American Association for Cancer Research
Almost all postmenopausal patients aged 50 to 69 years with stage I hormone receptor (HR)-positive breast cancer and low scores on a common genetic test who chose not to receive adjuvant radiation therapy were disease-free five years after surgery based on results from the IDEA clinical trial presented at the San Antonio Breast Cancer Symposium held December 5-9, 2023.
The results were simultaneously published in the Journal of Clinical Oncology .
Patients diagnosed with stage I HR-positive breast cancer typically undergo breast-conserving surgery followed by adjuvant radiation therapy and endocrine therapy to reduce the risk of disease recurrence, explained Reshma Jagsi, MD, DPhil, Professor and Lawrence W. Davis Chair of Radiation Oncology at Emory University School of Medicine and investigator at Emory University Winship Cancer Institute.
He added that in recent studies, patients 65 years or older who chose not to receive adjuvant radiation therapy had a low risk of disease recurrence, suggesting that older patients can safely skip radiation therapy after surgery. breast conservation. However, it was unclear whether younger patients could safely opt out of adjuvant radiotherapy.
"Although radiation treatment techniques have improved dramatically and are now much more efficient and tolerable than they used to be, patients appreciate being able to choose their treatments," Jagsi said.
To determine whether skipping radiation therapy 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 with HR stage I breast cancer. positive and HER2 negative. The Oncotype DX recurrence score was used to determine each patient’s risk of recurrence based on the genetic profiles of her tumors. Patients with a low risk of recurrence were eligible to omit radiation therapy after breast-conserving surgery while continuing to receive standard-of-care adjuvant endocrine therapy for at least five years.
Two hundred patients enrolled in the study were eligible to skip radiation therapy (60 patients aged 50 to 59 years and 140 patients aged 60 to 69 years). Among 186 evaluable patients, 100% were alive five years after surgery and 99% (184 patients) were free of breast cancer at that time.
"These findings indicate that younger postmenopausal patients with stage I breast cancer who skip radiation therapy after breast-conserving surgery have a very low risk of disease recurrence within five years," Jagsi said. “However, five years is an early point for this population, and longer-term follow-up from this study and others will be essential to determine whether this option can be safely offered to women in this age group.
“Studies like this are important in 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 seems to take away from them, and by ensuring that all patients are informed and empowered to make decisions that are right for them,” Jagsi said.
Limitations of the study include the short follow-up time and small sample size. The results come from a five-year follow-up; a long-term study is needed.
The study was supported by the Susan G. Komen Breast Cancer Foundation and the University of Michigan Rogel Cancer Center. Jagsi holds stock options as compensation for his advisory role at Equity Quotient; she has received personal fees from the Greenwall Foundation, the Doris Duke Foundation, and the National Institutes of Health (NIH); she has received grants or contracts for unrelated work from the NIH, the Doris Duke Foundation, the American Cancer Society, the Greenwall Foundation, the Susan G. Komen Breast Cancer Foundation, and Genentech; and she has served as an expert witness for Kleinbard LLC and Hawks Quindel, S.C.
