Colonoscopy findings after increasing two-stool faecal immunochemical test (FIT) cut-off: Cross-sectional analysis of the SCREESCO randomized trial.

BACKGROUND: We determined the impact of an increased two-stool faecal immunochemical test (FIT) cut-off on colonoscopy positivity and relative sensitivity and specificity in the randomized controlled screening trial screening of Swedish colons conducted in Sweden. METHODS: We performed a cross-sectional analysis of participants in the FIT arm that performed FIT between March 2014 and 2020 within the study registered with ClinicalTrials.gov, NCT02078804, who had a faecal haemoglobin concentration of at least 10 µg/g in at least one of two stool samples and who underwent a colonoscopy (n = 3841). For each increase in cut-off, we computed the positive predictive value (PPV), numbers needed to scope (NNS), sensitivity and specificity for finding colorectal cancer (CRC) and advanced neoplasia (AN; advanced adenoma or CRC) relative to cut-off 10 µg/g. RESULTS: The PPV for AN increased from 23.0% (95% confidence intervals [CI]: 22.3%-23.6%) at cut-off 10 µg/g to 28.8% (95% CI: 27.8%-29.7%) and 33.1% (95% CI: 31.9%-34.4%) at cut-offs 20 and 40 µg/g, respectively, whereas the NNS to find a CRC correspondingly decreased from 41 to 27 and 19. The PPV for AN was higher in men than women at each cut-off, for example 31.5% (95% CI: 30.1%-32.8%) in men and 25.6% (95% CI: 24.3%-27.0%) in women at 20 µg/g. The relative sensitivity and relative specificity were similar in men and women at each cut-off. CONCLUSION: A low cut-off of around 20-40 µg/g allows detection and removal of many AN compared to 10 µg/g while reducing the number of colonoscopies in both men and women.

The role of endoscopist adenoma detection rate in in sex differences in colonoscopy findings: cross-sectional analysis of the SCREESCO randomized controlled trial.

BACKGROUND: Fewer adenomas are detected at colonoscopy in women compared to men and failure to detect adenomas and sessile serrated polyps is associated with an increased risk of post-colonoscopy colorectal cancer. The aim of this study was to investigate whether this was in part due to the greater difficulty of conducting colonoscopy in women, with the difference being more apparent in colonoscopies conducted by less skilled endoscopists. MATERIAL AND METHODS: Cross-sectional exploratory analysis of data on 16,551 individuals undergoing a primary colonoscopy (PCOL group) or colonoscopy after positive faecal immunochemical test (FIT group) within the randomized controlled trial SCREESCO. Endoscopist adenoma detection rate (ADR; low or high) was determined based on each endoscopist's colonoscopies performed in SCREESCO. In each study group, the relationship between the sex difference in colonoscopy outcome and endoscopist ADR was assessed using multiplicative interaction tests. RESULTS: Endoscopists performed equally many colonoscopies in men and women (median 52% men). There were no signs of effect modification of the risk ratio of any finding (men vs women) by endoscopist ADR in the PCOL group (p = 0.33) or the FIT group (p = 0.30). The proportion of incomplete index colonoscopies was lower in men than in women in both groups and there was no effect modification by endoscopist ADR in either the PCOL group (p = 0.41) or the FIT group (p = 0.96). CONCLUSIONS: This study provides no evidence that endoscopist skill measured by ADR underlies the sex difference in adenoma detection at colonoscopy. This study has trial number NCT02078804 and is registered with ClinicalTrials.gov.

Detection rates of colorectal neoplasia during colonoscopies and their associated factors in the SCREESCO study.

