Cribriform breast cancer is a rare type of breast cancer that often develops alongside another form of the disease. It is typically low grade, slow growing cancer that has a better outlook than most other types.

Around 5–6% of invasive breast cancers have parts of the tumor that are cribriform, according to breastcancer.org.

However, a 2015 report and review appearing in Oncology Letters estimated a much lower incidence of 0.3–3.5% of people with breast cancer have the cribriform form.

In this article, we explain the grading and types of cribriform breast cancer, as well as ways of diagnosing the disease.

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The cells in cribriform breast cancer feature a distinctive pattern of holes.

This type of cancer involves breast cancer cells that feature a pattern of holes. According to BreastCancer.org, the appearance of these holes closely resembles those in Swiss cheese.

Cribriform cancer can also include features from other types of breast cancer.

A person may have more than one type of cancer in a tumor. A doctor may also diagnose invasive mammary carcinoma of no special type, which means the cancer cells do not resemble any specific type.

Several different types of cells can grow in breast cancers, including:

  • tubular
  • mucinous cribriform
  • micropapillary

Cribriform cells are among the least common.

Grading of a tumor means that a doctor examines the cancer cells and describes them as grade 1, 2, or 3. Grading is important, as it tells other doctors how different the cancerous cells are in comparison to healthy breast cells.

The higher the grade, the faster the cancer cells usually grow. The grading of breast cancer is:

  • Grade 1: The tumor cells are slow growing and closely resemble those of typical breast cells.
  • Grade 2: The tumor cells are moderately different from healthy cells.
  • Grade 3: The tumor cells are highly abnormal and appear to be growing quickly.

As well as the grading, a doctor will also need to decide the staging of the cancer when considering prognosis and treatments.

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Working out the stage of a cancer helps a doctor define a course of treatment.

Staging defines the extent of the cancer, including how far it has spread and the tumor size. Staging for cribriform breast cancer is as follows:

  • Stage 0 (carcinoma in situ): At this stage of breast cancer, the cancerous cells have not spread beyond the ducts of the breast into the fatty tissue. Early detection and treatment at this stage usually have an excellent outlook.
  • Stage 1: A tumor at this stage measures 2 centimeters (cm) or less in diameter and has not spread beyond the breast.
  • Stage 2: Doctors define a stage 2 tumor in one of several ways:

It will be:

  • smaller than 2 cm and have spread to one to three lymph nodes under the arm
  • between 2 and 5 cm with or without spreading to lymph nodes
  • larger than 5 cm without spreading to lymph nodes

Stage 3: As with stage 2, several characteristics constitute a stage 3 tumor:

  • The tumor is any size in diameter and has spread to more than three lymph nodes or into the chest wall.
  • The tumor is larger than 5 cm, with spread to one to three lymph nodes.

Stage 4: At its most severe stage, cancer will have spread outside the breast to other organs. This is known as metastasis.

The stage of cancer can help doctors decide on the most appropriate treatments. As a general rule, the lower the stage of breast cancer, the more likely that treatment will be effective.

Here, learn more about stage zero breast cancer.

Cribriform breast cancer metastasizes or spreads to lymph nodes under the arm less frequently than other forms. As a result, the prognosis for cribriform breast cancer is often "favorable" or good.

Hormones often influence cribriform breast cancer, especially estrogen and progesterone.

However, there are currently no standard treatment guidelines specific to cribriform breast cancer. A doctor will consider the cancer's stage and discuss treatment options.

Examples of the treatments for cribriform breast cancer include:

  • Surgical removal: A doctor may recommend a lumpectomy or mastectomy to remove some or all of the breast tissue. This way, the surgeon can be sure that they have extracted all cancerous cells from the breast.
  • Chemotherapy: Chemotherapy involves the administration of drugs to kill rapidly multiplying cancer cells.
  • Radiation: Radiation involves exposing the tumor to high energy radiation that targets and kills cancerous cells.
  • Hormone therapy: This involves drugs that inhibit the action of hormones, such as estrogen and progesterone, that contribute to breast cancer. Tamoxifen is a common hormone therapy drug, which prevents estrogen from binding to cancer cells.

Each of these treatments has side effects that range from mild to severe. A person should discuss all treatment options, and the risks of each, with their doctor.

Learn more about treating breast cancer.

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Cribriform cancer cells show distinctive holes under a microscope.
Image credit: Nephron, 2011

A doctor will usually order a mammogram, which is an X-ray image of the breast. They may also request an ultrasound scan, which uses sound waves to identify tumors or masses in the breast.

Cribriform breast cancer does not typically cause symptoms. The cancerous lesions are not always easily visible on a mammogram. If the diagnosis is not clear, the doctor may request further imaging studies, such as an MRI scan. These scans produce more precise images to aid in diagnosis.

When a doctor identifies a potentially cancerous lesion in the breast, they will often recommend a biopsy. This procedure involves extracting cells from the breast with a needle and send them to a lab for investigation.

A pathologist then examines the sample under a microscope to identify different types of cancerous cells.

A tumor with cribriform cells will show under a microscope with its characteristic porous appearance.

On receiving the results, the doctor will grade and stage the tumor. They can then make recommendations on the best course of treatment.

According to the American Cancer Society, cribriform breast cancer is a less common type of cancer than a typical invasive ductal carcinoma, which affects the milk ducts.

Cribriform breast cancer does not usually metastasize or spread to lymph nodes under the arm. As a result, the prognosis for cribriform breast cancer is usually favorable.

The 10 year overall survival rate for people with this type is 90–100%, according to a 2015 study.

This means that 90–100% of those with this form of breast cancer will survive for at least 10 years after diagnosis.

Q:

Can cribriform breast cancer come back after treatment?

A:

While cribriform breast cancer has a very favorable prognosis, there is always a chance that the cancer could return in the future.

Yamini Ranchod, PhD, MS Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.