29 july 2009-- A major study has good news for men who have prostate cancer surgery but leaves unanswered the complicated question of whether a man should have that operation, another treatment or just watchful waiting.
The study of almost 13,000 American men who had a radical prostatectomy -- surgical removal of a cancerous prostate gland -- between 1987 and 2005 found that only 12 percent of them died of the cancer, according to the report in the July 27 issue of the Journal of Clinical Oncology.
"Patients with what we thought of as high-risk prostate cancer had a much lower risk of dying of their cancers than we ever thought," said Dr. Peter T. Scardino, chairman of the department of surgery at Memorial Sloan-Kettering Cancer Center, and a member of the research team. "Patients with more favorable prostate cancers did remarkably well, so well that you have to begin to question whether they should have been treated."
The choice of surgery, radiation therapy or watchful waiting must be made each year for more than 190,000 American men, most middle-aged or older, who are diagnosed with prostate cancer. Most choose some kind of treatment, said Dr. Andrew Stephenson, head of urological oncology at the Cleveland Clinic's Glickman Urological and Kidney Institute, and another member of the research team. From 40 percent to 50 percent choose surgery, about 10 percent choose watchful waiting, and the rest choose some form of radiation therapy, Stephenson said.
For men who have surgery, the new research has produced a tool that can allow them to predict their chance of survival for at least 15 years, Scardino said. Survival is measured by essentially three elements: the clinical stage of the cancer when it is detected, determined in great part by how large it is; the Gleason score, a measure of how much of its normal structure the prostate gland has lost; and blood levels of prostate-specific antigen, a protein produced by the gland.
The study found that the score had an accuracy of 82 percent in predicting 15-year survival, Scardino said. "If you could predict what would happen in the stock market in the next 15 years with 82 percent accuracy, you would be a genius," he said.
Overall, there was a greater chance that a man in the study would die of a cause other than prostate cancer. The rate of death from other causes was 38 percent, compared to 12 percent attributed to prostate cancer.
The new predictive method will be made public soon, after medical review, so that physicians and men can learn about their anticipated survival after surgery, Scardino said.
"Any person can look at it and put in the numbers," he said.
The new predictive tool is an improvement over the existing method, which relies essentially on readings of prostate-specific antigen levels, Stephenson said.
But no such predictive method exists for newly diagnosed men who must chose between treatment and watchful waiting, and so the study presents a predicament for those men and their physicians, he said.
"It questions the lethality of prostate cancer," Stephenson said. "Perhaps a similarly low risk might have been seen if the men did not have prostatectomy. We can't say whether a cancer poses enough of a threat to the patient so that therapy is needed."
Prostate cancer surgery is not free of problems, Stephenson said. Its major side effects are incontinence and loss of sexual function.
Many prostate cancers grow slowly -- so slowly that an old medical byword is that "more men die with their prostate cancer than of it." No existing method can single out the cancers that will be fatal if left untreated.
"We really need better tools for really identifying prostate cancers that pose a threat to longevity," Stephenson said. "Many have been proposed. All are being investigated, and hopefully in the future we will have better tools that accurately predict the risk of dying from prostate cancer."
Until those tools are available, the question is often "a balance between quantity and quality of life," he added. "That is a very complicated decision that must take many factors into consideration."