Radiation Therapy for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a distinct and aggressive subtype of breast cancer that lacks estrogen receptors (ER), progesterone receptors (PR) and overexpression of the HER2 protein. Because TNBC lacks these three common treatment targets, it does not respond well to conventional hormone or HER2-targeted therapies, making it more challenging to treat than other types of breast cancer. Through ongoing research, however, scientists are continually developing and refining new treatment approaches for triple-negative breast cancer, paving the way for better outcomes and quality of life for many patients.

TNBC accounts for approximately 10 to 15% of all breast cancer cases, predominantly affecting women 50 and younger. While the exact cause is unknown, risk factors may include inherited gene mutations, a family history of breast cancer and certain reproductive or lifestyle factors.

The symptoms of triple-negative breast cancer can be similar to those of other types of breast cancer. Common warning signs include a new breast lump, changes in breast shape or size, skin dimpling and unusual nipple discharge. However, TNBC tends to grow and spread more rapidly. The diagnostic process typically involves a clinical breast exam, imaging studies, such as mammography or ultrasound, and a biopsy to analyze the tumor tissue. Once the diagnosis is confirmed, the physician will usually order further testing to stage the tumor and guide treatment decisions.

Treatment for triple-negative breast cancer may include a combination of surgery, chemotherapy and radiation therapy. Depending on the extent of the tumor, surgical treatment might involve lumpectomy (breast-conserving surgery) or mastectomy. Chemotherapy remains a cornerstone of TNBC treatment, mainly because this type of tumor is more likely to respond to chemo drugs than to targeted therapies.

Radiation therapy is often a key part of TNBC treatment. In many cases, it is administered after surgery to help reduce the risk of local recurrence, especially in a patient who has an early-stage tumor and opted to undergo breast-conserving surgery.

When is radiation therapy used for triple-negative breast cancer?

Radiation therapy is commonly incorporated into a comprehensive treatment plan for TNBC. It may be considered in the following clinical scenarios:

After breast-conserving surgery

Radiation therapy is often administered after lumpectomy to target any remaining microscopic cancer cells in the breast tissue. This treatment approach can reduce the likelihood of tumor cells returning to the same area, and it is considered standard of care for early-stage triple-negative breast cancer.

After mastectomy

For a patient who elects surgical removal of one or both breasts, follow-up radiation therapy may be recommended if the patient is at heightened risk of cancer recurrence. To make this determination, the physician will consider multiple factors, including the size and extent of the tumor. In general, the risk of recurrence is higher when the tumor is larger than five centimeters in diameter or has spread to the skin or chest wall.

When lymph nodes are involved

If TNBC has spread beyond the breast and invaded nearby tissues, radiation therapy can be delivered to regional lymph nodes under the arm or near the collarbone. This treatment technique can help eliminate any microscopic tumor cells that remain after surgery and reduce the risk of further cancer spread.

When the tumor is locally advanced or inoperable

In some cases, radiation therapy may be administered before surgery to help shrink the tumor and make it easier to remove. Alternatively, it may serve as the primary treatment for a patient who is not a candidate for surgery.

When the cancer has returned after initial treatment or metastasized

If TNBC recurs locally after treatment or has spread to other areas of the body, radiation therapy can be used as a supportive care measure to help relieve symptoms or control tumor growth.

What does radiation therapy for triple-negative breast cancer involve?

When radiation therapy is used for TNBC, the specific approach and schedule can vary based on several factors, including the location, size and extent of the tumor and the patient’s overall health. The types of radiation therapy for triple-negative breast cancer include:

Intensity-modulated radiation therapy (IMRT) for triple-negative breast cancer

An advanced form of external beam radiation therapy (EBRT), IMRT uses a computer-controlled linear accelerator to deliver precise radiation doses to the tumor or specific areas within it. By modulating the intensity of the energy beams and directing them to the targeted tissue from multiple angles, intensity-modulated radiation therapy allows for heightened treatment accuracy while minimizing exposure to the surrounding healthy tissues.

What are the possible side effects of intensity-modulated radiation therapy for triple-negative breast cancer?

The side effects of IMRT can be similar to those of other external radiation treatments, often including general fatigue and skin irritation, redness or dryness in the treated area. Some patients also experience mild swelling, tenderness or changes in skin pigmentation. These side effects are usually temporary and subside shortly after treatment is completed.

What are the risks and possible complications of intensity-modulated radiation therapy for triple-negative breast cancer?

While IMRT can reduce radiation exposure to nearby vital organs, such as the heart and lungs, it still carries some risks. These may include long-term skin changes, tissue hardening (fibrosis) and, in rare cases, the development of secondary cancers. However, due to its advanced precision, IMRT significantly lowers these risks compared to conventional radiation therapy techniques.

What to expect during recovery from intensity-modulated radiation therapy for triple-negative breast cancer

Recovery from IMRT is typically gradual, with most patients resuming their normal activities within a few weeks after treatment concludes. Supportive care may involve topical treatments for skin irritation, rest to manage fatigue and regular follow-up visits to monitor healing and detect any signs of recurrence.

How effective is intensity-modulated radiation therapy for triple-negative breast cancer?

