Were cancer patients worse off than the general population during the COVID-19 pandemic? A population-based study from Norway, Denmark and Iceland during the pre-vaccination era

Anna L V Johansson; Anna Skog; Tom Børge Johannesen; Tor Åge Myklebust; Charlotte Wessel Skovlund; Lina Steinrud Mørch; Søren Friis; Mads Gamborg; Marnar Fríðheim Kristiansen; David Pettersson; Elínborg J Ólafsdóttir; Helgi Birgisson; Runolfur Palsson; Elias Eythorsson; Sandra Irenaeus; Mats Lambe; Giske Ursin

doi:10.1016/j.lanepe.2023.100680

Were cancer patients worse off than the general population during the COVID-19 pandemic? A population-based study from Norway, Denmark and Iceland during the pre-vaccination era

Lancet Reg Health Eur. 2023 Jul 10:31:100680. doi: 10.1016/j.lanepe.2023.100680. eCollection 2023 Aug.

Authors

Anna L V Johansson^{1

2}, Anna Skog¹, Tom Børge Johannesen¹, Tor Åge Myklebust^{1

3}, Charlotte Wessel Skovlund⁴, Lina Steinrud Mørch⁴, Søren Friis⁴, Mads Gamborg⁴, Marnar Fríðheim Kristiansen^{5

6}, David Pettersson⁷, Elínborg J Ólafsdóttir⁸, Helgi Birgisson⁸, Runolfur Palsson^{9

10}, Elias Eythorsson⁹, Sandra Irenaeus^{11

12}, Mats Lambe^{2

11}, Giske Ursin^{1

13

14}

Affiliations

¹ Cancer Registry of Norway, P.O. Box 5313 Majorstuen, Oslo N-0304, Norway.
² Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, P.O. Box 281, Stockholm SE-17177, Sweden.
³ Department of Research and Innovation, Møre and Romsdal Hospital Trust, Ålesund, Norway.
⁴ Cancer Surveillance and Pharmacoepidemiology, Danish Cancer Society Research Center, Danish Cancer Society, Strandboulevarden 49, Copenhagen DK-2100, Denmark.
⁵ Center of Health Science, Faculty of Health Sciences, Tórshavn, Faroe Islands.
⁶ National Hospital of the Faroe Islands, Tórshavn, Faroe Islands.
⁷ National Board of Health and Welfare, Stockholm SE-106 30, Sweden.
⁸ ICS Research and Registration Center, Icelandic Cancer Society, P.O. Box 5420, 105 Reykjavík, Iceland.
⁹ Landspitali-The National University Hospital of Iceland, Saemundargata 2, 102 Reykjavík, Iceland.
¹⁰ University of Iceland, Reykjavik, Iceland.
¹¹ Regional Cancer Center Central Sweden, Akademiska Sjukhuset, Uppsala SE-751 85, Sweden.
¹² Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
¹³ Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
¹⁴ Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA.

Abstract

Background: In a population-based setting, we investigated the risks of testing positive for SARS-CoV-2 and developing severe COVID-19 outcomes among cancer patients compared with the general population.

Methods: In nationwide cohorts, we identified all individuals in Norway, Denmark and Iceland who tested positive for SARS-CoV-2 or had a severe COVID-19 outcome (hospitalisation, intensive care, and death) from March until December 2020, using data from national health registries. We estimated standardised incidence ratios (SIRs) with 95% confidence intervals (CIs) comparing cancer patients with the general population.

Findings: During the first wave of the pandemic, cancer patients in Norway and Denmark had higher risks of testing SARS-CoV-2 positive compared to the general population. Throughout 2020, recently treated cancer patients were more likely to test SARS-CoV-2 positive. In Iceland, cancer patients experienced no increased risk of testing positive. The risk of COVID-19-related hospitalisation was higher among cancer patients diagnosed within one year of hospitalisation (Norway: SIR = 2.43, 95% CI 1.89-3.09; Denmark: 2.23, 1.96-2.54) and within five years (Norway: 1.58, 1.35-1.83; Denmark: 1.54, 1.42-1.66). Risks were higher in recently treated cancer patients and in those diagnosed with haematologic malignancies, colorectal or lung cancer. Risks of COVID-19-related intensive care and death were higher among cancer patients.

Interpretation: Cancer patients were at increased risk of testing positive for SARS-CoV-2 during the first pandemic wave when testing availability was limited, while relative risks of severe COVID-19 outcomes remained increased in cancer patients throughout 2020. Recent cancer treatment and haematologic malignancy were the strongest risk factors.

Funding: Nordic Cancer Union.

Keywords: COVID-19; Cancer; Coronavirus disease 2019; Critical care outcomes; Denmark; Hospitalisation; Iceland; Intensive care; Mortality; Nordic; Norway; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2.