CSN Login
Members Online: 19

DPD enzyme test for 5FU toxicity

azgal
Posts: 31
Joined: Oct 2011

http://mayoresearch.mayo.edu/mayo/research/diasio_lab/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2563423/

http://www.healthanddna.com/healthcare-professional/dpd-enzyme-deficiency.html ...

"Who Should Be Tested
The DPD test for 5-FU is considered appropriate for any person who is taking or considering 5-FU based chemotherapy."

http://sheddinglightonthecancerjourney.wordpress.com/2010/06/13/three-colon-cancer-blood-tests-predict-efficacytoxicity-of-chemotherapy/ ...

"...31-35% of patients treated with 5FU develop severe toxicity reactions. The enzyme largely responsible for metabolism of 5FU is the DPD enzyme. A deficiency of this enzyme causes the 5FU to linger in the system rather than passing through; the build-up of 5FU can be toxic. Complete DPD toxicity is rare, occurring in only 1% of the population, but for that 1%, 5FU can be fatal in just one dose. However, 3%- 5% of all cancer patients are partially deficient in DPD– and of those who experience severe toxicity, 43-59% are DPD deficient.

A National Institutes of Health paper from 2007 went so far as to recommend that any patient suspected of DPD deficiency NOT receive 5FU chemo due to life-threatening toxicity: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2563423/. Warnings have been added to labeling of both 5FU and oral Xeloda which state that these drugs are contraindicated for patients with known DPD deficiency."

A random reply to the blog above lists inexpensive testing available (from 2010) at this lab: http://www.ittlabs.com/professionals.html ...
"...offering the test for $225.00 and we return the results to the oncologist within 2-3 business days. Please check out our website at http://www.ittlabs.com if you have any questions about the assay or call the lab at 205-533-7162."

Another lab link: https://www.myriadpro.com/test-offerings/chemotherapy-management/theraguide

1% equates to around 10,000 patients per year being completely deficient in the enzyme, with 1% of anal cancer patients being around 6-7 patients per year given the current yearly Dx numbers. 10,000 or 7 is far too many deaths from chemo toxicity when it is totally predictable, and preventable.

I think the DPD test should be standard for everybody prior to 5FU Tx, and also during Tx. As mentioned in one of the above sites, even for those many patients (31-35%) that will be discovered to be somewhat deficient in the enzyme via DPD testing and who can be predicted in advance to have a more severe reaction to it, the 5FU dosage can be adjusted accordingly as needed at the start and throughout Tx. For the other 1% that can easily be identified prior to Tx, a different chemo can be used.

I hope we all continue to speak up and keep one another informed. We are the front line.

Best wishes for us all...

mp327's picture
mp327
Posts: 2889
Joined: Jan 2010

However, I would like to know specific reactions to 5FU in people who are somewhat deficient in the enzyme and do not react so severely as to result in death. I will definitely check out the websites you have listed.

azgal
Posts: 31
Joined: Oct 2011

Hi mp327, symptoms are listed below, along with other DPD info links.
I had some problamatic reactions "due to toxicity" the oncs told me, so my oncs lowered the dose (along with 2 separate breaks in Tx totaling 28 days). I did not know about the test at that time and as far as I know I was not tested once symptoms appeared. It would be interesting to see research where the amount of deficiency is correlated with degree of symptoms.

http://www.valeant.com/fileRepository/products/PI/Efudex-40_Cream_5_Solution_2-5_PI_Apr04.pdf ...

"Patients should discontinue therapy with Efudex if symptoms of DPD
enzyme deficiency develop (see CONTRAINDICATIONS section).
Rarely, life-threatening toxicities such as stomatitis, diarrhea, neutropenia,
and neurotoxicity have been reported with intravenous administration of
fluorouracil in patients with DPD enzyme deficiency...symptoms included
severe abdominal pain, bloody diarrhea, vomiting, fever, and chills.
Physical examination revealed stomatitis, erythematous skin rash, neutropenia,
thrombocytopenia, inflammation of the esophagus, stomach, and
small bowel. Although this case was observed with 5% fluorouracil
cream, it is unknown whether patients with profound DPD enzyme deficiency
would develop systemic toxicity with lower concentrations of topically
applied fluorouracil.

http://www.cancer.org/Treatment/TreatmentsandSideEffects/GuidetoCancerDrugs/fluorouracil ..

If you lack dihydropyrimidine dehydrogenase (DPD deficiency). DPD is an enzyme the body uses to process this drug. This inborn genetic abnormality can cause extreme side effects if you use 5-FU (even on your skin) or capecitabine.

http://www.bcbs.com/blueresources/tec/vols/24/24_13.pdf ...

