Active monitoring of patients with localized prostate cancer is as effective as surgery and radiotherapy in terms of 10-year survival after diagnosis, according to findings from the largest prostate cancer study in the U.K. But treatment, in the form of surgery or radiotherapy, was also seen to reduce the risk of cancer progression and spread.
The findings may affect future policy decisions on screenings for prostate cancer, and offer men with the prostate cancer and their doctors better guidelines for managing the disease.
The study gave rise to two publications: “10-Year Outcomes after Monitoring, Surgery, or Radiotherapy for Localized Prostate Cancer,” and “Patient-Reported Outcomes after Monitoring, Surgery, or Radiotherapy for Prostate Cancer,” both published in the New England Journal of Medicine.
“What we have learnt from this study so far is that prostate cancer detected by prostate specific antigen blood test grows very slowly, and very few men die of it when followed up over a period of 10 years — around 1% — irrespective of the treatment assigned,” Freddie Hamdy, a professor at the University of Oxford and chief investigator of the study, said in a news release. “This is considerably lower than anticipated when we started the study.”
The ProtecT trial (NCT02044172), running for 10 years between 1999 and 2009, followed 1,643 men (ages 50–69) who were diagnosed with localized prostate cancer. The men were randomized to three groups: 545 who received radical radiotherapy, 553 who had radical prostatectomy (surgery), and 545 who underwent active monitoring.
At 10 years, 99 percent of men in all three groups were still alive, irrespective of the treatment assigned, suggesting that aggressive treatment is no better than active monitoring in terms of prolonged patient survival.
The treatment did, however, impact the rate of cancer progression and spread, with aggressive treatment showing reduced number of cases where the cancer spread to other parts of the body. One in 5 of the monitored men saw their cancer spread, while the number for men who received surgery or radiotherapy was 1 in 10.
Despite this, researchers are currently unable to say whether treatment will prolong survival in a particular group, and how it affects the quality of life of these men.
Another shortcoming of the findings is that researchers do not have any way of telling who will develop a lethal cancer, and who will do fine despite the disease.
In the study, researchers found that treatment was linked with increased rates of side-effects that, at times, persisted for a long period. Men who had surgery mainly reported sexual problems and urinary incontinence — problems worst during the first year after surgery but which continued to be reported by this group twice as often as those in other groups after six years.
Radiotherapy gave rise mainly to stomach problems. In contrast, researchers found no differences in overall quality of life between the groups, including the presence of anxiety and depression.
“Longer follow-up is now required to determine the ‘trade-off’ that patients need to make between cancer outcomes and quality of life, and further research to understand how we can distinguish lethal from non-lethal disease,” said Hamdy.
Researchers admit that a serious limitation is that the study was designed before the appearance of better treatments that give rise to fewer side effects. Nevertheless, the findings are likely to impact the treatment choices of men with prostate cancer.
“This is the first time radiotherapy, surgery and active monitoring treatments for prostate cancer have been compared directly,” said co-investigator Professor Jenny Donovan, from the University of Bristol.
“Interestingly, we saw that disease spread was reduced by half in men who were assigned to radical treatment, but no difference in survival outcomes with either surgery or radiotherapy, and no progression of the disease in three quarters of the men in the active monitoring treatment group, over the 10 years,” said David Neal, a co-author from Oxford.
“We need to continue to study these men to find out whether prevention of cancer progression by surgery or radiotherapy leads to better cancer control and survival in the longer term,” he added.