Deformable Registration of Multi-parametric MRI to Intra-operative Transrectal Ultrasound for Prostate Brachytherapy

Phase II Study of Focused Dose Painted I-125 Brachytherapy for Low to Intermediate Risk Prostate Cancer Using Deformable Registration of Multi-parametric MRI (Magnetic Resonance Imaging) to Intra-operative TRUS (Trans Rectal Ultrasound)

Objective:

To focus the high dose radiation to the gross tumor in the prostate while maintaining adequate dose for control of microscopic disease elsewhere in the prostate.

In order to test the incorporation of the robust MRI and TRUS fusion algorithm in the clinical setting the investigators planned a study of Focused therapy with a primary endpoint of accurate localization of the high risk region. This is a pilot study of dose painted permanent I-125 seed implant to verify absence of tumor cells outside a high risk region using multi-parametric MRI and deformable TRUS registration. The high risk region will be dose painted to 160 Gy and the rest of the prostate will receive the normal prescription dose.

Primary end-point:

Feasibility of dose painting will be determined by the absence of tumor outside the high-risk region on an intra-operative trans-perineal biopsy.

Frozen sections will not be obtained, however on receipt of the final pathology 2-4 weeks after the procedure 2 possible scenarios arise:

1. There is no evidence of cancer: this confirms the accuracy of the TRUS MRI registration.
2. There is evidence of tumor on the stereotactic biopsy: In this case a regular dosimetric check (this is performed in the Standard of care procedure and is known as post-operative dosimetry) will be performed to determine whether adequate dose was delivered. If not, as the involved needle position was recorded in the treatment plan and labeled with co-ordinates, the regular possibility of accurately adding radioactive seeds is possible.

Inclusion Criteria:

• Men suitable for monotherapy with permanent Iodine 125 implant

  • Age > 50 yrs
  • PS 0-2 (WHO)
  • Histologic diagnosis of prostate adenocarcinoma made on transrectal guided prostate biopsy with no fewer than 12 cores taken
  • No more than 50% of cores involved (summary)
  • MRI of Prostate with Diffusion Weighted Imaging and Dynamic Contrast Enhancement with demonstrable lesion compatible with biopsy result
  • Gleason sum no greater than 3+4 =7 in any core
  • Clinical T stage no higher than T T (tumor) 2A
  • Prostate volume ≤60 cc
  • Serum prostate-specific antigen (PSA) no higher than 15 ng/mL
  • No prior history of malignancy except non-melanoma skin cancer
  • Must be suitable for general or spinal anesthesia

Exclusion Criteria:

Have anesthesia surgical assignment category IV or greater

• Cannot cease anti-coagulant therapy
• Had a malignancy, other than prostate or skin cancer (except malignant melanoma), within 5 years
• urethral stricture
• Prior prostate cancer therapies