What to know about multifocal breast cancer
Medically reviewed by Elizabeth Berger, MD, MS — Written by Jamie Eske — Updated on January 7, 2025
In multifocal breast cancer, multiple tumours 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 tumours in the same quadrant of the breast.
A person who has received a diagnosis of multifocal breast cancer has two invasive tumours 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 tumour in the breast.
• Multifocal breast cancer: At least two invasive tumours develop in the same quadrant (area) of the breast, and all tumours arise from one original tumour.
• Multicentric breast cancer: At least two tumours 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) tumour. However, multifocal breast cancer does present more risk of larger tumours or of cancer spreading to the lymph nodes, so the outlook may be less favourable for some people with multifocal breast cancer than for those with unifocal breast cancer.
Other classifications of breast cancer
Healthcare professionals classify types of breast cancer according to the type of cells in which cancer develops. Most breast cancers are carcinomas, which grow in the cells that line the organs and body tissues.
Classifications of breast cancer
Breast cancer is either invasive or non-invasive:
• Non-invasive 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 non-invasive. 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 times 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 all 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% of all invasive breast cancers.
There are five stages of breast cancer that indicate whether and how far the cancer has spread. Stages range from non-invasive cancer that has not spread to surrounding tissue (stage 0) to metastatic cancer that has spread to other parts of the body (stage 4).
• Tumour (T): the size and location of the largest tumour and whether it has spread to surrounding tissue (tumours can be further classified as invasive or non-invasive)
• Node (N): whether the tumour 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 tumour is multifocal or unifocal.
Diagnosing multifocal breast cancer
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 accurately 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.
Outlook for multifocal breast cancer
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.
• 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%
Compared with single-tumour breast cancers, multifocal breast cancers have a higher risk of spreading to the lymph nodes. Overall survival rates for multifocal breast cancer depend on various factors, such as
• age
• overall health status
• tumour size
• how the cancer responds to treatment
• whether the cancer has spread beyond the original site
Treatment for multifocal breast cancer
• 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 tumour is large relative to the breast, doctors usually, but not always, favour 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 use 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 prevent cancer cells from multiplying. When treating multifocal breast cancer, healthcare professionals may recommend chemotherapy either before or after the primary treatment.
Original article:
https://www.medicalnewstoday.com/articles/324318?slot_pos=ar#treatment