Also titled: Why Did I Have 6 Weeks of Radiation and My Friend Only Needs 5 Days?

Short Answer: Science … and … Covid.

Long Answer: Recent studies have shown us that we have the technology to safely deliver higher doses of radiation in less treatments. The medical term for this is “hypofractionation” and your local radiation oncologist must have certain equipment to safely deliver higher doses of radiation.

Consider a woman with Stage I or II breast cancer.

The standard of care for many years was removal of the “lump” or tumor followed by daily radiation treatments to the entire breast for 5 weeks (25 treatments). Most patients also received an additional week of radiation to “boost the cavity”. Meaning that 5 more radiation doses were given to the area where the tumor was removed.

6 weeks of daily radiation is inconvenient and for approximately 30% of women in North America, they could not get their radiation due to transportation issues or cost (time off work, need for childcare, etc.)

In 2002, Dr. Whelan and colleagues in Canada published a study comparing 25 radiation treatments to 16 (basically the standard 5 weeks vs only 3 weeks). The 3-week course was just as good as the 5-week course in curing breast cancer. That chance of the breast cancer coming back in the same breast was 3% in each arm of the trial. Reported cosmetic outcomes were also similar.

The Canadian study was updated with long term results in 2010. Consequently, many radiation oncologists in the United States started offering the 3-week course of radiation to selected breast cancer patients. (Note: the approximately 1200 women in this trial had breast tumors < 5cm in size, clear surgical margins, and no lymph nodes involved by cancer). If you were not offered the 3-week course, it is likely that you had more advanced cancer, or required chemotherapy, or had larger breasts.

It is also important to note that there were 2 additional trials out of the United Kingdom that confirmed the Canadian findings. These trials are known as START A and START B and also compared 5 weeks of radiation with just 13 or 15 radiation treatments.

These 3 large studies resulted in adoption of the “3-week course” of radiation across the United States around 2010-2013.  Most radiation oncologists would prescribe either 15 or 16 treatments and if needed, a 4-treatment boost would be delivered to the surgical cavity. Ultimately, resulting in about 4 weeks of radiation.

I have been utilizing the 3 or 4-week course in my practice for many years as additional studies have confirmed these findings. In general, patients tolerate the shorter course of radiation well, though due to the increased dose delivered per day, there can be more short-term discomfort for some women. Remember that hypofractionated radiation is not less radiation dose, it is simply a higher dose per day delivered in fewer treatments.

This brings us to 2020 and Sars-Co-V2. Radiation Oncologists were faced with the ethical responsibility of weighing the need for breast radiation with their cancer patient’s risk of contracting Covid during treatment. Was it more dangerous to delay the breast radiation or riskier to have an infected Covid patient in your clinic which could result in the infection of doctors, nurses, therapists, and other more sick or elderly patients?

The compromise? Ultra-Hypofractionated Radiation.

The Brits had been studying even shorter courses of radiation using 5 treatments, with one treatment given per week. In 2011, the early results from the FAST Trialists Group were published. This trial examined 915 women and showed that this once weekly regimen was tolerated well, with similar side effects as the 5 week course. The updated data was published this year and confirmed the original findings. Breast radiation treatment delivered just once a week, for a total of 5 treatments had similar side effects and cure rate as the traditional daily radiation treatments, 25 treatments over 5 weeks.

Which bring us to….The Lancet publication in May 2020.

Dr. Brunt and colleagues showed that receiving 5 daily radiation treatments in a row was non-inferior to the standard 3 weeks of daily radiation. These researchers concluded that the 1 week of radiation was safe in terms of side effects for up to 5 years.

Consequently, many radiation oncologists like myself, elected to offer this shorter 1 week of radiation during Covid to minimize the risk of patient exposure in our clinics.

Caveat: Remember that we only have 5 years of follow up on this study. Which means that myself and other radiation oncologists are less likely to recommend the 5 treatments to younger patients who might incur 10- or 20-year side effects that have not yet manifested. 

More on FAST FORWARD to come.

[1] Whelan TJ, et al.  Long-term results of hypofractionated radiation therapy for breast cancer. N Engl J Med. 2010 Feb 11;362(6):513-20. PMID: 20147717.

[2] Whelan T, MacKenzie R, Julian J, et al. Randomized trial of breast irradiation schedules after lumpectomy for women with lymph node-negative breast cancer. J Natl Cancer Inst 2002;94:1143-1150

[3] Brunt AM, et al. Ten-Year Results of FAST: A Randomized Controlled Trial of 5-Fraction Whole-Breast Radiotherapy for Early Breast Cancer. J Clin Oncol. 2020 Oct 1;38(28):3261-3272. Epub 2020 Jul 14. PMID: 32663119; PMCID: PMC7526720.

Patient-focused treatment, and an individualized approach to oncology means Dr. Norleena Gullett is not just treating cancer, she's treating the whole person.