ask about your risk of VERY serious side effects before starting 5-FU Chemotherapy

Date of latest revision: 20 December 2021


The Advocates for Universal DPD/DPYD Testing established themselves in 2021 and have succeeded in promoting the need for pre-screening at the ASCO Quality of Care Symposium (Boston Sep 2021) and in creating a great new website— see www.test4DPD.org


The National Community Oncology Dispensing Association’s (NCODA) mission is to " empower the medically-integrated oncology team to deliver positive, patient-centered outcomes (emphasis added) by providing leadership, expertise, quality standards and best practices." NCODA has published a Positive Quality Intervention recommending screening for DPD/DPYD prior to the use of fluoropyrimidine based chemotherapy: see https://www.ncoda.org/dpyd-testing-prior-to-fluoropyrimidine-treatment/


The Institute for Safe Medicine Practices recommends the start of pre-screening in the US. See ISMP's 15 July 2021 newsletter that asks "why not" screen?


Thanks to the suggestion of Dr. Howard McLeod, we have submitted a new petition to the NCCN's Colon Cancer Panel that is scheduled to meet 2 Aug 2021. You may see the petition here.


With the Guidance and Support of Oncologists and Pharmacologists (see Blog entry of today), I have been able to submit a new Citizen's Petition to the US Food and Drug Administration. You may read and comment on the petition at the following FDA site https://www.regulations.gov/document/FDA-2020-P-2213-0001 (or you may read it here at Petitions for Change)


Exciting News:  the European Medicines Agency published a letter to healthcare professionals recommending pre-treatment testing to identify DPD-deficient patients at increased risk of severe toxicity in June 2020.  See the Blog entry dated 27 July 2020 for more information. Now it is time for the US to join the leaders in improving the standard of care for patients!


If you have been diagnosed with stage III or IV colon, rectal, or anal cancer, chances are your doctors are discussing with you the need for chemotherapy.  The standard drug for treating these types of cancers is fluorouracil (popularly known as 5-FU); capecitabine (Xeloda) may also be prescribed.


Oncologists have used these drugs for many years in treating gastrointestinal cancers, and in some cases for treating breast, head and neck cancers, and the perception is that they are "fairly well tolerated" by patients.


Wrong!  In fact a significant number of patients  (between 10% -- 40% of treated patients) suffer severe toxic reactions that lead to costly hospital stays and over 1,000 patients will DIE ANNUALLY in the US.


5-FU and capecitabine depend on the patient's body to metabolize the drug quickly to prevent it from damaging healthy cells.  Thismetabolic process is critically dependent on an enzyme: dihydropyrimidine dehydrogenase (aka DPD).  When a patient's DPD activity is compromised, 5-FU and capecitabine destroy healthy cells andput a person at grave risk.  DPD deficiency presents a single point of failure.  

 The FDA places the burden of proof on the patient to identify a DPD deficiency as its drug warning states the patient should advise the physician of this condition. Most people are unaware of this condition until too late: do not wait until you suffer an adverse reaction. Test for the deficiency before starting treatment.


There are tests available to determine if a person has DPD deficiency (see Help) though there is controversy over which type of test to use and their efficacy (see Quick Facts); there are also too many oncologists who even question the need for a test that affects so "few" people. 


You should insist on discussing with your oncologist ways to minimize your risk and to provide you a better outcome before you start chemotherapy.



The goal of this site is to encourage patients suffering colon, rectal, or anal cancer to discuss personalized chemotherapy regimens with their oncologists before starting treatment.   You should not take at face value that the treatment is "fairly well tolerated".


Fluorouracil (also known as 5-FU) and Capecitabine (or Xeloda) have been used for many years as a key chemotherapy agent in the treatment of patients with colon, rectal, anal cancers and is sometimes used to treat head/neck and breast cancer patients.  Oncologists consider this treatment an effective and low risk means of destroying cancerous cells. 


However, medical journals in recent years point to a greater risk of toxic reactions that can lead to hospitalization and, in rare cases, to death.


The intent here is NOT to scare patients, facing cancer is frightening enough, nor to discourage patients from seeking professional medical care.  Instead, the intent is to increase awareness of the risk and to embolden patients and their families to have an educated discussion with their physicians about the risks associated with 5-FU chemotherapy. 


So the following information may prepare you to have a frank discussion with your care provider:


Kathryn received one round of FOLFOX (5-FU, leucovorin, and oxaliplatin) and passed away within 3 weeks (see Personal Stories).  Kathryn inspired many people in our community in many ways and here her inspiration takes form among these pages in the hope that it will achieve one of her last wishes:

"I am optimistic and very grateful to all who have traveled this path before me and contributed to the knowledge and experience of those whose vocation is to heal people like me.  May my experience also contribute to the body of learning."


This site is dedicated to honor her wish and to help others avoid the fate she suffered.

"May my experience contribute to the body of learning."

images: Before and after the treatment that  led to kathryn's death