You will need to initiate discussion of testing for DPD/DPYD deficiency with your oncologist

Testing is NOT the standard of care in the US. In fact the US Food and Drug Administration instructs patients to notify their doctor if they are deficient (which of course most people do not know unless they are tested). See Initiatives for our advocacy to improve treatment guidelines and drug safety labels.

Share with your oncologist why testing is important to you. If your request is dismissed, share information we make available on this web site or consider an alternative provider.

There still is risk of severe toxicity even if you are tested

Research continues to identify DPYD variants and other factors that may contribute to DPD deficiency. Nonetheless by pre-screening, you will significantly lower your risk of severe toxicity.

Once treatment begins, you should be vigilant and report any signs early on-set toxicity.