On October 24, 2022, a study at the annual meeting of the American Society of Radiation Oncology (ASTRO) showed that shortening the duration of radiation therapy did not affect the efficacy
of patients with early-stage breast cancer who are at high risk of recurrence.
Previous studies have shown that a three-week course of radiation therapy is just as safe and effective as a traditional six-week course of radiation therapy for patients at low risk of tumor recurrence, but additional radiation therapy to the site of tumor resection is required
for patients at higher risk of tumor recurrence.
Vicini, MD, radiation oncologist, director of research at GenesisCare, principal investigator of FASTRO, said
- Supplemental radiation therapy can reduce the likelihood of breast tumour recurrence by 20% to 30%, but adding this increased dose of radiotherapy after hypofractionated radiotherapy increases the duration
of treatment by one week.
This is a challenge
for patients who need to take time off or travel long distances for treatment.
- The trial wanted to investigate whether this increased dose of radiotherapy could be equally effective in delivering efficacy while shortening the treatment process, without increasing side effects or affecting breast appearance
Participants in the trial included 2262 patients
with early-stage breast cancer who were at high risk of local recurrence after lumpectomy.
Risk factors include tumor grade, age, whether to receive preoperative chemotherapy and estrogen receptor status
The median age of the patients was 55 years, and patients were treated
at 276 different sites in the United States, Canada, Switzerland, Israel, Hong Kong, Japan, South Korea and Singapore.
In this study, patients were randomly divided into two study groups
Group A patients (n=1124) received routine total breast radiation therapy for 4 to 5 weeks, followed by continuous increased treatment
at the tumor resection site within 6 to 7 days.
Group B patients (n=1138) received hypofractionated whole-breast radiotherapy for three weeks, while the surgical site was given increased radiotherapy
during these three weeks.
At a median follow-up of 7.
3 years, there were 56 cases of intramammary recurrence
among nearly 2300 study participants.
Regarding breast tumor recurrence, the primary endpoint of the study, group B was no lower than group A (HR: 1.
32, 90% CI: 0.
84 to 2.
The 5-year and 7-year recurrence rates were 1.
9% and 2.
6% in group B, and 2.
0% and 2.
in group A, respectively.
There were also no significant differences
between the two groups in terms of appearance or side effects.
At 3 years after treatment, 86% and 84% of patients in groups A and B, respectively, had their appearance rated as excellent or good
by their doctors.
Severe (grade ≥ 3) side effects were uncommon in both groups, 3.
3% in group A and 3.
in group B.
Vicini, MD, radiation oncologist, director of research at GenesisCare, principal investigator of FASTRO, said:
- This approach cuts the treatment time of these patients in half and is suitable for patients at
high risk of recurrence.
- In-depth knowledge of breast cancer therapies and advances in treatment techniques may be behind
the low recurrence rates and side effects.
Over the years, surgery, pathology reports, radiotherapy, chemotherapy – these things have been constantly improving
We can administer it
in a more complex way.
As a result, the recurrence rate is decreasing, while the success rate of treatment is rising
The next questions the team needs to answer include whether more patients could benefit from the three-week treatment, such as those whose cancer has spread to lymph nodes, and whether treatment time can be shortened
For example, a study in the United Kingdom is giving a week of radiotherapy
to patients at low risk of recurrence.
Commentary first published: Medical press
Written by the American Society for Radiation Oncology