medwireNews: Researchers have found no significant difference in the tolerability of the Moderna (mRNA-1273) SARS-CoV-2 vaccine among cancer patients who received radiotherapy in the 6 months prior to vaccination and cancer-free controls.
They explain in a comment published in The Lancet Oncology that “[b]ecause radiotherapy might affect the immune system by both suppressing and enhancing the immune response, the safety of the COVID-19 vaccines might be different in this specific setting.”
The team therefore assessed the early (up to 7 days after vaccine administration) and late (up to 28 days after) local and systemic side effects of the Moderna vaccine in 153 cancer patients who had received radiotherapy in the past 6 months. The first dose of the vaccine was administered between April 5 and 8, 2021, and the second between May 3 and 6. One patient received just a single dose as they had contracted the virus 4 months before the first dose.
Participants were aged a median of 72 years, and the most common tumor type was breast cancer (49%), followed by prostate cancer (27%). The majority (62%) had received radiotherapy in the postoperative setting, and treatment was ongoing in 27% at the time of vaccination.
The study also included a group of 185 cancer-free volunteers who received two doses of the Moderna vaccine between March 1 and May 10, 2021, and were interviewed during June 10–16 to grade the previously recorded adverse events (AEs) according to the US Centers for Disease Control and Prevention vaccine AE reporting system.
In all, 58% of cancer patients experienced an early or late AE of grade 1 after the first dose, as did 72% of controls, and an identical 41% of participants of each group experienced such AEs after the second dose.
Among participants with cancer, the rates of grade 2 or worse AEs after the first and second dose were 9% and 34%, respectively, with corresponding rates of 8% and 60% among the controls.
In both cancer patients and controls, the maximum grade of early AEs after the first dose was grade 3, while it was grade 4 after the second dose. For late AEs, the maximum grade after the first dose was grade 3 in both groups, but was grade 2 after the second dose among patients and grade 3 among controls.
There was a significant increase in the use of antipyretic or pain medication between the first and second dose in participants with cancer, rising from 5% to 21%, and also among the cancer-free controls, from 3% to 35%.
“We found that tolerance to the Moderna mRNA-1273 vaccine was not worse in patients who have undergone or are having radiotherapy than in healthy controls both for early adverse events […] and late adverse effects,” summarize Silvia Scoccianti (Santa Maria Annunziata Hospital, Florence, Italy) and collaborators.
They continue: “[O]ur data, although based on a small number of patients and limited by the observational nature of the study, showed that the safety profile of the Moderna mRNA-1273 vaccine does not raise any specific concerns in patients with cancer who received radiotherapy in the past 6 months.”
medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2021 Springer Healthcare Ltd, part of the Springer Nature Group
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Lancet Oncol 2021; doi:10.1016/ S1470-2045(21)00427-7