Salvage Radiation Therapy
Table of Contents:
In males with a rising PSA after radical prostatectomy in whom the disease is felt to be locally recurrent, rather than metastatic, salvage radiation therapy is an option. The ASTRO (American Society for Therapeutic Radiology and Oncology) consensus panel concluded that the appropriate PSA seemed to be 1.5ng/ml for the institution of salvage radiation therapy. Others have demonstrated improved outcomes using a PSA threshold of 0.6. Gleason score 8-10, pre-radiotherapy PSA level > 2.0, negative surgical margin, PSA doubling time of 10 months or less, and seminal vesicle invasion are significant predictors of disease progression despite salvage radiation therapy. Conversely, a positive surgical margin suggests a greater likelihood that the recurrence is due to residual pelvic disease, therefore a patient with a history of a positive margin who develops an increasing PSA is most likely to benefit from salvage radiation therapy.
If your disease is metastatic, you are not a candidate or you are not interested in salvage radiation therapy, your doctor will discuss with you the options of watchful-waiting and hormone therapy.
In one study, watchful waiting was used in men with a rising PSA after radical prostatectomy, and they were monitored until they had evidence of metastases. About 8 years after the radical prostatectomy, these men developed metastases, and an additional 5 years later, they died from their prostate cancer. In general, when watchful waiting is used for PSA progression after radical prostatectomy, the PSA is checked on an every 3 to 6 month basis to determine how quickly the PSA is rising (PSA velocity). If the doubling time, the time that it takes for
the PSA level to double, is long (a year or longer), then the tumor is slow growing. If the doubling time is short (every 3 months), then the tumor is fast growing, and the patient would probably benefit from early treatment as opposed to continuing with watchful waiting.
Hormone therapy tends to be used more commonly for men with recurrent cancer in whom the recurrence is believed to be outside of the pelvic area. Although hormone therapy may delay the progression of the prostate cancer, its impact on survival in this situation is not well known. Men with high-grade tumors (Gleason sum > 7) or with cancer in the seminal vesicles or lymph nodes at the time of radical prostatectomy and in whom the PSA rises within 2 years after prostatectomy most likely have distant disease and are candidates for hormone therapy or watchful waiting.
What if the PSA rises after EBRT?
Historically, three consecutive PSA rises after achieving a PSA nadir was felt to be indicative of biochemical recurrence after EBRT. However, in 2005, a consensus panel meeting was held, which concluded that a PSA value of 2 ng/mL greater than the absolute nadir represents the best revised definition of failure following external-beam radiation monotherapy. In individuals with biochemical failure after EBRT, the options of treatment include salvage prostatectomy, salvage cryotherapy, hormone therapy, and watchful waiting. The decision regarding the most appropriate therapy is based on the likelihood of the cancer being confined to the prostate.
Salvage Prostatectomy after EBRT
The ideal patient for a salvage radical prostatectomy after EBRT is one who is believed to have had prostate-confined disease initially at the time of EBRT and who is still believed to have organ-confined disease. Individuals in this group include those who have a Gleason score < 6, a low pretreatment PSA level (< 10 ng/mL), and low clinical stage tumor (T1c or T2a). At the time of the salvage prostatectomy, they should still have a favorable Gleason score, a low clinical stage, and, ideally, a PSA that is < 4 ng/mL. Salvage prostatectomy is a challenging procedure, and if you are considering this option, you should seek out an urologist who has experience with it because there is an increased risk of urinary incontinence, erectile dysfunction, and rectal injury with this procedure. Rarely, because of extensive scarring, it is necessary to remove the bladder in addition to the prostate, and a urinary diversion would be necessary. A urinary diversion is a procedure that allows urine to be diverted to a segment of bowel that can be made into a storage unit similar to a bladder or allows urine to pass out of an opening in the belly wall into a bag, similar to a colostomy.
One of the main uses of cryotherapy is in patients with a rising PSA after EBRT. In patients who have not responded locally to EBRT, approximately 40% who then undergo salvage cryotherapy will have an undetectable PSA level after cryotherapy, and 78% will have negative prostate biopsy results. It appears that a drop in the PSA to < 0.5 ng/mL after cryotherapy is associated with a good prognosis. In men with postcryotherapy PSA levels > 0.5 ng/mL, there is a higher likelihood that the PSA will increase or that the prostate biopsy result will be positive.
Hormone Therapy and Watchful Waiting
Use of these two options in patients with a rising PSA after EBRT is similar to their use in those with a rising PSA after radical prostatectomy.
Treatment of Rising PSA after Interstitial Seed Therapy
Treatment options for a rising PSA after interstitial seed therapy include salvage prostatectomy, EBRT, watchful waiting, and hormone therapy. It is important to remember that after interstitial seed therapy, there may be a benign rise in the PSA level, and this should not be misconstrued as being indicative of recurrent prostate cancer. In both interstitial seed and radiation therapy, for a rising PSA to be indicative of recurrent/persistent prostate cancer, it must rise sequentially on three occasions at least two weeks apart. The treatment options are dependent on the likelihood of the disease being confined to the prostate. Salvage prostatectomy for interstitial seed failure carries the same risks as with EBRT failures. The ability to use EBRT depends on the amount of radiation that was delivered at the time of the interstitial seeds and the likelihood of the disease being confined to the prostate.