Evaluation of data quality in the National Prostate Cancer Register of Sweden

Cohort profile: The Obesity and Disease Development Sweden (ODDS) study, a pooled cohort

PURPOSE

The Obesity and Disease Development Sweden (ODDS) study was designed to create a large cohort to study body mass index (BMI), waist circumference (WC) and changes in weight and WC, in relation to morbidity and mortality.

PARTICIPANTS

ODDS includes 4 295 859 individuals, 2 165 048 men and 2 130 811 women, in Swedish cohorts and national registers with information on weight assessed once (2 555 098 individuals) or more (1 740 761 individuals), in total constituting 7 733 901 weight assessments at the age of 17-103 years in 1963-2020 (recalled weight as of 1911). Information on WC is available in 152 089 men and 212 658 women, out of whom 108 795 have repeated information on WC (in total 512 273 assessments). Information on morbidity and mortality was retrieved from national registers, with follow-up until the end of 2019-2021, varying between the registers.

FINDINGS TO DATE

Among all weight assessments (of which 85% are objectively measured), the median year, age and BMI (IQR) is 1985 (1977-1994) in men and 2001 (1991-2010) in women, age 19 (18-40) years in men and 30 (26-36) years in women and BMI 22.9 (20.9-25.4) kg/m2 in men and 23.2 (21.2-26.1) kg/m2 in women. Normal weight (BMI 18.5-24.9 kg/m2) is present in 67% of assessments in men and 64% in women and obesity (BMI≥30 kg/m2) in 5% of assessments in men and 10% in women. The median (IQR) follow-up time from the first objectively measured or self-reported current weight assessment until emigration, death or end of follow-up is 31.4 (21.8-40.8) years in men and 19.6 (9.3-29.0) years in women. During follow-up, 283 244 men and 123 457 women died.

FUTURE PLANS

The large sample size and long follow-up of the ODDS Study will provide robust results on anthropometric measures in relation to risk of common diseases and causes of deaths, and novel findings in subgroups and rarer outcomes.

The National Swedish Lymphoma Register - a systematic validation of data quality

BACKGROUND AND PURPOSE

The Swedish Lymphoma Register (SLR) was initiated in the year 2000 with the aim to monitor quality of care in diagnostics, treatment and outcome of all lymphomas diagnosed nationally among adults. Here, we present the first systematic validation of SLR records as a basis for improved register quality and patient care.

PATIENTS AND METHODS

We evaluated timeliness and completeness of register records among patients diagnosed with lymphoma in the SLR (n = 16,905) compared with the National Cancer Register for the period 2013-2020. Comparability was assessed through evaluation of coding routines against national and international guidelines. Accuracy of 42 variables was evaluated through re-abstraction of data from medical records among 600 randomly selected patients diagnosed in 2016-2017 and treated across all six Swedish healthcare regions.  Results: Completeness was high, >95% per year for the period 2013-2018, and >89% for 2019-2020 compared to the National Cancer Register. One in four patients was registered within 3 months, and 89.9% within 2 years of diagnosis. Registration instructions and coding procedures followed the prespecified guidelines. Missingness was generally low (<5%), but high for occasional variables, for example, those describing maintenance and consolidative treatment. Exact agreement of categorical variables was high overall (>80% for 24/34 variables), especially for treatment-related data (>80% for 17/19 variables).

INTERPRETATION

Completeness and accuracy are high in the SLR, while timeliness could be improved. Finetuning of variable registration guided by this validation can further improve reliability of register reports and advance service to lymphoma patients and health care in the future.

Population-based study of disease trajectory after radical treatment for high-risk prostate cancer

OBJECTIVES

To investigate long-term disease trajectories among men with high-risk localized or locally advanced prostate cancer (HRLPC) treated with radical radiotherapy (RT) or radical prostatectomy (RP).

MATERIAL AND METHODS

Men diagnosed with HRLPC in 2006-2020, who received primary RT or RP, were identified from the Prostate Cancer data Base Sweden (PCBaSe) 5.0. Follow-up ended on 30 June 2021. Treatment trajectories and risk of death from prostate cancer (PCa) or other causes were assessed by competing risk analyses using cumulative incidence for each event.

RESULTS

In total, 8317 men received RT and 4923 men underwent RP. The median (interquartile range) follow-up was 6.2 (3.6-9.5) years. After RT, the 10-year risk of PCa-related death was 0.13 (95% confidence interval [CI] 0.12-0.14) and the risk of death from all causes was 0.32 (95% CI 0.31-0.34). After RP, the 10-year risk of PCa-related death was 0.09 (95% CI 0.08-0.10) and the risk of death from all causes was 0.19 (95% CI 0.18-0.21). The 10-year risks of androgen deprivation therapy (ADT) as secondary treatment were 0.42 (95% CI 0.41-0.44) and 0.21 (95% CI 0.20-0.23) after RT and RP, respectively. Among men who received ADT as secondary treatment, the risk of PCa-related death at 10 years after initiation of ADT was 0.33 (95% CI 030-0.36) after RT and 0.27 (95% CI 0.24-0.30) after RP.

CONCLUSION

Approximately one in 10 men with HRLPC who received primary RT or RP had died from PCa 10 years after diagnosis. Approximately one in three men who received secondary ADT, an indication of PCa progression, died from PCa 10 years after the start of ADT. Early identification and aggressive treatment of men with high risk of progression after radical treatment are warranted.

Natural History of Nonmetastatic Prostate Cancer Managed With Watchful Waiting

Importance

It is uncertain to what extent watchful waiting (WW) in men with nonmetastatic prostate cancer (PCa) and a life expectancy of less than 10 years is associated with adverse consequences.

Objective

To report transitions to androgen deprivation therapy (ADT), castration-resistant prostate cancer (CRPC), death from PCa, or death from other causes in men treated with a WW strategy.

Design, Setting, and Participants

This nationwide, population-based cohort study included men with nonmetastatic PCa diagnosed since 2007 and registered in the National Prostate Cancer Register of Sweden with WW as the primary treatment strategy and with life expectancy less than 10 years. Life expectancy was calculated based on age, the Charlson Comorbidity Index (CCI), and a drug comorbidity index. Observed state transition models complemented observed data to extend follow-up to more than 20 years. Analyses were performed between 2022 and 2023.

Exposure

Nonmetastatic PCa.

Main Outcomes and Measures

Transitions to ADT, CRPC, death from PCa, and death from other causes were measured using state transition modeling.

Results

The sample included 5234 men (median [IQR] age at diagnosis, 81 [79-84] years). After 5 years, 954 men with low-risk PCa (66.2%) and 740 with high-risk PCa (36.1%) were still alive and not receiving ADT. At 10 years, the corresponding proportions were 25.5% (n = 367) and 10.4% (n = 213), respectively. After 10 years, 59 men with low-risk PCa (4.1%) and 221 with high-risk PCa (10.8%) had transitioned to CRPC. Ten years after diagnosis, 1330 deaths in the low-risk group (92.3%) and 1724 in the high-risk group (84.1%) were from causes other than PCa.

Conclusions and Relevance

These findings suggest that the WW management strategy is appropriate for minimizing adverse consequences of PCa in men with a baseline life expectancy of less than 10 years.

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.

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.

A Standard Framework for Evaluating Large Health Care Data and Related Resources

Since 2000, the availability and use of large health care data and related resources for conducting surveillance, research, and evaluations to guide clinical and public health decision-making has increased rapidly. These trends have been related to transformations in health care information technology and public as well as private-sector efforts for collecting, compiling, and supplying large volumes of data. This growing collection of robust and often timely data has enhanced the capability to increase the knowledge base guiding clinical and public health activities and also has increased the need for effective tools to assess the attributes of these resources and identify the types of scientific questions they are best suited to address. This

MMWR supplement presents a standard framework for evaluating large health care data and related resources, including constructs, criteria, and tools that investigators and evaluators can apply and adapt.

Validation of primary and outcome data quality in a Swedish population-based breast cancer quality registry

BACKGROUND

Population-based cancer quality registries are of great importance for the improvement of cancer care. However, little is known about the quality of recurrence data in cancer quality registries. The aim of this study was to evaluate data quality in the regional Breast Cancer Quality Registry of Central Sweden, with emphasis on the validity of recorded information on recurrence.

METHODS

Validation by re-abstraction was performed on a random sample of 800 women with primary invasive breast cancer stage I-III diagnosed between 1993 and 2010, of which 400 had at least one registered recurrence and 400 had no registered recurrence. Registry data were compared with data from medical records. Exact agreement, correlation and kappa values, sensitivity and specificity were calculated.

