ImportanceActive monitoring (AM) for low-risk ductal carcinoma in situ (DCIS) has been considered as a potential alternative to guideline-concordant care (GCC; inclusive of surgery with or without radiation). Reported data comparing patient-reported outcomes (PROs) between GCC and AM for DCIS are lacking.ObjectiveTo compare PROs at baseline and over time in patients with low-risk DCIS randomized to receive either AM or GCC.Design, Setting, and ParticipantsThis prespecified secondary outcome analysis used prospectively collected validated questionnaires at baseline, 6 months, 1 year, and 2 years from participants enrolled from June 2017 to January 2023 in the Comparing an Operation to Monitoring, With or Without Endocrine Therapy (COMET) study for low-risk DCIS, which randomized participants to receive GCC or AM.InterventionRandomization to GCC or AM.Main Outcomes and MeasuresContext-relevant PROs, including health-related quality of life, anxiety, depression, and symptoms measured by validated survey instruments. Mixed models, including sensitivity analyses, with group, point, and group-by-point effects were used to compare PROs between groups.ResultsOf the 957 participants in COMET, 225 (24%) were younger than 55 years at enrollment, 325 (34%) were aged 55 to 65 years, and 403 (42%) were older than 65 years, and 953 (99.5%) completed questionnaires at some point within the first 2 years, with a completion rate of more than 83% at all points. Quality of life, anxiety, depression, worries about DCIS, and symptom trajectories were comparable between groups, with modest fluctuations over time of limited clinical significance. Physical functioning was the only specific Medical Outcomes Study 36-item short-form health survey (SF-36) domain for which changes in the score trajectory differed by group over time, with mean scores ranging from 50 (baseline) to 48 (6, 12, and 24 months) in the GCC group and 50 (baseline) to 47 (12 months) and 48 (6 and 24 months) in the AM group (pooled SD, 9.9; P = .01), although these were also of limited clinical significance.Conclusions and RelevanceIn this prespecified secondary analysis of the COMET prospective randomized trial, the overall lived experience of women randomized to undergo AM for low-risk DCIS was similar to that of women randomized to GCC during the 2 years following diagnosis.Trial RegistrationClinicalTrials.gov Identifier: NCT02926911
