Narrow DCIS Margins May Not Always Warrant Reexcision - Summary - MDSpire
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Narrow DCIS Margins May Not Always Warrant Reexcision
An ancillary analysis found less than 2-percentage-point differences in 10-year recurrence across margin thresholds, with no statistically significant adjusted association.
To evaluate the association between margin width and ipsilateral breast tumor recurrence (IBTR) in postmenopausal patients with hormone receptor-positive ductal carcinoma in situ (DCIS).
Approach:
Study Design: Ancillary analysis of prospectively collected margin data from the phase 3 NRG Oncology/National Surgical Adjuvant Breast and Bowel Project B-35 trial.
Patient Population: 3,104 postmenopausal patients with hormone receptor-positive DCIS and tumor-free margins enrolled from January 2003 to June 2006.
Margin Analysis: Evaluated IBTR using protocol-defined margin groups of <1 mm vs ≥1 mm and guideline-based groups of <2 mm vs ≥2 mm.
Statistical Methods: Calculated 10-year cumulative incidence while accounting for competing risks and adjusted for age, endocrine therapy assignment, and tumor size.
Key Findings:
10-year cumulative incidence of IBTR was 5.6% for margins <1 mm and 4.0% for margins ≥1 mm (unadjusted difference significant).
In the 2-mm analysis, IBTR was 5.3% for margins <2 mm and 3.8% for margins ≥2 mm (unadjusted difference significant).
After adjustment, margin width was not statistically significantly associated with IBTR at either threshold.
Tumor size was associated with recurrence; tumors ≥1 cm had approximately twice the adjusted hazard of IBTR compared to smaller tumors.
65% of patients completed 5 years of endocrine therapy, with no difference in adherence by margin group.
Interpretation:
Limitations:
Margin width was not randomized and no intervention based on margin width was included.
Margin status assessed by local pathologists without real-time central review.
Excluded patients included those with positive margins and missing pathology forms.
Tumor size was estimated in a significant portion of patients.
Analysis did not address premenopausal patients or hormone receptor-negative DCIS.
Severe social jet lag among surgeons was associated with higher rates of major adverse events, independent of sleep duration, workload, and patient risk.
National survey data found lower per-capita representation across 23 occupations in nonmetropolitan communities, with the largest workforce differences observed among psychologists, physicians, and surgeons.
