Findings from the SqeDCIS trial indicated that DCISionRT was predictive of radiotherapy benefit in patients with ductal carcinoma in situ of the breast.
Testing with DCISionRT appeared to predict the benefit of radiation in reducing 10-year local invasive breast cancer risk in patients with ductal carcinoma in situ (DCIS) of the breast, according to a press release for the randomized SqeDCIS trial.1
The trial enrolled a total of 504 patients who had complete data and negative surgical margins. DCISionRT divided patients into either the elevated- (52%) or low-risk groups (48%).2 Patients with elevated-risk achieved a significantly decreased relative 10-year ipsilateral total recurrence (TotBE; HR, 0.32) and 10-year ipsilateral invasive recurrence (InvBE; HR, 0.24) rates following treatment with radio therapy. This translated to absolute decreases of 15.5% and 9.3% in each group, respectively. Notably, no significant risk differences were observed in the low-risk group following treatment with radiotherapy.
Investigators noted that findings from the trial are consistent with 3 previous studies assessing DCISionRT, which served to further validate the test as a potential strategy.
“In this study, DCISionRT demonstrated statistically significant radiation therapy benefit in patients with higher Decision Scores (DS), and minimal benefit in lower scores," principal investigator, Fredrik Wärnberg, MD, PhD, a professor in the Department of Surgery at the Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sweden, said in a press release. “This was a highly valuable use of bio-banked tissue from the landmark SweDCIS patient cohort as no other randomized studies have been able to identify DCIS patients who can omit RT.”
Additional findings from the study indicated that, when using a cut off of DS more than 3.0, the test did not appear to be predictive of a benefit from radiotherapy (P = .093). However, investigators noted that using a cut off of 2.8 revealed that radiotherapy benefit was higher in terms of InvBE interaction (P = .038). Per the DS 5 units, 10-year recurrence without radiotherapy was found to significantly increase (TotBE: HR, 1.5; InvBE: HR, 1.5). Moreover, continuous DS was found to be prognostic of TotBE risk, however categorical DS did not reach significance.
“We are thrilled to publish this latest data on DCISionRT, the only DCIS test validated with peer-reviewed published level 1b clinical evidence. The results confirm the power of the DCISionRT assay to predict radiotherapy benefit and enabling personalized treatment decisions,” Dan Forche, president and chief executive officer at PreludeDx, said in a press release. "The consistency of results with prior validation studies substantiates the robustness and reliable performance of DCISionRT. We believe these much-anticipated results will have a significant impact on clinical practice for DCIS patient management.”