For many women diagnosed with DCIS, one of the toughest questions is whether surgery is truly necessary — especially if the DCIS looks low-risk. The idea of active monitoring (close follow-up with imaging and exams, without immediate surgery) is gaining attention in clinical trials. But one challenge remains: how can doctors be sure a biopsy really shows the whole truth about the DCIS?
If the biopsy misses an area of higher-risk DCIS or an early invasive cancer, a patient who thought she was safe for monitoring might actually need more aggressive treatment. This new study from Brazil looked at whether a type of biopsy called vacuum-assisted biopsy (VAB) can help doctors more accurately separate true low-risk DCIS from higher-risk disease.
What the researchers did:
The team reviewed 116 cases of breast cancer (including DCIS and invasive cancers) where patients were diagnosed by VAB and then went on to have surgery. They compared what the biopsy showed versus what the surgical pathology — the “gold standard” — found.
They then asked:
- How often did the biopsy correctly identify higher-risk cases?
- How often did it correctly confirm truly low-risk cases?
- What might this mean for patients considering active monitoring?
What they found:
- High accuracy for higher-risk disease. VAB performed very well at detecting cases that turned out to be higher-risk DCIS or invasive cancer. In this study, the sensitivity was about 95%, meaning it correctly identified most higher-risk disease.
- Perfect “yes” calls — but less perfect “no” calls. When the biopsy indicated that disease was more serious, surgery always confirmed it (100% accuracy in this group). But when the biopsy suggested the disease was low risk, the picture was more mixed: about 1 in 3 cases (33%) were later “upgraded” at surgery to higher-risk DCIS or invasive cancer. This means that while VAB is strong at confirming higher-risk disease, its ability to confidently rule out higher-risk disease was more limited — the study’s negative predictive value was about 67%.
- Balancing benefit and risk. Using VAB results to guide active monitoring could:
- Reduce unnecessary surgeries by about 7% (in this cohort).
- But 2–3% of women would have been underdiagnosed (thought to be low risk when they weren’t).
The authors also compared two versions of the procedure (standard VAB and more extensive sampling) and found no significant advantage to taking larger samples in this group.
What this means for patients:
• Encouraging step forward. This study shows that advanced biopsy methods like VAB can provide useful information when determining who might be a good candidate for active monitoring instead of immediate surgery.
• Not the full answer. The test isn’t perfect. A meaningful number of patients who appear “low risk” on biopsy may still have more serious disease. This is why active monitoring — when offered — requires careful imaging review, strict eligibility criteria, and close follow-up.
• Bigger picture. Studies like this add to the growing evidence that precision medicine — tailoring treatment intensity to actual risk — may be possible for DCIS.
Takeaway:
Vacuum-assisted biopsy is a promising tool that may help distinguish truly low-risk DCIS from cases needing more aggressive treatment. It could eventually give more women the option to safely avoid immediate surgery. But it’s not foolproof, and continued clinical trials, better imaging tools, and careful monitoring remain essential to making active surveillance a safe and reliable option.
To read the full study, click here.