Executive Summary
Background
Severe toxicity occurs in about 30% of patients treated with 5-fluorouracil (FU)-based chemotherapy regimens. 5-FU has a narrow therapeutic window and the drug concentration required for tumor response is within the general range where toxicity may occur. Inherited genetic variability in key enzymes involved in the 5-FU metabolic pathway may be related to the variable patient experience of toxicity. Dihydropyrimidine dehydrogenase (DPD) is a saturable and rate-limiting enzyme in the 5-FU catabolic pathway. In the anabolic pathway, 5-FU is converted into several active metabolites, one of which inhibits the action of thymidylate synthase (TS), a key enzyme in normal and tumor DNA synthesis. Genetic polymorphisms in the genes coding for DPD and TS may result in enzyme products with different activity levels, resulting in 5-FU excess, the accumulation of 5-FU anabolic
products, and severe toxicity.

http://www.cancercompass.com/message-board/message/all,2909,0.htm

mp327's picture
mp327
Posts: 2889
Joined: Jan 2010

Thanks for posting this info. It is too late for me, since I'm 3+ years out of treatment, but perhaps some of our newbies will benefit.

azgal
Posts: 31
Joined: Oct 2011

You're welcome!
It's 4+ years out for me yet I would like to be tested to know my level, and find out more regarding whether those that have lower levels of the enzyme also experience increased long term side effects like some of us do. It would explain a lot, if so.
Sending good thoughts for all,
Aurora

Lorikat's picture
Lorikat
Posts: 558
Joined: Jul 2011

Interesting. Doing research on my own. (it IS more comfortable to research after you are through treatment). Although being who I am I was on this board BEFORE treatment and was thrilled to have people to ask questions of, to know so many have survived, and make special friends to help walk me through. I had a very good idea of what was going to happen, what test were going to be done, and what questions to ask. So knowledge REALLY helped me make it. But that is me....Lorie

mxperry220
Posts: 360
Joined: Mar 2011

Each of us has enough on our minds when we first hear we have anal cancer. My oncologist advised me to stay off the internet when I had my first consultation with him. This was some of the best advice I received as I was so upset and nervous at the time. During the diagnosis, testing and before treatment I did not sleep for 2 weeks even after taking sleep medication.

eihtak
Posts: 835
Joined: Oct 2011

Although I wish I had had a bit more info before treatment, most of my research and knowledge came towards the end or after. It is still a lot to sort through but much easier when you're a bit less stressed. At least we do in time learn and can pass that on and share bits and pieces with others. I am so thankful to have found everyone here and feel so much more relaxed knowing that I can look here for other opinions any time. Thanks to all!!!!!

eihtak
Posts: 835
Joined: Oct 2011

Although I wish I had had a bit more info before treatment, most of my research and knowledge came towards the end or after. It is still a lot to sort through but much easier when you're a bit less stressed. At least we do in time learn and can pass that on and share bits and pieces with others. I am so thankful to have found everyone here and feel so much more relaxed knowing that I can look here for other opinions any time. Thanks to all!!!!!

eihtak
Posts: 835
Joined: Oct 2011

Although I wish I had had a bit more info before treatment, most of my research and knowledge came towards the end or after. It is still a lot to sort through but much easier when you're a bit less stressed. At least we do in time learn and can pass that on and share bits and pieces with others. I am so thankful to have found everyone here and feel so much more relaxed knowing that I can look here for other opinions any time. Thanks to all!!!!!

azgal
Posts: 31
Joined: Oct 2011

Hi Lori, same here, and knowledge greatly helped me, too.

I'm sure each situation is different...in my case there were some other issues, so being connected to knowledgeable people is probably the reason I am still around today. My original doctors had me scheduled for treatment that would not have had any good outcome. It was scary, distressing, and totally exhausting to have to fight that battle for the correct treatment, but it was SO worth it. :D

mxperry220
Posts: 360
Joined: Mar 2011

Just curious. What treatments did your original doctors recommend?

azgal
Posts: 31
Joined: Oct 2011

Well, I had had surgery, which accidently ended up discovering the cancer. That surgeon did not take cancer precautions during surgery and believed cells entered the blood stream. The cancer had penetrated the wall and vessel. Unfortunately, the surgeon had not been careful with the surgery and was quick to state that.

