Thyroid and chemo?

[MonaL]

Has anyone had their thyroid tested while on chemo?

Found because of the PET scan, Dad seems to have thyroiditis and blood results that show that he should be on supplementation. For some reason he decided not to start thryoid treatment, but to retest at a later date. Now we are trying to figure out when to retest. I have to imagine the fatigue from the surgery, the chemo, AND the thyroid have to be very difficult.

We had talked about waiting until after his second round of chemo when he is supposed to be done with chemo (he just started first round, post surgery), but why wait?

Does anyone have any thyroid experiences? Those of you that were already on thyroid meds, did your levels change when you were on chemo?

[CRguy]

Quick reply here :

1. Thyroid "itis" = inflammation and may not be HYPOthyroid, requiring supplementation. There are oher causes of thyroiditis. Other tests can be done which can confirm this ( TSH, TSH response test, autoantibody tests, free T3, free T4, imaging etc. )

2. ANY other disease or disorder we are dealing with can and often WILL affect thyroid hormone levels (and subsequetly the test results...), so retesting Is a viable option. The docs need to assess whether the levels are borderline or seriously low. Check with them.

Cheers
CRguy

[gofisch]

I have a family history of Graves disease (hyper thyroid) and I have been hyperthyroid on 2 occasions in my life--both surrounding huge hormonal changes (preganancy, nursing) Because I was pregnant and nursing during my entire treatment, they could not do the radioactive iodine scan to properly diagnose me, but the assumption is I have Graves Disease also.

Then, at my last chemo appointment, I asked for a TSH. My pulse was a little high. It turns out I was hyperthyroid again, and I finally had a scan, which showed THYROIDITIS. And now I am on PTU which I probably don't need but he wants me to stay on it for 18 months to prevent recurrence of the thyroiditis. sigh. And it makes me fat.

Now after reading your post, I wonder...

[MonaL]

Dad had a fine needle biopsy. his findings are consistent with autoimmune thyroiditis, his TSH is higher than it should be, and his FT4 is at the lowest it can be in the range w/o technically being hypo. I have Hashimoto's thyroiditis and my sister has/had Graves. So, he really should be on the hormone, there is no reason not to address this - it just makes everything worse.

Thyroid can affect liver, and liver can affect thyroid. But I'm comfortable, with the whole picture here, that this is something that won't be resolve on it's own.

Seems like this is something that should be studied - maybe I didn't google the right phrases...

[wendy1]

After finishing chemo I found out that I had thyroid issues. I was sent for complete blood work and a throat scan. I found out that I had small nodules on my thyroid but at that time the suggestion was to just check again in 3 months. So once again I had bloodwork done and at this time I was put on Synthroid and in 3 more months I was scheduled for another scan. I just recently had the scan and my dr said that there was no reason to have anything biopsied and just continue on the Synthroid. Unfortunately since finishing chemo, I not only put back the weight I had lost, but I also gained about 5 more pounds, that I can't lose. Between my thyroid being underactive and other meds I take for neuropathy, I just keep gaining weight no matter how much I watch! Now I can wait till next year to check again, hopefully I won't keep putting on weight.

[MonaL]

I have lots of nodules. On one side of my thyroid they respond to treatment, on the other, not as well. They are biopsied every 3-4 years, or if they seem to have a growth spurt.

One thing Frances & Wendy, you might want to double check what value they are holding your TSH at. My endocrinologist said that for most of these cases, it should be kept close to 1. My former endo kept me at about 3, and when I complained how miserable I felt said the only alternate was to remove the thyroid. So do keep an eye on where they keep you.

Sure wish there was an answer for the weight thing, my metabolism doe not work the way it should, and suspect that chemo would really mess that up too. I know there is a thyroid guru Mary Shoman (sp?) that has diet and supplement advice for thyroid folks.

If I get a chance, I will try to ask Dad's onc and/endo some more questions regarding the chemo. Hmmmmm, makes me wonder about radiation too...

[weisssoccermom]

I have a Hashimoto's goiter and have had one for 20+ years and have been on Synthroid and Levoxyl (what I am on now). I didn't notice any substantial difference in my thyroid levels and they were tested before during and after my chemo. I have always had to have them tweaked every 18 months or so - sometimes longer, rarely shorter - as my body changes and I age. I can honestly say that I didn't notice anything unusual with my thyroid during my chemo. I actually don't recall having any new dose changes or anything like that. My last dose change, which was decreasing my dose (ever ever ever so slightly which as I said earlier is very common) occured about 6 months ago - about two years after I was done with the chemo.

So, I can honestly say from the perspective of someone who has been on supplementation for quite a long time, chemo had no effect on my thyroid levels then or now.

Jaynee

[MonaL]

Thanks Jaynee.

Kinda wondering if it's one of those things that, if an individual has an inclination to have thyroid problems, that it could be triggered by the chemo, and "normal" folks, and those with supplementation where the body doesn't depend on supply it's own, might not be affected. Kinda like how pregnancy triggered my sister's Graves, and it seems a stupid knee really triggered mine.

Or maybe, it's all just luck of the draw!?!!?!!

[wendy1]

I believe that chemo had a part in why I have thyroid issues. Since chemo I also have rhematoid arthritis, and chronic dry eyes, which I also believe is due to chemo. Chemo breaks down the immune system, so all these things could be laying dormant in the body and it just comes out afterwards. Gaining weight is also a change that occurs, plus the fact that I'm getting older. There are so many changes since my diagnosis, surgery, and chemo, some good and some not so good. But I'm so greatful to be NED and to be here to complain about all these changes!! LOL

[MonaL]

I definitely hear you - the huge part is that you are still here, thank goodness!! And I hope, remaining NED - I'm afraid to mention that term with respect to Dad!

