Radiation plays a significant role in treating patients with breast cancer, but there are more options now that can reduce the time spent in therapy or the amount of healthy tissue treated. Dr. Maria C. E. Jacobs, director of radiation oncology at Mercy Medical Center, explains some new techniques and their benefits.
What is the benefit of using radiation on breast cancer patients and what does it typically entail?
We use radiation in patients with early-stage breast cancers after lumpectomy (breast conserving treatment); we also use radiation after mastectomy and in patients with locally advanced disease. The benefit of radiation is to improve local control by killing or eradicating microscopic disease in the breast and/or lymph nodes near the breast. Radiation also plays a role in the care of patients with metastatic disease.
In the last 25 years, breast-conserving therapy — lumpectomy followed by radiation therapy — has become the standard of care for patients with early-stage breast cancer. Multiple studies have shown that breast conserving treatment achieves local control equivalent to mastectomy, while providing superior cosmetic results. The standard course of treatment consists of whole breast irradiation for 25 to 28 daily treatments followed by five to 10 treatments to the lumpectomy site. It does represent a six to seven-week treatment course.
Can you explain a few advances of radiotherapy in breast cancer?
External beam radiotherapy: There is a growing interest toward hypofractionation, which involves delivering a higher dose per fraction for a shorter course of treatment.
Intensity modulated radiation therapy: We have been using three-dimensional conformal in the treatment of breast cancer patients with the goal of reducing the volume of normal tissue receiving a high dose while increasing the dose to the target volume. With IMRT, we can improve the dose distribution within the breast while sparing normal tissues in the most adequate fashion. This can be particularly significant in those patients with left breast cancers in whom we are concerned about doses of radiation to the heart.
High-dose rate brachytherapy: This technique utilizes temporary radioactive implants placed in the breast through catheters or other devices for a relatively short period of time. This treatment brings up the concept of partial breast irradiation. Radiotherapy significantly reduces the local recurrence risk in patients with breast cancer undergoing lumpectomy and most recurrences take place around or near the lumpectomy cavity. In a very well- selected group of patients, whole breast irradiation may not be necessary.
Intraoperative radiation therapy: It consists in delivering a single dose of radiation to the lumpectomy cavity following tumor removal. The standard protocol includes a very strict patient selection based of tumor size and lymph nodal status.
We have task forces in radiation oncology organizations developing consensus and implemented changes as these options continue to evolve with the development of new technology and awareness in outcomes.
How are they combined with surgery and chemotherapy?
In patients with early-stage breast cancer treated with lumpectomy, we first need to establish the benefit of systemic chemotherapy based on risk factors for relapse, such as metastatic lymph nodes, triple-negative breast cancers. If such risk is defined, patients will receive chemotherapy first followed by radiotherapy upon completion.
In patients with locally advanced breast cancers, neoadjuvant (prior to surgery) chemotherapy has become a standard practice. It can potentially reduce the size of the primary tumor and/or lymph node metastasis. It may also increase the probability for conserving surgery to be performed in women interested in breast preservation. In these patients as well as in those undergoing mastectomy after chemotherapy, we will make recommendations for loco-regional radiotherapy that includes the affected chest wall and loco-regional lymph nodes.
The new technology allows reducing the duration of a treatment course. In those patients eligible for partial breast treatment, radiotherapy is implemented intraoperatively or shortly after surgery.
Are there specific risks, side effects or benefits for each?
Radiotherapy is a local and regional treatment. So there are local and regional side effects and complications; however, fatigue happens to be a systemic side effect.
In patients receiving whole breast irradiation, we do expect skin and breast reactions. Redness, darkening, skin breakdown with associated pain and swelling of the breast are often seen during treatment. Chronic pain and swelling of the breast or without swelling of the arm (lymphedema) may be seen several months after completion of treatment. Early detection and intensive physical therapy will prevent limited range of motion and lymphedema, complications that can seriously affect quality of life.
Radiation pneumonitis with cough and associated shortness of breath may develop in less than 5 percent of patients. Nerve damage is also a possible complication of regional lymph node irradiation above certain doses. The potential risk of cardiac damage has been extensively investigated. Recognizing that old techniques may have caused cardiac mortality after radiation, modern equipment, CAT scan guided treatment planning and new techniques of treatment delivery minimize exposure to the adjacent heart and lung reducing cardiac toxicity. We continue to be cognizant of the potential effects of radiation, particularly in patients with a left breast cancer receiving chemotherapy agents such as adriamycin and trastuzumab (Herceptin).
Another risk of radiation is the very uncommon risk for secondary cancers such as lung, esophagus and sarcoma. Again, the evidence suggest that techniques, doses of radiation and volume of tissue exposed to radiation as well as other factors, such as smoking may enhance the carcinogenic effect of each one.