So the next anal cancer "specialist" (a surgeon) I was sent to scheduled me for more surgery, and surgery only, which was to also involve the sphinctor, and then just waiting and watching. No chemo, no rad, no standard protocol treatment for anal cancer. Just surgery.

Thanks to members at the yahoo anal cancer group that I stumbled upon, it finally ended up that the Head of Oncology at Mayo Clinic and his team there and a team of other Mayo oncology specialists/surgeons intervened very forcefully on my behalf and in no uncertain terms with those other doctors...they were beyond outraged that such treatment would even be suggested in my case and especially in this day and age and by "specialists" no less, and did testing I should have had in the first place, and contacted those original doctors and set them straight regarding the needless surgery and the results of cutting the sphinctor, and they also wrote letters to them stating it all and that the planned course of treatment that those docs had me scheduled for would end gravely, period.

Had I just trusted those original expert docs (who were extremely convincing and reassuring), and if not for knowledgeable internet group members, I most likely wouldn't be here today.

mp327's picture
mp327
Posts: 2889
Joined: Jan 2010

Your story is quite alarming to me. To think that the original docs were going to do life-altering surgery (and possibly life-threatening) without consulting other docs who had experience in treating anal cancer is quite disturbing. I'm so glad you had the courage to go elsewhere and get the proper treatment. Thank God for those people on the other support forum. I am currently in communication on another board with a woman who had local excision done. Her path report indicates the surgeon did not get clear margins, but her oncologist is telling her that no more treatment is necessary--I guess taking the "watch and wait" approach. He finally agreed to take her case before the tumor board at the hospital for input. Tumor boards are made up of doctors from all specialties and not necessarily those who would have a lot of (or any) knowledge about treating anal cancer. I find it maddening that this doctor will not contact a specialist in this woman's case to discuss what needs to be done.

Again, I mention the National Comprehensive Cancer Network guidelines, which are readily available to doctors and patients alike. Anyone joining this board or any other forum needs to be aware that these exist, so that they can become an informed patient. Your story and the one I mentioned both demonstrate the need for us to have as much knowledge as we can. Doctors do NOT know everything and they also make mistakes. We must be our own advocates, just as you were.

We have a member on this board who is starting treatment very soon and is scared out of their mind, some of that due to things they've read on this board. I apologize if we have frightened you. I guess not everyone wants to have as much information as they can going in. I had some information, but didn't know nearly as much as I should have. After being involved on support sites for over 3 years now, I feel like I could finally go head to head with a doctor who was not up on the latest treatment protocol. Support forums allow us to get and give as much information as we want. However, we all have to remember that each person's situation and journey is unique to that person. I am so very thankful to be a part of these sites.

azgal, your story should be very encouraging to those who are hesitant to join a forum. We really do need each other.

Lorikat's picture
Lorikat
Posts: 558
Joined: Jul 2011

YES WE DO NEED EACH OTHER!

azgal
Posts: 31
Joined: Oct 2011

Thank you for your great post. It is very alarming but unfortunately it's not too uncommon. The journey from point A to Z ("Z" being finally receiving protocol treatment) was quite an ordeal, and I am forever grateful to the group. Sadly, a dear member of the group at that time was in palliative care w/mets just a couple of years after being dx'd with low stage AC and receiving only surgery and watch & wait from doctors that did not follow the gold standard for tx.

Is the woman you are in contact with able to go over her primary doc's head and get a qualified private 2nd opinion from AC oncs? I'm glad it's going before a board and I hope she gets started on protocol tx as a result. Otherwise, going outside of that circle of docs and obtaining a qualified 2nd opinion sounds like the route to go, even if having to beg and borrow to self pay for it, but most insurances pay for 2nd opinions. Is she in the US?

It's so true, we really do all need each other.

mp327's picture
mp327
Posts: 2889
Joined: Jan 2010

Unfortunately, I don't know where this other blogger is located. I have given her some suggestions, such as MDA, MSK, UCSF and Fox Chase, but don't know if any of those locations would be doable for her. My hope is that someone on that tumor board will research those treatments guidelines, just as I have, and see that it specifically recommends chemo/rad if margins are not clear post local excision. According to what she posted, the margins are definitely not clear.

I think this once again demonstrates the fact that this is still a rare cancer and many doctors just don't have the knowledge to correctly treat it. But even so, any doctor can get tons of information from the NCCN guidelines--enough, perhaps, to render the appropriate treatment. If not, then they should recommend that the patient see someone more experienced. I used to work for a doctor and I know how their egos can sometimes get in the way of the patient's care. That should never happen, but it does.