RESULTS

Seven hundred forty-seven women (93%) were available for analysis. Exact agreement was high for diagnostics, tumor characteristics, surgery, and adjuvant oncological treatment (90% or more for most variables). The registry's sensitivity was low for regional recurrence (47%), but higher for local and distant recurrence (80% and 75%), whereas specificity was overall high (≥ 95%). Combining all recurrence categories irrespective of localization improved sensitivity to 90% with a specificity of 91%. In 87% of women, the date of first recurrence according to medical records fell within ± 90 days of the date recorded in the registry.

CONCLUSIONS

While the quality of data in the regional Breast Cancer Quality Registry was generally high, data accuracy on recurrences was lower. The overall precision of identifying any recurrence, irrespective of localization, was high. However, the accuracy of classification of recurrences (local, regional or distant) was lower, with evidence of underreporting for each of the recurrence categories. Given the importance of recurrence-related outcomes in the assessment of quality of care, efforts should be made to improve the reporting of recurrences.

MBSAQIP database: are the data reliable?

BACKGROUND

The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database collects data from all accredited centers in the US. A prior study showed data quality issues limiting use of up to 20% of the 2015 database.

OBJECTIVES

To evaluate the completeness and data quality (internal validity, accuracy, and consistency) of the MBSAQIP database between 2015 and 2019.

SETTING

United States.

METHODS

All subsets of data from the MBSAQIP Participant User Data File (PUDF) were compiled into one main file. Completeness, internal validity, accuracy, and consistency were evaluated. Completeness was determined via missing values. Internal validity was assessed using the percentage of patients with a body mass index (BMI) < 30 kg/m2 who underwent primary bariatric surgery. Accuracy was evaluated using reported versus calculated BMI. Consistency was assessed using the percentage of patients with a gain of >5 or a loss of >20 units of BMI change in 30 days. Effects across years were assessed using a chi-squared test.

RESULTS

Missing data for age, BMI, and ASA was consistently low (<2.5%) with no significant difference across years. Only .02% of patients who underwent a primary bariatric procedure had a reported BMI <30 kg/m2. The mean difference between reported versus calculated BMI was -.02 units. A maximum of .33% of patients gained >5 units of BMI, and a maximum of .85% of patients lost > 20 units of BMI in early follow-up.

CONCLUSIONS

While the MBSAQIP is a database with acceptable data quality and minimal changes from 2015-2019, ongoing efforts are needed to improve data.

Body mass index, triglyceride-glucose index, and prostate cancer death: a mediation analysis in eight European cohorts

BACKGROUND

Insulin resistance is a hypothesised biological mechanism linking obesity with prostate cancer (PCa) death. Data in support of this hypothesis is limited.

METHODS

We included 259,884 men from eight European cohorts, with 11,760 incident PCa's and 1784 PCa deaths during follow-up. We used the triglyceride-glucose (TyG) index as indicator of insulin resistance. We analysed PCa cases with follow-up from PCa diagnosis, and the full cohort with follow-up from the baseline cancer-free state, thus incorporating both PCa incidence and death. We calculated hazard ratios (HR) and the proportion of the total effect of body mass index (BMI) on PCa death mediated through TyG index.

RESULTS

In the PCa-case-only analysis, baseline TyG index was positively associated with PCa death (HR per 1-standard deviation: 1.11, 95% confidence interval (CI); 1.01-1.22), and mediated a substantial proportion of the baseline BMI effect on PCa death (HRtotal effect per 5-kg/m2 BMI: 1.24; 1.14-1.35, of which 28%; 4%-52%, mediated). In contrast, in the full cohort, the TyG index was not associated with PCa death (HR: 1.03; 0.94-1.13), hence did not substantially mediate the effect of BMI on PCa death.

CONCLUSIONS

Insulin resistance could be an important pathway through which obesity accelerates PCa progression to death.

Risk of prostate cancer death after radical radiotherapy with neoadjuvant and adjuvant therapy with bicalutamide or gonadotropin-releasing hormone agonists

BACKGROUND

Oncological outcome after radical radiotherapy (RRT) combined with neoadjuvant and adjuvant androgen suppression therapy (AST) may differ according to type of AST. The aim of this nationwide register-based study was to investigate risk of prostate cancer (Pca) death after different neoadjuvant and adjuvant ASTs; (i) bicalutamide, (ii) gonadotropin-releasing hormone agonists (GnRH) or (iii) combined bicalutamide and GnRH (CAB), together with RRT.

MATERIALS AND METHODS

Data for 6882 men diagnosed with high-risk Pca between 2007 and 2020 and treated with primary RRT was retrieved from Prostate Cancer data Base Sweden (PCBaSe) 5.0. Time to Pca death according to type of neoadjuvant and adjuvant AST was assessed by use of Kaplan-Meier plots and Cox proportional hazard models adjusted for putative confounders.

RESULTS

Data were stratified by RRT type since the effect of AST in risk of Pca death differed according to type of RRT. Compared with the reference RRT combined with neoadjuvant CAB/adjuvant GnRH, risk of Pca death for men treated with CAB/bicalutamide and conventionally fractionated external beam radiotherapy (CF-EBRT) was hazard ratio (HR) 0.73 (95% CI: 0.50-1.04), hypofractionated EBRT (HF-EBRT), HR 1.35 (95% CI: 0.65-2.81) and EBRT with high dose rate brachytherapy (EBRT-HDRBT), HR 0.85 (95% CI: 0.37-1.95). Risk of Pca death for men treated with bicalutamide/bicalutamide and: (i) CF-EBRT was HR 2.35 (95% CI: 1.42-3.90), (ii) HF-EBRT, HR 0.70 (95% CI: 0.26-1.85), (iii) HF-EBRT, HR 4.07 (95% CI: 1.88-8.77) vs the reference.

CONCLUSION

In this observational study, risk of Pca death between men receiving different combinations of AST varied according to RRT type. No difference was found in risk of Pca death for men treated with bicalutamide or GnRH as adjuvant therapy to RRT following neoadjuvant CAB. Risk of Pca death was increased for men with monotherapy neo-/adjuvant bicalutamide in combination with CF-EBRT or EBRT-HDRBT.

Risk of colorectal adenocarcinoma in men receiving androgen deprivation therapy for prostate cancer; a nationwide cohort study

PURPOSE

To assess whether androgens play a role in explaining the sex related differences in the incidence of colorectal cancer (CRC).

METHODS

A nationwide matched cohort study was conducted employing the Prostate Cancer data Base Sweden (PCBaSe) 4.0 during the study period 2006-2016. Prostate cancer (PC) patients receiving androgen deprivation therapy (ADT) were treated as exposed. Prostate cancer-free men from the general population were randomly selected and matched to the index case by birth year and county of residence, forming the unexposed group. All were followed until a diagnosis of CRC, death, emigration, or end of the study period. The risk of CRC among ADT exposed PC patients compared to unexposed cancer-free men was calculated using a flexible parametric survival model and expressed as hazard ratios (HRs) with 95% confidence intervals (CIs).

RESULTS

There was an increased risk of CRC among ADT exposed PC patients compared to unexposed cancer-free men (HR 1.27 [95% CI 1.15-1.41]), in particular an increased risk of adenocarcinoma of the colon (HR 1.33 [95% CI 1.17-1.51]) and more specifically an increased risk of adenocarcinoma of the distal colon (HR 1.53 [95% CI 1.26-1.85]). Examination of latency effects yielded significantly decreased HRs over time for CRC (p = 0.049 for trend).

CONCLUSIONS

This population-based study found an increased risk of CRC among PC patients exposed to ADT, specifically adenocarcinoma of the distal colon, which indicates an increased association between ADT (PC + ADT) and CRC but not a positive dose-response trend questioning a true causal effect.

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.

Frequency of Biopsy and Tumor Grade Before vs After Introduction of Prostate Magnetic Resonance Imaging

Importance

In randomized clinical trials (RCTs), magnetic resonance imaging (MRI) before prostate biopsy has been associated with fewer biopsies, decreased detection of Gleason score 6 cancers, and increased detection of Gleason score 7 or higher cancers.

Objective

To study whether MRI of the prostate before the decision to biopsy is associated with biopsy frequency and distribution of Gleason score in clinical practice.