[MonaL]

Hmmmm....

http://www.mdconsult.com/das/article/bo ... html?issn=

[MonaL]

Found it. Please excuse the inelegant paste-job -- I don't have time right now to make it pretty.

CAPECITABINE-INDUCED
ABNORMALITIES IN
THYROID FUNCTION
TESTS
To the Editor:
Drugs can have profound effects
on thyroid function tests (1). We report
a patient who developed marked
abnormalities in her thyroid function
tests while receiving capecitabine (2)
for treatment of metastatic breast
cancer.
A 58-year-old woman with hypothyroidism
and metastatic breast cancer
was first seen for management of
her hypothyroidism in April 2001;
she was euthyroid while taking levothyroxine
125g/d and tamoxifen 20
mg/d (Table). Similar values were obtained
in November 2001, following
which tamoxifen was discontinued
and she began taking capecitabine
3000 mg/d for 2 of every 3 weeks. Repeat
thyroid studies in June and July
2002 revealed elevated serum concentrations
of thyroid stimulating hormone
(TSH), total thyroxine (T4),
free thyroxine index, and thyroxinebinding
globulin, with normal values
for direct free T4 and total triiodothyronine
(T3), but a subnormal free T3
concentration (Table). Her dose of
levothyroxine was increased to 150
g/d, and serum TSH levels normalized
over the next several months,
with elevated total T4 levels and normal
free thyroxine index. Capecitabine
was stopped in November 2002.
In March 2003, serum TSH level was
slightly suppressed, with a mildly elevated
total serum T4 level and borderline
high free thyroxine index on the
same dose of levothyroxine (150 g/
d), but now off capecitabine. Her
dose of levothyroxine was decreased
to 125 g/d (her precapecitabine
dose), with return of serum TSH levels
to normal. In November 2003, she
was begun on chemotherapy with a
cyclophosphamide/methotrexate/5-
fluorouracil regimen, and in December
2003 her serum TSH and T4 levels
were again elevated with serum T3
and thyroxine-binding globulin levels
at the upper limit of normal.
Capecitabine is currently approved
for use in advanced breast and colon
cancer. Orally adminstered capecitabine
is converted in the liver and in
tumor cells to its active metabolite,
5-fluorouracil, which is responsible
for its antineoplastic activity. There
have been no reports of effects of
capecitabine on thyroid function tests
and no reports of interference by
5-fluorouracil or capecitabine in the
assays for TSH, total or free T4 or T3,
or for thyroxine-binding globulin.
Drugs can affect the production,
secretion, transport, and metabolism
of thyroid hormones and may also alter
the absorption of exogenously administered
thyroid hormone (1).
Beex et al (3,4) reported that euthyroid
patients receiving 5-fluorouracil
as part of combination chemotherapy
for breast cancer had thyroid function
test abnormalities somewhat
similar to our patient, with elevated
total serum T4 and T3 concentrations
but normal free T4 and normal TSH.
The most plausible explanation of
their results was that 5-fluorouracil
induced an increase in the serum
concentration of thyroxine-binding
globulin, the main serum carrier protein
for thyroid hormones. In accord
with those observations, our patient
demonstrated an increase in the serum
serum
concentration of thyroxinebinding
globulin, which raised the
total serum T4 concentration, as
expected. However, total serum T3
level, which should also have increased,
was normal, and free T3 concentration
was actually low; this raises
the possibility that capecitabine may
also interfere with the deiodination of
T4 to T3.
In our patient, adminstration of
capecitabine or, to a lesser extent,
5-fluorouracil, was associated with elevation
of serum thyroxine-binding
globulin; being hypothyroid, she was
unable to increase her thyroid hormone
production to compensate for
the increase in serum protein binding
sites for T4 and T3, thus leading to an
elevated serum TSH and necessitating
an increase in her thyroxine dose.
On discontinuing capecitabine, her
dose requirement for thyroxine decreased,
suggesting that capecitabine
was responsible for the observed
changes in thyroid function tests.
We did not see any abnormalities
in thyroid function tests in 5 euthyroid
patients receiving capecitabine
2000 mg/m2/d for 14 days of each 21-
day cycle in a combination chemotherapy
protocol for colon cancer.
This suggests that certain regimens
containing capecitabine may be more
likely than others to cause changes in
thyroid function tests. Alternatively,
it is possible that our patient was
uniquely sensitive to an effect of the
drug. Further study is needed to define
the factors that may influence the
effects of capecitabine on thyroid
function tests.
Harmeet S. Narula, MD
Harold E. Carlson, MD
Department of Medicine
Endocrinology Division
Stony Brook University
Stony Brook, New York
1. Surks MI, Sievert R. Drugs and thyroid
function. N Engl J Med. 1995;333:1688–
1694.
2. Capecitabine/Xeloda [package insert].
Available at: www.Xeloda.com. Accessed
May 20, 2003.
3. Beex LV, Ross A, Smals AG, Kloppenborg
PW. 5-fluorouracil and the thyroid. Lancet.
1976;1:866–867.
4. Beex L, Ross A, Smals A, Kloppenborg P.
5-fluorouracil-induced increase of total serum
thyroxine and triiodothyronine. Cancer
Treat Rep. 1977;61:1291–1295

[Shana]

I just came across this topic from 2009 and wondered if anyone currently has had their thyroid function affected by chemo.

I've been hypothyroid and on medication since 2009, current dosage had been fine and unchanged. I requested a recent test since it had been nearly 18 months since my TSH was tested and sure enough it was over 10 now when it had been around 2 before.

Having T4 and T3 tested now to determine what dosage I need now and consulation with my endocronoligist.

Thanks for any input!