Long-term study shows most prostate cancer patients don’t need aggressive treatment

Nearly 30 years after it began, a study of prostate cancer patients shows both that the disease will not cause harm to the majority of men who have it, and that aggressive treatment is warranted for men with an intermediate risk of spread.

The nuanced results come from a new update to a landmark study, published Wednesday in the New England Journal of Medicine, that has followed 695 Swedish men since they were diagnosed with localized prostate cancer between October 1989 and February 1999.

The study’s duration and insights into one of the most common forms of cancer make it “arguably one of the most important publications of the year,” said Dr. Adam Kibel, a professor of surgery at Harvard Medical School and chief of urology at Brigham and Women’s Hospital in Boston, who is not involved in the research.

Half of the men had their prostates removed to get rid of the cancer, and half were put on “watchful waiting,” a now-discredited approach that essentially amounted to doing nothing.

Today, roughly 20 percent of the men are still alive, although prostate cancer is generally diagnosed late in life. Of those who died, 70 percent died of something other than prostate cancer, the study found.

“Which really reminds us that we should try to treat only those who will benefit, who have a lethal disease and who are healthy enough to otherwise be able to die from prostate cancer,” said Dr. Anna Bill-Axelson, the study’s first author and an associate professor in urology at Uppsala University in Sweden.

Overtreatment is an issue because radical prostatectomy and similar therapies often cause side effects, Bill-Axelson said, most commonly erectile dysfunction and urinary leakage.

In Sweden today, 80 percent of men with newly diagnosed prostate cancer are not treated, but “actively surveilled,” to make sure their tumor is not becoming more dangerous, Bill-Axelson said. Active surveillance includes regular checkups, whereas with “watchful waiting,” follow-ups were often deferred until a man had symptoms.  “The majority who are diagnosed today are diagnosed so early from PSA detection and also have usually low-risk disease. They will very likely be overtreated if they are treated immediately.”

Two American experts saw the study’s results differently: as further justification to treat intermediate prostate cancers as aggressively as possible.

The study’s take-home message is: “If you live a long time, you’re likely to live longer if you get treated than if you don’t,” according to Dr. Anthony D’Amico, chief of genitourinary radiation oncology at the Dana-Farber Cancer Institute and a professor at Harvard Medical School, both in Boston.

Men with a result of 7 on a test called the Gleason score, who are today considered at intermediate risk, should be treated, and should not wait to see if their tumors become more dangerous, D’Amico said.

“This study proves that if a man’s going to live 20-25 years and he’s got intermediate prostate cancer, he has an opportunity to save his life,” D’Amico said.

According to the study, those men who had a radical prostatectomy at the start of the study lived an average of 2.9 years longer than men who got no therapy. But that really means more men in the treatment group were able to live out their natural lives, while men who got watchful waiting died early, D’Amico said.

D’Amico also highlighted what he called “a pretty striking statistic”: that just eight men needed to undergo treatment to save one life, according to the study. For comparison, 233 women in their 60s would need to get a mammogram to prevent one of those woman from dying of breast cancer, according to a 2012 study.

Kibel, the Brigham and Women’s urologist, said the Swedish study has been “central to our understanding of how we manage prostate cancer,” for decades, and confirms that many patients benefit from aggressive treatment.

The Swedish study was started so long ago that men didn’t routinely get PSA tests to diagnose prostate cancer, as they often do today. Routine PSA screening can overdiagnose cancers that won’t turn lethal. But combined with their Gleason score — and maybe someday with a diagnostic MRI — men should be able to figure out whether their cancer is advanced enough to warrant treatment, or to monitor it to make sure it isn’t turning more aggressive, Bill-Axelson said.

A man’s health and his disease risk — not his age — should be the determining factors in whether he should be treated for prostate cancer, Bill-Axelson said. When asked whether an 80-year-old should be treated, she said, only half-joking: “If he comes with his parents, it’s a good idea.”