Long-term, surgery for localized prostate cancer offers little extra benefit

By Gene Emery

(Reuters Health) - A large new study that has followed prostate cancer patients for up to two decades concludes that surgery is probably not the best option for most men with localized tumors.

Men who had the surgery were only slightly more likely to live longer, but they were definitely more likely to be forced to live with the side effects of surgery such as urinary incontinence and erectile or sexual dysfunction.

For every 100 men diagnosed with early-stage prostate cancer who underwent surgery, only four fewer died from the disease compared with those who were just kept under observation and treated for symptoms.

For every 100 men with low-risk disease who had a radical prostatectomy, no more than one was saved by surgery, a statistically insignificant difference, the researchers report in the New England Journal of Medicine.

Yet 30 to 40 men out of 100 who had surgery experienced erectile dysfunction within five years, 30 developed problems holding their urine within 10 years and 20 to 40 reported dissatisfaction with their ability to perform sexually.

The study, known as PIVOT, was designed to shed light on the ongoing controversy over how best to treat prostate cancer, a tumor that is diagnosed in 161,000 men in the U.S. each year but often fails to kill them because the cancer grows so slowly they are more likely to die from some other cause. Thus, many doctors simply recommend some form of watchful waiting.

The cancer kills about 27,000 annually, according to the American Cancer Society.

Because men today are being diagnosed earlier, with smaller tumors than they were 20 years ago, any benefits of surgery are probably even smaller than the study suggests, lead author Dr. Timothy Wilt said in written comments to Reuters Health.

By the same token, "Men currently diagnosed with prostate cancer will have even better long-term overall and prostate cancer survival with observation than men enrolled in PIVOT," Wilt said.

The findings "reassure men with low-risk disease who have a life expectancy greater than 10 years that active surveillance is safe and offers better overall quality of life compared to radical treatment," said Dr. Behfar Ehdaie of the Memorial Sloan-Kettering Cancer Center in New York, who was not part of the study.

Some men with an intermediate risk may also be able to avoid surgery as well, he told Reuters Health in an email.

But Dr. Alexander Kutikov, chief of urologic oncology at the Fox Chase Cancer Center in Philadelphia, who also was not connected with the research, said the "quite controversial" study of 731 men, most treated at Veterans Affairs hospitals, was too small to be definitive and 20 percent of the men didn't stick with their assigned treatment, muddying the results.

The study also falls short because the men were selected because they were thought to have a life expectancy of 10 years, Kutikov added. Yet at the 10-year mark nearly half had died. "Prostate cancer treatment is an investment at least 10 years into the future," he said by email. "Men with limited life-expectancy only risk side effects of treatment and don't live long enough to reap its benefits."

"A potential harm of observation is that prostate cancer may spread if left untreated and could result in prostate cancer death," Wilt acknowledged. "Fortunately for most men, this is very unlikely (about 10 percent of men after 20 years) and was not different in men treated with observation or surgery. Systemic progression and prostate cancer death are rare (about 5 percent) in men with low risk disease and are not decreased by surgery."

Only men at intermediate risk showed a benefit from surgery; where survival was 14.5 percentage points higher. That translated to a 20 percent reduction in death from all causes.

With 731 men followed for a median of 12.7 years, PIVOT is one of the longest and largest cancer studies ever conducted.

In the surgery group, 61.4 percent of the men died from all causes and just 7.4 percent in the surgery group died from prostate cancer. In the observation group, 66.8 percent died, 11.4 percent from prostate cancer.

SOURCE: http://bit.ly/2u0BIwI New England Journal of Medicine, online July 12, 2017.