medwireNews: Child, adolescent and young adult survivors of childhood cancer do not have a greater risk of COVID-19 infection and severe illness than individuals without a history of cancer, suggest findings from a population-based study published in the Journal of Clinical Oncology.
“These results can be used to inform appropriate risk-counseling of survivors and their caregivers, particularly those in their thirties and younger”, says the team of Canadian researchers, led by Sumit Gupta, from The Hospital for Sick Children in Toronto, Ontario.
The investigators identified 12,410 individuals who had survived for at least 5 years after being diagnosed with either a childhood cancer by age 17 years between 1985 and 2014 or with an adolescent or young adult cancer at age 15–21 years between 1992 and 2012.
These survivors were each matched by birth year, sex and residence to 10 cancer-free individuals in the general population. On 1 January 2020, the cancer survivors were aged a median of 24 years and had survived a median 14.3 years since cancer diagnosis. A minority of survivors had experienced a relapse (8.5%) or a second malignancy (1.6%).
The survivors and controls were followed up until 31 July 2021. Analysis of population-based laboratory and healthcare databases revealed that survivors were significantly more likely than controls to have undergone at least one SARS-CoV-2 PCR test (41.6 vs 35.4%). But the rate of positive PCR tests for COVID-19 infection was similar in the groups, at 3.1% and 3.2%, respectively.
Multivariable analysis taking into consideration a raft of factors including demographics, tumour type, treatment and comorbidities showed that a positive test was significantly predicted by younger age, diabetes and living in a poor urban neighbourhood, observe Gupta et al.
The cancer survivors were 1.23 times more likely to be fully vaccinated than the controls (52.8 vs 47.0%), defined as having received at least one dose of the Johnson & Johnson (Ad26.COV2.S) vaccine or at least two doses of the Pfizer–BioNTech (BNT162b2), Moderna (mRNA-1273) or Oxford–AstraZeneca (ChAdOX1 nCoV-2019) vaccines at least 2 weeks prior to infection.
“No differences in severity outcomes were seen between infected survivors and infected controls”, the researchers write.
The cancer survivors and controls had comparable rates of emergency department visits (14.8 vs 12.9%) and hospitalisation (2.8 vs 1.7%), with a median of 3 days between a COVID-19 positive test result and either of these events.
Furthermore, there were no intensive care unit admissions or deaths among the cancer survivors, which the researchers describe as being “very reassuring”.
And in multivariable analysis, the only predictive factor for emergency department admission among the cancer survivors was a diagnosis of hypertension in the prior 2 years (adjusted odds ratio=4.1).
Noting that some studies of older cancer patients have suggested an increased risk of severe COVID-19 infection, Gupta et al suggest that “the protection afforded by the relatively young age of our survivor cohort (median age of 24 years, with a maximum age of 51 years) outweighs any risk associated with cancer survivorship.”
But the authors note that the study data collection ended before the SARS-CoV-2 Delta and Omicron variants became dominant in Toronto, and so their findings “may not be generalizable” to all variants.
They conclude: “Further study is warranted to determine the risk in older survivors, specific subsets of survivors, and that associated with novel COVID-19 variants.”
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This independent news story was supported by an educational grant from L’Institut Servier, Suresnes, France.