BACKGROUND AND AIM: Colonoscopy quality, including lesion detectability, is variable, and factors influencing lesion detection are not fully understood. This study investigated lesion detection rates during colonoscopies and the associated factors in the SCREEning of Swedish COlons (SCREESCO) study. METHODS: In this cross-sectional analysis of data from SCREESCO, a large-scale randomized controlled trial of colorectal cancer screening in the Swedish population aged 60 years, we assessed data of first-time colonoscopies performed in both colonoscopy and fecal immunochemical test (FIT) arms. RESULTS: This study included 16 552 individuals. The adenoma detection rate was 23.9% and 37.8% in colonoscopy and FIT arms, respectively. Regarding colonoscopy procedures, a withdrawal time ≥ 6 min was associated with higher detection rates of advanced adenomas (adjusted odds ratio [AOR] 2.474, 95% confidence interval [CI] 1.295-4.723), adenomas (2.181, 1.515-3.140), and proximal serrated lesions (pSLs) (1.713, 1.007-2.915). Antispasmodic use was associated with higher detection rates of these lesions and sessile serrated lesions (SSLs) (AOR, 95% CI: 1.523, 1.295-1.791; 1.361, 1.217-1.522; 1.450, 1.247-1.687; and 1.810, 1.512-2.167, respectively). Insertion time > 20 min was related to lower detection rates of adenomas, pSLs, and SSLs (AOR, 95% CI: 0.753, 0.639-0.887; 0.640, 0.495-0.828; and 0.704, 0.518-0.955, respectively). The relationship between a recent period and higher detection rates of pSLs and SSLs was also demonstrated. CONCLUSION: Lesion detectability in SCREESCO was mostly acceptable with room for improvement. In addition to sufficient withdrawal time, antispasmodic use and acquiring skills enabling short insertion time may improve lesion detection. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT02078804.

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.

Changes in treatment and mortality in men with locally advanced prostate cancer between 2000 and 2016: a nationwide, population-based study in Sweden.

OBJECTIVE: To evaluate whether the effects of radical treatment in men with locally advanced prostate cancer (PCa) on PCa mortality observed in randomised clinical trials are applicable on a population basis. PATIENTS AND METHODS: We conducted a population-based cohort study using the Prostate Cancer data Base Sweden of 20 350 men diagnosed between 2000 and 2016 with locally advanced PCa, defined as clinical local stage T3/T4, M0, Mx and a prostate-specific antigen level of <100 ng/mL. Cumulative PCa mortality was examined using competing risk analysis of all men with locally advanced PCa, and also including men who did not undergo radical treatment. Multivariate regression analysis, including prognostic factors, was used to calculate hazard ratios (HRs) for all-cause and PCa-specific death. RESULTS: The proportion of men treated with primary radical radiotherapy (n = 4174) or prostatectomy (n = 1210) increased from 15% in 2000-2003, 25% in 2004-2007, 33% in 2008-2011 to 43% in 2012-2016. The corresponding 5-year PCa mortality decreased from 19%, 18%, 17%, to 15% for all men, with the steepest decrease in men aged 65-74 years, from 16% to 8%. The risk of PCa mortality in men aged <80 years was lower in the last period compared to the first period, with a HR of 0.65 (95% confidence interval 0.56-0.76) in multivariate analysis. CONCLUSIONS: The threefold increase in use of radical treatment was accompanied by a modest decrease in PCa mortality in all men with newly diagnosed locally advanced PCa. For men aged 65-74 years, there was a 50% decrease in the relative risk of PCa death. This indicates that the benefits previously observed in randomised trials can also be achieved in a real-life setting.

Temporal changes in survival in men with de novo metastatic prostate cancer: nationwide population-based study.

Background: There have been large changes in the pattern of detection, work-up and treatment of men with prostate cancer during the last two decades. Therefore, we aimed to investigate temporal changes in survival in men with metastatic prostate cancer.Methods: Population-based cohort study in Prostate Cancer data Base Sweden of 13,709 men with de novo metastatic prostate cancer diagnosed between 1998 and 2015. Overall survival in four calendar periods were compared by the use of Kaplan-Meier analyses and Cox regression models including age at diagnosis, T stage and serum levels of prostate-specific antigen (PSA).Results: Between 1998-2001 and 2010-2015, median survival increased with 6 months for all men. The largest increase in survival was 14 months in men age 60-69 at diagnosis and in multivariable analysis risk of death decreased for men diagnosed in 2010-2015 compared to 1998-2001, hazard ratio (HR) 0.77 (95% CI: 0.68-0.86). The median PSA at date of diagnosis decreased with 46% from 181 ng/mL in 1998 to 98 ng/mL in 2015.Conclusions: There was an increase in survival among men with de novo metastatic prostate cancer in Sweden between 1998 and 2015. This increase was due to a decreased cancer extent indicated by lower PSA levels with ensuing longer lead times and speculatively also due to an increased use of chemotherapy in the latest time period. Given the increasing use of systemic treatment for advanced prostate cancer, our results are likely heralding larger increases in survival in men with metastatic prostate cancer in the near future.

Proportion and characteristics of men with unknown risk category in the National Prostate Cancer Register of Sweden.

