PostMastectomy Radiotherapy Who needs it

1
Seroma Development Following MammoSite
Accelerated Partial Breast Irradiation (MBT)
John M. Watkins, M.D.1, Jennifer L. Harper,
M.D.1, Anthony E. Dragun, M.D.1, Michael S.
Ashenafi, M.S.1, Debajyoti Sinha, Ph.D.2, Jun Li,
Ph.D.1, David J. Cole, M.D.3, and Joseph M.
Jenrette, III, M.D.1 Medical University of South
Carolina, Departments of 1Radiation Oncology,
2Biostatistics, Biometrics, and Epidemiology, and
3Surgery, Charleston, SC, U.S.A.
2
Study Design

• Single institution retrospective analysis.
• Describe incidence and identify predictive
  factors of predictive for seroma development.
• Analysis of patient-, tumor-, and
  treatment-related factors.
• Subset analysis for clinically significant
  seromas (CSS).
• Minimum 6 month post-MBT follow-up, or seroma
  development.

Clinically Significant
3
Study Design

• Predictive Factors Assessed
• Age (lt/gt60y, lt/gt70y)
• Race
• Diabetes
• Tobacco Use
• Weight (lt/gt150lbs, lt/gt200lbs)
• Re-excision vs none
• Time Resection to Mammosite
• (0 vs gt1 day, lt/gt5 days, lt/gt8 days)
• Open vs Closed Placement

• Lateral Trocar vs Seroma Entry Technique
• Catheter Dwell Time (lt/gt15days)
• Overlying Skin Thickness (continuous)
• Dwell Positions (single vs multiple)
• Dosimetric (V100, V150, V200)
• Chemotherapy (no vs yes)
• Anti-Estrogen Therapy (no vs yes)
• Antibiotic Prophylaxis (no vs yes)
• Post-MBT Infection (no vs yes)

4
Results

• Outcomes
• From 5/02 through 8/06, 109 pts underwent MBT
• 12 excluded from analysis (insufficient
  follow-up)
• Median follow-up 36 months (range 4-57)
• Seroma developed in 40 patients (41)
• Median MBT to seroma interval
• 3 months (range 0.1-24.8)
• Clinically significant seroma (CSS)
• constituted 1/3 of seromas (n13)

5
Results

• Predictive Factors
• Any Seroma
• Day 0 catheter placement (59 vs 33 p0.0066)
• Clinically Significant Seroma
• Post-MBT Infection (64 vs 7 plt0.0001)
• Prophylactic Antibiotics reduced infection risk
  (37.5 vs 7 p0.0011)

6
Conclusions

• The majority of MBT-associated seromas are
  minimally symptomatic and do not require
  significant intervention.
• Placement of MBT catheter at initial resection
  increases risk of seroma development.
• Post-MBT infection increases the risk of
  clinically significant seroma development.
• Prophylactic antibiotics reduce the risk of
  MBT-associated infection.