Urologists Urged to Get on Board With Prostate Brachytherapy

PALM BEACH, Fla--A urologist believes his unique viewpoint can be helpfulto radiation oncologists doing brachy-therapy and to his fellow urologists."By 2005," said Nelson Stone, MD, of Mt. Sinai Medical Center,NY, "projections indicate that two thirds of prostate cancer caseswill be treated with brachyther-apy or external beam irradiation. If urologistsdon't get on board, they'll be treating half of the cases they are now."

By looking at radical prostatectomy data and comparing the pathologicalresults with pretreatment PSA levels, urologists can help improve patientselection for brachytherapy, Dr. Stone said.

"Prognostic variables help determine whether patients should haveradical prostatectomy alone; seed implant plus external beam radiation;hormonal treatment plus seed implant; or some other combination of thevarious therapies," Dr. Stone said at the 19th annual meeting of theAmerican Brachytherapy Society (ABS).

By evaluating prognostic data, Dr. Stone and his colleagues at Mt. Sinaihave come up with treatment guidelines for use of brachytherapy and/orcombined modalities in prostate cancer (see table).

Dr. Stone feels that seminal vesicle biopsy and even lymph node dissectionmay be important in determining whether a patient needs monotherapy ora combined therapy.

A number of years ago, Dr. Stone said, he began investigating whetherseminal vesicle involvement could be detected by doing a simple prostateneedle biopsy of the seminal vesicles in addition to the prostate biopsy.

Being able to determine seminal vesicle involvement allows the physicianto change therapies up front if needed. The physician can tell the patientwho has positive seminal vesicles that with radical prostatectomy alone,he will have a 75% chance of biochemical failure down the road. "Thisallows the patient to participate in deciding the best treatment,"Dr. Stone said.

His selection criteria for performing seminal vesicle biopsy are PSAabove 10 ng/mL, Gleason grade of 4 or 5, and stage T2b disease or higher."This gives a one in five chance of diagnosing cancer in the seminalvesicles," he said.

Dr. Stone emphasized that urologists and radiation oncologists mustwork together on this. If a patient with the above scores is referred tothe oncologist without having had a seminal vesicle biopsy, the patientshould be referred back to have one done, since this information is neededto help determine the applicability of brachytherapy.

Lymph Node Dissection

Using the Partin-Walsh nomogram, a patient with a Gleason score of 7,PSA of 11, and stage T2b prostate cancer would have a 33% likelihood ofpositive seminal vesicles and a 24% likelihood of positive lymph node involvement.If the seminal vesicle biopsy shows positivity, the chance that the lymphnodes are involved increases to 38%.

"If we do a multiple regression analysis using these four factors,we find that seminal vesicle biopsy is the most important predictor oflymph node disease. Gleason scores, PSA, and staging almost dropped outas being important predictors," he said.

Laparoscopic lymph node dissection has little or no associated morbidity,Dr. Stone said, and it should not be ruled out "just because we'renot operating on the patient."