Will tumors grow wildly after stopping the targeted drug Erdafitinib/Bocco?

Many urothelial cancer (bladder cancer) patients who are being treated with Erdafitinib (Erdafitinib) are most worried about whether their tumors will suddenly grow as soon as they stop taking the drug. This concern is very common in the field of targeted drugs, but judging from the explanations of professional organizations, the so-called "crazy growth after drug withdrawal" is not a direct rebound caused by the drug itself, but the natural process of the disease that becomes more prominent after the suspension of treatment.

Erdafitinib blocks tumor-dependent signaling pathways by inhibiting FGFR kinase activity. When patients stop taking drugs due to side effects, drug resistance, or other reasons, the originally inhibited pathways are reactivated, and the tumor may return to its own growth rate. This change makes people feel "sudden growth", but it is actually the original driving force of the disease being rediscovered, rather than the "acceleration" caused by the drug. After discontinuation of FGFR-targeting drugs, more attention should be paid to the resistance mechanism rather than uncontrolled proliferation. In some patients, the tumor has developed resistance to the drug before stopping the drug, so the progression of the disease may appear faster after stopping the drug.

Importantly, erdafitinib is an oral targeted drug with adjustable doses. In most cases, if the drug needs to be temporarily discontinued due to adverse reactions, disease control can still be regained by adjusting the dose and resuming use. Therefore, patients do not need to be unduly anxious about short-term drug withdrawal. Scientific monitoring is more important than worrying about "rebound growth". If symptoms change, timely communication should be made, and professional doctors can judge whether to adjust the plan.

Clinically, it is more recommended"Planned managed discontinuation", such as brief discontinuation based on the level of side effects and subsequent resumption at a tolerated dose, rather than long-term discontinuation on its own. The behavior of tumors is affected by multiple factors such as genetic background, drug resistance status, and patient constitution, and will not cause a "crazy jump" just because of drug withdrawal for a few days. Maintaining follow-up and standardizing treatment are the most reliable ways to avoid the risk of progression.

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