Design, Setting, and Participants

This is a retrospective, population-based cohort study of men in Jönköping Region, Sweden. Men with prostate-specific antigen (PSA) level measured between November 2011 and 2020 were monitored until January 31, 2021. Men with known prostate cancer were excluded. Data analysis was performed from July to December 2022.

Exposures

Data on repeated PSA measures, prostate biopsies, and MRI prostate were extracted from health care records, and cancer characteristics were obtained from The National Prostate Cancer Register.

Main Outcomes and Measures

The proportions of men who underwent prostate biopsy and risk of Gleason score 6 or Gleason score 7 or higher cancer and negative biopsy before and after introduction of MRI were calculated.

Results

In this cohort study of 23 802 men (mean [SD] age, 60.8 [13.6] years) who underwent PSA testing, when the use of MRI increased, fewer biopsies were performed (adjusted odds ratio [OR], 0.84; 95% CI, 0.72-0.97) and the odds of detecting Gleason score 6 cancer decreased (OR, 0.47; 95% CI, 0.33-0.64), whereas the odds of detecting Gleason score 7 or higher cancer increased (OR, 1.24; 95% CI, 1.02-1.50).

Conclusions and Relevance

In this study, the introduction of MRI to clinical practice was associated with a decreased proportion of men who underwent a biopsy and decreased detection of Gleason score 6 cancer but increased detection of Gleason score 7 or higher cancer. These clinical data support the use of prostate MRI before biopsy in an effort to avoid unnecessary biopsies.

Risks of alcohol and drug use disorders in prostate cancer survivors: a national cohort study

BACKGROUND

Prostate cancer (PC) survivors may potentially use substances to cope with psychological distress or poorly controlled physical symptoms. Little is known, however, about the long-term risks of alcohol use disorder (AUD) or drug use disorders in men with PC.

METHODS

A national cohort study was conducted in Sweden of 180 189 men diagnosed with PC between 1998 and 2017 and 1 801 890 age-matched population-based control men. AUD and drug use disorders were ascertained from nationwide records through 2018. Cox regression was used to compute hazard ratios (HRs) while adjusting for sociodemographic factors and prior psychiatric disorders. Subanalyses examined differences by PC treatment from 2005 to 2017.

RESULTS

Men with high-risk PC had increased risks of both AUD (adjusted HR = 1.44, 95% confidence interval [CI] = 1.33 to 1.57) and drug use disorders (adjusted HR = 1.93, 95% CI = 1.67 to 2.24). Their AUD risk was highest in the first year and was no longer significantly elevated 5 years after PC diagnosis, whereas their drug use disorders risk remained elevated 10 years after PC diagnosis (adjusted HR = 2.26, 95% CI = 1.45 to 3.52), particularly opioid use disorder (adjusted HR = 3.07, 95% CI = 1.61 to 5.84). Those treated only with androgen-deprivation therapy had the highest risks of AUD (adjusted HR = 1.91, 95% CI = 1.62 to 2.25) and drug use disorders (adjusted HR = 2.23, 95% CI = 1.70 to 2.92). Low- or intermediate-risk PC was associated with modestly increased risks of AUD (adjusted HR = 1.38, 95% CI = 1.30 to 1.46) and drug use disorders (adjusted HR = 1.19, 95% CI = 1.06 to 1.34).

CONCLUSIONS

In this large cohort, men with PC had significantly increased risks of both AUD and drug use disorders, especially those with high-risk PC and treated only with androgen-deprivation therapy. PC survivors need long-term psychosocial support and timely detection and treatment of AUD and drug use disorders.

Endogenous incretin levels and risk of first incident cancer: a prospective cohort study

Concerns have been raised regarding a potentially increased risk of cancer associated with treatment with glucagon-like peptide-1 (GLP-1) receptor agonists. Here, we explored whether fasting and oral glucose tolerance test post-challenge glucose-dependent insulinotropic peptide (GIP) and GLP-1 levels were associated with incident first cancer. Within the cardiovascular re-examination arm of the population-based Malmö Diet Cancer study (n = 3734), 685 participants with a previous cancer diagnosis were excluded, resulting in 3049 participants (mean age 72.2 ± 5.6 years, 59.5% women), of whom 485 were diagnosed with incident first cancer (median follow-up time 9.9 years). Multivariable Cox-regression and competing risk regression (death as competing risk) were used to explore associations between incretin levels and incident first cancer. Higher levels of fasting GLP-1 (462 incident first cancer cases/2417 controls) showed lower risk of incident first cancer in competing risk regression (sub-hazard ratio 0.90; 95% confidence interval 0.82-0.99; p = 0.022). No association was seen for fasting GIP, post-challenge GIP, or post-challenge GLP-1 and incident first cancer. In this prospective study, none of the fasting and post-challenge levels of GIP and GLP-1 were associated with higher risk of incident first cancer; by contrast, higher levels of fasting GLP-1 were associated with lower risk of incident first cancer.

The effect of a phytoestrogen intervention and impact of genetic factors on tumor proliferation markers among Swedish patients with prostate cancer: study protocol for the randomized controlled PRODICA trial

BACKGROUND

A high intake of phytoestrogens, found in soy, rye, and seeds, is associated with a reduced risk of a prostate cancer diagnosis. Previously, we found that the overall decreased risk of prostate cancer diagnosis in males with a high intake of phytoestrogens was strongly modified by a nucleotide sequence variant in the estrogen receptor-beta (ERβ) gene. However, we do not know if phytoestrogens can inhibit the growth of prostate cancer in males with established diseases. If there is an inhibition or a delay, there is reason to believe that different variants of the ERβ gene will modify the effect. Therefore, we designed an intervention study to investigate the effect of the addition of foods high in phytoestrogens and their interaction with the ERβ genotype on prostate tumor proliferation in patients with prostate cancer.

METHOD

The PRODICA trial is a randomized ongoing intervention study in patients with low- and intermediate-risk prostate cancer with a Gleason score < 8, prostate-specific antigen (PSA) < 20, and scheduled for radical prostatectomy. The study is conducted at Sahlgrenska University Hospital in Gothenburg, Sweden. The intervention consists of a daily intake of soybeans and flaxseeds (~ 200 mg of phytoestrogens) until the surgery, approximately 6 weeks. The aim is to recruit 200 participants. The primary outcome is the difference in the proliferation marker Ki-67 between the intervention and the control groups. The genotype of ERβ will be investigated as an effect-modifying factor. Secondary outcomes include, e.g., concentrations of PSA and steroid hormones in the blood.

DISCUSSION

The results of the PRODICA trial will contribute important information on the relevance of increasing the intake of phytoestrogens in patients with prostate cancer who want to make dietary changes to improve the prognosis of their cancer. If genetic factors turn out to influence the effect of the intervention diet, dietary advice can be given to patients who most likely benefit from it. Dietary interventions are cost-effective, non-invasive, and result in few mild side effects. Lastly, the project will provide basic pathophysiological insights which could be relevant to the development of treatment strategies for patients with prostate cancer.

TRIAL REGISTRATION

CLINICALTRIALS

gov NCT02759380. Registered on 3 May 2016.

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.

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.

Surgeon volume and patient-reported urinary incontinence after radical prostatectomy. Population-based register study in Sweden

OBJECTIVE

To investigate the association between surgeon volume and urinary incontinence after radical prostatectomy.

METHODS

A total of 8326 men in The National Prostate Cancer Register of Sweden (NPCR) underwent robot-assisted radical prostatectomy (RARP) between 2017 and 2019 of whom 56% (4668/8 326) had responded to a questionnaire one year after RARP. The questionnaire included the question: 'How much urine leakage do you experience?' with the response alternatives 'Not at all', 'A little', defined as continence and 'Moderately', 'Much/Very much' as incontinence. Association between incontinence and mean number of RARPs/year/surgeon was analysed with multivariable logistic regression including age, Charlson Comorbidity Index (CCI), PSA, prostate volume, number of biopsy cores with cancer, cT stage, Gleason score, lymph node dissection, nerve sparing intent and response rate to the questionnaire.

RESULTS

14% (659/4 668) of the men were incontinent one year after RARP. There was no statistically significant association between surgeon volume and incontinence. Older age (>75 years vs. < 65 years, OR 2.29 [95% CI 1.48-3.53]), higher CCI (CCI 2+ vs. CCI 0, OR 1.37 [95% CI 1.04-1.80]) and no nerve sparing intent (no vs. yes OR 1.53 [95% CI 1.26-1.85]) increased risk of incontinence. There were large differences in the proportion of incontinent men between surgeons with similar annual volumes, which remained after adjustment.

