Multifocal breast cancer is a form of breast cancer in which multiple tumors arise in the same area of the breast.
There are many types of breast cancer. The type and characteristics, including the number of tumors and where they are, can affect a person’s treatment and long-term outlook.
This article covers information about multifocal breast cancer, including how doctors diagnose and treat the condition, its prognosis, and recurrence rates.
A person who has received a diagnosis of multifocal breast cancer has more than one invasive tumor in one area of their breast.
Experts classify breast cancers into different categories, depending on their characteristics. A person can receive one of the following diagnoses:
- Unifocal breast cancer, where there is only one tumor in the breast.
- Multifocal breast cancer, when at least two invasive tumors develop in the same quadrant, or area, of the breast. All tumors arise from one original tumor.
- Multicentric breast cancer, where at least two tumors develop separately, often in different areas of the breast.
Multifocal breast cancer is not necessarily more advanced or aggressive than single tumor breast cancer. Staging multifocal breast cancer depends primarily upon the characteristics of the primary, or largest, tumor.
However, there is more risk of larger tumors or cancer spreading to the lymph nodes, so that the prognosis may be less favorable for some people with multifocal compared with unifocal breast cancer.
As a result of differences in definitions and diagnostic techniques, anywhere from 4 to 75 percent of breast tumors are multifocal or multicentric.
One study involving 1,158 people with breast cancer of stages 1, 2, and 3 found multifocal breast cancer in 131 of the participants, or 11.3 percent. They found multicentric breast cancer in 60 cases, or 5.2 percent of participants.
Doctors classify different types of breast cancers based on the type of cells in which cancer develops. Most breast cancers are carcinomas, which means they grow in the cells that line the organs and body tissues.
Breast cancer is either invasive or noninvasive:
- Noninvasive breast cancers develop inside the milk-producing glands, or lobules, or inside the milk ducts and do not spread outside these areas.
- Invasive breast cancers grow beyond the lobules or ducts and spread into other areas of the breast or parts of the body.
The main types of breast cancer include the following:
- Ductal carcinoma in situ (DCIS) initially develops in the milk ducts, and doctors consider it noninvasive. Having DCIS increases a person’s risk of developing cancer again compared with someone who has never had breast cancer. The chance of a recurrence is less than 30 percent.
- Lobular carcinoma in situ (LCIS) is another form of noninvasive breast cancer that initially develops in the lobules. LCIS can increase someone’s risks of developing invasive breast cancer later in life. LCIS usually does not show up on a mammogram.
- Invasive ductal carcinoma (IDC) is a form of breast cancer that has spread beyond the ducts and into the surrounding breast tissue. IDCs are the most common type of breast cancer, accounting for 80 percent of all breast cancer diagnoses.
- Invasive lobular carcinoma (ILC) is a form of breast cancer that has spread beyond the lobules and into the surrounding breast tissue. ILCs make up a small percentage of all breast cancer diagnoses.
Staging for multifocal breast cancer varies with doctors basing this on the characteristics of the primary tumor and whether or not cancer is present in other areas of the body. Treatment plans and long-term outlook depend on the cancer stage.
There are five stages, starting from zero, that indicate if, and how far, a tumor has spread.
Stages range from noninvasive cancer that has not spread to surrounding tissue (stage 0) to metastatic cancer that has spread to other parts of the body (stage IV).
A doctor will be able to work out a person’s cancer stage by looking at the tumor, node, and metastasis (TNM) factors. These vary between individuals:
- Tumor (T): Size and location of the largest tumor and whether or not it has spread to surrounding tissue.
- Node (N): Whether or not the tumor has spread to the lymph nodes and how many lymph nodes are affected.
- Metastasis (M): Whether or not cancer has spread to other parts of the body, where they are, and how far from the original site.
The TNM system does not include whether a tumor is multifocal or unifocal.
Diagnosing multifocal breast cancer involves multiple examinations and, in some cases, minor procedures:
- Breast exam. A healthcare provider will examine the breasts and chest area for signs of lumps or other changes.
- Mammogram. This is a regular breast cancer screening procedure that captures X-ray images of the breasts. A healthcare provider examines these images for early signs of breast cancer.
- Ultrasound. An ultrasound machine creates detailed images of the body’s internal structures in real time.
- MRI scan. An MRI detects multifocal breast cancers more accurately than ultrasounds and mammograms.