BACKGROUND: Knowledge on missing data in a clinical cancer register is important to assess the validity of research results. For analysis of prostate cancer (Pca), risk category, a composite variable based on serum levels of prostate specific antigen (PSA), stage, and Gleason score, is crucial for treatment decisions and a strong determinant of outcome. The aim of this study was to assess the proportion and characteristics of men in the National Prostate Cancer Register (NPCR) of Sweden with unknown risk category. MATERIAL AND METHODS: Men diagnosed with Pca between 1998 and 2012 registered in NPCR with known or unknown risk category were compared with respect to age, socioeconomic factors, comorbidity, cancer characteristics, cancer treatment, and mortality from Pca and other causes. RESULTS: In total, 3315 of 129 391 (3%) men had unknown risk category. Compared to other men in NPCR, these men more often had a concomitant bladder cancer diagnosis, 19% versus 1%, diagnosis of benign prostatic hyperplasia 31% versus 5%, received unspecified Pca treatment 16% versus 3%, had higher comorbidity, Charlson Comorbidity Index 2 or higher, 34% versus 13%, and had lower Pca mortality 12% versus 30%, but similar mortality from other causes. CONCLUSION: Men with unknown risk category were rare in NPCR but distinctly different from other men in NPCR in many aspects including higher comorbidity and lower Pca mortality.

Target trial emulation using new comorbidity indices provided risk estimates comparable to a randomized trial.

OBJECTIVES: To quantify the ability of two new comorbidity indices to adjust for confounding, by benchmarking a target trial emulation against the randomized controlled trial (RCT) result. STUDY DESIGN AND SETTING: Observational study including 18,316 men from Prostate Cancer data Base Sweden 5.0, diagnosed with prostate cancer between 2008 and 2019 and treated with primary radical prostatectomy (RP, n = 14,379) or radiotherapy (RT, n = 3,937). The effect on adjusted risk of death from any cause after adjustment for comorbidity by use of two new comorbidity indices, the multidimensional diagnosis-based comorbidity index and the drug comorbidity index, were compared to adjustment for the Charlson comorbidity index (CCI). RESULTS: Risk of death was higher after RT than RP (hazard ratio [HR] = 1.94; 95% confidence interval [CI]: 1.70-2.21). The difference decreased when adjusting for age, cancer characteristics, and CCI (HR = 1.32, 95% CI: 1.06-1.66). Adjustment for the two new comorbidity indices further attenuated the difference (HR 1.14, 95% CI 0.91-1.44). Emulation of a hypothetical pragmatic trial where also older men with any type of baseline comorbidity were included, largely confirmed these results (HR 1.10; 95% CI 0.95-1.26). CONCLUSION: Adjustment for comorbidity using two new indices provided comparable risk of death from any cause in line with results of a RCT. Similar results were seen in a broader study population, more representative of clinical practice.

Colorectal cancer screening with fecal immunochemical testing or primary colonoscopy: inequities in diagnostic yield.

BACKGROUND: Socioeconomic inequalities in the uptake of colorectal cancer screening are well documented, but the implications on inequities in health gain remain unclear. METHODS: Sixty-year-olds were randomly recruited from the Swedish population between March 2014 and March 2020 and invited to undergo either 2 rounds of fecal immunochemical testing (FIT) 2 years apart (n = 60 137) or primary colonoscopy just once (n = 30 400). By linkage to Statistics Sweden's registries, we obtained socioeconomic data. In each defined socioeconomic group, we estimated the cumulative yield of advanced neoplasia in each screening arm (intention-to-screen analysis). In the biennial FIT arm, we predicted the probability of exceeding the yield in the primary colonoscopy arm by linear extrapolation of the cumulative yield to (hypothetical) additional rounds of FIT. RESULTS: In the lowest income group, the yield of advanced neoplasia was 1.63% (95% confidence interval [CI] = 1.35% to 1.93%) after 2 rounds of FIT vs 1.93% (95% CI = 1.49% to 2.40%) in the primary colonoscopy arm. Extrapolation to a third round of FIT implied a 86% probability of exceeding the yield in the primary colonoscopy arm. In the highest income group, we found a more pronounced yield gap between the 2 screening strategies-2.32% (95% CI = 2.15% to 2.49%) vs 3.71% (95% CI = 3.41% to 4.02%)- implying a low (2%) predicted probability of exceeding yield after a third round of FIT. CONCLUSIONS: Yield of advanced neoplasia from 2 rounds of FIT 2 years apart was poorer as compared with primary colonoscopy, but the difference was less in lower socioeconomic groups. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02078804.

