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BACKGROUND: Capture rate and representativity of quality registers need to be assessed in order to ensure that register data are generalizable. MATERIAL AND METHODS: In 1998-2009, 103 047 men had been diagnosed with prostate cancer and registered in the Swedish Cancer Register to which registration is mandated by law and of these men, 100 849 men (98%) had also been registered in The National Prostate Cancer Register (NPCR) of Sweden. We compared demographics, cancer treatment, comorbidity, and mortality in men in NPCR, with those who had only been registered in the Cancer Register, by use of data from the Cause of Death Register, the In-Patient Register and the Prescribed Drug Register. In addition, we identified 1929 men who had prostate cancer as underlying cause of death in the Cause of Death Register who had neither been registered in the Cancer Register nor in NPCR. RESULTS: Compared to men in NPCR, men only registered in the Cancer Register were slightly older, median age 72 versus 71 years, and a lower proportion underwent radical prostatectomy, 15% versus 27%. Ten year prostate cancer mortality was 23% (95% CI 20-25) for men in the Cancer Register only and 24% (95% CI 24-25) in NPCR, while mortality from competing causes was 28% (95% CI 26-31) and 30% (95% CI 30-30), respectively. Men identified with prostate cancer by a death certificate were old and had high comorbidity. CONCLUSION: The capture rate of NPCR is very high and there are only modest differences in demographics, cancer treatment, comorbidity, and mortality between the small proportion of men only registered in the Cancer Register and men registered in NPCR, indicating that information in NPCR can be generalized to all men with prostate cancer in Sweden.

BACKGROUND: Data in cancer quality registers are increasingly used for quality assurance, benchmarking, and research. 

MATERIALS AND METHODS: Data in the National Prostate Cancer Register (NPCR) of Sweden were evaluated for completeness, timeliness, comparability and validity. Completeness and timeliness were assessed by cross-linkage to the Swedish Cancer Register, comparability was examined by comparing registration routines in NPCR with national and international guidelines, and validity was assessed by re-abstraction of data from medical charts for 731 men diagnosed with prostate cancer (Pca) in 2009. Furthermore, data on treatment were validated by record linkage to the Swedish Patient Register and The Prescribed Drug Register. 

RESULTS: NPCR captured 98% of Pca cases in the Cancer Register and the mean value for completeness of the 48 evaluated variables was 90% (range 64-100%). Timeliness increased substantially from 2008 to 2012 with 95% of cases reported within 12months after diagnosis in 2012. NPCR complied with national and international coding routines. Overall, the agreement between original data and re-abstracted data from 731 charts was high. For example, the correlation between original and re-abstracted data was 1.00 for date of surgery, and 0.97 for serum levels of prostate specific antigen and exact agreement was 97% for Gleason score at biopsy, 83% for clinical local T stage and more than 95% of the androgen deprivation therapies registered in NPCR had a corresponding filled prescription. 

CONCLUSION: Record linkages with other data sources and re-abstraction of data showed that data quality in NPCR is high.

Introduction: 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 prostate cancer 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, 3 315 out 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% vs. 1%, diagnosis of benign prostatic hyperplasia 31% vs. 5%, received unspecified Pca cancer treatment 16% vs. 3%, had higher comorbidity, Charlson Comorbidity Index 2 or higher, 34% vs. 13%, and had lower Pca mortality 12% vs. 30%, but similar mortality from other causes.

Conclusion: Men with unknown risk category were rare in NPCR but distinctly different from other men in many aspects in particular regarding comorbidity and Pca mortality.

Patients with high socioeconomic status (SES) have better cancer outcomes than patients with low SES. This has also been shown in Sweden, a country with tax-financed health care aiming to provide care on equal terms to all residents. The association between income and educational level and diagnostics and treatment as outlined in national guidelines and prostate cancer (Pca) and all-cause mortality was assessed in 74,643 men by use of data in the National Prostate Cancer Register of Sweden and a number of other health care registers and demographic databases. In multivariable logistic regression analysis, men with high income had higher probability of Pca detected in a health-check-up, top versus bottom income quartile, odds ratio (OR) 1.60 (95% CI 1.45-1.77) and lower probability of waiting more than 3 months for prostatectomy, OR 0.77 (0.69-0.86). Men with the highest incomes also had higher probability of curative treatment for intermediate and high-risk cancer, OR 1.77 (1.61-1.95) and lower risk of positive margins, (incomplete resection) at prostatectomy, OR 0.80 (0.71-0.90). Similar, but weaker associations were observed for educational level. At 6 years of follow-up, Pca mortality was modestly lower for men with high income, which was statistically significant for localized high-risk and metastatic Pca in men with no comorbidities. All-cause mortality was less than half in top versus bottom quartile of income (12% vs. 30%, p < 0.001) among men above age 65. Our findings underscore the importance of adherence to guidelines to ensure optimal and equal care for all patients diagnosed with cancer.