Active Monitoring With or Without Endocrine Therapy for Low-Risk Ductal Carcinoma In Situ: The COMET Randomized...

Area of Science:

• Oncology
• Breast Cancer Research
• Clinical Trials

Background:

• Active monitoring for low-risk ductal carcinoma in situ (DCIS) is being explored as an alternative to standard treatment.
• The safety and efficacy of active monitoring compared to guideline-concordant care for DCIS remain unknown.

Purpose of the Study:

• To compare the incidence of invasive breast cancer in patients with low-risk DCIS undergoing active monitoring versus guideline-concordant care.
• To determine if active monitoring is a non-inferior treatment option for low-risk DCIS.

Main Methods:

• A prospective, randomized noninferiority trial involving 995 women aged 40+ with low-risk DCIS.
• Participants were randomized to either active monitoring (regular imaging and exams) or guideline-concordant care (surgery with or without radiation).
• The primary outcome was the 2-year cumulative risk of ipsilateral invasive cancer.

Main Results:

• The 2-year cumulative rate of ipsilateral invasive cancer was 4.2% for active monitoring versus 5.9% for guideline-concordant care.
• Active monitoring was found to be non-inferior to guideline-concordant care, with a difference of -1.7% (upper 95% CI limit of 0.95%).
• No significant differences in invasive tumor characteristics were observed between the two groups.

Conclusions:

• Active monitoring is a safe alternative for women with low-risk DCIS, showing no increased rate of invasive cancer compared to standard care.
• These findings support active monitoring as a viable option, potentially reducing overtreatment for selected DCIS patients.