Clinical Report: Narrow DCIS Margins May Not Always Warrant Reexcision
Overview
This study evaluates the association between lumpectomy margin width and ipsilateral breast tumor recurrence (IBTR) in postmenopausal patients with hormone receptor-positive ductal carcinoma in situ (DCIS). Findings indicate that margin width was not significantly associated with recurrence after adjustment for confounding factors.
Background
The management of ductal carcinoma in situ (DCIS) often involves breast-conserving surgery, and the width of surgical margins has been a critical factor in determining the need for reexcision. Current guidelines recommend a 2-mm negative margin; however, the necessity of this threshold has been questioned based on new evidence suggesting that narrower margins may not significantly impact recurrence rates.
Data Highlights
| Margin Width | IBTR Events | 10-Year Cumulative Incidence |
|---|---|---|
| < 1 mm | 24 of 502 | 5.6% |
| >= 1 mm | 66 of 2,205 | 4.0% |
| < 2 mm | 39 of 879 | 5.3% |
| >= 2 mm | 49 of 1,667 | 3.8% |
Key Findings
- Narrower margins (less than 1 mm) were associated with a 10-year IBTR rate of 5.6% compared to 4.0% for margins of at least 1 mm.
- After adjusting for age, endocrine therapy assignment, and tumor size, margin width was not significantly associated with IBTR.
- Approximately one-third of ipsilateral recurrences were invasive.
- 10-year cumulative incidence of all breast cancer events was 9.5% for margins less than 1 mm and 8.5% for margins at least 1 mm.
- 65% of patients completed 5 years of endocrine therapy, with no difference in adherence by margin group.
Clinical Implications
The findings indicate that reexcision for narrow margins may not be necessary in certain postmenopausal patients with hormone receptor-positive DCIS.
Conclusion
This study challenges the necessity of strict margin width criteria for reexcision in postmenopausal patients with DCIS.
Related Resources & Content
- The ASCO Post, 2025 -- Revisiting Margin Width Guidelines for Ductal Carcinoma In Situ and the Role of Routine Reexcision
- The ASCO Post, 2025 -- Revisiting Margin Width Guidelines for Ductal Carcinoma In Situ and the Role of Routine Reexcision KEY POINTS
- The ASCO Post, 2014 -- In Ductal Carcinoma in Situ, Margin Status Need Not Dictate Reexcision
- Society of Surgical Oncology–American Society for Radiation Oncology–American Society of Clinical Oncology Consensus Guideline on Margins for Breast-Conserving Surgery With Whole-Breast Irradiation in Ductal Carcinoma In Situ - PMC
- Rationale and impact | Early and locally advanced breast cancer: diagnosis and management | Guidance | NICE
- Lumpectomy Margins and Local Recurrence in DCIS: Results From the NRG Oncology/NSABP B-35 Randomized Clinical Trial - PubMed
- The ASCO Post — Recurrences Observed in More Than 50% of Inadequately Treated Patients With Ductal Carcinoma in Situ
- Society of Surgical Oncology–American Society for Radiation Oncology–American Society of Clinical Oncology Consensus Guideline on Margins for Breast-Conserving Surgery With Whole-Breast Irradiation in Ductal Carcinoma In Situ - PMC
- Rationale and impact | Early and locally advanced breast cancer: diagnosis and management | Guidance | NICE
- Lumpectomy Margins and Local Recurrence in DCIS: Results From the NRG Oncology/NSABP B-35 Randomized Clinical Trial - PubMed
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