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COMET asked whether women with low-risk DCIS could safely be watched rather than operated on; after two years the rate of invasive cancer in the monitored group was no worse than with surgery, so careful monitoring is now a reasonable choice for some women.
Most ductal carcinoma in situ is treated with surgery and often radiotherapy although only a fraction would ever become invasive. COMET, run by the Alliance Foundation Trials group, was a pragmatic randomised non-inferiority trial of 995 women aged 40 or over with low-risk (grade 1 or 2, hormone receptor-positive, HER2-negative) DCIS, comparing active monitoring with mammography every six months, with endocrine therapy offered, against standard surgery with or without radiotherapy. The primary endpoint was the rate of ipsilateral invasive cancer at two years.
At two years the invasive cancer rate in the monitoring arm was not inferior to that in the surgery arm, and quality of life was similar. The follow-up is short and many monitored women's cancers were found at planned surgery, so longer results and the parallel LORD and LORIS trials are awaited, but COMET is the first randomised evidence that active monitoring of low-risk DCIS is safe in the short term.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.
997 enrolled.
Difference -1.7 percentage points (upper 95% CI limit 0.95); non-inferiority bound 5 points; median follow-up 36.9 months
Source| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Ipsilateral invasive cancer at 2 years (non-inferiority)primary | Active monitoring | 484 | 4.2% | - | - | link |
| Guideline-concordant care (surgery with or without radiotherapy) | 473 | 5.9% |
Shares Ductal carcinoma in situ (DCIS), Tamoxifen, Endocrine therapy (SERMs, AIs, SERDs), Breast cancer (all types) and the tag subtype-trials.
Shares Letrozole (and other aromatase inhibitors), Breast cancer (all types) and the tag subtype-trials.
Shares Alliance for Clinical Trials in Oncology and the tag subtype-trials.
Shares Breast cancer (all types) and the tag subtype-trials.
Shares Breast cancer (all types) and the tag subtype-trials.
Shares Breast cancer (all types) and the tag subtype-trials.
Shares Breast cancer (all types) and the tag subtype-trials.
Shares Breast cancer (all types) and the tag subtype-trials.