What is Breast Cancer Screening?

By Dr. Garvit Chitkara in Nanavati Max Institute of Cancer Care , Breast Cancer Program

Apr 24 , 2023 | 5 min read


Breast cancer screening involves checking a woman’s breasts for cancer before the development of any sign or symptom. Breast cancer is a condition where malignant (cancerous) cells develop in the breast tissue. 

The breast has 15-20 lobes with smaller lobules. These lobules end in bulbs where milk is produced. All the lobes, lobules, and bulbs are interlinked with tubes called ducts. 
Breast cancer is more likely to affect older women. Although men can be affected too, they can easily feel any lump that forms, and screening tests are not useful for men.
There are many breast cancer screening tests available and the goal of such tests is to detect cancer at an early stage. The earlier treatment is started, the better the prognosis. 
It must be kept in mind that breast cancer screening cannot prevent breast cancer. Screening tests are generally recommended for women who have a family or medical history of cancer. Once a woman is deemed to have such risk factors, she is advised to undergo screening tests at regular intervals.

If the test result indicates an abnormality, the person needs a few diagnostic tests that can confirm the presence of cancer.

Breast Cancer Screening Tests


Mammography is the most common test for breast cancer screening. It offers a picture of the inside of the breast, called a mammogram, and can spot small tumors that cannot be felt. It is useful in detecting ductal cancer that may become invasive.

There are 3 types of mammograms:

  • Film mammogram or the conventional X-ray 
  • Digital mammograms create a computerized picture.
  • DBT (Digital Breast Tomosynthesis) takes a series of X-rays from different angles to make a 3-D picture using a computer. An advantage of DBT is that it reduces the number of false-positive results.

Mammography is not very useful in younger women. They generally have dense breast tissue and it becomes difficult to spot a tumor when both the tumor and dense tissue appear white on the mammogram.

Breast Magnetic Resonance Imaging (MRI)

Women who have a high risk of developing breast cancer are advised a Breast MRI along with an annual mammogram. The risk factors for breast cancer are:

  • Genetic testing that shows mutations in BRCA1 (BReast CAncer1) or BRCA2 genes.
  • A woman who has a first-degree relative with breast cancer
  • Other rare genetic conditions

The procedure involves radio waves, a computer and a strong magnet to create a detailed view of the inside of the breast. Sometimes, a contrast dye is injected intravenously to distinguish tissues easily. A breast MRI can show pictures of soft tissues that are not visible with other imaging techniques. It produces more false-positive results than mammography. 

Other Exams

Clinical Breast Exam 

A visual examination is also done by a specialist to check for breast cancer. The doctor will perform what is known as a clinical breast exam by palpating or feeling the breasts for any unusual lump or discharge. It will also involve checking under the arms for enlargement of lymph nodes. 

Breast Self-Awareness 

A woman or a man can do a self-check to see if there are any swellings or unusual changes to their breasts. This can be done between regular breast cancer screening tests. Women need to understand what a healthy breast is and how their breasts look and feel. In many cases, women can detect unusual changes themselves. 

When there is a gap of 3 years between mammograms, there are chances that cancer could develop during that period. These are called interval cancers. These could also arise because mammograms sometimes miss cancer. 

Breast cancer screening done, now what?

The results of a screening test are usually available in a couple of weeks. In most instances, the result is normal.

When the result is normal

The concerned person will receive a report which informs them that their mammogram showed no sign of cancer. It will also suggest another screening test after 3 years. Meanwhile, if any physical change or symptoms are noticed, it is important to visit the doctor.

When the results aren’t clear

This scenario could mean that the X-ray wasn’t clear enough to rule out any abnormality, or there could be an unusual or abnormal mass that was visible. Either way, the woman will be called back to repeat the test.

In case of a recall 

After a screening test, about 4% of women are recalled for more tests. But not every one of these women will have cancer.

The mammogram might show an abnormal area, and this requires a magnified mammogram. It shows calcified areas and the borders of any swelling with greater clarity. 
The recalled women might also be advised an ultrasound scan or a biopsy.

Benefits of breast cancer screening

  • Cancer treatment works best when it is started early. For that to happen, the diagnosis should be confirmed in the early stages of cancer.
  • Cancers that are detected by breast cancer screening are usually at an early stage. Once the cancer is confirmed, treatment is started immediately. In such cases there wouldn’t be any need for extensive procedures, and affected persons are cured completely more often than not.
  • Many statistics and studies show that breast cancer screening tests reduce the number of fatalities from cancer by about 1300 in the UK. When this number is extrapolated to a wider population, the number of deaths that can be prevented will be significant.

Risks of breast cancer screening


  • Every time a woman undergoes a mammogram she is exposed to a little radiation from the X-rays. Even though the amount is too small to cause significant harm, repeated mammograms over many years will increase the risks of developing cancer.


  • A false-negative result means that cancer that is present was not detected in the test. It could delay diagnosis and treatment.
  • False-positive results can occur when the test indicates an abnormality in the absence of any cancerous tissue. Such a result could lead to unnecessary anxiety and further testing.

Overdiagnosis and overtreatment: 

  • Sometimes, breast cancers that are not capable of causing any issue or problem may show up on the screening test. It isn’t possible to predict whether a mass will grow quickly or slowly or stop growing. For instance, DCIS (Ductal Carcinoma In Situ) consists of changes in the lining of the ducts of the breast. It is almost impossible to predict whether it will become invasive or not. In almost all such cases, women are surgically treated to remove the tumor. Some of them are even given radiotherapy or chemotherapy. 


Currently, there are no proven ways to prevent breast cancer, but there are things women can do to lower their risk of getting affected. All women are advised to reach a healthy body weight in adulthood and maintain it, to be safe after menopause. Moderate physical activity of 150-300 minutes per week is also beneficial. Women who breastfeed for at least a few months after childbirth reduce the risk of developing breast cancer.