Prostate Cancer: Information for Patients

Radiation Seeds: Rule of thumb: if you have previously had a TURP for any reason, you are unlikely to be a candidate for seed implant because the complication rate is so much higher. Called "interstitial radiation therapy" or "brachytherapy", seeds of every type can now be accurately placed into the gland with U/S visualization. Radiation beams into gland from within the gland. The advantage here is the delivery of a compact, high dose of radiation while limiting exposure to surrounding structures such as the rectum. With a decision for seed therapy (whether permanent or HDR), precise prostate volume and shape measurements must now be made with another U/S session, see differences, below. IMRT & IGRT accomplish about the same thing but deliver from externally.

In order for treatment success rates to be comparable, the 10 year survival rate is the key benchmark. Much data is available on gold seeds, the actual "gold standard" (short half-life, deep gamma penetration) by which any other radiation seed survival data will eventually be compared. However, even with gold seeds, much of that older survival data was based on open-abdomen, operative seed implantation which could not be as accurate as modern transperineal implantation by U/S guidance. Newer isotopes have some attractive features, but survival data has accumulated for a lesser period of years. Note that use of a high-penetration isotope such as gold will not demand as much precision, meticulousness, and compulsiveness of the radiation oncologist and urologist team as will the short-penetration isotopes (iodine or palladium).

We use palladium seeds. As with e-coil MRI, our pathologist may be asked to render a schematic of the biopsy findings in order that the radiation oncologist physician and the physicist have optimal opportunity to consider and execute any seed additions or special pattern arrangements based on the cancer distribution in the prostate gland as suggested by the biopsy findings [even so, the whole gland is treated under the presumption that prostate cancer tends to be a multifocal disease].

In our program, real-time ultrasound images and 3D-generated images are evaluated; and the urologist, radiation physicist, and radiation oncologist (in the operating room, at the time of surgery) consider numerous factors in deciding whether or not to over-ride the computer-generated designation of seed placement. There is no delay of days or weeks between measurement and seed placement during which there could be slight prostate changes and , almost certainly, re-positioning of the ultrasound probe slightly differently than at the measurement session. That is, we do measurement, planning, and execution of surgical seed placement all at one sitting. (Be aware that there are at least 3 patterns of seed placement that can be used: uniform, peripheral, and "peripheral plus periglandular").

After final, time-consuming, meticulous seed placement of upwards of 100 seeds via 24 or more carefully placed needles by the urologist, a permanent image is taken to document correct seed placement; some days later, another image is taken to be sure that the proper seed pattern has continued in place.

Meticulousness is essential because only a 10-25% under-dosage is said to leave the patient at a 2.3 fold risk of recurrence...25% under-dosage, 6.7 fold risk! And, a lesser level of meticulousness probably means that one should be quicker to use XRT overlay...such double radiation adds 2-3 percentage points of increased risk of serious bowel or bladder injury. Our program relatively seldom uses combination XRT/seeds.

But, we now have the PSA test to help with early detection of most treatment failures...regardless of the type of treatment... so that one may be safer in opting early for new treatments. NOTE: a phenomenon called "PSA bounce" may be seen in seed-implant PSA follow-up...in as many as 35% of patients. Within a year or two after seed implantation (median 18 months), the PSA having been down, starts to rise for 12 months or more, the median PSA increase being 0.4 ng/ml, with a range of 0.1 to 15.8 ng/ml. About 22 percent of the men had more than one bounce. Biopsies are problematic because cancer cells which have been shocked but not yet eliminated can be seen in the biopsy in "bounce" situations and don't really mean recurrence. A true cancer recurrence rise happens later, at a median of 30 months after seed implant.

Be warned that some practitioners (elsewhere) of this seed method are known to take on marginal, even contra-indicated cases and almost routinely refer for added XRT (where XRT would have been sufficiently comprehensive alone)...such urologists get their pay for seed treatment and also divest [to the radiation oncologist] themselves of patient follow-up responsibility for at least 2 years! Or, they may much more hurriedly and imprecisely place the seeds and rely on XRT to mop up whatever was missed. They may even have a way to make money from both the seeds and the XRT (RCOG has even come up with an "eye catching" name for their ploy, ProstRcision). Such entrepreneurial types are often beloved by the patients because, in fact, they are expertly sensitive as to how to please patients.

XRT overlay is legitimately more likely if high confidence the cancer is organ confined but Gleason score is 8 or higher (or there is a "significant" amount of Gleason 4 or 5 component), or evidence of large tumor by imaging (T2b or T2c) or by PSA of 10 or higher, or a biopsy finding of "significant" perineural space invasion...anything suspicious of increased likelihood of minor (microscopic) penetration of the capsule.

Clearly, interested and focused multidisciplinary collaboration...common sense tells us...should be a real advantage here. We started seeds about 1992 here and ceased in about 2002 & began again in 2007.

Premier Programs in the U.S. have included: Seattle Prostate Institute, Seattle, Washington.