For November 23, 2008
LOCAL TREATMENT OF PROSTATE CANCER: A CAUSE FOR CELEBRATION?
Everyone knows that breast sparing surgery is about as effective as radical surgery (mastectomy) for many cases of breast cancer. Could the same sort of sea change in treatment now be taking place in prostate cancer?
Could doctors limit their intervention to areas of known malignancy and thereby spare the rest of the prostate gland? And could this be done in a way that spares the nerves that make sexual potency possible, while avoiding the risk of urinary incontinence. Yes on all counts, according to a team of urologists writing in a well-respected cancer journal.
Sexual impotence and urinary incontinence are two major threats to the quality of life of many prostate cancer patients. These things "affect the male self image no less than the loss of a breast does a woman," according to Gary Onik, MD.
Dr. Onik is director of Florida Hospital/Celebration Health's prostate cancer research program. He is a Harvard graduate who received his medical degree from New York Medical College. He completed his residency at the University of California San Francisco and has specialized training in ultrasound from New England Deaconess Hospital (Harvard) in Boston. He is the inventor and pioneer of ultrasound guided cryosurgery for both the prostate and the liver. In 2005 he published a textbook titled The Male Lumpectomy: Focal Therapy for Prostate Cancer.
Why haven't other doctors thought of simply removing or otherwise destroying just the cancerous tissue in appropriate cases? According to Dr. Onik, "traditional thinking has held that prostate cancer is multifocal and therefore not amenable to a focal treatment approach." But recent literature on the pathology of prostate cancer indicates that up to 25 percent of all prostate cancers are in fact solitary and unilateral. This fact therefore raises the question of whether or not such patients can be identified and treated with a limited "lumpectomy" or focal cancer treatment.
The authors used a method called "focal cryoablation." This is the use of an extreme cold probe to destroy areas of the prostate that were known to be cancerous based on previous staging biopsies. Patients were then followed with prostate specific antigen tests (PSAs) that were obtained every 3 months for 2 years and then every 6 months thereafter.
Forty-eight patients who had at least 2-year follow-up had this type of focal cryoablation for their cancer. Follow-up has now ranged from 2 to 10 years, with a mean of 4.5 years. At the time of publication of their report in the Journal of Urologic Oncology, 45 of the 48 patients (or 94 percent) have stable PSAs with no evidence of cancer. This was so despite the fact that 25 of these patients were considered to be at medium to high risk for recurrence.
Twenty-four patients who had stable PSAs were also routinely biopsied after the treatment; all were negative for cancer. No local recurrences were noted in the areas that were treated with the cold probe. As hoped for, sexual potency was maintained to the satisfaction of the patient in of 36 of 40 patients who had been potent preoperatively. Of the 48 patients treated, all had maintained urinary continence.
Comparisons to Radical Prostatectomy
This was not a randomized trial, so we do not know exactly how men who received radical prostatectomy (RP) for similar types of prostate cancer would have done by comparison. But consider the Prostate Cancer Outcomes Study (PCOS). This large, multi-center study concluded that sexual dysfunction among men who underwent surgical removal of the prostate was far more prevalent than previously believed. The results first appeared Jan. 19, 2000, issue of the Journal of the American Medical Association. At 18 or more months after surgery, the impotence rate among 1,288 men was an astonishing 60 percent.
In 2008, the same authors followed up on these 1,288 men after five years. Of these men 14 percent now reported frequent urinary leakage or no urinary control five years after diagnosis. This was slightly higher than the 10 percent reporting such incontinence at 24 months. In addition, at 60 months 28 percent of the men had erections firm enough for intercourse compared with just 22 percent at 24 months. Thus, even after recovering from the surgery, 76 percent of these men were sexually incontinent, although about half of the men who used Viagra reported that it was helpful - "somewhat" or "a lot." The authors concluded that a large percentage of radical prostatectomy patients suffered from incontinence or impotence at least five years following surgery.
By contrast, the preliminary results coming out of Celebration, Florida, are indeed a cause to celebrate. For a select group of patients, these findings indicate that a "male lumpectomy," in which only the region of frank malignancy is destroyed, appears to preserve potency in a majority of patients and also limit other complications (particularly incontinence), without compromising control of the cancer. If this is confirmed by further studies and by longer-term follow-up, this new approach could, as Dr. Onik suggests, have a profound effect on the management of prostate cancer.
--Ralph W. Moss, Ph.D.
Resources:
Dr. Onik is at the Department of Radiology and Urology, Division of Surgical Imaging, Center for Surgical Advancement, Celebration Health/Florida Hospital, Celebration, FL 34747, USA. [email protected]
References:
Onik G, Vaughan D, Lotenfoe R, Dineen M, Brady. The "male lumpectomy": focal therapy for prostate cancer using cryoablation results in 48 patients with at least 2-year follow-up. J. Urol Oncol. 2008 Sep-Oct;26(5):500-5.
Penson DF, McLerran D, Feng Z, et al. 5-year urinary and sexual outcomes after radical prostatectomy: results from the Prostate Cancer Outcomes Study. J Urol. 2008 May;179(5 Suppl):S40-4. The authors are at the Department of Urology, Keck School of Medicine, University of Southern California, Los Angeles, California 90089, USA. [email protected]
Stanford JL, Feng Z, Hamilton AS, et al. Urinary and sexual function after radical prostatectomy for clinically localized prostate cancer: the Prostate Cancer Outcomes Study. JAMA. 2000 Jan 19;283(3):354-60.
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