Prostate tumors are often multifocal, which means they tend to occur in more than one place within the gland. The digital rectal exam performed by the urologist will often miss tumors. The PSA test, used to screen for prostate cancer, has a sensitivity of about 70% and will often yield unclear results. And the random prosate biopsy, which seeks to identify tumors, while performed systematically, is also done blindly, resulting in roughly one-third false negative results.
In recent years, Multi-parametric Magnetic Resonance Imaging (MP-MRI) has played an increasing role in prostate cancer detection. MP-MRI scans are now more effective in distinguishing cancer from normal prostate tissue. And although MP-MRI is not yet considered the standard tool for diagnosis, it can uncover cancer that has been missed during biopsy. Moreover, MP-MRI plays a significant role in helping to determine whether active surveillance is a safe procedure, or whether a patient requires definite treatment.
Advances in MP-MRI technology include specific targeting known as MRI-guided biopsy. Since cancers that occur in the anterior or front part of the prostate are often not being sampled because they are “out of the reach” of standard biopsy techniques, they often contain undetected areas of cancer. An optimal magnetic resonance imaging study employs a powerful magnet to create detailed images that are then displayed on a computer screen. According to K.J. Macura, MD, at Johns Hopkins:
Based on the scans, radiologists assign scores of 1 to 5 for the presence of prostate tumor on MRI, with 1 being deifinitely benign, 3 either benign or not (i.e. we can't tell), 4 being probably malignant, and 5 definitely malignant.
This greater specificity is valuable since a lower score indicates that a follow up biopsy may not be necessary, while high scores indicate that a confirmatory biopsy may be advisable, and that the disease may require up-grading.
There are various types of MRI equipment available. When my MRI was performed, the MRI unit was operating at “3T”, T standing for Tesla and 3 the current state of the art technology, a unit of magnetic strength that provides hundreds of images and a detailed anatomy of the prostate. However as of 2014, most of the men I have spoken with have undergone MRI testing with the older, less comprehensive 1.5 Tesla unit.
And while the number of the MRI centers that use the latest technology is increasing, progress has been slow. So if you are scheduled to undergo an MP-MRI-guided biopsy using transrectal ultrasound and MRI guidance, make sure your MRI guidance is performed with the 3-Tesla machine. The results may make the difference between your being subjected to unnecessary, invasive treatment versus continued on active surveillance.
If necessary, make a fuss. It's your prostate cancer and your life.
FIND OUT MORE ABOUT RALPH'S STORY IN THE BOOK Invasion of the Prostate Snatchers