Development and validation of a multi-dimensional diagnosis-based comorbidity index that improves prediction of death in men with prostate cancer: Nationwide, population-based register study.

Assessment of comorbidity is crucial for confounding adjustment and prediction of mortality in register-based studies, but the commonly used Charlson comorbidity index is not sufficiently predictive. We aimed to develop a multidimensional diagnosis-based comorbidity index (MDCI) that captures comorbidity better than the Charlson Comorbidity index. The index was developed based on 286,688 men free of prostate cancer randomly selected from the Swedish general population, and validated in 54,539 men without and 68,357 men with prostate cancer. All ICD-10 codes from inpatient and outpatient discharges during 10 years prior to the index date were used to define variables indicating frequency of code occurrence, recency, and total duration of related hospital admissions. Penalized Cox regression was used to predict 10-year all-cause mortality. The MDCI predicted risk of death better than the Charlson comorbidity index, with a c-index of 0.756 (95% confidence interval [CI] = 0.751, 0.762) vs 0.688 (95% CI = 0.683, 0.693) in the validation cohort of men without prostate cancer. Men in the lowest vs highest MDCI quartile had distinctively different survival in the validation cohort of men with prostate cancer, with an overall hazard ratio [HR] of 5.08 (95% CI = 4.90, 5.26). This was also consistent within strata of age and Charlson comorbidity index, e.g. HR = 5.90 (95% CI = 4.65, 7.50) in men younger than 60 years with CCI 0. These results indicate that comorbidity assessment in register-based studies can be improved by use of all ICD-10 codes and taking related frequency, recency, and duration of hospital admissions into account.

Risk of prostate cancer death in men diagnosed with prostate cancer at cystoprostat-ectomy. A nationwide population-based study.

BACKGROUND AND AIMS: One out of three men who undergo cystoprostatectomy for bladder cancer is diagnosed with incidental prostate cancer (PCa) at histopathological examination. Many of these men are PSA tested as part of their follow-up, but it is unclear if this is needed. The aim of this study was to assess the risk of PCa death in these men and the need of PSA-testing during follow-up. METHODS: Between 2002 and 2020, 1,554 men were diagnosed with PCa after cystoprostatectomy performed for non-metastatic bladder cancer and registered in the National Prostate Cancer Register (NPCR) of Sweden. We assessed their risk of death from PCa, bladder cancer and other causes up to 15 years after diagnosis by use of data in The Cause of Death Register. The use of androgen deprivation therapy (ADT) as a proxy for PCa progression was assessed by fillings in The Prescribed Drug Register. RESULTS: Fifteen years after diagnosis, cumulative incidence of death from PCa was 2.6% (95% CI 2.3%-2.9%), from bladder cancer 32% (95% CI: 30%-34%) and from other causes 40% (95% CI: 36%-44%). Only 35% of men with PCa recorded as primary cause of death in The Cause of Death Register had started ADT before date of death, indicating sticky-diagnosis bias with inflated risk of PCa death. CONCLUSIONS: For a large majority of men diagnosed with incidental PCa at cystoprostatectomy performed for bladder cancer, the risk of PCa death is very small so there is no rationale for PSA testing during follow-up.

Patient-reported Side Effects 1 Year After Radical Prostatectomy or Radiotherapy for Prostate Cancer: A Register-based Nationwide Study.

