Many Small Streams Make One Big River
-- French Proverb
It will take the efforts of many individuals to create a change in the standard practice of administering 5-FU, a practice that fails to assess the risk of patient toxicity.
Research continues to identify genetic factors that contribute to DPD deficiency. More importantly, some researchers are showing that compromised DPD levels are also factors of non-genetic conditions (see Research, Risk Awareness).
While the reported rate of toxicity appears compelling, many practitioners hold to the belief that DPD deficiency is a very rare condition not worth the effort to detect. Even if there was wide agreement on the need to screen patients, care providers have not identified a standard test.
Hope is not lost, however, for some respected professionals are now advocating new dose management practices -- lower initial dosage followed up with tests to determine the necessary adjustments (see Caudle/Diasio in Research). The Colon Cancer Alliance encourages patients to learn more about personalized dosage levels:
Accurate and Personalized Chemotherapy Dosing*
Blood tests are becoming “tools” for oncologists desiring data to customize the chemotherapy dose for individual patients in order to achieve maximum effectiveness over the course of their treatment. One particular test, My5-FU, sends a report back to the doctor within 24-hours of receiving a blood sample. This report includes a numerical result about the chemotherapy drug level and a detailed recommendation about the need for drug dose adjustment to bring a patient’s drug level into the therapeutic range. If dose adjustment is needed, it may require two to three rounds of tests and adjustments to bring the drug level in to range. Talk with your healthcare professional to learn more.
Pasted from <http://www.ccalliance.org/treatment/chemotherapy.html>
Even more promising, studies in France have shown great results in improving patient care using cost effective pre-screening and post-treatment monitoring (see Ciccolini and Gamelin in Research). One firm in France is commercializing the test kits but its venture into the US is years off (likely beyond 2020).
Update: the FDA has agreed to update the WARNINGS AND PRECAUTIONS section of the drug labels for fluorouracil and Xeloda to more clearly spell out the risk of severe toxicity and the chance of fatalities. For more information on the FDA approved changes see: Petitions -- FDA's Response.
Though introductory dosage and pre-screening measures have failed to become widely accepted practices, you can and should discuss with your oncologist how best to manage the risk of a toxic reaction before starting treatment.
The more patients become aware of this risk of DPD deficiency and discuss it with their oncologists, the greater the chance personalized treatment (pre-treatment screening and dose management) will become commonly accepted.
So get the care you deserve and have this important conversation with your care provider; not only will you be serving yourself and your family, you will do your part to form the Big River that can lead to changing today's medical practices.
* For more information concerning the My 5-FU test, refer to:
2. the National Institute for Health and Care Excellence (NICE), in the UK, which has an assessment of the effectiveness of this test.