Use of Intraoperative Radiation Therapy in Retroperitoneal Sarcomas: Update of the Mayo Clinic Roche

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Use of Intraoperative Radiation Therapy in
Retroperitoneal Sarcomas Update of the Mayo
Clinic Rochester Experience

• Ivy Petersen

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IORT for Retroperitoneal SarcomasAnalysis Group

• March 1981- January 2008
• 226 patients with retroperitoneal soft tissue
  sarcoma
• Treated
• Maximum surgical resection
• Intraoperative irradiation (IOERT/IOHDR)
• External beam irradiation (EBRT) when feasible
• Median follow-up 3.3 years (range 0.2 23.7)

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IORT for Retroperitoneal SarcomasPopulation

• Age (years)
• Median 57
• Range 10 - 88
• Gender
• Female 102 (45)
• Male 124 (55)

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IORT for Retroperitoneal SarcomasTumor
Characteristics

• Disease status
• Primary 116 (51)
• Recurrent 110 (49)
• Size (cm)
• Median 10 cm
• Range 2 36 cm

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IORT for Retroperitoneal SarcomasTumor
Characteristics

• Primary (116) Recurrent (110)
• Grade
• Low 30 (26) 49 (45)
• High 86 (74) 61 (55)
• Prior surgery 35 (30) 110 (100)
• Prior EBRT 8 (7) 28 (25)
• Prior chemo 8 (7) 91 (83)
• Up from 14 in prior Mayo review

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IORT for Retroperitoneal SarcomasSurgical
Treatment

• Surgical outcome
• R0 89 (39)
• R1 112 (50)
• R2 25 (11)

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IORT for Retroperitoneal SarcomasExternal Beam
Treatment

• Patients receiving EBRT
• Primary tumors 115/116 (99)
• Recurrent tumors 96/110 (87)
• Dose (Gy)
• Median 45
• Range 10 - 65
• Timing of EBRT
• Preoperative 172 (82)
• Postoperative 27
• Both 12

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IORT for Retroperitoneal SarcomasIORT Treatment

• Number of fields treated
• One 175
• Two 41
• gt 3 10
• Dose (Gy)
• Median 12.5
• Range 5 - 30
• (95 7.8 23 Gy)

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IORT for Retroperitoneal SarcomasIORT Treatment

• Energy
• Median 9 MeV (54)
• Range 6 20 MeV
• Field size
• Median length 12 cm
• Median width 8 cm
• Range 4.5 20 cm

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IORT for Retroperitoneal SarcomasOverall Outcome

• Overall Survival
• 3 year 67
• 5 year 50

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IORT for Retroperitoneal SarcomasSurvival
Impact of Surgery

• Median survival
• R0 39
• R1 50
• R2 11
• p 0.08

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IORT for Retroperitoneal SarcomasSurvival
Impact of Surgery
p 0.08
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IORT for Retroperitoneal SarcomasSurvival
Impact of Disease Status
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IORT for Retroperitoneal SarcomasSurvival
Impact of Grade
p 0.053
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IORT for Retroperitoneal SarcomasLocal Control
Overall

• Local control
• 3 years 81
• 5 years 69

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IORT for Retroperitoneal SarcomasLocal Control
Impact of Surgery
p 0.548
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IORT for Retroperitoneal SarcomasLocal Control
Impact of Grade
p 0.73
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IORT for Retroperitoneal SarcomasLocal Control
Impact of Disease Status
p 0.003
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IORT for Retroperitoneal SarcomasDistant
Metastases Rate

• Distant metastases
• 3 year 36
• 5 year 43

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IORT for Retroperitoneal SarcomasDistant
Metastases Rate Impact of Grade
p 0.0004
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IORT for Retroperitoneal SarcomasNeurotoxicity

• Grade No. of patients
• Total 69 (31)
• Mild 29 (42)
• Moderate 24 (35)
• Severe 16 (23)
• IORT felt to contribute to gt90

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IORT for Retroperitoneal SarcomasAny Grade 3-5
Toxicity (including neuro)

• Grade 3 4 toxicity
• 28/226 (12)
• Grade 5 toxicity
• 12/228 (5)
• RT contributed to 6
• Surgery contributed to 7
• Disease contributed to 2
• Other causes contributed to 8
• None were felt to be related to IORT

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IORT for Retroperitoneal SarcomasSummary

• Study suggests
• Importance of complete surgical resection to
  microscopic residual
• Impact of grade on survival/rate of distant
  metastases and therefore the need for better
  systemic agents
• Primary disease has better local control but this
  does not translate to a higher survival

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Acknowledgements

• My colleagues
• Michael G. Haddock
• Scott L. Stafford
• John H. Donohue
• David M. Nagorney
• Leonard L. Gunderson
• Physics team
• Our patients.