PSA test results and Gleason scores have long been the benchmark to
determine whether patients require treatment and in turn which treatments
may be appropriate. Still, there have always been areas of uncertainty in
determining suitable treatments. Patients with low PSA & Gleason scores
may not require any immediate treatment, but some do develop more
aggressive forms of Prostate Cancer. Of those with similar PSA values and
Gleason scores most respond well to Radiotherapy while a few do not.

What was needed was a new tool to determine which cancers may become
aggressive and which may respond well to certain treatments and not to others.
In an extensive histological study of prostate glands, donated by surgical patients,
a pattern began to evolve that may help to explain the differences between
aggressive and non-aggressive cancers and point the way to more effective
individualized treatment.

What they found in those patients with more aggressive cancers were areas of
the prostate gland that were Hypoxic ( Poorly Oxygenated ). The greater the
area of hypoxic cells the greater the likelihood that the cancer would be
aggressive and not respond well to Radiotherapy. This is due to the fact that
Radiotherapy requires oxygen to be affective. In low oxygen environments
cancer cells are far more likely to survive treatment. It was also found that
Hypoxic cancer cells were more resistant to Chemotherapy treatments as well.

In studies that combined Hormone Therapy with Radiotherapy it was found
that treatment results improved and this appears to be related to the fact that
hormone therapy actually increases the oxygen levels of the prostate cells.
Future studies and research will look at using this information to both target
hypoxic cells within the prostate as well as further increase the oxygen levels
in the prostate to limit growth and facilitate treatments.

The Talk was followed by a detailed and lively Question and Answer session. Al Hutton's
emailed question on "Hyperbaric Chambers" was the first to be addressed by Dr. Bristow folllowed by
numerous other questions from the audience.

AUDIO & SLIDES DOWNLOADS may be availed by clicking the links provided below.

About Dr. Bristow:
Dr. Bristow has a brilliant background with degrees, scholarships, awards, research, positions and
publications too numerous to list here. He is involved across a vast scope of research activities and
programs both provincially and at international levels.

Amongst the key positions he holds currently are:
* Clinician-Scientist, Ontario Cancer Institute and Princess Margaret Hospital (University Health Network)
* Associate Professor, Depts. Radiation Oncology and Medical Biophysics, University of Toronto
*Director, Core I-STTARR and LEGEND Labs Canadian Cancer Society Research Scientist
* Chair, Scientific and Medical Advisory Committee, Prostate Cancer Research Foundation of Canada (PCRFC)
* Chair, Biomarkers Planning Committee, Canadian Prostate Cancer Research Initiative (CPCRI)
* Full Member, Institute of Medical Science (IMS), University of Toronto