Proportion of Patients With Ductal Carcinoma In Situ That Qualify for Observation Criteria Set Forth by Clinical Trials.

BACKGROUND The COMET, LORD, and LORIS clinical trials are investigating the role of active surveillance in low-risk ductal carcinoma in situ (DCIS). The objective of this study was to identify the proportion of patients eligible for these trials amongst a cohort of patients treated at our institution. METHODS Retrospective chart review was performed of patients diagnosed with DCIS who were treated from 2013 to 2022. Clinical, tumor, and imaging inclusion and exclusion criteria of the aforementioned observation trials were applied to determine the proportion of patients eligible for each trial. Upgrade rate to invasive cancer were examined across all three groups. RESULTS Of 1223 patients diagnosed with DCIS, applying the criteria of each trial, 245 (20%), 238 (19.4%), and 264 (21.6%) patients were eligible for the COMET, LORD, and LORIS trials, respectively. High-grade DCIS and mass on imaging had the largest impact on exclusion. Nineteen (7.8%) of women who qualified for COMET were upgraded to invasive disease at excision, compared to 18 (7.6%) for LORD, and 19 (7.2%) for LORIS. CONCLUSIONS One in five patients diagnosed with DCIS at our institution would qualify for observation with current trial eligibility. Observation of DCIS may have limited impact on all DCIS patients.