Targeted Focal Therapy Emerges as Alternative to Active Surveillance or Definitive Treatment

E. David Crawford, MD

It is well known that PSA testing leads to the overdiagnosis and overtreatment of prostate cancer, according to E. David Crawford, MD, professor of Surgery and Radiation Oncology, head of the Section on Urologic Oncology, University of Colorado Health Sciences Center in Denver. To address some of the ramifications of screening with PSA, Crawford advocates using the emerging technique known as targeted focal therapy.

Although he supports PSA testing, Crawford said its inability to determine which tumors require treatment frequently leaves patients and physicians in a difficult predicament. Small-volume tumors are often detected, but with no accompanying knowledge of which tumors are indolent, the course of action is unclear.

Crawford said that active surveillance is given a lot of “lip service,” but that studies have shown its use has actually decreased over time. Patients are often unwilling to do nothing when they know they have a tumor inside them. Given this reality, he said that focal therapy offers some men with localized tumors a solution between active surveillance and definitive treatment with surgery and/or radiation.

Referred to as the “male lumpectomy,” focal therapy treats only the tumor, not the entire prostate. Crawford said that following the initial biopsy, the ideal candidates for focal therapy have a “PSA that is <10 and a Gleason score of 6 in one or two cores, not involving more than 20% of the cores.”

To definitely confirm focal therapy eligibility and the location of the patient’s tumor cells, Crawford uses a transperineal 3D mapping biopsy.

In the procedure, a grid template covers the perineum, and, guided by transrectal ultrasound, biopsies are obtained from specific areas of the prostate. The results are used to reconstruct a 3D image of the prostate that shows the location of the tumor cells.

Crawford said that about 50% of his patients who undergo a mapping biopsy can receive focal therapy. “In the other half, we find things–cancers on both sides, high-grade cancer–and say, ‘You really do need to have a radical prostatectomy or radical radiation.’”

For those with successful imaging, Crawford said there are multiple methods for destroying the tumor cells. While Crawford uses cryotherapy, or freezing the cancer cells, other techniques include high-intensity focused ultrasound, intensity- modulated radiation therapy, brachytherapy, and photodynamic therapy.

Crawford said that longer patient follow-up is needed to make a definitive conclusion about focal therapy’s efficacy and safety. However, he noted that, “Over five years, it looks pretty good. Our failure rates in properly selected patients are just a few percent, and the side effects have been minimal–certainly a lot less than you would expect to see with more aggressive therapies– and patients are maintaining potency and continence. Also, the patient satisfaction has been very high.”

Focal therapy use is becoming more widespread, according to Crawford, but many places are inadequately conducting the mapping biopsies. “There are only a few places, I think, that are doing it right,” he noted.

Looking ahead, Crawford said that the future of focal therapy and prostate cancer treatment overall will involve improved imaging techniques that enhance diagnosis, show the location of the cancer, and lower the use of needle biopsies.