A hypofractionated, or accelerated, schedule of radiation therapy that includes five treatments over 1 week seems to offer the same benefits as a schedule of 15 treatments over 3 weeks for early-stage breast cancer, according to a study.
The research was published in the May 23, 2020, issue of The Lancet. Read “Hypofractionated breast radiotherapy for 1 week versus 3 weeks (FAST-Forward): 5-year efficacy and late normal tissue effects results from a multicentre, non-inferiority, randomised, phase 3 trial.”
Hypofractionated vs. traditional radiation therapy
In March 2018, the American Society for Radiation Oncology released updated guidelines on whole-breast radiation therapy saying that most people diagnosed with breast cancer should be treated with a hypofractionated radiation schedule.
In many cases, people diagnosed with early-stage breast cancer have radiation therapy after surgery to remove the cancer. Radiation therapy lowers the risk of the cancer coming back (recurrence).
Whole-breast radiation therapy after breast cancer surgery is usually given as one treatment per day, 5 days a week, for 5 to 7 weeks. A Gray (Gy) is the way radiation oncologists measure the dose of radiation therapy; if you’re on a 5-week treatment schedule, 50 Gy is the usual amount given during the 5 weeks (2 Gy at each treatment). A supplemental “boost” dose may be included at the end of the regimen that targets the area where the cancer was.
Radiation treatment schedules were developed based on research results. But a 5- to 7-week nearly daily commitment may be difficult for some people, especially if they live far away from a treatment center. So doctors developed and studied different radiation therapy schedules that involve fewer treatments with higher doses of radiation at each treatment, but about the same total radiation dose. These hypofractionated radiation schedules put the same radiation dose into a 3- to 5-week schedule, instead of a 5- to 7-week schedule.
A hypofractionated whole-breast radiation schedule is appealing to doctors and people getting radiation therapy for several reasons:
- Convenience: arranging daily trips to get treatment can be a problem for some women, and fewer treatment days or a shorter period of time may be easier to schedule.
- Compliance: if radiation is more convenient to schedule, women may be more likely to get all of their recommended radiation therapy.
But a 3- to 5-week daily commitment to treatment can still be difficult for some people to complete. So researchers have been studying if even shorter radiation therapy schedules can be as effective as the longer schedules.
About the study
Done in the United Kingdom, this study, called FAST-Forward, included 4,096 people diagnosed with early-stage breast cancer. All the people had surgery to remove the cancer — either lumpectomy or mastectomy — and were then assigned to one of three radiation therapy schedules:
- 1,361 people received 40 Gy given in 15 treatments of 2.67 Gy over 3 weeks
- 1,367 people received 27 Gy in five treatments of 5.4 Gy over 1 week
- 1,368 people received 26 Gy in five treatments of 5.2 Gy over 1 week
The people in the study were allowed to have a boost dose of radiation at the end of their assigned schedule.
The researchers wanted to know if the radiation schedules would be equally effective at reducing recurrence risk. The researchers also looked to see if the different schedules caused different skin side effects.
After about 5 years of follow-up:
- 31 people treated with 40 Gy of radiation had a recurrence
- 27 people treated with 27 Gy of radiation had a recurrence
- 21 people treated with 26 Gy of radiation had a recurrence
The 5-year estimated rate of recurrence for each treatment group was:
- 2.1% for people treated with 40 Gy
- 1.7% for people treated with 27 Gy
- 1.4% for people treated with 26 Gy
This means that all three radiation schedules reduced the risk of recurrence by about the same amount.
Five years after radiation treatment, skin side effects were seen in:
- 9.9% of people treated with 40 Gy
- 15.4% of people treated with 27 Gy
- 11.9% of people treated with 26 Gy
The most common side effect was breast shrinkage, which happened in:
- 5.5% of people treated with 40 Gy
- 8.2% of people treated with 27 Gy
- 6.8% of people treated with 26 Gy
The researchers’ analysis showed that people treated with 27 Gy of radiation were more likely to have skin side effects 5 years after treatment than people treated with 40 Gy.
When the researchers compared the results for the schedule of 27 Gy over 1 week to those for the schedule of 26 Gy over 1 week, they found that the 26 Gy schedule was less likely to cause skin side effects and breast shrinkage.
“Five-year ipsilateral breast tumour relapse incidence after a 1-week course of adjuvant breast radiotherapy delivered in five fractions is non-inferior to the standard 3-week schedule,” the researchers wrote. “The 26 Gy dose level is similar to 40 Gy in 15 fractions in terms of patient-assessed normal tissue effects, clinician-assessed normal tissue effects, and photographic change in breast appearance, and is similar to normal tissue effects expected after 46–48 Gy in 2 Gy fractions. The consistency of FAST-Forward results with earlier hypofractionation trials supports the adoption of 26 Gy in five daily fractions as a new standard for women with operable breast cancer requiring adjuvant radiotherapy to partial or whole breast.”
What this means for you
The results of this study are encouraging and suggest that a 1-week radiation schedule offers the same level of recurrence risk reduction as a traditional 3-week hypofractionated schedule.
Still, it’s important to remember that there were only 5 years of follow-up.
“It’s good to have another treatment option for expedited whole-breast radiation,” said radiation oncologist Marisa Weiss, M.D., Breastcancer.org founder and chief medical officer. “Five years is a very early endpoint — that’s the median time to local recurrence for hormone-receptor-positive disease. Longer follow-up will be important so we can look at both efficacy and later side effects. I think women can consider this option with their doctors, knowing that it has a limited track record.”
If you’ve been diagnosed with early-stage breast cancer and radiation therapy is part of your treatment plan, you may want to talk to your doctor about this study and ask whether this 1-week hypofractionated radiation schedule of 26 Gy makes sense for you and your unique situation.
It’s also a good idea to talk to your doctor about skin reactions to radiation. Together, you can develop a plan to ease any skin irritation that happens during and after radiation therapy.
For more information, including tips for managing skin side effects, visit the Breastcancer.org Radiation Therapy pages.
To talk with others about radiation therapy and its side effects, join the Breastcancer.org Discussion Board forum Radiation Therapy - Before, During, and After.
Written by: Jamie DePolo, senior editor
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