Simulation model of disease incidence driven by diagnostic activity

Diagnostic activity impacts lifetime risk of prostate cancer diagnosis more strongly than life expectancy

The main aim of the study was to determine the impact of diagnostic activity and life expectancy on the lifetime risk of a prostate cancer diagnosis. We used a state transition simulation model based on Swedish population-based data to simulate life trajectories for 2,000,000 men from age 40 to 100 in order to estimate the lifetime risk of a prostate cancer diagnosis. Risk estimates were determined by the level of diagnostic activity and estimated life expectancy. Higher exposure to diagnostic activity resulted in more prostate cancer diagnoses. This was especially true for men diagnosed with low or intermediate grade disease. Men exposed to high diagnostic compared to low diagnostic activity had a five-fold increased lifetime risk (22% vs. 5%) of being diagnosed with a low or intermediate-risk prostate cancer and half the risk of being diagnosed with a high-risk prostate cancer (6% vs. 13%). Men with a long life expectancy had a higher lifetime risk of a prostate cancer diagnosis both overall (21% vs. 15%) and in all risk categories when compared to men with a short life expectancy. The lifetime risk of a prostate cancer diagnosis is strongly influenced by diagnostic activity and to a lesser degree by life expectancy.

Changes in Characteristics of Men with Lethal Prostate Cancer During the Past 25 Years: Description of Population-based Deaths

Background

Attempts to reduce prostate cancer (PC) mortality require an understanding of temporal changes in the characteristics of men with lethal PC.

Objective

To describe the diagnostic characteristics of and time trends for a nationwide population-based cohort of Swedish men who died from PC between 1992 and 2016.

Design, setting, and participants

Men with PC as the underlying cause of death from 1992 to 2016 according to the Swedish Cause of Death Register were included in the study. Characteristics at diagnosis were collected via links to other nationwide registries using personal identity numbers.

Outcome measurements and statistical analysis

Data on disease duration, age at death, and risk category were analyzed. Missing data for risk categories for men with an early date of PC diagnosis were imputed according to the method of chained equations.

Results and limitations

Between 1992 and 2016, age-standardized PC mortality decreased by 25%. Median PC disease duration increased from 3.3 yr (interquartile range [IQR] 1.6–6.3) to 5.9 yr (IQR 2.5–10.3) and the median age at death from PC increased from 78.9 yr (IQR 73.3–84.2) to 82.2 yr (IQR 75.2–87.5). The proportion of men with localized disease at diagnosis who died from PC increased from 34% to 48%, while the rate of distant metastases at diagnosis decreased from 56% to 42%. The rate of distant metastases at diagnosis was highest among the youngest men. Treatment trajectories could not be described owing to the large proportion of missing data before the start of registration in the National Prostate Cancer Registry.

Conclusion

Age-standardized PC mortality has decreased substantially since 1992. However, there is still a high proportion of men who die from PC who had localized disease at diagnosis, which indicates that more attention is needed to identify the underlying causes to prevent disease progression. Since the proportion of men with distant metastases at diagnosis remains high, early detection of lethal tumors is essential to further reduce PC mortality.

Patient summary

We investigated the characteristics of men who died from prostate cancer in Sweden between 1992 and 2016. We found that men with lethal prostate cancer live longer and are older when they die today in comparison to men who died at the beginning of the study period. However, the proportion of men with distant metastases at diagnosis remains high, which is why early detection of lethal tumors is essential to reduce mortality.

Variation in Prostate-Specific Antigen Testing Rates and Prostate Cancer Treatments and Outcomes in a National 20-Year Cohort

IMPORTANCE

The diagnostic activity for prostate cancer has increased during the past decades. However, the benefit and harm of the increased diagnostic activity have not been quantified in detail for a country or a large region.

OBJECTIVE

The aim of this study was to evaluate and quantify the association between increases in diagnostic activity driven by prostate-specific antigen testing and incidence of prostate cancer diagnosis, treatment, and mortality.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used the Proxy-Based Risk-Stratified Incidence Simulation Model-Prostate Cancer to examine observed data on all Swedish men with prevalent prostate cancer and compare them with a corresponding, hypothetical, simulated scenario with more restrictive diagnostic activity. All men aged 40 to 100 years living in Sweden during the time period 1996 to 2016 with incident and prevalent prostate cancer were included. The second scenario is the corresponding, hypothetical, simulated scenario where diagnostic activity remained constant as of 1996 (the beginning of the prostate-specific antigen testing era) throughout the study period.

EXPOSURES

High or low diagnostic activity for prostate cancer.

MAIN OUTCOMES AND MEASURES

Incidence of prostate cancer diagnosis, treatment (deferred treatment, curative treatment, and hormonal treatment), and prostate cancer mortality.

RESULTS

During the study period from 1996 to 2016, 188 884 men were diagnosed with prostate cancer at a median (interquartile range) age of 71 (64-77) years. Compared with the low-diagnostic activity scenario, in the high-diagnostic activity scenario, the number of men diagnosed with prostate cancer was 48% higher (423 vs 286 [95% CI, 271-302] per 100 000 men per year), 148% more men were diagnosed with low- or intermediate-risk cancer (221 vs 89 [95% CI, 73-105] per 100 000 men per year), and 108% more men received curative treatment (152 vs 73 [95% CI: 66-85] per 100 000 men per year). There were up to 15% fewer prostate cancer deaths in the scenario with high-diagnostic activity (incidence rate ratio, 0.85; 95% CI, 0.82-0.88).

CONCLUSIONS AND RELEVANCE

This study's results suggest that increased prostate-specific antigen testing and diagnostic activity are associated with a larger number of men being diagnosed with prostate cancer, predominately with low- and intermediate-risk disease. The increased diagnostic activity was associated with a 2-fold increase in curative treatment and a modest decrease in mortality.

Simulation model of disease incidence driven by diagnostic activity

It is imperative to understand the effects of early detection and treatment of chronic diseases, such as prostate cancer, regarding incidence, overtreatment and mortality. Previous simulation models have emulated clinical trials, and relied on extensive assumptions on the natural history of the disease. In addition, model parameters were typically calibrated to a variety of data sources. We propose a model designed to emulate real‐life scenarios of chronic disease using a proxy for the diagnostic activity without explicitly modeling the natural history of the disease and properties of clinical tests. Our model was applied to Swedish nation‐wide population‐based prostate cancer data, and demonstrated good performance in terms of reconstructing observed incidence and mortality. The model was used to predict the number of prostate cancer diagnoses with a high or limited diagnostic activity between 2017 and 2060. In the long term, high diagnostic activity resulted in a substantial increase in the number of men diagnosed with lower risk disease, fewer men with metastatic disease, and decreased prostate cancer mortality. The model can be used for prediction of outcome, to guide decision‐making, and to evaluate diagnostic activity in real‐life settings with respect to overdiagnosis and prostate cancer mortality.