- Biopsy. A biopsy is a minimally invasive procedure where a doctor removes a small sample of breast tissue or part of a lymph node, which goes to a lab for testing.
Recurrence is a significant concern for multifocal breast cancer treatment. Recurrence refers to cancers that come back after treatment. Recurrent cancers can develop in the same place as the original tumor, or they can develop in a new location in the body.
When doctors compare multifocal breast cancer with unifocal breast cancer, the former may carry a higher risk of recurrence. However, not all studies show that this is the case, so more research is needed.
One retrospective study followed a group of 152 people with either unifocal or multifocal breast cancer. The research team found no differences in recurrence or mortality rates between the two groups after 7 years, though doctors had given those with multifocal cancer more aggressive treatment.
The prognosis for someone with breast cancer will depend on the stage of the cancer. Experts calculate a person’s outlook by using average 5-year survival rates. However, these parameters are just a guide, and many people live much longer than these might suggest.
The 5-year survival rates for women with breast cancer are as follows:
- Stage 0 and 1 is close to 100 percent.
- Stage 2, about 93 percent.
- Stage 3, about 72 percent, and treatment is often successful.
- Stage 4, or metastatic breast cancer, about 22 percent. There are still many treatment options at this stage.
In one study, the researchers associated multifocal breast cancer with higher mortality rates and lower 5- and 10-year survival rates, but the only independent predictors of survival were tumor size and lymph node metastases.
Compared with single tumor breast cancers, multifocal breast cancers have a higher risk of spreading to the lymph nodes.
There is a wide variation between individuals, and scientists need to complete more research before they know how multiple tumors affect a person’s prognosis.
Overall survival rates for multifocal breast cancer depend on various factors, such as
- overall health status
- tumor size
- how the cancer reacts to treatment
- if the cancer has spread beyond the original site
The appropriate treatment option can vary, depending on many factors, such as the person’s age, the stage of cancer, and whether or not cancer has spread to the lymph nodes or other areas of the body.
Treatments for multifocal breast cancer include:
During a lumpectomy, a surgeon removes the cancerous cells while saving as much of the surrounding healthy breast tissue as possible. This procedure is especially promising if the cancer is only present in one quadrant of the breast.
A mastectomy is a surgical procedure that involves removing the entire breast and the surrounding lymph nodes. Unless a tumor is larger than 5 centimeters (or 2 inches) in diameter, or large relative to the breast, doctors usually favor breast-conserving surgery, such as a lumpectomy.
Doctors often recommend radiation therapy in combination with a lumpectomy. After removing as much of the cancer as possible, they may use radiation therapy to destroy any remaining cancer cells. Radiation therapy is an effective method of preventing later breast cancer recurrence.
Chemotherapy is a systemic, or body-wide, treatment that uses one or more cytotoxic medications that prevent cancer cells from multiplying. When treating multifocal breast cancer, chemotherapy may be used either before or after the primary treatment.
Breast cancer treatments can significantly increase a person’s long-term survival rate, but they can cause side effects.
Side effects of breast surgery, including lumpectomy and mastectomy, may be:
- tenderness or pain in the breast
- swelling of the breast
- changes in the shape and appearance of the breast
Radiation therapy side effects may include
- pain in the breast
- swelling of the breast
- change in shape or appearance of the breast
- redness of the skin
- flaking or peeling of the skin
- sore throat
- lymphedema, which is swelling in a specific area due to a buildup of fluid
Chemotherapy side effects are:
People recently diagnosed with multifocal breast cancer may experience a range of emotions and have many questions. A person and their family or friends can speak to a doctor about all stages of the process, including how and where to get psychological support.
Joining a support group is a good idea for people who want to discuss their feelings and concerns with others going through similar experiences. People can join support groups in person and online.
Building and maintaining strong relationships with family and friends can make it easier to have honest and open discussions with loved ones. These connections can help people cope with any difficulties that may arise throughout their journey through diagnosis, treatment, and recovery.
Multifocal breast cancer occurs when at least two invasive tumors are present in the same quadrant of the breast. There are conflicting clinical definitions, so the exact number of people who have multifocal breast cancer and the risk of developing it remains unclear.
There are several treatment options available for multifocal breast cancer. These include lumpectomy, mastectomy, radiation therapy, hormonal therapy, and chemotherapy.
The appropriate treatment plan will vary from person to person, so it is vital that people speak honestly and openly with their doctor about their treatment preferences and concerns.