Detection of local recurrence with multiparametric MR imaging in prostate cancer patients: a pilot study

Approximately 30% of patients with newly diagnosed prostate cancer undergo
external beam radiation therapy (EBRT) as initial definitive treatment, 50% of
which develop biochemical failure (rising prostate specific antigen after
nadir) after 5 years, presumably due to disease recurrence. Local recurrence
may be amenable to salvage therapy, while systemic recurrence may be an
indication for systemic treatment. Local control is usually assessed with
transrectal ultrasound (TRUS) guided biopsy, but this is invasive and has
limited accuracy after radiation. Ultimately, aggressive assessment of local
control 2 years after external beam radiation therapy might allow for earlier
salvage therapy and better long-term outcome. The emergence of novel local
salvage therapeutic options, such as high intensity focused ultrasound,
thermotherapy or cryo-therapy, is an additional factor driving the increased
interest in early and more detailed evaluation of local control. Evaluation of
local control in the radiated prostate gland by T2-weighted magnetic resonance
(MR) imaging is limited by treatment changes, but several reports suggest MR
spectroscopic imaging (MRSI), which detects abnormal metabolism rather than
abnormal anatomy, is accurate in this setting. It is conceivable that other
functional MR imaging techniques, such as diffusion-weighted (DW) MR imaging
(assessing tissue microstructure organization) and dynamic contrast-enhanced MR
imaging (assessing microvasculature) will yield similar results. The ability to
detect or exclude local recurrence within the prostate by multimodality MR
imaging could facilitate salvage local treatment, or potentially facilitate
systemic therapy in patients with presumed distant failure based on biochemical
failure in the absence of detectable local recurrence, ultimately improving the
care and lives of patients with prostate cancer.

To determine the diagnostic accuracy of multimodality MRI in detecting locally
recurrent prostate cancer two years after treatment with external beam
radiation therapy.

Prospective, non-randomized, single centre pilot study. Fifty patients will be
included in this pilot study.

MR imaging may cause some discomfort, such as feelings of claustrophobia and
discomfort due to loud sounds of the MR instrument during the study. Patients
are screened for prior claustrophobic symptoms using the same screening form
described above to search for metal device and foreign bodies. Earplugs are
provided to all patients in order to minimize the discomfort related to the
loud noise.
A topical anesthetic gel will be applied as lubricant at the time of the
digital rectal examination.