MRI of the prostate can give exacting information regarding the exact size and location of the prostate cancer. It may be more accurate than prostate biopsies in quantifying the size of the prostate cancer, and whether it is organ confined or close to or spread beyond the prostatic capsule. This information is crucial in deciding whether a man should remain on an active surveillance program for low risk (low Gleason grade, 3+3) prostate cancer.
ACTIVE SURVEILLANCE FOR LOW RISK PROSTATE CANCER
There is a consensus that there has been an overtreatment of low risk low grade prostate cancers. This has subjected some men to treatment-related side effects of impotence and urinary leakage, and a lesser quality of life. Instead of active treatment, one option is “active surveillance”. This means folllowing a man with low risk prostate cancer using regular PSA tests and rectal exams. Also, a repeat prostate biopsy is needed within 12-16 months. The aim of this srategy is to eventually treat the man with either surgery or radiation but to delay this treatment for as long as feasible so that quality of life is maintained. The problem is that we can never be sure when the exact right time to treat is and we do not want to wait to long such that the cancer progresses to a higher stage. MRI prostate can helo guide the decision making.
Prostate biopsies are the only way of getting tissue sampling and grading of the prostate cancer. It carries risks of infection, bleeding and erectile dysfunction. With the use of MRI, biopsies can now be targeted to the exact focus of cancer thereby reducing the number of overall biopsies. Using this technique typically 3 to 5 cores are taken. The other way to biopsy the whole gland in a systematic fashion in order to increase the chance to detecting a cancer and reduce the risk of missing one, is to perform systematic template biopsies. This template biopsy technique uses a trans-perineal grid and takes 30 to 40 overall cores – manu more than targeted biopsies.
FOCAL THERAPIES FOR PROSTATE CANCER
Focal therapy is an emerging area. This includes the use of different energy forms to destroy the focus or cancer, or destroy one half of the prostate gland. This is instead of surgically removing the whole gland, or delivering radiation therapy to the whole gland. The purported benefits of focal therapy are reduced side effects. The low and intermediate risk prostate cancers are the types of prostate cancer being considered for focal therapy. Also, radio-recurrent cancers (one that recur after primary radiotherapy) are being considered for salvage focal therapy. The problem with this technique is that there is still not that much long term outcomes data with long follow-up of cancer outcomes. The energy forms being used include HIFU (high intensity focued ultrasound), and Cryotherapy (freezing). There are controversies regarding PSA follow-up values and techniques of energy delivery.