Evaluation of coverage, generalisability and validity of the U-CAN lymphoma biobank in Sweden: A comparison with nationwide registers.

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.