CONCLUSIONS

The lack of association between surgeon volume and incontinence and the wide range in outcome between surgeons with similar volumes underline the importance of individual feedback to surgeons on functional results.

Modeling Disease Trajectories for Castration-resistant Prostate Cancer Using Nationwide Population-based Data

Background

Little is known about disease trajectories for men with castration-resistant prostate cancer (CRPC).

Objective

To create a state transition model that estimates time spent in the CRPC state and its outcomes.

Design, setting, and participants

The model was generated using population-based prostate-specific antigen data from 40% of the Swedish male population, which were linked to nationwide population-based databases. We compared the observed and predicted cumulative incidence of transitions to and from the CRPC state.

Outcome measurements and statistical analysis

We measured time spent in the CRPC state and the proportion of men who died of prostate cancer during follow-up by CRPC risk category.

Results and limitations

Time spent in the CRPC state varied from 1.1 yr for the highest risk category to 3.9 yr for the lowest risk category. The proportion of men who died from prostate cancer within 10 yr ranged from 93% for the highest risk category to 54% for the lowest. There was good agreement between the model estimates and observed data.

Conclusions

There is large variation in the time spent in the CRPC state, varying from 1 yr to 4 yr according to risk category.

Patient summary

It is possible to accurately estimate the disease trajectory and duration for men with castration-resistant prostate cancer.

Association of Blood Pressure with Prostate Cancer Risk by Disease Severity and Prostate Cancer Death: A Pooled Cohort Study

BACKGROUND

The association of blood pressure (BP) with prostate cancer risk after accounting for asymptomatic prostate-specific antigen (PSA) testing, and with prostate cancer death, is unclear.

METHODS

We investigated BP, measured at a mean age of 38 years among 430,472 men from five Swedish cohorts, in association with incident prostate cancer (n = 32,720) and prostate cancer death (n = 6718). HRs were calculated from multivariable Cox regression models.

RESULTS

Increasing systolic and diastolic BP levels combined were associated with a slightly lower prostate cancer risk, with a HR of 0.98 (95% CI, 0.97-0.99) per standard deviation (SD) of mid-BP (average of systolic and diastolic BP). The association was restricted to the PSA era (1997 onwards, HR, 0.96; 95% CI, 0.95-0.98), to diagnoses initiated by a PSA test in asymptomatic men (HR, 0.95; 95% CI, 0.93-0.97), and to low-risk prostate cancer (HR, 0.95; 95% CI, 0.92-0.97). There was no clear association with more advanced disease at diagnosis. In cases, a slightly higher risk of prostate cancer death was observed for higher BP levels (HR, 1.05; 95% CI, 1.01-1.08) per SD of mid-BP; however, the association was restricted to distant metastatic disease (Pheterogeneity between case groups = 0.01), and there was no association for BP measured less than 10 years prior to diagnosis.

CONCLUSIONS

Prediagnostic BP is unlikely an important risk factor for prostate cancer development and death. Less asymptomatic PSA testing among men with higher BP levels may explain their lower risk of prostate cancer.

IMPACT

Elevated BP is unlikely to be an important risk factor for prostate cancer.

Rates of Positive Abdominal Computed Tomography and Bone Scan Findings Among Men with Cambridge Prognostic Group 4 or 5 prostate cancer: A Nationwide Registry Study

European and American guidelines recommend abdominal computed tomography (CT) and bone scans for staging of high-risk prostate cancer (PC). To improve clinical risk stratification of nonmetastatic PC a new, five-tier risk classification system has been developed, the Cambridge Prognostic Groups (CPG), in which “high-risk” PC is divided into favourable CPG 4 and unfavourable CPG 5. We used the National Prostate Cancer Register of Sweden (NPCR) to define the rates of positive CT and bone scan findings among men with CPG 4 or 5 cancer. Among men with CPG 4 and prostate-specific antigen (PSA) <50 ng/ml, only 3.6% (95% confidence interval 2.9–4.5%) of the CT scans showed regional lymph-node metastasis (N1M0), while 6.2% (95% confidence interval 5.4–7.0%) of the bone scans were positive. Rates for both were higher in the subgroups with PSA 50–99 ng/ml (10% and 15%) and with CPG 5 disease. The low positivity rate questions routine use of CT for men with CPG 4 cancer and PSA <50 ng/ml, particularly considering the poor sensitivity and specificity for detection of lymph node metastasis. The positivity rate was higher for bone scans, and as current clinical practice relies on trials using bone scans for staging (eg, to define low- versus high-volume metastatic disease), continued routine use of bone scans seems justified.

Patient summary

Our analysis of data from the National Prostate Cancer Register of Sweden showed that for men with favourable high-risk prostate cancer (Cambridge Prognostic Group 4), the rate of positive computed tomography (CT) scans was low. This result suggests that CT scans may not be necessary for detecting cancer spread in men with Cambridge Prognostic Group 4 prostate cancer .

Time to castration-resistant prostate cancer and prostate cancer death according to PSA response in men with non-metastatic prostate cancer treated with gonadotropin releasing hormone agonists

Objectives: To predict castration-resistant prostate cancer (CRPC) and prostate cancer (Pca) death by use of clinical variables at Pca diagnosis and PSA levels after start of gonadotropin-releasing hormone agonists (GnRH) in men with non-metastatic castration sensitive prostate cancer (nmCSPC).Materials and Methods: PSA values for 1603 men with nmCSPC in the National Prostate Cancer Register of Sweden who received GnRH as primary treatment were retrieved from Uppsala-Örebro PSA Cohort and Stockholm PSA and Biopsy Register. All men had measured PSA before (pre-GnRH PSA) and 3-6 months after (post-GnRH PSA) date of start of GnRH. Unadjusted and adjusted Cox models were used to predict CRPC by PSA levels. PSA levels and ISUP grade were used to construct a risk score to stratify men by tertiles according to risk of CRPC and Pca death.Results: 788 (49%) men reached CRPC and 456 (28%) died of Pca during follow-up. Post-GnRH PSA predicted CRPC regardless of pre-GnRH PSA. CRPC risk increased with higher post-GnRH PSA, HR 4.7 (95% CI: 3.4-6.7) for PSA > 16 ng/mL vs 0-0.25 ng/mL and with ISUP grade, HR 3.7 (95%: 2.5-5.4) for ISUP 5 vs ISUP 1. Risk of Pca death in men above top vs bellow bottom tertile of post-GnRH PSA and ISUP grade was HR 4.1 (95% CI: 3.0-5.5).Conclusion: A risk score based on post-GnRH PSA and ISUP grade could be used for early identification of a target group for future clinical trials on additional therapy to GnRH.

Smoking and Risk of Prostate Cancer and Prostate Cancer Death: A Pooled Study

BACKGROUND

Prospective and detailed investigations of smoking and prostate cancer (PCa) risk and death are lacking.

OBJECTIVE

To investigate prediagnosis smoking habit (status, intensity, duration, and cessation) as a risk factor, on its own and combined with body mass index (BMI), for PCa incidence and death.

DESIGN, SETTING, AND PARTICIPANTS

We included 351448 men with smoking information from five Swedish cohorts.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We used Cox regression to calculate hazard ratios (HRs) and confidence intervals (CIs) for PCa incidence (n = 24731) and death (n = 4322).

RESULTS AND LIMITATIONS

Smoking was associated with a lower risk of any PCa (HR 0.89, 95% CI 0.86-0.92), which was most pronounced for low-risk PCa (HR 0.74, 95% CI 0.69-0.79) and was restricted to PCa cases diagnosed in the prostate-specific antigen (PSA) era. Smoking was associated with a higher risk of PCa death in the full cohort (HR 1.10, 95% CI 1.02-1.18) and in case-only analysis adjusted for clinical characteristics (HR 1.20, 95% CI 1.11-1.31), which was a consistent finding across case groups (p = 0.8 for heterogeneity). Associations by smoking intensity and, to lesser degree, smoking duration and cessation, supported the associations for smoking status. Smoking in combination with obesity (BMI ≥30 kg/m²) further decreased the risk of low-risk PCa incidence (HR 0.40, 95% CI 0.30-0.53 compared to never smokers with BMI <25 kg/m²) and further increased the risk of PCa death (HR 1.49, 95% CI 1.21-1.84). A limitation of the study is that only a subgroup of men had information on smoking habit around the time of their PCa diagnosis.

