Evaluation of Anticancer Therapy-Related Tumor Flare Reaction: Insights From Food and Drug Administration's Adverse...

Tumor flare reaction (TFR) is characterized by an increase in tumor size during immunotherapy, often resembling disease progression. This study explores the relationship between anti-tumor drugs and tumor flare reaction (TFR) through the FAERS database to assist clinicians in better patient management.

We analyzed the FAERS database to identify TFR cases reported from Q1 2004 to Q3 2024. For signal detection, we employed disproportionality analysis with four algorithms-reported odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN), and empirical Bayes geometric mean (EBGM). These algorithms assessed statistical correlations between anticancer drugs and TFR, based on a 2 × 2 contingency table framework.

From Q1 2004 to Q3 2024, 566 TFR cases were recorded in the FAERS database. The incidence of TFR peaked in 2023, with the highest increase in cases from 2021 to 2022, at 4.9%. A total of 28 anticancer drugs were identified as strongly associated with TFR, of which only 4 are explicitly listed in the medication instructions as having TFR-related adverse reactions. Lenalidomide was the most frequent drug causing TFR, accounting for 38% of all TFR reports.

Our findings highlight the key associations between treatment drugs and TFR, particularly targeted therapies such as Rituximab, which are not explicitly marked for this side effect in the FAERS database. The study emphasizes the need for clinicians to closely monitor TFR in patients receiving certain cancer treatments and improve therapeutic strategies to mitigate TFR risks, ensuring safer cancer treatment outcomes.