't show a tumor, if you or your doctor can feel a lump you may need a biopsy. The exception would be if ultrasound shows that the lump is a cyst.

Mammograms often don't work as well in younger women, mostly because their breasts are dense and this can hide a tumor. This is also true for pregnant women and women who are breast-feeding. Since most breast cancers occur in older women, this is usually not a major problem. But it is a problem for young women who have a genetic risk factor for breast cancer because they often get breast cancer at a younger age. For this reason, some doctors now suggest MRI along with mammograms for screening these women.

A mammogram cannot show for sure whether or not cancer is present. If your mammogram shows a possible problem, a sample of breast tissue is removed and looked at under a microscope. This is called a biopsy.

MRI scans: MRI scans can be used along with mammograms for screening women who have a high risk of getting breast cancer. Or they can be used to look at areas of concern found on a mammogram. MRI is also sometimes used for women who have breast cancer in order to help figure out the size of the cancer.

MRI scans use radio waves and strong magnets instead of X-rays to make pictures. A contrast material called gadolinium is often put into a vein before the scan to better show details. MRI scans can take a long time — often up to an hour. You have to lie inside a narrow tube, which may upset people with a fear of enclosed spaces. The machine makes loud buzzing and clicking noises that you may find disturbing. Some places will give you headphones with music to block this out.

Breast ultrasound: An ultrasound uses sound waves to outline a part of the body. The sound wave echoes are picked up by a computer to create a picture on a computer screen.

Ultrasound is a good test to use along with mammograms because it is widely available and costs less than other tests. But ultrasound should not be used instead of mammograms. Usually, it is used to look at a certain area of concern found by the mammogram. It sometimes helps to tell the difference between cysts and solid masses without using a needle to draw out fluid.

Ductogram (also called a galactogram): This is a special kind of X-ray that is sometimes helpful in finding the cause of a nipple discharge. A very thin plastic tube is placed into the opening of the duct at the nipple. A dye is injected to outline the shape of the duct on an X-ray picture. It will show if there is a tumor inside the duct. If there is a discharge, the fluid can be tested for cancer cells.

There are several other tests that can help tell the doctor more about your situation. Feel free to ask your doctor to explain any test to you.