Breast Cancer Study Shows Minimal Score Variation After Radiation Boost

Firas Eladoumikdachi, MD, FACS, and M. Michele Blackwood, MD, FACS, discuss the findings of a phase 2 prospective clinical trial examining the impact of preoperative radiation boost on 21-gene assay recurrence scores in patients with early-stage breast cancer.

The study focused on patients with tumors averaging 1.3 cm, primarily invasive ductal carcinoma, with estrogen and progesterone receptor-positive, HER2-negative tumors, and clinically negative nodes. The patients' median age was 68.

A key finding was that while the average recurrence score showed a slight increase after the radiation boost (from 12 to 13.47), this difference was not statistically significant. Approximately 60% of patients experienced a slight increase in their recurrence score, while 40% saw a slight decrease, but these variations did not result in a significant change in the overall risk assessment.

Eladoumikdachi, breast surgical oncologist, associate professor of surgery, Rutgers Robert Wood Johnson Medical School, emphasizes that this result is clinically important, suggesting that administering a pre-operative radiation boost does not significantly alter the genomic profile or the subsequent decision regarding chemotherapy. He clarifies that, while the study showed that it is safe to perform the radiation boost, that because this was a small sample study, that larger studies are needed to make any major conclusions.

Blackwood, director of breast surgery, RWJBarnabas Health, director of women’s oncologic health, RWJBarnabas Health and Rutgers Cancer Institute, head of breast surgery, Cooperman Barnabas Medical Center, reinforces this point, highlighting the reassurance this provides to medical oncologists. The findings indicate that the radiation boost does not alter the tumor's biology in a way that would necessitate a change in treatment recommendations. This is significant for multidisciplinary care, ensuring consistent and appropriate treatment based on the tumor's intrinsic biology.

Furthermore, Blackwood stresses the feasibility of implementing this type of complex, multi-site clinical trial. While initially perceived as logistically challenging, the team successfully coordinated preoperative radiation, localization procedures, and surgical interventions. She encourages other clinicians to pursue innovative research, emphasizing the importance of strong multidisciplinary collaboration. She additionally emphasizes that the further studies, and continued publications, from the team of Bruce Haffty, MD, MS, may be the key to making this a standard of care option.

The study's results suggest that preoperative radiation boost does not significantly impact 21-gene recurrence scores, thus preserving the reliability of this tool for treatment planning. While the sample size was limited, the findings are encouraging and warrant further investigation.