Popular Prostate Cancer Therapy Is Short, Intense and Unproven

Paul Kolnik, a photographer, underwent stereotactic body radiation therapy for his prostate cancer, which is now in remission. Credit Yana Paskova for The New York Times

After learning he had early stage prostate cancer, Paul Kolnik knew he wanted that cancer destroyed immediately and with as little disruption as possible to his busy life as the New York City Ballet’s photographer.

So Mr. Kolnik, 65, chose a type of radiation treatment that is raising some eyebrows in the prostate cancer field. It is more intense than standard radiation and takes much less time — five sessions over two weeks instead of 40 sessions over about two months or 28 sessions over five to six weeks.

The newer therapy is surging in popularity, but no one knows whether it is as effective in curing prostate cancer, or how its side effects compare.

The rise of short-course radiation is an example of the evidentiary blind spots that bedevil the treatment of prostate cancer. It is second only to lung cancer in men, striking 180,000 patients a year. But treatments for lung cancer, and for other common cancers like those of the breast and colon, have been evaluated in randomized clinical trials more often than those for prostate cancer.

The number of men getting the short, intense treatment, called stereotactic body radiation therapy, or S.B.R.T., more than doubled to 1,886 in 2013 from 716 in 2007, according to the most recent Medicare data. The number of men getting standard radiation therapy fell over that same time period, according to Medicare, to 47,512 from 66,549.

The National Cancer Institute has just agreed to fund a clinical trial that researchers hope will settle which treatment is better. It will randomly assign 538 men to have either a short course of five intense radiation sessions over two weeks or 28 treatments over five and a half weeks, comparing outcomes for quality of life as well as disease-free survival.

But it will be at least eight years before the answers are in. In the meantime, men and their doctors are left with uncertainty.

“Ideally, we want to show five treatments is better,” said Dr. Rodney J. Ellis, a radiation oncologist at Case Comprehensive Cancer Center in Cleveland and the principal investigator for the trial.

One reason for the dearth of data is that prostate cancer usually grows slowly, if at all, so it can take many years to see if a treatment saved lives. It is expensive and difficult to follow patients for such a long time, and the treatments given to the men often change over a decade, making doctors wonder if the results are relevant.

Also, researchers who have tried to conduct studies comparing treatments often failed because specialists were already convinced that the method they used was best and were reluctant to assign men to other treatments. Dr. Ian Thompson of the University of Texas Health Science Center in San Antonio, said he was involved with several clinical trials that withered for that reason.

When clinical trials succeed, though, they can provide important information. For example, a recent one showed that hormone-blocking drugs can prolong life for men whose prostate cancer recurs after surgery to remove the prostate.

The researchers on the new study think recruitment will not be a major problem because they are comparing different courses of radiation, rather than entirely different approaches — for example, surgical removal of the prostate versus implantation of radioactive seeds in the prostate. A study to investigate those two approaches closed because investigators were able to enroll only 20 patients, Dr. Thompson said.

For men, quality of life is often pivotal in choosing a treatment, weighing which possible side effects sound worse: with surgery, urinary incontinence and impotence; or, with radiation, bowel problems including diarrhea and rectal leakage, and impotence. With the shorter radiation treatment, there is also a possibility that scarring can block the urethra, an effect that might not emerge until years after the treatment.

In the absence of a broad base of solid evidence, men often make decisions based on personal preferences or on the advice of a trusted doctor. Like Mr. Kolnik, some want as short a recuperation as possible and find the newer kind of radiation treatment appealing.

But prostate cancer specialists worry about the lack of data.

Dr. James Yu, a radiation oncologist at Yale, who will lead the quality of life assessment for the new clinical trial, says crucial unanswered questions are, “How fast can you give it and how fast is too fast?”

Very high dose radiation was studied in the treatment of lung cancer, said Dr. Anthony V. D’Amico, a radiation oncologist at Brigham and Women’s Hospital and the Dana Farber Cancer Institute in Boston. For lung cancer patients with small tumors that are not near sensitive structures, like large blood vessels, it appears to be just as curative as surgery.

But lung cancer is easier to treat because, with properly selected patients, doctors can avoid sensitive tissues — all the oncologist has to worry about is hitting the cancer.

Not so with prostate cancer.

“The urethra is within the prostate and the bladder neck is literally touching to top of the prostate,” Dr. D’Amico said. Also, the rectum is directly behind the prostate. Radiation can damage those other tissues, he said.

Injuries to the urethra and bladder neck might not show up until five or 10 years after the treatment, Dr. D’Amico noted. Those structures can scar and close, limiting the flow of urine. It also can take years before rectal scarring produces symptoms like bleeding.

A few years ago, Dr. Yu and his colleagues looked at Medicare data and reported that men who had more intense radiation therapy were more likely to have urinary problems after two years than those who had the longer-course therapy.

Dr. Yu noted that his study was not a randomized trial, the gold standard, but he said the results were not reassuring. Now, though, he is not so sure the intense therapy is worse.

“In my own experience, these men have done really well,” he said. “That tells us that techniques improved, or the medical claims we evaluated were not indicative of major toxicity, or the way we and others at high-volume centers deliver radiotherapy is different.”

The lack of solid data bothers Dr. Daniel W. Lin, chief of urologic oncology at the University of Washington. When men ask him about the shorter radiation course, he tells them, “It probably can work but it doesn’t have long-term results and it hasn’t been tested against standard radiation.”

At centers like Sloan Kettering, doctors are relying on their own experience.

Dr. Michael J. Zelefsky, a radiation oncologist who treated Mr. Kolnik there, said that several years ago, 90 percent of his patients had the standard course of treatment. Now 90 percent choose the shorter course. On the basis of Sloan Kettering’s experience with several hundred men who had the intense radiation therapy over the past three years, the treatment, he said, “is emerging as a very exciting form of therapy.”

Mr. Kolnik is more than satisfied.

During his treatment, he said, “I totally kept up with my schedule.” He did not even tell anyone other than a few close friends that he was having radiation therapy.

“The treatment begins and it finishes before you even realize it,” Mr. Kolnik said.

Source: NYTimes