Results are from a five-year follow-up; long-term study is needed
Results of the IDEA clinical trial, reported by Winship Cancer Institute of Emory University researcher Reshma Jagsi, MD, DPhil, Lawrence W. Davis professor and chair of radiation oncology at the Emory University School of Medicine, noted that omitting radiation may be safe in certain postmenopausal patients aged 50-69 years with stage I hormone receptor (HR)-positive breast cancer.
The five-year follow-up of the IDEA clinical trial, presented at the 2023 San Antonio Breast Cancer Symposium and simultaneously published in the Journal of Clinical Oncology, reveals that almost all patients who opted out of adjuvant radiotherapy after breast-conserving surgery were disease-free five years post-surgery. This is especially significant for younger postmenopausal patients, shedding light on the potential to safely omit adjuvant radiotherapy in certain cases.
Traditionally, patients diagnosed with stage I HR-positive breast cancer undergo breast-conserving surgery followed by adjuvant radiotherapy and endocrine therapy. Jagsi's research reveals an alternative option to this standard practice, indicating that omitting radiotherapy may be safe for certain individuals. The study focused on patients between 50 and 69 years of age, utilizing the Oncotype DX recurrence score to assess the risk of recurrence based on genetic tumor profiles.
Jagsi emphasizes the importance of providing patients with choices in their treatment plans. "Although radiation treatment has become more efficient and tolerable, patients appreciate having a say in their treatments," she noted.
To determine if omitting radiotherapy would be feasible for younger postmenopausal patients with early-stage breast cancer, Jagsi and colleagues conducted the IDEA clinical trial, which enrolled patients between 50 and 69 years of age who had stage I HR-positive, HER2-negative breast cancer. The Oncotype DX recurrence score was used to determine each patient’s risk of recurrence based on the genetic profiles of their tumors. Patients with a low risk of recurrence were eligible to skip radiotherapy after breast-conserving surgery while still receiving standard-of-care adjuvant endocrine therapy for at least five years.
The study enrolled 200 patients eligible to skip radiotherapy, with 100% of the 186 evaluable patients alive five years after surgery, and 99% (184 patients) breast cancer-free at this critical juncture.
"These findings suggest that younger postmenopausal patients with stage I breast cancer may have a very low risk of disease recurrence within five years when opting out of radiotherapy after breast-conserving surgery," said Jagsi. However, she cautions that longer-term follow-up is essential to determine conclusively the safety and efficacy of this option for women in this age group.
Jagsi underscores the significance of studies like these in enhancing the patient experience in addition to obtaining positive outcomes. “Studies like this one,” Jagsi said, “are important for identifying ways to improve the patient experience, both by identifying multiple treatment options to help patients regain a sense of control that a cancer diagnosis can seem to take away, and by ensuring that all patients are informed and empowered to make the decisions that are right for them.”
Limitations of the study include the short follow-up time and the small sample size. The study was supported by the Susan G. Komen Breast Cancer Foundation and the University of Michigan Rogel Cancer Center.