Radiation Therapy for the Treatment of Breast Cancer

Internal Radiation

Brachytherapy (also called internal radiation) is an experimental method currently being developed to use on breast cancer patients. Instead of using radiation beams from outside the body, radioactive substances are placed directly into the breast tissue next to the cancer. Brachytherapy involves the surgical placement of 10 to 20 plastic catheters (tiny tubes called implants) into the breast tissue next to the tumor to help guide the radioactive materials to the correct area of the body. Technologists then insert pellets of radioactive substances (called Iridium-192) into the catheters. Nine or more times over the course of a week, the catheters are briefly connected to a high-dose-rate brachytherapy machine for internal radiation treatment. The treatments usually take about 10 minutes each and are painless. The tubes are usually removed after a week.

Brachytherapy is not standard practice for breast cancer patients but is currently used on cancers in other areas of the body such as the mouth, cervix, or prostate.

Possible advantages of brachytherapy:

• The reduction of time a patient has to undergo radiation therapy from at least six weeks to one week.
• Less irritation of healthy breast tissues.
• Patients who must also undergo chemotherapy as part of their breast cancer treatment do not have to delay treatment for as much time.
• Fewer skin reactions, such as redness, rashes, or irritations

Physicians are unsure whether brachytherapy is as effective in destroying breast cancer cells as external beam radiation therapy. Several clinical trials are currently being run to evaluate the safety and effectiveness of brachytherapy. Side effects of brachytherapy include risk of infection and breast swelling.

Dose Verification System

The dose verification system (DVS), which is manufactured by Sicel Technologies, has been approved by the U.S. Food and Drug Administration (FDA) for radiation treatment of breast and prostate cancer in 2006. DVS helps radiologists determine the amount of radiation a patient receives is within the prescribed range each time radiation treatments are administered. To do so, the radiologist can use the system measures the amount of radiation that is delivered to the tumor tissue, tumor bed, or healthy tissue. DVS differs from normal radiation therapy in that the physician must implant DVS radiation dosimeters near the tumor or tumor bed and/or surrounding normal tissue during a minimally invasive procedure. Most patients receive one or two dosimeters. Once implanted, wireless technology transmits the information to a hand-held monitor and radiation absorption rates are read during daily treatments, enabling radiologists to verify that the dose received by the patient is within the prescribed range. The dosimeter does not produce radiation itself.

The DVS implantable dosimeter is 0.8 inches (20mm) long and 0.08 inches (2.1mm) in diameter. During radiation treatment, each dosimeter transmits the amount of radiation that is received at its location. The dosimeter near the tumor should receive the highest dose, while the other receives a lower dose. After radiation treatment sessions are completed, the dosimeters will remain inside the patient without an effect on a patient's daily routine.

In January 2008, the U.S. Centers for Medicare and Medicaid created a new HCPCS code (Healthcare Common Procedure Coding System) for the DVS. The code will cover the cost for the Dose Verification System (DVS). The code, which reimburses radiation therapy centers for the medical device when implanted in any body site, makes DVS more accessible to patients undergoing radiation treatment for breast and prostate cancer because private insurers will cover the cost for the device. The cost for the device is also adequately covered by the new code for Medicare patients treated in freestanding centers. Separate codes are available to cover the cost associated with implanting the device.

The patient's physician will determine whether she is a candidate for DVS. Some patients have experienced discomfort after the implantation of the DVS dosimeters; however, according to Sicel Technologies, no adverse long-term effects have been reported.

Short Duration, High Dose Radiation Therapy

Researchers have been investigating whether a shorter duration, higher dose of radiation may be as effective as the conventional six to seven week regimen. Recent research suggests that limiting radiation therapy to four weeks at a higher dose may be as effective as the traditional regimen and could reduce side effects. IMRT (intensity-modulated radiation therapy) uses a highly sophisticated system of delivering external-beam radiation. According to recent research, this system uses advanced computer optimized planning and radiation delivery techniques that create more optimal dose distributions, greater sparing of the skin and lower doses to organs such as lung and heart--thus reducing potential side effects.

In a study presented at the November 2009 meeting of the American Society for Radiation Oncology, researchers from Fox Chase Center Center examined the effectiveness of delivering a higher daily dose of radiation over four weeks, compared to a lower dose over six to seven weeks. According to the researchers, another way of reducing treatment length was by incorporating a "boost" into the same four weeks. The lumpectomy site where the tumor was removed is usually treated with a high-dose radiation "boost." The standard "boost" is typically administered after the five weeks of whole breast irradiation and can add another one to two weeks to the treatment time.

The researchers found that the risk of a breast cancer recurrence was low for women in the study. The study included 75 women treated with 2.25 Gy for 20 days (versus 2 Gy per day with conventional therapy) and a 2.8 Gy boost concurrently (versus sequentially delivering the boost after whole breast irradiation). The risk of recurrence within five years in the treated breast was 1.4%, which the researchers say compares favorably to results with conventional radiation. In addition, the researchers report that patients and their physicians considered the cosmetic results good or excellent in most women.

"This more accelerated treatment regimen should be an option for women who want to be treated in a shorter period of time," says Freedman, in a Fox Chase Center news release. "This may particularly appeal to women who drive a long distance for radiation, have busy schedules at home or work, or have a large insurance co-pay for each daily radiation treatment."

Freedman cautioned that this treatment schedule may not be for all women. "There may be patients who are uncomfortable with the idea of an accelerated treatment and want to be treated with a more conventional six to seven week course of treatment," he said in the news release. "In addition, we need more research to determine which women are ideal candidates for this treatment because of differences in anatomy or other treatments for their breast cancer."

Click here to read more about this research.

Additional Resources and References

• To learn more about radiation therapy for cancer treatment, please visit http://www.imaginis.com/radiotherapy/
• The American Cancer Society provides information on radiation therapy for breast cancer at http://www.cancer.org/
• The National Cancer Institute provides information on radiation therapy for breast cancer at http://www.cancer.gov/
• Cancer Treatment Centers of America (CTCA) provides information on breast brachytherapy at http://www.brachytherapy.com/breast-brachy.html.
• To learn more about DVS, please visit http://www.imaginis.com/breasthealth/news/news6.08.08.asp
• Visit the diagnosis and treatment section of the Imaginis.com breast health bookstore for additional resources: http://www.imaginis.com/bookstore/breasthealth/diagnosis.asp

Updated: December 29, 2009

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