A mammogram is a specialized X-ray of the breast tissue that screens for breast cancer. They can be an effective tool for detecting breast cancer in its early stages, which is when it is most treatable.

During a mammogram, the breast is compressed between two plates while the machine takes X-ray images. These images can show signs that may indicate breast cancer.

Mammography image showing left breast calcification, which may indicate breast cancer.Share on Pinterest
Mammography image showing left breast calcification, which may indicate breast cancer. Casa nayafana/Shutterstock.

Mammograms are an effective method of detecting stage 1 breast cancer and other stages of the disease. They can detect small tumors that a person may not be able to feel during a breast exam and other changes in the breast tissue that may be indicative of cancer, such as calcifications.

On a mammogram, breast masses and cancers look white. Dense breasts contain a high proportion of fibrous and glandular tissue, which also appears white on a mammogram. This makes it difficult to detect issues in people with dense breasts. In contrast, fatty tissue appears dark gray or black on a mammogram, making irregularities easier to spot.

However, it is important to note that mammograms are imperfect and may not always detect early stage breast cancer.

Find more mammogram images here.

The American Joint Committee on Cancer (AJCC) TNM system is the most commonly used staging system for breast cancer.

TNM stands for:

  • T: tumor size
  • N: node involvement
  • M: metastasis — the spread of cancer to other parts of the body

Doctors also use four other key pieces of information to determine the stage:

  • Estregon receptor (ER) status: This indicates whether the cancer has the ER protein.
  • Progesterone receptor (PR) status: This signifies whether the cancer has the PR protein.
  • HER2 status: This indicates whether the cancer makes too much of the HER2 protein.
  • Cancer grade (G): This reflects how much the cancer cells look like regular cells.

Breast cancer staging is an important factor in determining an appropriate treatment plan. Earlier detection makes treatment more straightforward and improves a person’s outlook.

Learn more about breast cancer staging.

Stage 1 breast cancer is an early stage of the disease. Doctors divide it into two subcategories: stage 1A and stage 1B.

Stage 1A breast cancer is a small tumor that has not yet spread beyond the breast. The tumor is 2 centimeters or smaller.

Stage 1B breast cancer is slightly more advanced than Stage 1A. Cancer cells are present in the lymph nodes under the arm in this stage. These are larger than 0.2 millimeters (mm) but smaller than 2 mm. There may or may not be a tumor present in the breast.

Doctors also consider ER, PR, and HR2 status alongside the cancer grade when differentiating between stage 1A and stage 1B breast cancer.

Learn more about early stage breast cancer.

Doctors use several methods to diagnose breast cancer, including physical exams, imaging tests, and biopsy results.

  • Physical exam: A healthcare professional will feel the breasts and underarm area for lumps or other irregularities.
  • Imaging tests: Mammograms, ultrasound, and MRI create detailed images of the breast tissue and surrounding area. These images can help determine the size and location of any tumors.
  • Biopsy: Results from a biopsy, which involves removing and examining tissue samples from the breast, can also help diagnose breast cancer. The pathologist will examine the tissue under a microscope to determine the type and grade of cancer, and this information can help determine the stage.

Find breast cancer information and resources in our dedicated hub.

The symptoms of stage 1 breast cancer may include:

  • a lump or thickening in the breast tissue or underarm area
  • a change in the size or shape of the breast
  • discharge from the nipple
  • a change in the appearance of the nipple, such as inversion or scaling of the skin
  • a change in the feel or texture of the breast or nipple, such as skin dimpling or puckering

These symptoms do not necessarily mean that a person has breast cancer. However, if a person experiences any of these issues, it is important to consult a healthcare professional for further evaluation.

Learn more about the signs and symptoms of breast cancer.

There are several treatment options for stage 1 breast cancer. Treatment varies widely based on a person’s ER, PR, and HER2 status.

Some common treatment options for stage 1 breast cancer may include:

  • Surgery: This may involve a lumpectomy, which removes the tumor and a small margin of healthy tissue surrounding it. It may also include a mastectomy, which is a procedure to remove the entire breast. In some cases, surgeons may also remove the lymph nodes under the arm.
  • Radiation therapy: This uses high-energy radiation to kill cancer cells.
  • Chemotherapy: This involves the use of drugs to kill cancer cells.
  • Hormonal therapy: This involves the use of drugs that block the action of hormones such as estrogen, which can fuel the growth of certain types of breast cancer.
  • Targeted therapy: This involves using drugs that target specific proteins or pathways involved in the growth and spread of cancer cells.

The outlook for stage 1 breast cancer is generally very good. This is because the cancer is confined to the breast and has not yet spread to other parts of the body.

The 5-year survival rate for people with stage 1 breast cancer is 99%. This means that nearly all people with stage 1 breast cancer are alive 5 years after diagnosis.

However, it is important to note that these are overall survival rates and do not consider individual factors that could affect a person’s outcome.

Learn more about breast cancer survival rates.

While mammograms may not always identify early-stage breast cancer, they are an important tool for detecting the disease early on.

Doctors may also recommend other imaging tests and a biopsy to help diagnose breast cancer. They then use a system such as the TNM staging system to determine the stage of cancer.

Stage 1 breast cancer is an early stage of the disease. According to statistics, 99% of people with stage 1 breast cancer are still alive 5 years after diagnosis.