The Lynx Group

Death Rates Unaffected by Treatment Choice for Patients with Localized Prostate Cancer

October 2016, Vol 7, No 9

Men with localized prostate cancer have similar rates of prostate cancer−specific death 10 years after diagnosis, regardless of whether they receive radiotherapy, surgery, or active monitoring (ie, watchful waiting), according to the first clinical trial directly comparing contemporary treatments of radiation, surgery, and active monitoring in patients with prostate cancer.

The ProtecT trial was conducted by chief investigator Freddie C. Hamdy, MD, Professor of Surgery, Nuffield Department of Surgical Sciences, University of Oxford, United Kingdom, and colleagues (Hamdy FC, et al. N Engl J Med. 2016 Sep 14. Epub ahead of print).

Over a 10-year period, approximately 1% of patients across all 3 interventions died from prostate cancer, and approximately 10% died from any cause. Choice of treatment was found to make a difference in the rate of metastasis and disease progression. Patients randomized to active monitoring experienced a higher rate of metastases and disease progression compared with patients who underwent radiotherapy or surgery.

“These differences show the effectiveness of immediate radical therapy over active monitoring, but they have not translated into significant differences—nor have they ruled out equivalence—in disease-specific or all-cause mortality; thus longer-term follow-up is necessary,” said Dr Hamdy and colleagues.

In an accompanying editorial, Anthony V. D’Amico, MD, PhD, Chief, Division of Genitourinary Radiation Oncology, Brigham and Women’s Hospital and Dana-Farber Cancer Institute, Boston, MA, commented on the results of the ProtecT trial.

“Given no significant difference in death due to prostate cancer with surgery versus radiation and short-course androgen-deprivation therapy, men with low-risk or intermediate-risk prostate cancer should feel free to select a treatment approach using the data on health-related quality of life and without fear of possibly selecting a less effective cancer therapy,” Dr D’Amico said.

Dr D’Amico also noted that the incidence of metastatic disease was more than twice as high in the active-monitoring group compared with the other 2 treatment cohorts, stating, “If a man wishes to avoid metastatic prostate cancer and the side effects of its treatment, [active] monitoring should be considered only if he has life-shortening coexisting disease such that his life expectancy is less than the 10-year median follow-up of the current study.”

In addition, he pointed out that a trend toward improved prostate cancer−specific survival was observed favoring radiation and androgen-deprivation therapy (ADT). If that trend were to become significant with longer follow-up, then radiation plus ADT could be considered a preferred option for otherwise healthy men aged ≥65 years with early-stage prostate cancer.

Study Details

The ProtecT trial included 1643 men diagnosed with prostate-specific antigen (PSA)-detected localized prostate cancer: 545 were randomized to active monitoring, 553 to surgery (ie, radical prostatectomy), and 545 to radiotherapy. In the surgery group, adjuvant or salvage radiation therapy was offered to patients with positive surgical margins, extracapsular disease, or a postoperative PSA level of ≥0.2 ng/mL. The patients in all 3 groups were offered ADT when their PSA levels reached ≤20 ng/mL. The median age at baseline was 62 years; the median PSA level was 4.6 ng/mL; and although 77% of the patients had tumors with a Gleason score of 6, 76% had stage T1c at baseline.

Over the course of the study, 17 prostate cancer−specific deaths were reported, with 8 in the active-monitoring cohort, 5 in the surgery group, and 4 in the radiotherapy group. The mortality rates were 1.5 deaths per 1000 person-years, 0.9 per 1000 person-years, and 0.7 per 1000 person-years, respectively, and the differences were not significant.

The number of deaths from any cause was 169, with no significant difference observed between the 3 groups. The rates of metastases were 6.3 events per 1000 person-years in the active-monitoring group, 2.4 events per 1000 person-years in the surgery group, and 3.0 events per 1000 person-years in the radiotherapy group.

The rate of disease progression was highest in the active-monitoring group as well, with 22.9 events per 1000 person-years versus 8.9 events per 1000 person-years in the surgery group, and 9.0 events per 1000 person-years in the radiotherapy group.

“Men with newly diagnosed, localized prostate cancer need to consider the critical trade-off between the short-term and long-term effects of radical treatments on urinary, bowel, and sexual function and the higher risks of disease progression with active monitoring, as well as the effects of each of these options on quality of life,” Dr Hamdy and colleagues concluded.

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