CONCLUSIONS

The lower PCa risk for smokers in the PSA era, particularly for low-risk PCa, can probably be attributed to low uptake of PSA testing by smokers. Poor survival for smokers, particularly obese smokers, requires further study to clarify the underlying causes and the preventive potential of smoking intervention for PCa death.

PATIENT SUMMARY

Smokers have a higher risk of dying from prostate cancer, which further increases with obesity.

Assessing the Validity and Cover Rate of the National Swedish Hernia Register

Aim

To assess the validity and cover rate of the Swedish hernia register.

Material and Methods

Since the start of the Swedish Hernia register an annual review of randomly selected hospitals has been carried out, and since 2013 in a more standardized form to allow a systematic data collection and evaluation. 10% of all clinics were randomly selected each year in a specific region of Sweden, ensuring a systematic validation of all regions from north to south. Data from 2013 to 2018 were analyzed regarding data quality and from 2014 to 2018 regarding cover rate. All operations registered at the validated clinics were compared with the Swedish Hernia Register to assess cover rate. Fifty operations were randomly selected at each clinic and data in the Swedish Hernia register were compared with the medical records to evaluate data quality.

Results

Fifty-five clinics was evaluated and a total of 73,764 variables were compared with the medical records. Cover rate between 2014 and 2018 was 97%. The proportion of correct variables was 98% between 2013 and 2018. Most frequent errors were ASA score, date at which the patient was put on the waiting list and postoperative complications.

Conclusion

This unique validation of a national hernia register shows a high cover rate and good quality of data. Efforts to maintain and improve national registers are of great importance. Research with data from the Swedish hernia register should be evaluated on the basis of the results presented in this study.

Timing of the Pubertal Growth Spurt and Prostate Cancer

Simple Summary

Men’s pubertal timing lacks distinct markers that are easily available retrospectively. Therefore, the association between objectively assessed pubertal timing and the risk of prostate cancer is unknown. Our aim was to evaluate the association between the age at the pubertal growth spurt, an objective assessment of pubertal timing, and the risk of prostate cancer and high-risk prostate cancer. We used a population-based cohort including over 30,000 men with age at the pubertal growth spurt available and with follow-up in high quality national registers. During 1.4 million years of follow up, 1759 cases of prostate cancer were diagnosed. We demonstrate that late pubertal timing is a protective factor for prostate cancer, and especially for the clinically important high-risk or metastatic prostate cancer. Identification of early life risk- and protective factors for prostate cancer could provide new opportunities to unravel the underlying biological mechanism of the origins of prostate cancer.

Abstract

Previous studies of pubertal timing and the risk of prostate cancer have used self-reported markers of pubertal development, recalled in mid-life, and the results have been inconclusive. Our aim was to evaluate the age at the pubertal growth spurt, an objective marker of pubertal timing, and the risk of prostate cancer and high-risk prostate cancer. This population-based cohort study included 31,971 men with sufficient height measurements to calculate age at peak height velocity (PHV). Outcomes were accessed through national registers. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated by Cox regressions with follow up starting at 20 years of age. In total, 1759 cases of prostate cancer including 449 high-risk were diagnosed during follow up. Mean follow up was 42 years (standard deviation 10.0). Compared to quintiles 2–4 (Q2–4), men in the highest age at PHV quintile (Q5) had lower risk of prostate cancer (HR 0.83, 95% CI 0.73–0.94), and of high-risk prostate cancer (0.73; 0.56–0.94). In an exploratory analysis with follow up starting at age at PHV, late pubertal timing was no longer associated with reduced risk of prostate cancer. Later pubertal timing was associated with reduced risk of prostate cancer and especially high-risk prostate cancer. We propose that the risk of prostate cancer might be influenced by the number of years with exposure to adult levels of sex steroids.

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.

Androgen deprivation therapy and excess mortality in men with prostate cancer during the initial phase of the COVID-19 pandemic

Background

Men have a higher risk of death from COVID-19 than women and androgens facilitate entrance of the SARS-CoV-2 virus into respiratory epithelial cells. Thus, androgen deprivation therapy may reduce infection rates and improve outcomes for COVID-19. In the spring of 2020, Sweden was highly affected by COVID-19. The aim was to estimate the impact of androgen deprivation therapy on mortality from COVID-19 in men with prevalent prostate cancer by comparing all-cause mortality in the spring of 2020 to that in previous years.

Patients and methods

Using the Prostate Cancer data Base Sweden all men with prostate cancer on March 1 each year in 2015–2020 were followed until June 30 the same year. Exposure to androgen deprivation therapy was ascertained from filled prescriptions for bicalutamide monotherapy, gonadotropin-releasing hormone agonists (GnRH), or bilateral orchidectomy.

Results

A total of 9,822 men died in March-June in the years 2015–2020, of whom 5,034 men were on androgen deprivation therapy. There was an excess mortality in 2020 vs previous years in all men. The crude relative mortality rate ratio for 2020 vs 2015–2019 was 0.93 (95% confidence interval (CI) 0.83 to 1.04) in men on GnRH, and 0.90 (95% CI 0.78 to 1.05) in men on bicalutamide monotherapy. After multivariable adjustment these ratios were attenuated to 1.00 (95% CI 0.89 to 1.12) and 0.97 (95% CI 0.84 to 1.12), respectively. When restricting the analysis to the regions with the highest incidence of COVID-19 or to the time period between 2 April to 10 June when mortality in 2020 was increased >30% compared to previous years, the results were similar to the main analysis.

Conclusions

In this large national population-based cohort of men with prevalent prostate cancer, there was no clear evidence in support for an effect of androgen deprivation therapy on COVID-19 mortality.

Comparison of Relative Survival and Cause-Specific Survival in Men With Prostate Cancer According to Age and Risk Category: A Nationwide, Population-Based Study

Net survival, estimated in a relative survival (RS) or cause-specific survival (CSS) framework, is a key measure of the effectiveness of cancer management. We compared RS and CSS in men with prostate cancer (PCa) according to age and risk category, using Prostate Cancer data Base Sweden, including 168,793 men younger than age 90 years, diagnosed 1998–2016 with PCa. RS and CSS were compared according to age and risk category based on TNM (tumor, nodes, and metastases) stage, Gleason score, and prostate-specific antigen level. Each framework requires assumptions that are unlikely to be appropriate for PCa. Ten-year RS was substantially higher than CSS in men aged 80–89 with low-risk PCa: 125% (95% confidence interval: 113, 138) versus 85% (95% confidence interval: 82, 88). In contrast, RS and CSS were similar for men under age 70 and for all men with regional or distant metastases. Both RS and CSS produce biased estimates of net survival for men with low- and intermediate-risk PCa, in particular for men over 80. Due to biases, net survival is overestimated in analysis of RS but underestimated in analysis of CSS. These results highlight the importance of evaluating the underlying assumptions for each method, because the “true” net survival is expected to lie between the limits of RS and CSS.

The 90-day cause-specific mortality after radical prostatectomy: a nationwide population-based study

OBJECTIVE

To investigate the cause-specific mortality in the postoperative period after radical prostatectomy (RP) for prostate cancer (PCa).

METHODS

In the National Prostate Cancer Register of Sweden (NPCR), we identified all men who died within 90 days after RP performed 1998-2018 and we assessed cause of death in a chart review. We compared the adjudications of death from our medical record review with those in in the Swedish Cause of Death Registry (CDR).

RESULTS

Out of 44 635, 58 (0.13%) men who had undergone RP from 1998 through 2018 died within 90 days after RP. Per medical record review the most common causes of death were cardiac disease (30%) and venous thromboembolic events (VTE; 21%). No men died of metastatic PCa as was first indicated in the CDR. After robot-assisted RP (RARP) or open retropubic RP (RRP), the postoperative mortality was 0.09% (19/21 520) and 0.19% (37/19 635), respectively. The effect off modality was confounded mainly by year of surgery, age at surgery, Charlson Comorbidity Index score and the concomitant pelvic lymph node dissection.

CONCLUSION

The validated absolute 90-day mortality after RP was 1.3/1000 during the 21-year study period. Cardiovascular diseases were the most common causes of death after RP. Our validation of the CDR refuted the occurrence of postoperative deaths from metastatic PCa. There were differences in rates and type of mortality between RRP and RARP, but the RARP cohort was more recent than the RRP cohort, which likely explain the differences.