The other thing that really chaps my cheeks (pun intended) about this cancer is the high percentage of people who are initially misdiagnosed, getting the old bleeding hemorrhoid diagnosis. That's what happened in my case, but lucky for me, I was about 4 years overdue for my first screening colonoscopy and my internist (who misdiagnosed me) referred me to a colorectal surgical group because they could do both the colonoscopy and take care of the "hemorrhoid." As soon as the colorectal doctor heard my symptoms, she took me in the exam room, performed anoscopy, and told me she was 99% sure I had cancer. I just don't understand how a doctor can make a definitive diagnosis of a bleeding hemorrhoid, as my internist did, with just a digital rectal exam.

Based on my own experience, I tell everyone now who has rectal bleeding and is told by their doctor that it's a bleeding hemorrhoid after a simple rectal exam that they must go to a specialist for further evaluation, including visual exam by anoscopy. I also remind them that colonoscopy is not for viewing the anal canal and many anal cancers are missed during colonoscopy. The things we learn as we take this journey.

azgal
Posts: 31
Joined: Oct 2011

Those were very good suggestions you gave her. Another possible option (like you mentioned regarding tx by oncs that do not specialize in rare cancers) if she does not have access to a treatment facility/oncs that specialize in AC is long distance consulting with docs that do...my oncs here in Arizona consulted with the Mayo Clinic oncs here, and also with the University of Chicago for precise set up of IMRT (http://www.uchospitals.edu/specialties/cancer/patient-stories/).

My original surgery was done by a general surgeon, no clear margins of course. The incorrect tx advice after that and the scheduled 2nd surgery (which was cancelled) was going to be done by a well respected board certified colorectal surgeon in practice for diagnostic and surgical procedures. She assured me and 2 oncs here that further surgery was the answer and I would be cured.

When I asked my Mayo oncs why the other oncs here would have taken the CR surgeon's advice when it was so clearly not gold standard tx, the Mayo oncs said that onc MD's can be very intimidated by specialist surgeons. The Mayo oncs told me that they could not be intimidated so easily and started fighting like heck for me to receive protocol tx to save my life.

Thank goodness for your doc's more thorough exam! I'm with you, and I, too, always recommend the same to those with symptoms. The ol' "bleeding hemmi" and "harmless skin tag" diagnosis by DRE alone needs to be brought current. The "harmless skin tag" dx by GP's and GYN's delayed my cancer from being addressed for several years. Given that micro cells cannot be detected even by the most state of the art scans, it's purely assumptive for docs to routinely pronounce everything normal with just a DRE.

After my dx my family was checked, and thank goodness, because one of my siblings was found to have precancerous polyps, which were removed, and has routine checks now.

Yes, the things we learn through this journey are amazing.

mp327's picture
mp327
Posts: 2889
Joined: Jan 2010

Yes, phone consults are done quite routinely these days, made much easier by the ability to send scan films and test results online. I know for a fact that MDA does them. I would hope, at the very least, this other blogger's doctor will agree to a phone consult with a specialist in anal cancer treatment.

azgal
Posts: 31
Joined: Oct 2011

Yes, and I believe all the major AC tx facilities are very open to consultations like that. Sometimes the inexperienced treating oncs need determined prodding from the patient for sure, some more than others, to go outside for expert input. It's not always easy but it's always well worth the effort. The Mayo oncs that examined/tested me were more than happy to consult with oncs involved in my tx, as was Chicago, and Chicago has specific mapping info available online for onc teams that request it, which was utilized for me. I learned that long distance consults were a fairly routine option (especially when requested/pressed for by the patient) over 4+ years ago when I was going through it, but I would never have known that when it counted without experienced input from other AC group members that had more collective information than 99.9% of oncs. Way back then, as a new AC patient armed at first with little to no knowlege, I felt apologetic when asking anything of my docs. I hope the woman on the other blog will turn the tide on her behalf when armed with knowledge. I know for a fact that it's an exhausting battle but it's well worth it. :)

mp327's picture
mp327
Posts: 2889
Joined: Jan 2010

It's all worth it when someone's life is on the line.

alis7910
Posts: 80
Joined: Jun 2010

Hi:
I was one of those who got a missed diagnosis; I was seeing a colon specialist for a special banding procedure for my hemmhroids, and despite all her exams, she missed the diagnosis! I think it is quite common.
Alison

mp327's picture
mp327
Posts: 2889
Joined: Jan 2010

I agree, as so many of us begin with a misdiagnosis of hemorrhoids. I think it happens mostly with our primary care doctors, but your story reminds us that even specialists can miss anal tumors.

mxperry220
Posts: 360
Joined: Mar 2011

Thank goodness the original surgeon discovered you had cancer, otherwise your situation may have been more serious. Was your original surgery for anal cancer? You are very lucky your doctors admitted any wrong doing and the Mayo doctors shared any information with you regarding their position on the original doctors surgery procedure. Hope for the best for you.

azgal
Posts: 31
Joined: Oct 2011

:) Thanks so much.

