Post-Treatment Prostate Cancer Outcomes Predicted by MRI

Findings of a magnetic resonance imaging (MRI) study in patients about to undergo radiation therapy for prostate cancer can help forecast the likelihood that the cancer will recur and metastasize post-treatment.

"This is the first study to show that MRI detection and measurement of the spread of prostate cancer outside the capsule of the prostate is an important factor in determining outcome for men scheduled to undergo radiation therapy,” said study co-author Fergus V. Coakley, M.D., professor of radiology and urology, vice chair for clinical services and section chief of abdominal imaging in the department of radiology at the University of California, San Francisco (UCSF; USA).

When diagnosed and treated early, the five-year survival rate for patients with prostate cancer is nearly 100%. However, once the cancer spreads or recurs beyond the prostate, the chance of survival decreases considerably. One common treatment for prostate cancer is external beam radiation therapy. Dr. Coakley and colleagues tried to determine if MRI results prior to radiation therapy were an indicator of potential recurrence and spread.

The researchers retrospectively reviewed the MR images of 80 men with prostate cancer who had undergone MRI of the prostate before external beam radiation therapy. Details of tumor characteristics, treatment, and outcome were recorded. Utilizing a Cox regression analysis (a technique that correlates the relationship between survival of a patient and several contributing variables), the researchers determined that the presence and level of extracapsular extension (spread of cancer beyond the membrane that surrounds the prostate gland) seen on the pre-treatment MR images was a significant predictor of post-treatment recurrence and spread. Specifically, patients with extracapsular extension greater than 5 mm were more likely to experience recurrence and metastasis of their cancers.

The study was published in the April 2008 issue of the journal Radiology.


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