Risk of Metastasis With Active Monitoring in PSA-Detected Localized Prostate Cancer: The ProtectT Trial


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It would be prudent to advise a man who is otherwise in good health, has a life expectancy beyond the 10-year median follow-up of the ProtecT study, and wishes to avoid metastatic prostate cancer and its treatment-related side effects that monitoring places him at potentially increased risk for metastatic disease.
— Anthony V. D’Amico, MD, PhD

The ProtecT study findings1 are provocative. Despite having a control arm of active monitoring with serial prostate-specific antigen (PSA) testing, as compared with watchful waiting in the prior randomized trials (ie, SPCG-42 and PIVOT3), and also enrolling men with more favorable-risk disease (ie, T1c disease in 76% vs 12%–50%, median PSA of 4.6 ng/mL vs 7. 8–13 ng/mL, and Gleason score of ≤ 6 in 77% vs 52%–60%), a more than twofold reduction in metastasis (to 2.4 and 3.0 from 6.3 per 1,000 person-years; P = .004) was observed in men randomized to surgery or radiation therapy as compared with monitoring. This risk reduction is similar to that observed in both the SPCG-42 and PIVOT3 studies.

One would have expected with the use of monitoring vs watchful waiting and the more favorable disease characteristics that the risk reduction in metastasis would have been reduced compared with what was observed in SPCG-42 and PIVOT.3 Whether the use of 12 and not 10 cores (as performed in ProtecT) during transrectal ultrasound–guided prostate biopsy, annual repeat prostate biopsy while on surveillance, and multiparametric magnetic resonance imaging (MRI) enabling transrectal ultrasound–MRI fusion-targeted biopsy techniques will reduce the risk of placing a man or continuing him on surveillance who is at risk for developing metastatic disease remains unknown and deserves study.

Until that information becomes available, it would be prudent to advise a man who is otherwise in good health, has a life expectancy beyond the 10-year median follow-up of the ProtecT study,1 and wishes to avoid metastatic prostate cancer and its treatment-related side effects4 that monitoring places him at potentially increased risk for metastatic disease. ■

Disclosure: Dr. D’Amico reported no potential conflicts of interest.

References

1. Hamdy FC, Donovan JL, Lane JA, et al: 10-year outcomes after monitoring, surgery, or radiotherapy for localized prostate cancer. N Engl J Med. September 14, 2016 (early release online).

2. Bill-Axelson A, Holmberg L, Garmo H, et al: Radical prostatectomy or watchful waiting in early prostate cancer. N Engl J Med 370:932-942, 2014.

3. Wilt TJ, Brawer MK, Jones KM, et al: Radical prostatectomy versus observation for localized prostate cancer. N Engl J Med 367:203-213, 2012.

4. Sharifi N, Gulley JL, Dahut WL: Androgen deprivation therapy for prostate cancer. JAMA 294:238-244, 2005.


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