Risk of esophageal and gastric adenocarcinoma in men receiving androgen deprivation therapy for prostate cancer

The aim of this study was to explore the male predominance in esophageal and gastric adenocarcinoma by evaluating the preventive potential of androgen deprivation therapy (ADT). This matched cohort study was based on a national Swedish database of prostate cancer patients in 2006-2013. Prostate cancer patients receiving ADT were the exposed group. Prostate cancer-free men from the general population were randomly selected and matched to the index case by birth year and county of residence, forming the unexposed control group. The participants were followed until a diagnosis of esophageal or gastric cancer, death, emigration, or end of the study period. The risk of esophageal adenocarcinoma, cardia gastric adenocarcinoma, non-cardia gastric adenocarcinoma, and esophageal squamous-cell carcinoma among ADT-exposed compared to unexposed was calculated by multivariable Cox proportional hazard regression. The hazard ratios (HRs) and 95% confidence intervals (CIs) were adjusted for confounders. There was a risk reduction of non-cardia gastric adenocarcinoma among ADT-users compared to non-users (HR 0.49 [95% CI 0.24-0.98]). No such decreased risk was found for esophageal adenocarcinoma (HR 1.17 [95% CI 0.60-2.32]), cardia gastric adenocarcinoma (HR 0.99 [95% CI 0.40-2.46]), or esophageal squamous cell carcinoma (HR 0.99 [95% CI 0.31-3.13]). This study indicates that androgen deprivation therapy decreases the risk of non-cardia gastric adenocarcinoma, while no decreased risk was found for esophageal adenocarcinoma, cardia gastric adenocarcinoma, or esophageal squamous-cell carcinoma.

Temporal changes in cause-specific death in men with localised prostate cancer treated with radical prostatectomy: a population-based, nationwide study

Background and Objective

Changes in diagnostic work‐up, histopathological assessment, and treatment of men with prostate cancer during the last 20 years have affected the prognosis. The objective was to investigate the risk of prostate cancer death in men with clinically localised prostate cancer treated with radical prostatectomy in Sweden in 2000–2010.

Methods

Population‐based, nationwide, study on men with clinically localised prostate cancer treated with radical prostatectomy in the period 2000–2010. Cox regression analyses were used to assess differences in risk of prostate cancer death according to calendar period for diagnosis and stratified on risk category.

Results

The study included 19 330 men with a median follow‐up of 12.4 years. Men diagnosed in 2007–2008 and 2009–2010 had a significantly lower risk of prostate cancer death compared to men diagnosed in 2000–2002. The reduced risk of prostate cancer death was restricted to men with intermediate‐risk prostate cancer with no differences observed in men with low‐ or high‐risk prostate cancer.

Conclusion

During the study period, the risk of prostate cancer death decreased in the total population of men with localised prostate cancer treated with radical prostatectomy. The decrease was restricted to men with intermediate‐risk prostate cancer.

Association of surgeon and hospital volume with short-term outcomes after robot-assisted radical prostatectomy: Nationwide, population-based study

Background and objective

Few studies have investigated the association between surgical volume and outcome of robot-assisted radical prostatectomy (RARP) in an unselected cohort. We sought to investigate the association between surgical volume with peri-operative and short-term outcomes in a nation-wide, population-based study group.

Methods

9,810 RARP’s registered in the National Prostate Cancer Register of Sweden (2015–2018) were included. Associations between outcome and volume were analyzed with multivariable logistic regression including age, PSA-density, number of positive biopsy cores, cT stage, Gleason score, and extent of lymph node dissection.

Results

Surgeons and hospitals in the highest volume group compared to lowest group had shorter operative time; surgeon (OR 9.20, 95% CI 7.11–11.91), hospital (OR 2.16, 95% CI 1.53–3.06), less blood loss; surgeon (OR 2.58. 95% CI 2.07–3.21) hospital (no difference), more often nerve sparing intention; surgeon (OR 2.89, 95% CI 2.34–3.57), hospital (OR 2.02, 95% CI 1.66–2.44), negative margins; surgeon (OR 1.90, 95% CI 1.54–2.35), hospital (OR 1.28, 95% CI 1.07–1.53). There was wide range in outcome between hospitals and surgeons with similar volume that remained after adjustment.

Conclusions

High surgeon and hospital volume were associated with better outcomes. The range in outcome was wide in all volume groups, which indicates that factors besides volume are of importance. Registration of surgical performance is essential for quality control and improvement.

How reliable are surgeon-reported data? A comparison of the British Association of Urological Surgeons radical prostatectomy audit with the National Prostate Cancer Audit Hospital Episode Statistics-linked database

OBJECTIVES

To evaluate the accuracy and completeness of surgeon-reported radical prostatectomy outcome data across a national health system by comparison with a national dataset gathered independently from clinicians directly involved in patient care.

PATIENTS AND METHODS

Data submitted by surgeons to the British Association of Urological Surgeons (BAUS) radical prostatectomy audit for all men undergoing radical prostatectomy between 2015 and 2016 were assessed by cross linkage to the National Prostate Cancer Audit (NPCA) database. Specific data items collected in both databases were selected for comparison analysis. Data completeness and agreement were assessed by percentages and Cohen's kappa statistic.

RESULTS

Data from 4707 men in the BAUS and NPCA databases were matched for comparison. Compared with the NPCA, dataset completeness was higher in the BAUS dataset for type of nerve-sparing procedure (92% vs 42%) and postoperative margin status (89% vs 48%) but lower for readmission (87% vs 100%) and Charlson score (80% vs 100%). For all other variables assessed completeness was comparable. Agreement and data reliability were high for most variables. However, despite good agreement, the inter-cohort reliability was poor for readmission, M stage and Charlson score (κ < 0.30).

CONCLUSIONS

For the first time in urology we show that surgeon-reported data from the BAUS radical prostatectomy audit can reliably be used to benchmark peri-operative radical prostatectomy outcomes. For comorbidity data, to assist with risk analysis, and longer-term outcomes, NPCA routinely collected data provide a more comprehensive source.

Waist circumference and a body shape index and prostate cancer risk and mortality

We recently found a negative association between body mass index (BMI) and the risk of localised prostate cancer (PCa), no association with advanced PCa, and a positive association with PCa‐specific mortality. In a 15% subpopulation of that study, we here investigated the measures of abdominal adiposity including waist circumference (WC) and A Body Shape Index (ABSI) in relation to PCa risk and mortality. We used data from 58,457 men from four Swedish cohorts to assess WC and ABSI in relation to PCa risk according to cancer risk category, including localised asymptomatic and symptomatic PCa and advanced PCa, and PCa‐specific mortality. Cox regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). During, on average, 10 years of follow‐up, 3290 men were diagnosed with PCa and 387 died of PCa. WC was negatively associated with the risk of total PCa (HR per 10 cm, 0.95; 95% CI 0.92–0.99), localised PCa (HR per 10 cm, 0.93, 95% CI 0.88–0.96) and localised asymptomatic PCa cases detected through a prostate‐specific antigen (PSA) test (HR per 10 cm, 0.87, 95% CI 0.81–0.94). WC was not associated with the risk of advanced PCa (HR per 10 cm, 1.02, 95% CI 0.93–1.14) or with PCa‐specific mortality (HR per 10 cm, 1.04, 95% CI 0.92–1.19). ABSI showed no associations with the risk of PCa or PCa‐specific mortality. While the negative association between WC and the risk of localised PCa was partially driven by PSA‐detected PCa cases, no association was found between abdominal adiposity and clinically manifest PCa in our population.

The Value of Real-World Data in Understanding Prostate Cancer Risk and Improving Clinical Care: Examples from Swedish Registries

Simple Summary

Real-world data (RWD), i.e., data reflecting normal clinical practice collected outside the constraints of randomised controlled trials, provide important insights into our understanding of prostate cancer and its management. Clinical cancer registries are an important source of RWD. Depending on their scope and the potential linkage to other data sources, registry-based data can be utilised to address a variety of questions including risk factors, healthcare utilisation, treatment effectiveness, adverse effects, disparities in healthcare access, quality of care and healthcare economics. This review describes the various registry-based RWD sources for prostate cancer research in Sweden (namely the National Prostate Cancer Register, the Prostate Cancer data Base Sweden (PCBaSe) and the Patient-overview Prostate Cancer) and documents their utility for better understanding prostate cancer aetiology and improving clinical care.

