In multifocal breast cancer, multiple tumors develop in the same area of the breast. Treatment may involve surgery, radiation therapy, chemotherapy, or a combination of treatments.

Multifocal breast cancer is not a single specific type of breast cancer. Rather, healthcare professionals often use the term “multifocal breast cancer” to indicate the presence of two or more tumors in the same quadrant of the breast.

This article covers information about multifocal breast cancer, including how doctors diagnose and treat it and what the outlook and recurrence rates are.

A person who has received a diagnosis of multifocal breast cancer has two invasive tumorsTrusted Source in the same area of their breast.

Experts classify breast cancers according to their characteristics. A person can receive one of the following diagnoses:

  • Unifocal breast cancer: There is only one tumor in the breast.
  • Multifocal breast cancer: At least two invasive tumors develop in the same quadrant (area) of the breast, and all tumors arise from one original tumor.
  • Multicentric breast cancer: At least two tumors develop separately, often in different quadrants of the breast.

Multifocal breast cancer is not necessarily more advanced or aggressive than unifocal breast cancer. Staging multifocal breast cancer depends primarily on the characteristics of the primary (largest) tumor.

However, multifocal breast cancer does present more risk of larger tumors or of cancer spreading to the lymph nodes, so the outlook may be less favorable for some people with multifocal breast cancer than for those with unifocal breast cancer.

In one 2015 studyTrusted Source involving 1,158 people with breast cancer at stages 1, 2, and 3, researchers found multifocal breast cancer in 131 of the participants, or 11.3%. They found multicentric breast cancer in 60 participants, or 5.2%.

Healthcare professionals classify types of breast cancer according to the type of cells in which cancer develops. Most breast cancersTrusted Source are carcinomas, which grow in the cells that line the organs and body tissues.

Classifications of breast cancer

Breast cancer is either invasive or noninvasive:

  • Noninvasive breast lesions develop inside the milk-producing glands (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 other parts of the body.

The main types of breast cancer are as follows:

Ductal carcinoma in situ (DCIS)

DCIS initially develops in the milk ducts, and healthcare professionals consider it noninvasive. A person who has had DCIS has a greater risk of developing invasive cancer later in life than someone who has never had breast cancer.

Lobular carcinoma in situ (LCIS)

LCIS is not considered a type of cancer. However, it involves noncancerous changes that can increase a person’s risk of developing cancer. According to the American Cancer Society (ACS), people with LCIS have a 7 to 12 timesTrusted Source higher risk of developing invasive breast cancer in either breast.

LCIS does not usually show up on mammograms, though in rare cases it can appear as calcifications. Instead, doctors typically discover it during a biopsy for other issues.

Invasive ductal carcinoma (IDC)

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 80% of allTrusted Source breast cancer diagnoses, according to the ACS.

Invasive lobular carcinoma (ILC)

ILC is a form of breast cancer that has spread beyond the lobules and into the surrounding breast tissue. ILCs make up about 10%Trusted Source of all invasive breast cancers.

Read more about the types of breast cancer.

Staging for multifocal breast cancer varies, with healthcare professionals basing the stage on the characteristics of the primary tumor and on whether cancer is present in other areas of the body. Treatment plans and the long-term outlook depend on the cancer stage.

There are five stages of breast cancer that indicate whether and how far the cancer 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 4).

A healthcare professional can work out the cancer stage by looking at the tumor, node, and metastasis (TNM) factors, which vary among individuals:

  • Tumor (T): the size and location of the largest tumor and whether it has spread to surrounding tissue (tumors can be further classified as invasive or noninvasive)
  • Node (N): whether the tumor has spread to the lymph nodes and how many lymph nodes are affected
  • Metastasis (M): whether the cancer has spread to other areas of the body, where those areas are, and how far they are from the original site

The TNM system does not consider whether a tumor is multifocal or unifocal.

Read more about breast cancer stages.

Diagnosing multifocal breast cancer involves multiple examinations and, in some cases, minor procedures:

  • Breast exam: A healthcare professional will examine the breasts and the chest area for signs of lumps or other changes.
  • Mammogram: A mammogram is a regular breast cancer screening procedure that captures X-ray images of the breasts. A healthcare professional 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 may detect multifocal breast cancers more accuratelyTrusted Source than ultrasound or mammogram.
  • Biopsy: A biopsy is a minimally invasive procedure in which a healthcare professional removes a small sample of breast tissue or part of a lymph node and sends the sample to a lab for testing.

Recurrence is a concern for multifocal breast cancer treatment. A cancer recurrence is an instance in which cancer comes 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 healthcare professionals 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.

The authors of a 2019 research reviewTrusted Source examined the results of 17 comparative studies and 7 case series involving a total of 3,537 people undergoing breast-conserving surgery.

The analysis demonstrated a recurrence rate of 2% to 23% after breast-conserving surgery in multifocal multicentric breast cancer at an average follow-up of 59.5 months. These are equivalent rates to those of mastectomy.

The outlook for someone with breast cancer depends on the stage of the cancer, the person’s overall health, and the cancer’s response to treatment. Experts calculate the outlook for a disease by using 5-year relative survival rates.

Relative survival rate

A relative survival rate compares people with the same type and stage of breast cancer to people without breast cancer.

The 5-year relative survival ratesTrusted Source for people with breast cancer are as follows:

  • Localized (no spread) ductal carcinoma in situ (DCIS): 99%
  • Regional (localized spread to nearby structures or lymph nodes): 86%
  • Distant (spread to other areas of the body): 31%
  • Overall rate for all stages: 91%

In one study from 2015Trusted Source, 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.

However, there is wide variation among individuals, and scientists need to complete more research before they will know how having multiple tumors affects a person’s outlook.

Overall survival rates for multifocal breast cancer depend on various factors, such as

  • age
  • overall health status
  • tumor size
  • how the cancer responds to treatment
  • whether the cancer has spread beyond the original site

The right treatment option for each person can depend on many factors, such as the person’s age, the stage of cancer, and whether the cancer has spread to the lymph nodes or other areas of the body.

Treatment options can also depend on the size of the breast. For example, multifocal tumors are more challenging to remove with a lumpectomy in smaller breasts. Multifocal tumors are more easily approved for lumpectomy in people who have a larger breast size.

Lumpectomy

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 present in only one quadrant of the breast.

Mastectomy

A mastectomy is a surgical procedure that involves removing the entire breast. Unless a tumor is large relative to the breastTrusted Source, doctors usually, but not always, favor breast-conserving surgery, such as a lumpectomy.

Radiation therapy

Healthcare professionals may recommend radiation therapy in combination with a lumpectomy and sometimes a mastectomy. After removing as much of the cancer as possible, they may useTrusted Source radiation therapy to destroy any remaining cancer cells. Radiation therapy is an effective method of preventing breast cancer recurrence.

Chemotherapy

Chemotherapy is a systemic (whole-body) treatment that uses one or more cytotoxic medications that preventTrusted Source cancer cells from multiplying. When treating multifocal breast cancer, healthcare professionals may recommend chemotherapy either before or after the primary treatment.

Learn more about breast cancer treatments.

Breast cancer resources

Visit our dedicated hub for more research-backed information and in-depth resources on breast cancer.

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 chances of developing it remain unclear.

Several treatment options are available for multifocal breast cancer, including lumpectomy, mastectomy, radiation therapy, hormone therapy, and chemotherapy.

The appropriate treatment plan will vary from person to person. it is important that people speak honestly and openly with healthcare professionals about their treatment preferences and concerns.