BACKGROUND: Data on functional and psychological side effects following curative treatment for prostate cancer are lacking from large, contemporary, unselected, population-based cohorts. OBJECTIVE: To assess urinary symptoms, bowel disturbances, erectile dysfunction (ED), and quality of life (QoL) 12 mo after robot-assisted radical prostatectomy (RARP) and radiotherapy (RT) using patient-reported outcome measures in the Swedish prostate cancer database. DESIGN, SETTING, AND PARTICIPANTS: This was a nationwide, population-based, cohort study in Sweden of men who underwent primary RARP or RT between January 1, 2018 and December 31, 2020. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Absolute proportions and odds ratios (ORs) were calculated using multivariable logistic regression, with adjustment for clinical characteristics. RESULTS AND LIMITATIONS: A total of 2557 men underwent RARP and 1741 received RT. Men who underwent RT were older (69 vs 65 yr) and had more comorbidities at baseline. After RARP, 13% of men experienced incontinence, compared to 6% after RT. The frequency of urinary bother was similar, at 18% after RARP and 18% after RT. Urgency to defecate was reported by 14% of men after RARP and 34% after RT. At 1 yr, 73% of men had ED after RARP, and 77% after RT. High QoL was reported by 85% of men after RARP and 78% of men after RT. On multivariable regression analysis, RT was associated with lower risks of urinary incontinence (OR 0.25, 95% confidence interval [CI] 0.19-0.33), urinary bother (OR 0.79, 95% CI 0.66-0.95), and ED (OR 0.54, 95% CI 0.46-0.65), but higher risk of bowel symptoms (OR 2.86, 95% CI 2.42-3.39). QoL was higher after RARP than after RT (OR 1.34, 95% CI 1.12-1.61). CONCLUSIONS: Short-term specific side effects after curative treatment for prostate cancer significantly differed between RARP and RT in this large and unselected cohort. Nevertheless, the risk of urinary bother was lower after RT, while higher QoL was common after RARP. PATIENT SUMMARY: In our study of patients treated for prostate cancer, urinary bother and overall quality of life are comparable at 1 year after surgical removal of the prostate in comparison to radiotherapy, despite substantial differences in other side effects.

Estimation in discrete time coarsened multivariate longitudinal models.

We consider the analysis of longitudinal data of multiple types of events where some of the events are observed on a coarser level (e.g. grouped) at some time points during the follow-up, for example, when certain events, such as disease progression, are only observable during parts of follow-up for some subjects, causing gaps in the data, or when the time of death is observed but the cause of death is unknown. In this case, there is missing data in key characteristics of the event history such as onset, time in state, and number of events. We derive the likelihood function, score and observed information under independent and non-informative coarsening, and conduct a simulation study where we compare bias, empirical standard errors, and confidence interval coverage of estimators based on direct maximum likelihood, Monte Carlo Expectation Maximisation, ignoring the coarsening thus acting as if no event occurred, and artificial right censoring at the first time of coarsening. Longitudinal data on drug prescriptions and survival in men receiving palliative treatment for prostate cancer is used to estimate the parameters of one of the data-generating models. We demonstrate that the performance depends on several factors, including sample size and type of coarsening.

Survival Trend in Individuals With De Novo Metastatic Prostate Cancer After the Introduction of Doublet Therapy.

Importance: Recently, life-prolonging treatments for patients with advanced prostate cancer have been introduced in clinical practice. Objective: To investigate if the introduction of doublet therapy is associated with changes in survival on a population-basis. Design, Setting, and Participants: This nationwide population-based cohort study used data from the Prostate Cancer data Base Sweden from 2008 to 2020. Men registered with de novo metastatic castration-sensitive prostate cancer (mCSPC) were included. Exposure: The proportion of men with mCSPC who received doublet therapy, ie, androgen deprivation therapy plus androgen receptor pathway inhibitor drugs or chemotherapy was assessed. Main Outcomes and Measures: Standardized overall survival, taking age, comorbidity, and cancer characteristics into consideration, was estimated by use of a parametric survival model. Results: A total of 11 382 men were included in this study (median [IQR] age, 74.0 [68-81] years). There was a shift toward less advanced prostate cancer during the study period with a decrease in median (IQR) prostate-specific antigen at diagnosis in men with mCSPC from 145 (39-571) ng/mL to 107 (27-426) ng/mL. Upfront treatment with doublet therapy in these men simultaneously increased from 1% (7 of 991) in 2016 to 44% (402 of 922) in 2020. The adjusted 5-year overall survival increased from 26% (95% CI, 25%-28%) from 2008 to 2012 to 35% (95% CI, 31%-40%) from 2017 to 2020. During the first 5 years after diagnosis, there was an increase in mean survival of 6 months, from 2.7 (95% CI, 2.6-2.8) years from 2008 to 2012 to 3.2 (95% CI, 3.1-3.1) years from 2017 to 2020. Conclusions and Relevance: In parallel with improvements in treatment of advanced prostate cancer, a clinically meaningful increase in mean survival was observed in men with de novo mCSPC in Sweden between 2008 and 2020 in this study.

Choice of imputation method for missing metastatic status affected estimates of metastatic prostate cancer incidence.

