Dana Casciotti, PhD, Anna E. Mazzucco, PhD, and Danielle Shapiro, MD, MPH, Cancer Prevention and Treatment Fund
Almost all women with early-stage breast cancer will live just as long if they choose lumpectomy (also called breast conserving surgery) instead of mastectomy. However, traditional radiation treatment is recommended for lumpectomy patients because it lowers their chances of the cancer returning.
Traditional radiation therapy is given on an outpatient basis 5 days each week for 6-8 weeks, and that is a difficult schedule for many patients. Many women living in rural areas or far from the hospital choose to get a mastectomy because daily radiation is so inconvenient.
For some women, radiation to a smaller area of the breast over a shorter period of time may be a useful alternative. These options are called partial breast irradiation (PBI).
PBI can be given with just 5-10 treatments over about a week’s time, and researchers are testing if treatments can be shortened to 2 days. According to experts, PBI can reduce the chances of a tumor coming back in the area around the lumpectomy from 10-25% to 3-4%.
Based on a comprehensive 2016 research review, women who had PBI were more likely to have their tumor come back or to have a new tumor form in the same breast than women who had whole breast radiation treatment (WBRT). However, women who had PBI were not more likely to die any sooner or to later need a mastectomy.
PBI is not for everyone (see considerations below). Each type of PBI carries a different potential risk than the other types. For example, PBI with brachytherapy carries a higher risk of infection or seroma (fluid filled pocket in the breast tissue after surgery) than PBI with external beam radiation. However, PBI with external beam radiation, increases risk for harmful effects to the lungs and heart. Three-dimensional models can reduce the radiation exposure to normal tissue, but do not completely eliminate risk.
Across many studies, it is not clear whether PBI is more harmful to skin tissue than traditional radiation therapies.[5, 6,7] Harmful effects on the skin are rated on a scale of 1 to 4, with 4 being the worst. The changes in skin appearance include wrinkling, shrinkage, color change, red blotches, thickening, skin loss and destruction, etc.
PBI has been studied in clinical trials lasting no longer than 5 years, which isn’t really long enough to know if the therapy works the same or better than traditional radiation treatment. Traditional radiation therapy has been proven to be safe and effective for women for at least 15 years after treatment.
Who Should Consider PBI?
The American Society of Therapeutic Radiology and Oncology (ASTRO) provides the following recommendations: 
- Women aged 50 and over
- Early-stage breast cancer that is confined to one defined area of one breast only
- Estrogen receptor-positive breast cancer
- Women who had a breast lump removed with “clean margins” (no cancer cells were found in the area that was removed surrounding the lump)
- Women who did not have chemotherapy prior to surgery
Who should not be given PBI?
- Women aged 40 and younger
- Women who had the cancer removed but the margins contained cancer cells (“positive margins”)
What are the Types of PBI?
PBI can be given in the following ways:
- Intracavitary brachytherapy or MammoSite- A radiation bead is placed in the surgical cavity (the space left in the breast tissue after the breast lump is removed). This can be done at the time of surgery or later.
- Interstitial brachytherapy- Several catheters are placed into the surgical cavity. Radioactive beads can be put in the breast through the catheters.
- Intra-operative technique- During the surgery, a machine is used that gives local radiation to the surgical cavity before the wound is closed.
- External beam radiotherapy using 3D modeling- Beams of radiation are given from different directions to match the 3D shape of the tumor. This focuses the rays on the tumor while reducing damage to the rest of the breast.
What are the Benefits and Harms of PBI?
Advantages of PBI:
- Smaller area of breast is given radiation, which reduces damage to normal breast tissue.
- Treatments can be given over days instead of weeks, making it more convenient and easier to schedule with other medical appointments.
- Because of the more convenient schedule, more women may be able to choose to get lumpectomy instead of mastectomy.
Disadvantages of PBI:
- Increased chances of tumor coming back or new tumor forming in the same breast compared to traditional radiation therapy.
- Because PBI can give a bigger dose of radiation, women may have later toxic effects, which affect the way the breast looks.
- Invasive approaches (placing beads in the surgical wound or catheters in the wound) can increase the chance of infection and can slow wound healing, which may affect the way the breast looks.
The Bottom Line
Radiation treatment can help women to conserve breast and prevent cancer spread after lumpectomy. PBI can be more convenient in the short run, but in the long run, we do not know if it is as safe or effective as traditional radiation treatment.
All articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff.
1. Kuznar, W. ASCO Reading Room: APBI: A Compromise Solution Following BCT–In low-risk breast cancer patients, recurrence rates equivalent to those for WBI. Medpage Today. (July 26, 2016). Available Online: https://www.medpagetoday.com/reading-room/asco/breast-cancer/59322?pop=0&ba=1&xid=tmd-md&hr=trendMD
2. Hickey BE, Lehman M, Francis DP, See AM. Partial breast irradiation for early breast cancer. Cochrane Database of Systematic Reviews 2016, Issue 7. DOI: 10.1002/14651858.CD007077.pub3.
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7. Akhtari M, Abboud M, Szeja S, et al. Clinical outcomes, toxicity, and cosmesis in breast cancer patients with close skin spacing treated with accelerated partial breast irradiation (APBI) using multi-lumen/catheter applicators. Journal of Contemporary Brachytherapy. 2016;8(6):497-504. doi:10.5114/jcb.2016.64830.
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