Active Surveillance Versus Watchful Waiting for Localized Prostate Cancer: A Model to Inform Decisions

Abstract

Background

An increasing proportion of prostate cancer is being managed conservatively. However, there are no randomized trials or consensus regarding the optimal follow-up strategy.

Objective

To compare life expectancy and quality of life between watchful waiting (WW) versus different strategies of active surveillance (AS).

Design, setting, and participants

A Markov model was created for US men starting at age 50, diagnosed with localized prostate cancer who chose conservative management by WW or AS using different testing protocols (prostate-specific antigen every 3–6 mo, biopsy every 1–5 yr, or magnetic resonance imaging based). Transition probabilities and utilities were obtained from the literature.

Outcome measurements and statistical analysis

Primary outcomes were life years and quality-adjusted life years (QALYs). Secondary outcomes include radical treatment, metastasis, and prostate cancer death.

Results and limitations

All AS strategies yielded more life years compared with WW. Lifetime risks of prostate cancer death and metastasis were, respectively, 5.42% and 6.40% with AS versus 8.72% and 10.30% with WW. AS yielded more QALYs than WW except in cohorts age >65 yr at diagnosis, or when treatment-related complications were long term. The preferred follow-up strategy was also sensitive to whether people value short-term over long-term benefits (time preference). Depending on the AS protocol, 30–41% underwent radical treatment within 10 yr. Extending the surveillance biopsy interval from 1 to 5 yr reduced life years slightly, with a 0.26 difference in QALYs.

Conclusions

AS extends life more than WW, particularly for men with higher-risk features, but this is partly offset by the decrement in quality of life since many men eventually receive treatment.

Patient summary

More intensive active surveillance protocols extend life more than watchful waiting, but this is partly offset by decrements in quality of life from subsequent treatment.

Introduction

Prostate cancer (PCa) screening reduces advanced disease and PCa-specific death [1], [2], but also leads to “overdiagnosis” and overtreatment of indolent tumors [3], [4]. Conservative management is increasingly utilized for favorable-risk PCa to delay or avoid aggressive treatment and potential side effects [5]. Prior comparative-effectiveness models have confirmed that this is a valid strategy for certain patients [6], [7], [8], with improved quality of life (QOL) and reduced initial resource utilization [9].

Despite agreement on the importance of conservative management to preserve screening benefits and reduce overtreatment [10], there is no consensus what to do next [11], [12]. Conservative management encompasses two very different strategies: “watchful waiting” (WW) without curative intent and “active surveillance” (AS) with serial testing for “disease progression” to offer selective delayed treatment with curative intent. No randomized trials have compared benefits and harms between WW and contemporary AS. Furthermore, for patients choosing AS, there is no consensus on the type, frequency, or sequence of follow-up tests to monitor for disease progression [11]. Thus, the objective of this clinical decision analysis is to compare life expectancy and quality-adjusted life expectancy between WW and different AS protocols for US men ≥50 yr.