What is the appropriate margin for focal therapy of prostate cancer when using MRI/MRSI for treatment planning?

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What is the appropriate margin for focal therapy
of prostate cancer when using MRI/MRSI for
treatment planning?
Proposed secondary study for ACRIN 6659 data

• Fergus Coakley MD, Professor of Radiology and
  Urology,
• Chief, Abdominal Imaging, University of
  California San Francisco

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Objective

• Determine the appropriate margin for focal
  therapy of prostate cancer when planned from
  MRI/MRSI

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Background

• Increasing interest in focal therapy as middle
  way for prostate cancer treatment
• Active surveillance minimalist
• Definitive treatment (RRP or RT) high morbidity
• Three requirements for focal therapy
• Clinical selection no consensus
• Radiological selection MRI criteria on next
  slide
• Adequate margin purpose of this proposal

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UCSF selection study

• 88 patients with MRI/MRSI before RRP and with
  detailed tumor maps
• MRI/MRSI reviewed by two independent readers
• Dominant treatable foci largest lesion gt
  0.5cc
• Results
• ALL visible lesions on T2 with 0.54 cm3 of
  concordant MRSI abnormality (n 27 and 25 for
  reader 1 and 2, respectively) were correctly
  identified dominant treatable tumor foci

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Proposal (two steps)

• Apply UCSF criteria to ACRIN database
• T2 visible 0.54 cm3 concordant MRSI
• Two readers (remote or travel to ACRIN HQ?)
• Anticipate small number will meet criteria (lt10?)
• Co-register digital pathology with T2
• Pick largest/best T2 image and best match
  pathology slide
• Morph gland outline on pathology to T2 (allows
  margin measurement using MRI calipers)
• Measure maximum margin (per quadrant and separate
  capsular from non-capsular?)

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Example
Best match T2 MRI and pathology slice
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Example
Morph pathology to T2
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Example
Morph pathology to T2
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Example
Measure margins maximum capsular and
non-capsular plus by quadrant?
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Analysis

• Presumably will be essentially descriptive what
  margin would have encompassed all the tumors?
• Issues for discussion
• Explore additional selection criteria?
• More than two reads?
• Can readings be done remotely?
• Who will fuse images and measure margins?
• Funding level? Travel and/or time?