Prostate Tumor Hypoxia Predicts PCa Recurrence
Men with intermediate-risk prostate cancer (PCa) who have low oxygen levels in their prostate tumors prior to radiation treatment are at increased risk of PCa recurrence, according to researchers.
Michael Milosevic, MD, of Princess Margaret Hospital in Toronto, and his colleagues measured tumor oxygen levels in 247 men with localized intermediate-risk PCa prior to radiation therapy. After a median follow-up of 6.6 years, the five-year biochemical relapse-free rate was 78%. Tumor hypoxia, defined as an oxygen percentage less than 10 mm Hg, predicted early biochemical failure after treatment. The investigators defined biochemical failure as a PSA increase of 2 ng/mL or more above nadir.
“This is the first study to identify a relationship between pretreatment prostate hypoxia and local recurrence after radiotherapy,” the researchers noted in Clinical Cancer Research (2012;18:2108-2114).
The findings “provide a strong rationale for integrating radiotherapy with new hypoxia-targeted treatment approaches in future clinical trials,” the authors observed.
A Reuters report on a forthcoming study in the Journal of Clinical Oncology has suggested that some men with intermediate-risk prostate cancer may be able to safely defer treatment in favor of monitoring the disease over time (through active surveillance) for a period of at least 4 years.
The Reuters report addresses a paper by Cooperberg et al. The paper is based on a series of 466 prostate cancer patients who have been managed with active surveillance at the University of California, San Francisco (UCSF).
According to Dr. Cooper, in the USA today, between 25 and 40 percent of all newly diagnosed prostate cancer patients have localized disease that falls into the intermediate-risk category. The wide range is a consequence of the fact that there are varying definitions of “intermediate risk.” However, it has been clear for a while that active surveillance held potential as a management starategy for at least some of these men.
Of the 466 patients managed at UCSF, 90 were categorized as having intermediate-risk disease and the other 376 had low-risk disease. After their initial diagnosis, they received PSA tests and digital rectal exams about every 3 months, ultrasound tests every 6 to 12 months, and follow-up biopsies every 1 to 2 years.
###
Jody A. Charnow