Active surveillance in low-risk prostate cancer. Patient acceptance and results

Cost-utility analysis of focal high-intensity focussed ultrasound vs active surveillance for low- to intermediate-risk prostate cancer using a Markov multi-state model

OBJECTIVES

To estimate the relative cost-effectiveness of focal high-intensity focussed ultrasound (F-HIFU) compared to active surveillance (AS) in patients with low- to intermediate-risk prostate cancer, in France.

PATIENTS AND METHODS

A Markov multi-state model was elaborated for this purpose. Our analyses were conducted from the French National Health Insurance perspective, with a time horizon of 10 years and a 4% discount rate for cost and effectiveness. A secondary analysis used a 30-year time horizon. Costs are presented in 2016 Euros (€), and effectiveness is expressed as quality-adjusted life years (QALYs). Model parameters' value (probabilities for transitions between health states, and cost and utility of health states) is supported by systematic literature reviews (PubMed) and random effect meta-analyses. The cost of F-HIFU in our model was the temporary tariff attributed by the French Ministry of Health to the overall treatment of prostate cancer by HIFU (€6047). Our model was analysed using Microsoft Excel 2010 (Microsoft Corp., Redmond, WA, USA). Uncertainty about the value of the model parameters was handled through probabilistic analyses.

RESULTS

The five health states of our model were as follows: initial state (AS or F-HIFU), radical prostatectomy, radiation therapy, metastasis, and death. Transition probabilities from the initial F-HIFU state relied on four articles eligible for our meta-analyses. All were non-comparative studies. Utilities relied on a single cohort in San Diego, CA, USA. For a fictive cohort of 1000 individuals followed for 10 years, F-HIFU would be €207 520 more costly and would yield 382 less QALYs than AS, which means that AS is cost-effective when compared to F-HIFU. For a threshold value varying from €0 to 100 000/QALY, the probability of AS being cost-effective compared to F-HIFU varied from 56.5% to 60%. This level of uncertainty was in the same range with a 30-year time horizon.

CONCLUSION

Given existing published data, our results suggest that AS is cost-effective compared to F-HIFU in patients with low- and intermediate-risk prostate cancer, but with high uncertainty. This uncertainty must be scaled down by continuing to supply the model with new published data and ideally through a randomised clinical trial that includes cost-effectiveness analyses.

Active surveillance for prostate cancer

It is worth distinguishing between the two strategies of expectant management for prostate cancer. Watchful waiting entails administering non-curative androgen deprivation therapy to patients on development of symptomatic progression, whereas active surveillance entails delivering curative treatment on signs of disease progression. The objectives of the two management strategies and the patients enrolled in either are different: (i) to review the role of active surveillance as a management strategy for patients with low-risk prostate cancer; and (ii) review the benefits and pitfalls of active surveillance. We carried out a systematic review of active surveillance for prostate cancer in the literature using the National Center for Biotechnology Information's electronic database, PubMed. We carried out a search in English using the terms: active surveillance, prostate cancer, watchful waiting and conservative management. Selected studies were required to have a comprehensive description of the demographic and disease characteristics of the patients at the time of diagnosis, inclusion criteria for surveillance, and a protocol for the patients' follow up. Review articles were included, but not multiple papers from the same datasets. Active surveillance appears to reduce overtreatment in patients with low-risk prostate cancer without compromising cancer-specific survival at 10 years. Therefore, active surveillance is an option for select patients who want to avoid the side-effects inherent to the different types of immediate treatment. However, inclusion criteria for active surveillance and the most appropriate method of monitoring patients on active surveillance have not yet been standardized.

