Trial Information

Fiducial Localization and Individualized Radiotherapy in Prostate Cancer (FLIP)

The success of dose escalation strategies in prostate cancer over the last decade has relied
on high accuracy in target delineation, localization and radiation delivery. Improved
biochemical control with acceptable levels of toxicity (specifically rectal) has been
achieved by stringently monitoring the location of the prostate during the course of
radiation treatment. Studies in the early 1990's demonstrated that daily bony alignment was
a poor surrogate for prostate gland location. Since then, various strategies have been
devised to localize the prostate precisely during treatment. Of these, Transrectal
Ultrasound (TRUS)-guided gold fiducial marker (FM) insertion and x-ray imaging of markers
has been a broadly successful approach. TRUS guidance has been used for fiducial marker
insertion within the prostate since 1985 in various centers throughout the world and has
also been a standard practice in PMH since 1997 in men undergoing radical external beam
radiotherapy. A retrospective comparative study of 106 patients evaluating the relative
accuracy of endorectal MRI and TRUS in detecting the location of tumor reported an improved
performance of endorectal MRI especially in the base and midgland regions. Over the last few
years, mounting experience in the interpretation of prostate MRI, and addition of
physiologic imaging sequences has further improved the performance of MRI in detecting and
localizing the GTV.