Breast cancer radiation therapy: Understanding treatment options

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Breast cancer represents the most common non-skin cancer among women in the United States with over 250,000 new cases each year1. Most diagnoses represent DCIS (Ductal Carcinoma In Situ) or early stage cancers which can be safely treated with mastectomy or breast conservation. Following breast conservation, also known as lumpectomy or partial mastectomy, radiation therapy is associated with a significant reduction in the rate of recurrence in the breast, as well as the rate of dying of breast cancer2.

It is important for women to recognize that there is no difference in survival or outcomes between mastectomy (removal of the breast) and breast conservation with multiple studies demonstrating this with long term follow up. As such, patients can preserve their breast without compromising their outcome in most cases.

At this time, there are many radiation therapy options for women who elect for breast conservation. Traditionally, all women undergoing breast conservation received 5-6 weeks of whole breast radiation therapy; besides the lengthy treatment course requiring 30 minutes-hour every day, standard whole breast radiation is associated with side effects including fatigue, redness and peeling of the skin, and chronic skin changes. More recently, a 3-4 week course of whole breast radiation has emerged though this still requires 30 minutes-hour daily for several weeks with similar side effects.3

Whole breast radiation has historically been the standard; however, technology continues to advance and data demonstrates that breast cancer recurrences happen close to the original site of the tumor which have allowed for the development of partial breast irradiation4.  Partial breast irradiation treats the area of the breast where the tumor originated from with a margin of normal tissue around it, rather than the whole breast. This allows for shorter treatment courses (often 1 week or less) and less dose (and therefore potentially less toxicity) to the remaining breast.  The significance of this approach is that it provides comparable outcomes to whole breast irradiation while providing a more targeted, shorter treatment course that can reduce side effects since less normal tissue is treated and improve cosmetic outcomes.

Breast HDR Brachytherapy represents one technique to deliver partial breast irradiation and is the partial breast technique with the strongest and longest data supporting its use.5  HDR Brachytherapy is a radiation therapy treatment for cancer that involves the temporary placement of a radioactive material inside the body, in or near a tumor, for a specific amount of time and then withdrawn. In HDR brachytherapy, a high dose of radiation is delivered to the tumor in a short burst, lasting only a few minutes.

Two randomized trials comparing HDR brachytherapy to whole breast radiation have found comparable outcomes and reduced toxicities as compared to whole breast irradiation. Cosmetic outcomes are also improved with brachytherapy; a trial comparing brachytherapy to whole breast irradiation found significant improvements in cosmetic outcomes, with the benefit limited primarily to partial breast delivered with HDR brachytherapy4.  Additionally, HDR brachytherapy can be delivered with multiple techniques based on the patient's anatomy and disease characteristics, allowing for a more patient specific treatment option.

Peter Orio, DO, President of the American Brachytherapy Society and Vice Chair of Network Operations, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, commented: "Women must be informed of their treatment options and understand the benefits of brachytherapy as a potential component in the treatment of their breast cancer. This option may not always be discussed and as such women must advocate for themselves and seek the advice of a radiation oncologist specializing in partial breast irradiation to fully inform their treatment choice. In medicine, knowledge is power, and patients must be provided both the knowledge and power to make informed treatment decisions."

Recently, updated guidelines from the American Brachytherapy Society were released for partial breast irradiation5. Appropriate patients include those age 45 years or older with all types of breast cancer, tumors less than 3 cm in size, and no lymph node involvement with negative margins at surgery. The guidelines also review techniques with strong/moderate recommendations given for interstitial and applicator HDR brachytherapy.

Breast HDR Brachytherapy represents a great option for appropriate patients with early stage breast cancer. Patients should ask their breast surgeon and radiation oncologist about whether partial breast radiation is an option for them and the techniques available.

Chirag Shah, MD, Director of Breast Radiation Oncology and Director of Clinical Research, Department of Radiation Oncology, Cleveland Clinic notes, "Patients diagnosed with breast cancer must be presented with all of their treatment options including radiation therapy choices.  For many patients who undergo breast conservation, partial breast brachytherapy may be the optimal choice, allowing for excellent clinical outcomes, potentially reduced toxicities, and improved cosmesis. It is important that patients diagnosed with breast cancer see a radiation oncologist who is able to offer them multiple treatment options when available and patients should feel empowered to seek an opinion of a breast cancer radiotherapy expert."

REFERENCES

  1. Siegel RL, Miller KD, Jemal A. Cancer statistics, 2018. CA Cancer J Clin 2018; 68:7-30.
  2. Shah C, Tendulkar R, Smile T, et al. Adjuvant radiotherapy in early-stage breast cancer: evidence-based options. Ann Surg Oncol 2016; 23:3880-90.
  3. Smith BD, Bellon JR, Blitzblau R, et al. Radiation therapy to the whole breast; Executive summary of an American Society for Radiation Oncology (ASTRO) evidence-based guideline. Pract Radiat Oncol 2018; 8:145-52.
  4. Vicini F, Shah C, Tendulkar R, et al. Accelerated partial breast irradiation: An update on published Level I evidence. Brachytherapy 2016; 15:607-15.
  5. Shah C, Vicini F, Shaitelman SF, et al. The American Brachytherapy Society consensus statement for accelerated partial-breast irradiation. Brachytherapy 2018; 17:154-70.

 

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Breast cancer radiation therapy: Understanding treatment options.  Appl Rad Oncol. 

October 18, 2018


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