Understanding DCIS Risk and Why Excision IS Standard Management
Excision (surgical removal) is indeed the standard of care for DCIS, and you are correct to question any characterization of this as "overtreatment"—the evidence overwhelmingly supports surgical excision as essential management. 1, 2
Why Surgical Excision Remains Standard
The statistics you cite are accurate and concerning:
- Progression risk without treatment: 20-30% of untreated DCIS will progress to invasive breast cancer 1, 3
- Upstaging at surgery: 25.9% of DCIS diagnosed on core needle biopsy is found to have occult invasive disease at surgical excision 1
- Recurrence patterns: When DCIS recurs after breast-conserving surgery, approximately 50% of recurrences are invasive carcinoma 1
These numbers justify surgical intervention because invasive recurrences carry mortality risk. 4 The 10-year overall survival rate of 97.2-98.6% for DCIS is achieved precisely because we treat it surgically, not despite treatment. 1
Current Treatment Standards
Surgical Options (Both Are Standard)
Breast-conserving surgery (lumpectomy) with negative margins is appropriate for most patients with localized DCIS. 1, 2 The NCCN guidelines explicitly state lumpectomy without lymph node surgery as standard management. 1
Mastectomy is indicated for:
- Multicentric disease or diffuse malignant-appearing microcalcifications 1, 2
- Persistent positive margins after reasonable surgical attempts 1
- Large tumor size relative to breast size where adequate excision would cause unacceptable cosmetic results 1
- Patient preference 2
The "Overtreatment" Controversy Explained
The overtreatment debate centers on whether radiation therapy and endocrine therapy should be added after excision, not whether excision itself should be performed. 5, 4, 6
Radiation therapy after lumpectomy reduces recurrence rates by approximately 50-70%, but does not improve overall survival. 1 This is where selective de-escalation is being studied—some low-risk patients may be candidates for excision alone without radiation. 1
Why Excision Cannot Be Omitted
The fundamental problem is that we cannot reliably predict which DCIS will remain indolent versus progress to invasive disease. 5, 6 Current molecular and histological markers (COX2, Ki67, c-erbB2, p53, nuclear grade, comedonecrosis) help stratify risk but cannot definitively identify truly harmless lesions. 7, 5
Without complete surgical excision:
- We cannot accurately assess margins 1
- We cannot detect occult invasive disease present in 26% of cases 1
- We cannot prevent the 20-30% that will progress to invasive cancer 1, 3
Invasive recurrences are associated with increased breast cancer mortality, making prevention of progression the primary treatment goal. 4, 6
The Real Clinical Question
The appropriate question is not "Should we excise DCIS?" but rather "After excision with negative margins, which patients need radiation therapy and/or endocrine therapy?" 1
For low-risk DCIS (small size, low grade, wide negative margins, older age), excision alone may be sufficient. 1 This represents appropriate de-escalation, not abandonment of surgical treatment.
For higher-risk features (larger size, high grade, close margins, young age), radiation therapy reduces recurrence by 50% and should be strongly considered. 1
Common Pitfall to Avoid
Do not confuse the overtreatment debate (which concerns adjuvant therapies after surgery) with questioning the need for surgical excision itself. 5, 4 Mastectomy may represent overtreatment for small lesions amenable to breast conservation, but some form of complete surgical excision with negative margins remains the foundation of DCIS management. 1, 2