Abstract

Real-world data (RWD), that is, data from sources other than controlled clinical trials, play an increasingly important role in medical research. The development of quality clinical registers, increasing access to administrative data sources, growing computing power and data linkage capacities have contributed to greater availability of RWD. Evidence derived from RWD increases our understanding of prostate cancer (PCa) aetiology, natural history and effective management. While randomised controlled trials offer the best level of evidence for establishing the efficacy of medical interventions and making causal inferences, studies using RWD offer complementary evidence about the effectiveness, long-term outcomes and safety of interventions in real-world settings. RWD provide the only means of addressing questions about risk factors and exposures that cannot be “controlled”, or when assessing rare outcomes. This review provides examples of the value of RWD for generating evidence about PCa, focusing on studies using data from a quality clinical register, namely the National Prostate Cancer Register (NPCR) Sweden, with longitudinal data on advanced PCa in Patient-overview Prostate Cancer (PPC) and data linkages to other sources in Prostate Cancer data Base Sweden (PCBaSe).

Validation of data quality in the National Swedish Kidney Cancer Register

INTRODUCTION

The National Swedish Kidney Cancer Register (NSKCR) was launched in 2005. It is used for health care quality improvement and research. The aim of this study was to validate the register's data quality by assessing the timeliness, completeness, comparability and validity of the register.

MATERIAL AND METHODS

To assess timeliness we evaluated the number of days between date of diagnosis and date of reporting the patient to the NSKCR. For completeness, we used data on number of cancer cases reported to the NSKCR compared to cases reported to the Swedish Cancer Register. Comparability was evaluated by reviewing coding routines and comparing data collected in the NSKCR to national and international guidelines. Validity was assessed by reabstraction of data from medical charts from 431 randomly selected patients diagnosed in 2007, 2010, 2013 and 2016.

RESULTS

Timeliness has improved since the register started. In 2016, 76.9% and 96.5% of the patients were reported within 6 and 12 months respectively. Completeness was high, with a 99.5% coverage between 2008 and 2017. Registration forms and manuals were updated according to national and European guidelines. Improvements have been made continuously to decrease the risk of reporting mistakes and misunderstandings. Validity was high where a majority of the variables demonstrated an exact agreement >90% and few missing values.

CONCLUSION

Overall, the data quality of the NSKCR is high. Completeness, comparability and validity is high. Timeliness can be further improved, which will make it easier to follow changes and improve the care and research of RCC patients.

Time spent in hormone-sensitive and castration-resistant disease states in men with advanced prostate cancer, and its health economic impact: registry-based study in Sweden

OBJECTIVE

To investigate time spent in hormone-sensitive and castration-resistant disease states in men with advanced prostate cancer in Sweden, and the associated health economic impact.

MATERIALS AND METHODS

Registry study (NCT03619980) of the Prostate Cancer data Base Sweden with data from the National Prostate Cancer Register, including the Patient-overview Prostate Cancer (PPC) and other national healthcare registries. The primary endpoint was time in each disease state. Secondary endpoints were co-medications, comorbidities and healthcare resource utilization (HRU) and cost in each disease state.

RESULTS

In total, 1,869 men with advanced prostate cancer registered in PPC between 2014 and 2016, with data on the start of androgen deprivation therapy, were identified. Median time to progression and median survival were 4 and 11 years, respectively, for men with non-metastatic (nm) hormone-sensitive prostate cancer (HSPC); 1 and 7 years for men with metastatic (m) HSPC; and 1 and 8.5 years for men with nm castration-resistant prostate cancer (CRPC). Median survival for men with mCRPC was 4 years. Total annual mean costs for HRU per patient increased with increasing severity of disease, from 41,064 Swedish krona (SEK) for nmHSPC to 288,242 SEK for mCRPC.

CONCLUSION

Progression time from mHSPC and nmCRPC to the mCRPC state was short and survival in the mCRPC state was approximately 4 years. Survival times were longer than expected, likely due to the selection of long-term survivors among prevalent cases. Healthcare costs were high for men with mCRPC. Further studies are needed to confirm our pilot study findings.

The power of empirical data; lessons from the clinical registry initiatives in Scandinavian cancer care

BACKGROUND

In Scandinavia, there is a strong tradition for research and quality monitoring based on registry data. In Denmark, Norway and Sweden, 63 clinical registries collect data on disease characteristics, treatment and outcome of various cancer diagnoses and groups based on process-related and outcome-related variables.

AIM

We describe the cancer-related clinical registries, compare organizational structures and quality indicators and provide examples of how these registries have been used to monitor clinical performance, develop prediction models, assess outcome and provide quality benchmarks. Further, we define unmet needs such as inclusion of patient-reported outcome variables, harmonization of variables and barriers for data sharing.

RESULTS AND CONCLUSIONS

The clinical registry framework provides an empirical basis for evidence-based development of high-quality and equitable cancer care. The registries can be used to follow implementation of new treatment principles and monitor patterns of care across geographical areas and patient groups. At the same time, the lessons learnt suggest that further developments and coordination are needed to utilize the full potential of the registry initiative in cancer care.

Height, body mass index and prostate cancer risk and mortality by way of detection and cancer risk category

Obesity is a risk factor for advanced, but not localised, prostate cancer (PCa), and for poor prognosis. However, the detection of localised PCa through asymptomatic screening might influence these associations. We investigated height and body mass index (BMI) among 431 902 men in five Swedish cohorts in relation to PCa risk, according to cancer risk category and detection mode, and PCa-specific mortality using Cox regression. Statistical tests were two-sided. Height was positively associated with localised intermediate-risk PCa (HR per 5 cm, 1.03, 95% CI 1.01-1.05), while overweight and obesity were negatively associated with localised low- and intermediate-risk PCa (HRs per 5 kg/m² , 0.86, 95% CI 0.81-0.90, and 0.92, 95% CI 0.88-0.97). However, these associations were partially driven by PCa's detected by asymptomatic screening and, for height, also by symptoms unrelated to PCa. The HR of localised PCa's, per 5 kg/m² , was 0.88, 95% CI 0.83 to 0.92 for screen-detected PCa's and 0.96, 95% CI 0.90 to 1.01 for PCa's detected through lower urinary tract symptoms. BMI was positively associated with PCa-specific mortality in the full population and in case-only analysis of each PCa risk category (HRs per 5 kg/m² , 1.11-1.22, P for heterogeneity = .14). More active health-seeking behaviour among tall and normal-weight men may partially explain their higher risk of localised PCa. The higher PCa-specific mortality among obese men across all PCa risk categories in our study suggests obesity as a potential target to improve the prognosis of obese PCa patients.

Radical radiotherapy for prostate cancer: patterns of care in Sweden 1998-2016

Introduction: Radiotherapy is an established treatment option for prostate cancer (PCa), both as primary treatment and secondary treatment after radical prostatectomy (RP). Since 1998, detailed data on radiotherapy delivered to Swedish men with PCa (e.g. treatment modalities, absorbed doses, fractionation) have been collated within PCa data Base Sweden (PCBaSe). This study reports patterns of radical radiotherapy for PCa in Sweden over the past two decades.Materials and methods: All men with non-metastatic PCa (1998-2016) who received external beam radiotherapy (EBRT) or high or low dose-rate brachytherapy (HDR-BT/LDR-BT) were identified in PCBaSe. Analyses included: trends in radiation techniques, fractionation patterns and total doses over time; PCa-specific survival comparing treatment in 2007-2017 with 1998-2006; and regional variation in type of primary radiotherapy.Results: About 20,876 men underwent primary radiotherapy. The main treatment modalities include conventionally fractionated (2.0 Gy/fraction) EBRT (51%), EBRT with HDR-BT boost (27%) and hypofractionated (>2.4 Gy/fraction) EBRT (11%). EBRT with photon or proton boost and HDR-BT and LDR-BT monotherapies were each used minimally. Use of dose-escalated EBRT (>74 Gy) and moderate hypofractionation increased over time, while use of HDR-BT declined. Considerable regional variation in treatment modalities was apparent. Risk of PCa death following primary radiotherapy had declined for intermediate-risk (HR: 0.60; 95%CI 0.47-0.87) and high-risk PCa (HR: 0.72; 95%CI 0.61-0.86).Discussion: Increased use of dose escalation and hypofractionated EBRT has occurred in Sweden over the past two decades, reflecting current evidence and practice guidelines. Disease-specific outcomes have also improved. Data collected in PCBaSe provide an excellent resource for further research into RT use in PCa management.

Androgen deprivation therapy in patients with localized disease: Comparison with curative intent treatments and time to castration resistance. Results of the Spanish Prostate Cancer Registry

BACKGROUND

The effect of primary androgen deprivation therapy (ADT) in patients with localized prostate cancer (PCa) has not been well documented. The objective of the present study was to analyze the outcome of tumors treated with ADT as primary therapy in the Spanish Prostate Cancer Registry (19.4% of the series).

