Page 137 - An Evidence Review of Active Surveillance in Men With Localized Prostate Cancer

every 12 or 18 months thereafter), duration of active followup during which biopsies were
performed (5 or 10 years after diagnosis) and the rate of “conversion” to active treatment (5
percent or 7 percent annually, obtained from literature sources). The model had a 15 year horizon
and used a 5 percent discount rate. The cost per patient in the AS models ranged from $6558 to
$11,992. Costs were higher with longer periods of active followup, more frequent biopsies and
higher rates of conversion to active treatment. Costs for the AS strategies were 43 percent to 78.7
percent of the per-patient cost of RP. In the RP group 92 percent of all costs occurred in the first
year; in contrast, most costs in AS strategies occurred in later years. Sensitivity analyses
demonstrated that increasing the cost of RP by $5000 affected the cost comparison results: it led
to a 14.2 percent to 20.2 percent increase in the cost of AS versus a 32.8 percent increase in the
cost or RP.
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Another study reported a cost comparison of AS versus open retropubic RP, robotic-
assisted RP, EBRT, and BT. Professional fees were obtained from 2010 Medicare
reimbursement values for the study region (Miami, Florida). For inpatient costs the model used
the mean inpatient costs of patients with clinically localized prostate cancer at the authors’
institution (Miller School of Medicine, Miami, Florida). The AS protocol included transrectal
ultrasound guided biopsies (within a year of diagnosis and annually thereafter), follow-up visits
for PSA testing and digital rectal examination of the prostate (every 3 months for the first 2 years
and every 6 months thereafter). The estimates also incorporated a 25 percent probability of
receiving treatment at 5 years on AS (10 percent were expected to receive EBRT and 15 percent
open retropubic RP). A disease history Markov model was used to determine the cost of
management of complication associated with different treatment strategies. The incidence of the
various complications was obtained from Hayes et al. 240 The model horizon was 10 years and the
reported stated that the model did “not account for inflation.” At year 1, the cumulative cost was
$9732 for retropubic RP, $17,824 for robotic-assisted RP, $20,730 for EBRT, $14,061 for BT,
and $1154 for AS. At year 10, the cumulative cost was $15,084 for retropubic RP, $22,762 for
robotic-assisted RP, $23,953 for EBRT, $17,284 for BT, and $13,116 for AS. The authors noted
that AS is associated with a different cost distribution because its initial cost is lower but the cost
of follow-up is relatively higher, compared to active treatments.
We caution that the cost estimates discussed in this section are model-based; as such, they are
sensitive to the model structure and inputs, including model assumptions about disease natural
history and treatment effectiveness.

Summary
No study reported clinical outcomes specifically for AS management strategies versus
immediate definitive treatment. Therefore, there is insufficient evidence for the comparative
short- and long-term outcomes of AS versus immediate definitive treatment for localized prostate
cancer.
We identified an updated analysis from a multicenter RCT (SPCG-4) and 11 multicenter
cohort studies that reported clinical outcomes comparing observational management strategies
with active treatments including RP and RT. We also identified a cost study based on the above
mentioned SPCG-4 trial and two additional observational studies comparing the costs of
treatments for localized prostate cancer. The majority of evidence for Key Question 4 came from
observational studies. Confounding bias (often referred to as “confounding by indication”) is a
concern for such studies, due to the differences in patient characteristics (that may be associated
with the outcomes of interest) between patients treated with observational strategies and those

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