Unfortunately that first surgery was completely unnecessary, and also likely spilled cells by the surgeon's own admission, and also contributed to bowel incontinence issues. The original "surgery" was purely elective to simply shave off "skin tag/hemmi" but it ended up being a somewhat larger surgery to say the least (went from a simple scheduled surface shaving to a quarter-silver dollar-ish size open wound that took around a year to fully close and still sometimes opens up) much to my surprise after surgery and upon the first shocking dressing change at home (the surgeon was unavailable for comment for 2 weeks after my surgery since he'd left "on vacation" immediately following my surgery). Nobody there could explain the gaping hole in my body, nor would they say anything more than the office would refill pain meds & for me to keep the area clean and dry, and go to ER if any signs of infection. It was 2 weeks later at the routinely scheduled follow up check for skin tag surgeries that the surgeon met with me and I was informed of the cancer and the surgical mishap.

I was later informed that the "skin tag/hemmi/wart" should have been just biopsied and that that first surgery should never have been performed. I've no troubling shoulda-coulda-woulda regrets over anything...what happened, happened. Awareness from the get-go would have spared me much as it would have many others, and hindsight is 20/20 (therefore I highly value the knowledge of those who have been there before me), and I have learned a lot the hard way and though it cannot be undone, I would hope at some time for someone that my experiences can assist another...yet the past is past for me and we can't control that or undo it, so we move forward and live our life.
Hugs to all XO :)

edited to clarify

toucheole
Posts: 1
Joined: Nov 2011

I am through with the first phase of treatment (chemo - 5FU and 28 days of radiation) for a Stage II anal cancer with no known lymph node involvement. I'll have surgery in February. My doctors have been great, but I think the test for DPD deficiency should be an automatic done before treatment starts. We are still waiting for the results to find out how deficient I am in the enzyme, but my over-reaction to 5FU started the 2nd week with mouth sores and diarrhea and I was taken off chemo entirely during the 4th week because the reactions were so severe. We are still trying to get the electrolytes in my body back to normal - almost all there except the magnesium levels are being stubborn. Since the number of people who are missing the enzyme or are at least deficient in the enzyme seem potentially to be relatively high, and the toxicity can be so severe, it seems to me that it should be a standard test. And this is particularly true because 5FU is such a staple of treatment for colo-rectal cancer. I've had some discussions already with my chemo oncologist (BTW, the radiation was a piece of cake compared to the chemo) about recommended chemo after surgery because all of the standard recommended treatments include 5FU in some form. On the other hand, one of my oncology nurses, who has been at this for 10 years, had never seen a reaction like I had to 5FU so maybe it's not that prevalent. The only thing I can say to others is that I have been told it is a Caucasian genetic abnormality, and, since cancer does not run in my family, it'll probably only impact me. However, I'm sure my brothers are glad to know so that if, by any chance, they end up with a similar cancer, they can request the test before theraqpy.

mp327's picture
mp327
Posts: 2889
Joined: Jan 2010

Perhaps you are right in that this test should become standard for anyone about to receive 5FU, given the severe reaction you had. In my case, it was really the radiation that knocked me on my butt. I had some unpleasant side effects from the chemo, but nothing severe.

I am curious and would like to know what type of surgery you are having following chemo/rad for stage II anal cancer if your cancer was localized to the tumor only. Thank you in advance for sharing.

duckyann
Posts: 162
Joined: Jun 2009

I don't know if I was tested for that enzyme or not but I did have to go into my oncologist before being hooked up to 5FU. They did a test drive on me to make sure I didn't have any reactions. NOt sure if they did the enzyme test or not.

Subscribe with RSS
About Cancer Society

The content on this site is for informational purposes only. It is not a substitute for professional medical advice. Do not use this information to diagnose or treat a health problem or disease without consulting with a qualified healthcare provider. Please consult your healthcare provider with any questions or concerns you may have regarding your condition. Use of this online service is subject to the disclaimer and the terms and conditions.

Copyright 2000-2014 © Cancer Survivors Network