Expectant management for men with early stage prostate cancer

Since the dissemination of prostate-specific antigen screening, most men with prostate cancer are now diagnosed with localized, low-risk prostate cancer that is unlikely to be lethal. Nevertheless, nearly all of these men undergo primary treatment with surgery or radiation, placing them at risk for longstanding side effects, including erectile dysfunction and impaired urinary function. Active surveillance and other observational strategies (ie, expectant management) have produced excellent long-term disease-specific survival and minimal morbidity for men with prostate cancer. Despite this, expectant management remains underused for men with localized prostate cancer. In this review, various approaches to the expectant management of men with prostate cancer are summarized, including watchful waiting and active surveillance strategies. Contemporary cancer-specific and health care quality-of-life outcomes are described for each of these approaches. Finally, contemporary patterns of use, potential disparities in care, and ongoing research and controversies surrounding expectant management of men with localized prostate cancer are discussed.

Systematic Review and Meta-analysis of Factors Determining Change to Radical Treatment in Active Surveillance for Localized Prostate Cancer

CONTEXT

Many men with clinically localized prostate cancer are being monitored as part of active surveillance (AS) programs, but little is known about reasons for receiving radical treatment.

OBJECTIVES

A systematic review of the evidence about AS was undertaken, with a meta-analysis to identify predictors of radical treatment.

EVIDENCE ACQUISITION

A comprehensive search of the Embase, MEDLINE and Web of Knowledge databases to March 2014 was performed. Studies reporting on men with localized prostate cancer followed by AS or monitoring were included. AS was defined where objective eligibility criteria, management strategies, and triggers for clinical review or radical treatment were reported.

EVIDENCE SYNTHESIS

The 26 AS cohorts included 7627 men, with a median follow-up of 3.5 yr (range of medians 1.5-7.5 yr). The cohorts had a wide range of inclusion criteria, monitoring protocols, and triggers for radical treatment. There were eight prostate cancer deaths and five cases of metastases in 24,981 person-years of follow-up. Each year, 8.8% of men (95% confidence interval 6.7-11.0%) received radical treatment, most commonly because of biopsy findings, prostate-specific antigen triggers, or patient choice driven by anxiety. Studies in which most men changed treatment were those including only low-risk Gleason score 6 disease and scheduled rebiopsies.

CONCLUSIONS

The wide variety of AS protocols and lack of robust evidence make firm conclusions difficult. Currently, patients and clinicians have to make judgments about the balance of risks and benefits in AS protocols. The publication of robust evidence from randomized trials and longer-term follow-up of cohorts is urgently required.

PATIENT SUMMARY

We reviewed 26 studies of men on active surveillance for prostate cancer. There was evidence that studies including men with the lowest risk disease and scheduled rebiopsy had higher rates of radical treatment.

Oncological outcomes in patients potentially eligible for active surveillance who underwent radical prostatectomy

OBJECTIVE

To determine whether there are differences in the oncological outcomes after radical prostatectomy (adverse pathology and biochemical recurrence) based on clinical selection criteria used in two active surveillance (AS) protocols.

MATERIAL AND METHODS

442 patients diagnosed with localized prostate cancer (CP) underwent radical prostatectomy at our institution between August 2003 and December 2009. We selected patients with low-risk CP, which could have been included in an AS program. Patients were divided into two groups: group i, those who met the most strict surveillance criteria described by Epstein (PSAD<.15; T1/T2a;<2 positive core, Gleason≤6,<50% involvement of the core) and group ii, those meeting the more open criteria described by Klotz (PSA≤10 or<15 at age 70, Gleason≤6 or<7 [3+4] in over 70 years). We compared both groups to determine differences in pathological stage, positive surgical margins and biochemical recurrence after radical prostatectomy.

RESULTS

Of the 442 patients 48% (213 patients) had low-risk PC, and become potential candidates for an AS program. Of the patients operated on 17% (76 patients) met the criteria for AS as of Epstein's and 48% (213 patients) according to Klotz. Comparing patients in both groups there were no statistically significant differences in the presence of pT3 (7.9% vs 10.8%) P=.55, positive margins (22.4% vs. 28.3%) P=.41, nor in biochemical recurrence at 3 years (5.3% vs 5.6%) P=.86.

CONCLUSIONS

In our series of patients theoretically candidates for inclusion in a program of active surveillance, we found no differences in the percentage of patients with pathological stage pT3, positive margins and biochemical recurrence according to clinical inclusion criteria currently used.