Background: The role of radiation therapy (RT) following breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS) continues to be controversial. Trials have yet to identify a low-risk cohort, based on clinicopathologic features, who does not benefit from RT. A biosignature (DCISionRT) that evaluates recurrence risk has been developed and validated. We evaluated the impact of DCISionRT on clinicians’ recommendations for adjuvant RT.
Objectives: Since traditional clinical and pathologic features have failed to identify a low-risk cohort of DCIS patients that does not benefit from RT following BCS, there is a need for biologic signatures to assess recurrence risk. One such risk profile, which integrates key cancer biologic pathways and clinicopathologic factors (DCISionRT), has previously been shown to be prognostic for 10-year total and invasive breast cancer risks and also predict the benefit of adjuvant RT. As data on this risk profile grow, a key question is how the DCISionRT test affects clinical decision-making. The purpose of the PREDICT study was to evaluate the impact of DCISionRT testing on clinicians’ recommendations in routine clinical practice to administer or omit RT in patients with DCIS following BCS.
Methods: The PREDICT study is a prospective, multi-institutional, observational registry in which patients underwent DCISionRT testing. The primary end point was to identify the percentage of patients where testing led to a change in recommended RT.
Results: At the time of this analysis, 539 women with DCIS treated with BCS were included in the PREDICT study. Prior to DCISionRT testing, RT was recommended to 69% of patients. However, after testing, a change in the RT recommendation was made for 42% of patients compared with the pretesting recommendation. The percentage of women who were recommended RT decreased by 20%. For women initially recommended not to receive an RT pretest, 35% had their recommendation changed to add RT following testing, while posttest, 46% of patients had their recommendation changed to omit RT after an initial recommendation for RT. When considered in conjunction with other clinicopathologic factors, the elevated DCISionRT score risk group (DS >3) had a statistically significant impact for a positive RT recommendation that was greater than age, grade, size, margin status, and other factors.
Conclusions: DCISionRT provided information that significantly changed the recommendations to add or omit RT. Compared with traditional clinicopathologic features used to determine recommendations for or against RT, the factor most strongly associated with RT recommendations was the DCISionRT result, with other factors of importance being patient preference, tumor size, and grade.
Shah C, Bremer T, Cox C, et al. The clinical utility of DCISionRT on radiation therapy decision making in patients with ductal carcinoma in situ following breast-conserving surgery. Ann Surg Oncol. 2021;28:5974-5984.
Erratum in: Ann Surg Oncol. May 16, 2021; PMID: 33821346.