OBJECTIVES: To study how handling missing data on M stage in a clinical cancer register affects estimates of incidence of metastatic prostate cancer. STUDY DESIGN AND SETTING: Estimates of age-standardized incidence of metastatic prostate cancer were obtained by the use of data in a population-based clinical cancer register in Sweden and using four methods for imputation of missing M stage. Adjusted survival was used to compare men with known and imputed M stage. RESULTS: The proportion of men with missing M stage was high (66%) and varied according to the risk group and over calendar time. The estimated incidence of metastatic disease varied depending on imputation method, with all methods indicating a decreasing incidence over time. A combination of deterministic imputation (DI) and multiple imputation (MI) produced adjusted survival curves for men with imputed M stage that best resembled the survival for men with known M stage. CONCLUSIONS: Plausible estimates of incidence of metastatic prostate cancer in clinical cancer registers can be obtained by the use of a combination of DI of missing M stage and MI.

Real World Outcomes in Patients With Metastatic, Castration-Resistant Prostate Cancer Treated With Radium-223 in Routine Clinical Practice in Sweden.

AIM: Estimate the effect of Radium-223 (Ra-223) on the incidence of bone fractures, prostate cancer death, and all-cause death compared with other standard treatments for metastatic, castration-resistant prostate cancer (mCRPC). METHODS: Using a cohort design, we estimated the effect of Ra-223 on the risk of bone fractures, all-cause and prostate cancer-specific mortality across different lines of treatment for mCRPC using Prostate Cancer data Base Sweden (2013-2018). The comparator group comprised other standard treatments for mCRPC. We used 36-month risk differences and hazard ratios (HRs) as effect estimates. RESULTS: The number of eligible individuals was 635, 453, 262, and 84 for the first-, second-, third-, and fourth-line cohorts, respectively. When compared Ra-223 to other standard treatments, the difference in the 36-month risk of fracture was 6% (95% confidence interval [CI], -7% to 18%) in the first-line cohort (n = 635) and 8% (95% CI, -7% to 18%) in the second-line cohort (n = 453). The number of fractures in the third-/fourth-line cohorts was too small for an adjusted comparison. The difference in 36-month mortality was higher in the first-line cohort 13% (95% CI, -3% to 31%), but lower in the second- and third-/fourth-line cohorts-8% (95% CI, -23% to 7%) and -14% (95% CI, -21% to 16%) respectively. Most deaths were due to prostate cancer. CONCLUSION: Results suggest that the difference in the risk of fractures is small, if any. A difference in the risk of mortality may be present in first-line treatment, but a decreased risk of mortality was observed in second and later lines of treatment. The results on mortality need to be considered in the context of potential unmeasured or residual confounding.

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.

Mortality in men with castration-resistant prostate cancer-A long-term follow-up of a population-based real-world cohort.

Objectives: The objective of this study is to find clinical variables that predict the prognosis for men with castration-resistant prostate cancer (CRPC) in a Swedish real-life CRPC cohort, including a risk group classification to clarify the risk of succumbing to prostate cancer. This is a natural history cohort representing the premodern drug era before the introduction of novel hormonal drug therapies. Methods: PSA tests from the clinical chemistry laboratories serving health care in six regions of Sweden were retrieved and cross-linked to the National Prostate Cancer Registry (NPCR) to identify men with a prostate cancer diagnosis. Through further cross-linking with data sources at the Swedish Board of Health and Welfare, we retrieved other relevant information such as prescribed drugs, hospitalizations, and cause of death. Men entered the CRPC cohort at the first date of doubling of their PSA nadir value with the last value being >2 ng/ml, or an absolute increase of >5 ng/ml or more, whilst on 3 months of medical castration or if they had been surgically castrated (n = 4098). By combining the two variables with the largest C-statistics, "PSA at time of CRPC" and "PSA doubling time," a risk group classification was created. Results: PSA-DT and PSA at date of CRPC are the strongest variables associated with PC specific survival. At the end of follow-up, the proportion of men who died due to PC was 57%, 71%, 81%, 86%, and 89% for risk categories one through five, respectively. The median overall survival in our cohort of men with CRPC was 1.86 years (95% CI: 1.79-1.97). Conclusion: For a man with castration-resistant prostate cancer, there is a high probability that this will be the main cause contributing to his death. However, there is a significant difference in mortality that varies in relation to tumor burden assessed as PSA doubling time and PSA at time of CRCP. This information could be used in a clinical setting when deciding when to treat more or less aggressively once entering the CRPC phase of the disease.