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90th Annual Meeting Abstracts
Pre-operative Predictors of Positive or Close Margins Following Initial Partial Mastectomy for Breast Cancer
*Alicia R Privette, MD, Laurence McCahill, MD, *Johanna Sheehey-Jones, RN
University of Vermont/Fletcher Allen Health Care, Burlington, VT
Objective: To identify pre-operative and intra-operative factors associated with involved margins (positive or <1mm) following initial partial mastectomy (PM).
Design: Analysis of prospectively collected surgical outcomes data from all initial breast cancer surgeries performed at a single hospital (March 2003- September 2009).
Setting: University medical center
Patients: All patients undergoing initial breast cancer surgery from March 2003-September 2009.
Interventions: N/A
Main Outcome Measures: Association between involved margins and various factors - patient age, surgeon volume, neoadjuvant therapy, multifocal disease, pre-op nodal status, anesthesia type, tumor localization technique, intra-operative specimen examination technique, tumor size.
Results: 996 initial breast cancer operations: 760 PM, 236 total mastectomies. Of PMs, 568 were for invasive disease and 192 for DCIS. Factors significantly associated with involved margins for invasive disease included: tumor size > 2 cm, presence of multifocal disease, and use of single intra-operative specimen examination techniques. The lack of nodal disease was nearly significant. For DCIS, only tumor size > 2cm was associated with the presence of involved margins. (See table)
Conclusions: Factors predictive of involved margins following initial PM for breast cancer are identifiable pre-operatively. These factors can be used to identify high risk patients, counsel patients regarding likelihood of re-excision, and potentially modify surgical practice to reduce the need for re-excision. Further investigation is needed to validate these factors and evaluate their utility in prospectively optimize initial PM.
Table: Factors associated with involved (positive or <1mm) margins after initial breast cancer surgery. Diagnosis of DCIS = 192, Invasive = 568. | | | | | | Factors Analyzed | DCIS Involved Margin | p-value | Invasive Involved Margin | p-value | Surgeon case volume
- High volume
- Low volume | 41.3
36.0 | 0.61 | 28.1
19.0 | 0.1 | Age (mean)
- <= 50
- > 50 | 45.1
39.0 | 0.45 | 31.5
25.8 | 0.2 | Neoadjuvant therapy
- Yes
- No | N/A | | 30.8
26.8 | 0.6 | Multifocal Disease
- Yes
- No | 39.0
55.0 | 0.23 | 49.0
24.9 | <0.0001 | Known axillary disease
- Yes
- No | N/A | | 37.7
26.0 | 0.068 | Type of anesthesia
- General
- Local/IV sedation | 38.7
41.9 | 0.72 | 27.4
25.6 | 0.72 | Tumor localization method
- Palpation
- Mammogram
- Ultrasound | 100
43.1
38.1 | 0.18 | 31.3
33.3
25.2 | 0.26 | Intra-operative specimen examination
- None
- Palpation
- Specimen mammogram
- Ultrasound
- Pathology | N/A | | 23.9
30.9
35.3
38.4
24.9 | 0.17 | Intra-operative specimen examination
- Single Modality
- Multiple Modalities | 40.4
42.1 | 0.85 | 30.4
20.5 | 0.02 | Tumor size
- <= 2 cm
- > 2 cm | 35.2
72.4 | <0.0001 | 24.9
37.3 | 0.02 |
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