Redness and inflammation are common signs of an infection or injury, but when these symptoms occur in the breast, they may signal a rare type of breast cancer known as inflammatory breast cancer (IBC).

IBC is among the most aggressive types of breast cancer, and it can progress over the course of months or even just a few weeks. Because of this, early diagnosis and care are crucial. All too often, however, IBC isn’t diagnosed until later stages, when it’s harder to treat. In general, IBC has a poorer prognosis than do most other types of breast cancer.

In the U.S., IBC makes up only between 1–5% of all breast cancer cases. On average, it affects women at younger ages than other forms of breast cancer—often occurring in women under 40, but it has a median age at diagnosis of 57. And though it is very rare, IBC can also occur in men.

“Patients diagnosed with inflammatory breast cancer benefit from specialized multidisciplinary care and access to the latest breast cancer trials to improve clinical outcomes,” says Maryam Lustberg, MD, MPH, director of The Breast Center at Smilow Cancer Hospital and chief of Breast Medical Oncology at Yale Cancer Center.

Breast cancer develops when cells grow in an uncontrolled and abnormal fashion in the breast. (The breast is made up of various types of tissues and structures, and cancer can develop in any of them.) Over time, these cells may grow into tumors. 

Sometimes tumors are benign, meaning they are noncancerous and cannot spread to nearby or distant tissues. Other times, however, tumors are cancerous, or malignant, meaning they can invade nearby tissues and spread to other parts of the body.

In IBC, cancerous cells infiltrate and block the lymph vessels in the breast. Normally, the lymph vessels drain fluids away from the breast. But in IBC, cancer cells block these vessels, which means they cannot efficiently drain fluids away from the breast. This results in the buildup of fluid, which in turn causes some of the characteristic symptoms of IBC including swelling of the breast and reddening of the breast skin.

In IBC, cancer cells that originated in breast tissue tend to quickly migrate to lymph nodes under the armpit or near the collarbone and to more distant parts of the body.

Little is known about which risk factors may increase the chances of developing IBC. One risk factor that has consistently been linked to IBC, however, is having a body mass index (BMI) of 30 or higher (a BMI of 30 or above is considered obese).

Symptoms of IBC tend to develop quickly, often progressing over a period of weeks or a few months. They may include:

• Rapid increase in breast size (enlarged breast)
• Breast pain or tenderness
• Breast redness and swelling
• Dimpled, pitted breast skin that may resemble the skin of an orange (called “peau d’orange”)
• Breast feels warm
• Inverted nipple
• Swollen lymph nodes under the armpit or above the collarbone

Some people who have IBC may feel a lump in the breast, though this is not a common sign of this type of breast cancer.

The doctor will ask questions about symptoms, including when they began and how quickly they progressed. He or she will need to conduct a physical exam to check for findings associated with IBC. During the physical exam, the doctor will closely examine the breasts and will feel the lymph nodes under the armpit and around the collarbone for any signs of swelling. The doctor may also take a photograph of the affected breast to establish a reference image against which changes to the breast during treatment can be compared.

Other tests are necessary to confirm the diagnosis of IBC, and to rule out other possible causes of symptoms, including:

• Imaging tests can help doctors see tumors, thickened skin, or other abnormalities in breast tissue. Tests may include a mammogram, breast ultrasound, and/or a magnetic resonance imaging (MRI) study of the breast.
• Biopsy of breast tissue is required for diagnosis. In this procedure, a health care provider removes a small piece of breast tissue, usually with a needle. A pathologist analyzes the tissue sample in a lab to check for the presence of cancer cells and other indications of IBC. If cancer is detected, the pathologist will also determine the hormone receptor and HER2 status of the cancer cells. Sometimes biopsy of the skin of the breast is also necessary. 

If the doctor diagnoses IBC, he or she will order some additional tests to see whether the cancer has spread to other parts of the body. This process is known as staging. It typically involves a computed tomography (CT) scan, positron emission tomography (PET), or a bone scan. After the doctor has determined the extent of the cancer, he or she will assign it to a stage, which helps in making a prognosis and planning the best course of treatment.

It’s worth noting that many of the symptoms of IBC are similar to those of other, more common conditions such as an infection of the breast tissue. Because of this, IBC is sometimes initially misdiagnosed and treated with antibiotics, which do not improve symptoms or deal with the underlying cancer.

Treatment of IBC usually involves chemotherapy, surgery, radiation therapy, and, in cases in which the cancer is hormone receptor-positive and/or HER2-positive, targeted therapies.

• Chemotherapy. Chemotherapy uses drugs to kill cancer cells. For people who have IBC, chemotherapy is usually used before surgery (when it is known as “neoadjuvant” chemotherapy), with the aim of reducing the size of tumors. But chemotherapy may also be necessary after surgery (when it is known as “adjuvant” chemotherapy) to eliminate any remaining cancer cells.
• Surgery. In patients whose tumors respond well to neoadjuvant chemotherapy, surgery to remove cancerous breast tissue is usually the next stage of treatment. This usually involves a mastectomy, which is the surgical removal of the entire breast, typically along with the lymph nodes under the adjacent armpit. Once treatment is complete, patients may wish to undergo breast reconstruction surgery.
• Radiation therapy. This treatment kills cancer cells by exposing them to radiation. It is typically used following surgery to eradicate any remaining cancer cells. If a patient’s IBC does not respond well to neoadjuvant chemotherapy, radiation therapy may be used prior to surgery to reduce the size of the tumor.
• Hormone therapy. Breast cancer cells may be hormone receptor-positive (HR-positive). Such cells have receptors for hormones (estrogen and/or progesterone). When these hormones bind to the receptors, they help the cancer cells grow. Medications can target HR-positive cancer cells either by reducing the body’s production of the relevant hormones or by blocking the hormone receptors on cancer cells. Hormone therapy is usually used after surgery.
• Targeted therapies. Breast cancer cells that have high levels of human epidermal growth factor 2 (HER2) receptors are known as HER2-positive. HER2 is a protein that helps HER2-positive cancer cells grow. Drugs are available that target the HER2 protein, and consequently slow or stop the growth of cancer cells. This treatment may be used prior to or following surgery, with the aim of stopping or slowing the growth of cancer cells.

The outlook for people diagnosed with IBC depends on several factors including age and overall health, the extent to which the cancer has spread, and the timing of the diagnosis. In most cases, the earlier the diagnosis and sooner treatment begins, the better the prognosis.

Outcomes are usually best in patients who receive what is called “trimodal” treatment that involves chemotherapy, surgery, and radiation. After treatment, patients should follow up with their doctors to keep an eye on recurrence of breast cancer.

But because IBC is aggressive, it has a worse prognosis than most other types of breast cancer. What’s more, because it progresses rapidly, it is often diagnosed after the cancer has spread to nearby lymph nodes or distant parts of the body, which make effective treatment more difficult.

“The Yale Breast team will work closely together to deliver the highest level of personalized, evidenced-based care for all breast cancers including inflammatory breast cancer,” says Dr. Lustberg.