Written by Mary Marschner
Spoon Feed
Monitoring patients diagnosed with ductal carcinoma in situ (DCIS) with a mammogram every 6 months did not show an increased rate of progression to invasive cancer compared to guideline-directed therapy of surgery with radiation over the course of 2 years.
Is monitoring low risk DCIS a possibility over surgery and radiation?
DCIS is pre-invasive with a risk of progression to invasive cancer. Current guidelines recommend treatment of DCIS with surgery, radiation, and/or endocrine therapy, with excellent prognosis and life expectancy, but not all progress to invasive cancer. Are we overtreating DCIS? Surgery (mastectomy or lumpectomy) and radiation have significant implications and complications for our patients. The COMET trial compared active monitoring versus guideline-concordant care for low-risk DCIS. This prospective, randomized noninferiority trial involved 995 women ≥ 40 with hormone receptor-positive grade 1 or 2 DCIS. Results showed a 2-year cumulative rate of ipsilateral invasive cancer of 4.2% in the active monitoring group versus 5.9% in the guideline-concordant care group, indicating noninferiority of active monitoring.
This study had 3 significant limitations. First, after randomization, patients were able to self-select treatment routes at any time, and half of the patients randomized to the standard treatment group opted for observation. Second, the number of invasive cancers detected in this study is lower than the observed rate. Last, the study length was only 2 years.
How does this change my practice?
Clearly there is a need to further study how best to follow up low-risk DCIS, and I don’t think it is unreasonable for patients to elect for close monitoring over surgery, at least initially.
Source
Active Monitoring With or Without Endocrine Therapy for Low-Risk Ductal Carcinoma In Situ: The COMET Randomized Clinical Trial. JAMA. 2024 Dec 12. doi: 10.1001/jama.2024.26698. Epub ahead of print. PMID: 39665585