PATIENTS AND METHODS

Patients were classified in three groups: 1) with low/intermediate risk clinically localized tumors; 2) with high risk and locally advanced (T3-4) tumors; 3) with metastatic tumors. Time to castration resistance and overall cancer-specific survival were analyzed. In non-metastatic tumors, survivals in patients treated with ADT were compared with data from patients who underwent local treatments from the Spanish Prostate Cancer Registry.

RESULTS

703 cases were analyzed. There were significant differences in the time to castration resistance, which was lower in the group of metastatic tumors. During follow-up, there were 179 deaths (25.5%) of which 89 (12.6%) were due to PCa. After 3 years of ADT, only 14.6% of patients in group 1 had died (1% due to PCa), 20.5% in group 2 and 46.8% in group 3 (9.2% and 31.3% due to PCa, respectively). Cancer-specific survival was significantly worse in group 1 using ADT than radical prostatectomy or radiotherapy. In high-risk and locally advanced tumors, ADT also had a lower cancer-specific survival than local treatments.

CONCLUSION

A longer time until the castration resistance was observed in patients with well- and intermediate-risk localized tumors treated with ADT. Patients with metastatic tumors showed the shortest time to castration resistance.

Second Cancers in Patients With Locally Advanced Prostate Cancer Randomized to Lifelong Endocrine Treatment With or Without Radical Radiation Therapy: Long-Term Follow-up of the Scandinavian Prostate Cancer Group-7 Trial

BACKGROUND

Curative radiation therapy (RT) constitutes a cornerstone in prostate cancer (PC) treatment. We present long-term follow-up estimates for second cancer (SC) risk and overall survival (OS) in patients randomized to hormone therapy (ET) alone or combined with 70 Gy prostatic RT in the Scandinavian Prostate Cancer Group-7 (SPCG-7) study. We explored the effect of salvage RT (≥60 Gy to the ET group) and reported causes of death.

METHODS AND MATERIALS

The SPCG-7 study (1996-2002) was a randomized controlled trial that included 875 men with locally advanced nonmetastatic PC. In this analysis, including data from the Norwegian and Swedish Cancer and Cause of Death registries for 651 Norwegian and 209 Swedish study patients, we estimated hazard ratios (HRs) for SC and death, and cumulative incidences of SC.

RESULTS

Median follow-up of the 860 (431 ET and 429) ET + RT patients was 12.2 years for SC risk analysis and 12.6 years for the OS analysis. Eighty-three of the Norwegian ET patients received salvage RT, and median time to salvage RT was 5.9 years. We found 125 and 168 SCs in the ET and ET + RT patients, respectively. With ET alone as reference, ET + RT patients had an HR of 1.19 (95% confidence interval [CI], 0.92-1.54) for all SCs and 2.54 (95% CI, 1.14-5.69) for urinary bladder cancer (UBC). The total number of UBC was 31 (23 in ET + RT; 8 in ET), and the vast majority (85%) were superficial. The HR for SC in salvage RT patients was 0.48 (95% CI, 0.24-0.94). Median OS was 12.8 (95% CI, 11.8-13.8) and 15.3 (95%, CI 14.3-16.4) years in the ET and ET + RT groups, respectively. Compared with ET alone, the risk of death was reduced in ET + RT patients (HR, 0.73; 95% CI, 0.62-0.86) and in ET patients receiving salvage RT (HR, 0.44; 95% CI, 0.30-0.65).

CONCLUSIONS

Although the risk of UBC was increased in PC patients who received RT in addition to ET, this disadvantage is outweighed by the OS benefit of RT confirmed in our study. The risk of SC, and especially UBC, should be discussed with patients and be reflected in follow-up programs.

Prediction of metastatic prostate cancer by prostate-specific antigen in combination with T stage and Gleason Grade: Nationwide, population-based register study

The objective was to investigate the proportion of men with metastatic prostate cancer in groups defined by T stage, Gleason Grade Group (GGG) and serum levels of prostate-specific antigen (PSA) and if PSA can be used to rule in metastatic prostate cancer when combined with T stage and GGG. We identified 102,076 men in Prostate Cancer data Base Sweden 4.0 who were diagnosed with prostate cancer in 2006–2016. Risk of metastases was assessed for PSA stratified on T stage and five-tiered GGG. For men who had not undergone bone imaging, we used multiple imputation to classify metastatic prostate cancer. Advanced T stage, high GGG and high PSA were related to bone metastases. For example: only 79/38 190 (0.2%) of men with T1-2 and GGG 1 had PSA above 500 ng/mL, and 29/79 (44%) of these men had metastases; whereas 1 154/7 018 (16%) of men with T3-4 and GGG 5 had PSA above 500 ng/ml and 1 088/1 154 (94%) of these men had metastases. However, no PSA cut-off could accurately identify the majority of men with metastatic prostate cancer (i.e. high sensitivity) while also correctly classifying most men without metastasis (i.e. high specificity). In conclusion, these results support the use of imaging to confirm bone metastases in men with advanced prostate cancer as no PSA level in combination with T stage and GGG could accurately rule in metastatic prostate cancer and thereby safely omit bone imaging.

Current routines for antibiotic prophylaxis prior to transrectal prostate biopsy: a national survey to all urology clinics in Sweden

Background: The risk of infection after transrectal ultrasound (TRUS)-guided prostate biopsies is increasing. The aim of the study was to assess the use of antibiotic prophylaxis for prostate biopsy in Sweden. Methods: All public and private urology clinics reporting to the National Prostate Cancer Register of Sweden received a survey on TRUS-biopsy prophylaxis. Results: Of the 84 clinics surveyed, 76 replied (90%). If no risk factors for infection were present, a single dose of ciprofloxacin 750 mg was used by 50 clinics (66%). Multiple doses of ciprofloxacin 500 or 750 mg (n=14; 18%) or a single dose of trimethoprim-sulfamethoxazole 160/800 mg (n=7; 9%) were other common prophylaxes. Most clinics gave the prophylaxes immediately before the biopsy (n=41; 54%). Urine dipstick was used by 30 clinics (39%) and rectal enema by six (8%). In patients with high risk of infection, the survey mirrors a large variety of regiments used. Conclusions: The preference to use a single dose of ciprofloxacin 750 mg is in accordance with the Swedish national guidelines for patients with a low risk of infection. Better compliance to the guideline recommendation to use a urine dipstick would probably increase the number of patients classified as having an increased risk of infection. Being classified as a high-risk patient should lead to an extended duration of antibiotic prophylaxis, however, the variety of regimens used in the high-risk group reflects an inability to treat these patients in a standardized fashion and also highlights a need for more clear-cut guidelines. Pre-biopsy identification of high-risk patients is an important issue to tackle for the urologic clinics in order to reduce the number of infections.

Development and validation of a prediction model for identifying men with intermediate- or high-risk prostate cancer for whom bone imaging is unnecessary: a nation-wide population-based study

Objective: To develop and validate a nomogram that identifies men for whom bone scan is unnecessary.Material and methods: The study datasets were derived from the National Prostate Cancer Register (NPCR) of Sweden. All men in the NPCR ≤80 years of age who were diagnosed with intermediate- or high-risk prostate cancer and who had pretreatment bone imaging (^99mTc MDP scintigraphy, plain x-ray, computed tomography, magnetic resonance imaging, and/or positron emission tomography fused with computed tomography) were included. Men diagnosed from 2015-2016 formed a development dataset and men diagnosed in 2017 formed a validation dataset. Outcome was metastasis on bone imaging as registered in NPCR. Multivariable logistic regression was used to develop a nomogram.Results: In the development dataset 482/5084 men (10%) had bone metastasis, the corresponding percentage in the validation dataset was 282/2554 (11%). Gleason grade group, clinical T stage, and prostate-specific antigen were included in the final model. Discrimination and calibration were satisfactory in both the development (AUC 0.80, 95% CI 0.78-0.82) and validation dataset (AUC 0.80, 95% CI, 0.77-0.82). Compared with using the EAU guidelines' recommendation for selecting men for imaging, using the nomogram with a cut-off at 4% chance of bone metastasis, would have avoided imaging in 519/2068 men (25%) and miss bone metastasis in 10/519 (2%) men in the validation dataset.Conclusion: By use of our nomogram, bone scans of men with prostate cancer can be avoided in a large proportion of men.