Active surveillance for low-risk prostate cancer compared with immediate treatment: a Canadian cost comparison

Abstract

Background: Clinical consequences of active surveillance compared with immediate treatment have been evaluated in patients with low-risk prostate cancer; yet, its financial benefits have not been adequately studied in Canada or elsewhere. Our study objective was to evaluate the direct costs associated with active surveillance and immediate treatment in the Canadian context.

Methods: We developed a Markov model with Monte Carlo microsimulations to estimate the Canadian cost of prostate cancer associated with immediate treatment and active surveillance strategies. The patients receiving active surveillance were assumed to receive delayed treatment at a rate of 8.35%, 4.17% and 2.1% per year for the first 2 years, years 3 to 5, and years 6 to 10 of follow-up, respectively. All costs were assigned in Canadian dollars and reflect Quebec's health system.

Results: With active surveillance, the mean cost of prostate cancer management over the first year and 5 years of follow-up was estimated at $6200 (95% confidence interval [CI] $6083-$6317) per patient. The mean cost corresponding to immediate treatment was estimated at $13 735 (95% CI $13 615-$13 855) per patient. We estimated that patients receiving active surveillance who received delayed treatment incurred higher costs of $16 257 per patient.

Interpretation: Active surveillance could offer important economic benefits to the Canadian health system, estimated at $96.1 million for each annual cohort of incident prostate cancer. These results add to the economic rationale advocating active surveillance for eligible men with low-risk prostate cancer.

Figure 1:

Markov models with transition to death (red lines) and recurrence requiring additional treatment (blue lines) for (A) immediate treatment and (B) active surveillance. Note: ADT = androgen deprivation therapy, Brachy = brachytherapy, IMRT = intensity-modulated radiotherapy, p_ADT = probability of receiving ADT, p_AS = probability of receiving active surveillance, p_Brachy = probability of receiving brachytherapy, p_IMRT = probability of receiving IMRT, p_IMRT+ADT = probability of receiving IMRT + ADT, p_RP = probability of receiving radical prostatectomy, RP = radical prostatectomy. 
*p_exit = yearly rate of switch to active treatment, 0.0835 (year 1 and 2 of follow-up), 0.0417 (year 3 to 5 of follow-up) and 0.021 (year 6 to 10 of follow-up).11 Note: The following values were used in the Markov models: p_AS = 1, p_RP = 0.26, p_IMRT = 0.34, p_IMRT+ADT = 0.13, p_Brachy = 0.20, p_ADT = 0.074, 1-year probability of death = 0.038; 1-year probability of recurrence requiring additional treatment = 0.139 for active surveillance and 0.0257 for immediate treatment.