RESUMO
Validation of biobanks and large cancer cohorts is essential in ensuring high-quality research results. We examined the coverage, generalisability and validity of the lymphoma collection of the Uppsala-Umeå Comprehensive Cancer Consortium (U-CAN) biobank in Sweden, one of the largest cancer biobanks in Europe. Up until 2022, 889 lymphoma patients in U-CAN Uppsala had available samples, and 329 in U-CAN Umeå. Patients diagnosed in the U-CAN Uppsala area 2011-2021 (n = 843) were linked to the nationwide Swedish Lymphoma Register, and a subset diagnosed before 2019 (n = 727) to population-based registers. The coverage was 39% of all lymphoma patients between 2011 and 2019 diagnosed in the U-CAN Uppsala area, with a pandemic decline to 10% during 2020-2021. The patients included had superior overall survival (hazard ratio = 0.70 [95% confidence interval, CI: 0.60-0.82]) than all lymphoma patients in Sweden. They had better performance status, were younger (odds ratio [OR] = 0.21 [95% CI: 0.13-0.34]) and had less comorbidities (OR = 0.66 [95% CI: 0.56-0.78]). However, cause-specific survival and stage distribution were similar. The questionnaire data captured less comorbidities compared to the national registers. Evaluations of biobanks are important, as even population-based biobanks such as U-CAN select younger patients with higher socioeconomical status and better performance status. However, the similar cause-specific survival as in the registries suggests U-CANs usefulness for prognostic biomarker studies.
RESUMO
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.