Long-term Outcomes Among Men Undergoing Active Surveillance for Prostate Cancer in Sweden

Abstract

Importance: The long-term outcomes among men with prostate cancer (PC) whose disease is managed with active surveillance (AS) remains unknown.

Objective: To develop a simulation model with a 30-year follow-up for men with PC managed with AS.

Design, setting, and participants: In this cohort study, a state transition model was created using data from Prostate Cancer data Base Sweden (PCBaSe) on 23 655 men diagnosed with PC and managed with deferred treatment to estimate treatment trajectories. A simulation was performed with 100 000 men in each combination of age at diagnosis, Charlson Comorbidity Index, and PC risk with a follow-up of 30 years.

Main outcomes and measures: Death from PC and death from other causes were estimated, and the proportion of time without active PC treatment was assessed until date of death or age 85 years.

Results: This study included 23 655 men from PCBaSe with a median age at diagnosis of 69 years (IQR, 64-74 years). Of these, 16 177 men underwent active surveillance for PC and 7478 underwent watchful waiting. The proportion of men who were diagnosed at age 55 years and died of PC before age 85 years was 9% for very low-risk PC, 13% for low-risk PC, and 15% for intermediate-risk PC. Among men with a Charlson Comorbidity Index of 0 who were diagnosed at age 70 years, the corresponding percentages were 3%, 6%, and 7%, respectively. The mean proportion of remaining life-years without active PC treatment for men diagnosed at age 55 years was 12 of 25 years (48%) for very low-risk PC, 9 of 25 years (36%) for low-risk PC, and 7 of 25 (29%) for intermediate-risk PC. For men aged 70 years, the corresponding numbers were 10 of 13 years (77%), 9 of 13 years (66%), and 8 of 13 years (60%), respectively. Men with intermediate-risk PC who were younger than 60 years at diagnosis had a high risk of PC death (12%-15%) and fewer remaining life-years without active PC treatment (29%-33%). In contrast, men with low-risk PC who were older than 65 years at diagnosis had a lower risk of PC death (3%-5%) and more remaining life-years without active PC treatment (62%-77%).

Conclusions and relevance: The findings of this Swedish cohort study suggest that active surveillance may be a safe strategy for disease management among men with PC who were older than 65 years at diagnosis.

Figure 1.. State Transition Model of Transitions Between States Among Men Diagnosed With Prostate Cancer (PC) Managed With Active Surveillance (AS)

The states (circles) included were AS, watchful waiting (WW), radical prostatectomy (RP) or radiotherapy (RT), adjuvant or salvage radiotherapy following RP (A/S-RT), androgen deprivation therapy (ADT), PC death, and death from other causes. Arrows indicate transitions. Multicolored circles represent transient states; the size of each colored area represents the proportion of each disease risk category at date of transition. Orange circles represent absorbing states with no further transition possible. Dashed circles represent updated information that affected transition probabilities (eg, biopsy results, Charlson Comorbidity Index [CCI]). The detailed risk categories are provided in eTable 1 in the Supplement.

Figure 2.. Prevalence of Each State by Prostate Cancer (PC) Risk Category at Each Time Point

A, Very low-risk PC. B, Low-risk PC. C, Intermediate-risk PC. Curative treatment (CT) includes radical prostatectomy and radiotherapy. Upper graphs include men who made a transition to CT; lower graphs include men who made a transition to watchful waiting (WW).

Figure 3.. Estimates of Remaining Life-Years Without Active Prostate Cancer (PC) Treatment

Based on the results shown in Figure 2, we estimated proportions for each risk category by age group using the ratio between the proportion of the area under the curve for active surveillance (AS) and watchful waiting (WW) and the total remaining life-years. The denominator of these proportions was calculated as life-years resulting from the sum of all areas under the curve in Figure 2 excluding death from PC and death from other causes. ADT indicates androgen deprivation therapy; RP, radical prostatectomy; RT, radiotherapy.

Figure 4.. Association Between Proportion of Life-Years Without Active Treatment and Risk of Prostate Cancer (PC) Death