ROCHESTER, Minn. -- New findings from Mayo Clinic indicate that cT3 prostate cancer, a disease in which the cancer has spread locally from inside the prostate to immediately outside it, is operable and has 15-year cancer survival rates of almost 80 percent.
"These patients have a better chance if they undergo surgery and are living longer than if they undergo radiation therapy," says Horst Zincke, M.D., Ph.D., Mayo Clinic urologist and senior study investigator.
Treatment of this type of prostate cancer has been controversial, as it is a stage 3 cancer in which the malignancy has spread. Due to its advanced stage, some physicians have considered it inoperable via radical prostatectomy, according to Dr. Zincke. He explains that many patients come to him for a second opinion after being told their cT3 prostate cancers could not be surgically removed.
"It's considered inoperable by some urologists and referred to radiation oncology," says Dr. Zincke. "They think surgery can't be done because the cancer is outside the prostate. Currently, only 15 percent are referred for surgery."
The problem with radiation therapy as the first line of treatment for cT3 prostate cancer, according to the Mayo Clinic researchers, is the cancer survival rate, which is 79 percent at only five years. In contrast, with radical prostatectomy, 79 percent of the patients lived at least 15 years. Says Dr. Zincke, "So, obviously surgery does a better job for these patients."
Dr. Zincke also explains that when malignant prostate tumors are high grade -- more aggressive -- they are not especially responsive to radiation therapy alone.
He believes the current trend away from surgery is a disservice to patients. "Patients are being denied surgical treatment when indeed they could have had surgery," Dr. Zincke says.
The cancer survival rates for cT3 prostate cancer with radical prostatectomy not only approach those of cT2 prostate cancer (cancer confined to the prostate), which is 90 percent at 15 years, but they are even more impressive due to the ages of the patients, says Dr. Zincke. "It's significant because the average patient is only 62 years old," he says. "So, a 15-year survival is a long time."
In addition to a favorable survival rate for the cT3 prostate cancer patients studied, the Mayo Clinic researchers also found urinary incontinence rates and complications were akin to those for cT2 prostate cancer.
Some of the patients studied with cT3 prostate cancer had additional, or adjuvant, therapy after surgery, such as hormone therapy or radiotherapy. Dr. Zincke indicates that adjuvant therapy is necessary for patients whose prostate cancer affects the lymph nodes. Surgery alone may be sufficient treatment for those without lymph node involvement. Approximately 50 percent of the cases of cT3 prostate cancer do not involve the lymph nodes.
The study also found that 25 percent of the patients were overstaged -- told that they had a cT3 prostate cancer, a more advanced form, rather than what they really had a cT2 prostate cancer in which the malignancy is confined inside the prostate.
Dr. Zincke points to following patients over 15 years post-treatment as a strength of the study. "The highest incidence of prostate cancer death is not reached until 11 years after treatment, so 15-year data is significant," he says. "In contrast, five-year data is less meaningful."
Dr. Zincke recommends that patients with cT3 prostate cancer seek a surgeon who performs at least one prostate surgery per week and has completed at least 300 prostate surgeries. He explains that currently only 3 to 4 percent of urologists are doing more than one prostate cancer surgery per week. As they seek an appropriate surgeon, he encourages patients that "if someone tells you your cT3 prostate cancer is inoperable, don't give up."
With more common use of prostate-specific antigen (PSA) testing in the United States, more prostate cancers are now caught earlier, before the cancer spreads. Thus, the frequency of cT3 prostate cancers seen at Mayo Clinic has declined to 3 percent of all prostate cancers. Canada and Europe have much higher rates of cT3 prostate cancer, as PSA testing is not conducted as frequently and more cancers are discovered later than in the United States, allowing the cancers more opportunity to spread outside the prostate.
This study was conducted as a single-institution, retrospective study of 5,652 men who had radical prostatectomy at Mayo Clinic for confirmed prostate cancer.
The title of the paper is "Radical Prostatectomy for Clinically Advanced (cT3) Prostate Cancer Since the Advent of Prostate-Specific Antigen Testing: 15-Year Outcome." The first author is a former Mayo Clinic urology fellow, John F. Ward, M.D., Division of Urology, Naval Medical Center, Portsmouth, Va. Other Mayo Clinic authors include Jeffrey Slezak, Eric Bergstralh, and Michael Blute, M.D.
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