IMRT has demonstrated strong results in reducing local cancer recurrence and preserving healthy tissues, making it a highly effective treatment option for TNBC. Its precision and adaptability can make it especially beneficial for complex cases where the tumor is located near critical structures. It may also be a good option for a patient with left-sided breast cancer.

Three-dimensional computerized radiation therapy (3D CRT) for triple-negative breast cancer

3D CRT uses advanced imaging technology to shape the radiation beams to match the exact size and contours of the tumor. This targeted approach helps protect nearby healthy tissues while delivering an effective dose to the tumor site. Three-dimensional computerized radiation therapy is most commonly used after breast-conserving surgery, but it can also target regional lymph nodes when appropriate.

What are the possible side effects of three-dimensional computerized radiation therapy for triple-negative breast cancer?

The side effects of 3D CRT can vary based on the treatment area, but common reactions include skin irritation, redness and peeling similar to a sunburn. Fatigue often develops over the course of treatment. Additional side effects may include swelling in the breast or chest area, general discomfort and temporary changes in skin color or texture.

What are the risks and possible complications of three-dimensional computerized radiation therapy for triple-negative breast cancer?

Although 3D CRT is generally well-tolerated, potential risks include damage to the surrounding organs, such as the heart and lungs, especially when used to treat left-sided breast cancer. Though rare, possible long-term complications include rib fractures, swelling in the arm or chest (lymphedema) and changes in breast size or firmness.

What to expect during recovery from three-dimensional computerized radiation therapy for triple-negative breast cancer

Recovery from 3D CRT typically involves a gradual return of energy and resolution of skin-related side effects in the weeks following treatment. While most symptoms subside within a short period, some patients may continue to experience fatigue or localized tenderness. Regular follow-up with the healthcare team is important to assess healing and monitor for any signs of cancer recurrence.

How effective is three-dimensional computerized radiation therapy for triple-negative breast cancer?

3D CRT has been shown to effectively reduce the risk of local recurrence in patients with TNBC, particularly when administered after surgery. Given the aggressive nature of triple-negative breast cancer, timely and precise radiation delivery is essential for improving local tumor control and supporting overall quality of life.

INTRABEAM® intraoperative radiotherapy for triple-negative breast cancer

INTRABEAM® delivers a concentrated dose of radiation directly to the tumor bed during breast-conserving surgery, immediately following tumor removal. By targeting the area at the highest risk for recurrence, this technique limits radiation exposure to the surrounding healthy tissues and may reduce or eliminate the need for additional external radiation therapy.

How is INTRABEAM® intraoperative radiotherapy for triple-negative breast cancer delivered?

During breast-conserving surgery, the surgeon will remove the tumor and insert a small spherical applicator into the cavity left behind. The device will deliver a single dose of low-energy X-rays directly to the tumor bed to target any remaining microscopic cancer cells. The INTRABEAM® procedure typically adds 20 to 30 minutes to the surgical session and is performed under the same anesthesia.

What are the possible side effects of INTRABEAM® intraoperative radiotherapy for triple-negative breast cancer?

The side effects of INTRABEAM® are typically mild and well-tolerated. Some patients experience localized pain or tenderness, swelling or temporary changes in skin sensation at the treatment site. Because the radiation is delivered directly to the tumor bed, the side effects are often less severe than those associated with external beam radiation therapy.

What are the risks and possible complications of INTRABEAM® intraoperative radiotherapy for triple-negative breast cancer?

Though rare, complications of INTRABEAM® can include infection at the surgical site, delayed wound healing and localized skin changes. However, the limited radiation range greatly reduces the risk of damage to nearby organs and tissues.

What to expect during recovery from INTRABEAM® intraoperative radiotherapy for triple-negative breast cancer

Recovery from INTRABEAM® generally aligns with the typical surgical recovery process. Most patients are able to return to their normal activities within a few days. Follow-up visits will be scheduled to assess healing and ensure there are no complications. Since the radiation is delivered during surgery, additional treatment sessions are usually unnecessary.

How effective is INTRABEAM® intraoperative radiotherapy for triple-negative breast cancer?

INTRABEAM® can be highly effective for early-stage TNBC when used in carefully selected patients. It offers the convenience of single-dose radiation treatment and has shown promising results in reducing local cancer recurrence. However, it is not suitable for all patients, particularly those with large tumors or lymph node involvement.

Benefit from world-class care at Moffitt Cancer Center

The multispecialty team in Moffitt’s renowned Radiation Oncology Program—which is fully accredited by the American College of Radiology (ACR)—includes experienced radiation oncologists, radiation therapists, dosimetrists, physicists, nursing specialists and other medical professionals who focus exclusively on planning and delivering radiation therapy. Through our Don & Erika Wallace Comprehensive Breast Program, our patients have access to the latest options in triple-negative breast cancer treatment, including INTRABEAM® intraoperative radiotherapy and other advanced radiation-based treatments available only through our robust portfolio of clinical trials. We also utilize deep inspiration breath hold (DIBH), an innovative breathing technique that can reduce exposure to the heart during radiation therapy for left-sided breast cancer.

If you would like to learn more about radiation therapy for triple-negative breast cancer, you can request an appointment with a specialist at Moffitt by calling 1-888-663-3488 or submitting a new patient registration form online. We do not require referrals.