Current Practice in Partial Breast Irradiation

1
Current Practice in Partial Breast Irradiation
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Objectives

• Justification for Partial Breast Irradiation
  (PBI)
• Current Breast Irradiation Techniques
• Whole breast external beam
• Multi-catheter interstitial
• Single-catheter interstitial
• 3D-CRT
• MammoSite

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Necessity for Radiation Therapy

• Six randomized trials have been conducted
  attempting to determine if RT can be omitted
  after breast conserving surgery
• No subset of patients has yet been identified
  that can conclusively be treated with surgery
  alone
• RT after breast conserving surgery remains the
  standard of care

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Prospective Randomized Trials of Lumpectomy /-
Radiotherapy
of Patients With
Trial

Reduction

Recurrence

Recurrence

CS Alone

CS RT

(CS vs. CS RT)

NSABP B
-
06


36

12

67

Milan3

6
24


75

Scottish

25

6

76


24

9

63

Uppsala-Orebro
Ontario

35

11

69


English
35

13

63

Recently Updated
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Rationale For Partial Breast Irradiation (PBI)

• Up to 40 of patients who are candidates for
  breast conservation therapy do not receive it 1

• Why?
• Physician bias
• Patient choice
• More complex and prolonged treatment course
• 6 weeks daily treatment Monday to Friday
• Can be inconvenient or prohibitive for those with
  poor access to a radiation facility, the elderly
  and working women.

1 Nattinger, et al. 2000.
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Advantages of Partial Breast Irradiation (PBI)

• Improve documented underutilization of BCT
• Decrease time and inconvenience of BCT
• Improve quality of life
• Eliminate scheduling problems with systemic
  chemotherapy
• Intensifying radiotherapy to the tissue at
  greatest risk for subclinical disease
• May further reduce local recurrence rates
• Potentially reduce acute and chronic toxicity
• Cosmetic outcome may be improved because skin and
  integral breast parenchymal doses are lower,
  especially for women with large breasts

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Rationale for PBI

• A broad spectrum of clinical studies supports the
  ability to achieve local control with PBI,
  including
• Studies identifying disease extension and margin
  assessment
• Impact of RT on elsewhere failures
• Brachytherapy clinical data

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Impact of RT on Elsewhere Failures-Randomized
Trials Comparing BCS vs. BCS Plus RT-

• No impact of radiation on elsewhere failures

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Published Contemporary Data on Partial Breast
Irradiation as Primary Treatment
NSABP-B06 77 of in-breast failures occurred
within 5 years of treatment. After 5 years,
almost equal number of recurrences developed with
or without whole breast radiation therapy.
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Patient Selection Criteria
ABS Recommendations1 ASBS Recommendations2

1Arthur, et al. Accelerated partial breast
irradiation an updated report from the American
Brachytherapy Society. Brachytherapy, 1184-190,
2003. 2Consensus statement for accelerated
partial breast irradiation. The American Society
of Breast Surgeons. April 30, 2003.
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Breast Irradiation Technique

• External Beam
• Treats whole breast
• Large volume of incidental tissues
• Requires protracted (67 week) delivery

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Breast Irradiation Technique

• Interstitial Multi-Catheter
• Treats quadrant or less
• Effective in properly selected patients
• Requires special skill

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Breast Irradiation Technique

• MammoSite
• Distends cavity
• Very conformal
• Prescription limited by doses to skin and balloon
  surface

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Investigational Technique

• 3D CRT
• Requires added margin (breathing)
• Not as simple as it looks
• No clinical data

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MammoSite Product Line

• Spherical 4-5 and 5-6
• Recently FDA approved ellipsoidal sizes will
  broaden ability to implant different sized/shaped
  cavities
• Available Q3 2004

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MammoSite Dosing
95.79 4.21 28.57 33.33 38.1
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CT Image of MammoSite
Tissue Conformance
Skin Spacing
Balloon Diameter Symmetry
3-Dimensional rendering of applicator surface
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Patient Procedure Overview
Treatment Planning
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Patient Procedure Overview
Radiation Treatment Delivery Begins
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Patient Procedure Overview
Explant
Total 10 fractions delivered over 5 days
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NSABP/RTOG Phase III Study

• Randomized controlled study comparing whole
  breast external beam irradiation to accelerated
  partial breast irradiation
• MammoSite
• Interstitial catheter
• 3D conformal
• 3000 patients planned
• Initiated Q3 2004