Expert: Claes-Gustaf Nordquist, M.D. - 6/7/2007

Question
First of all, thanks for volunteering your time, doctor, it's so nice of you.  About 3 years ago I had mucinous  cancer, treated with a lumpectomy and mammosite radiation, followed by Tamoxifen, which I am still taking (and hate...)
Without going into history of it, recently I had a lumpectomy on my OTHER breast, where they found hyperlasia/DCIS (they weren't 100% sure) but the margins weren't clear and they had to do another surgery, and in that reexcision found 5mm of definite DCIS, and the margins were clear within about 5mm, which my surgeon isn't thrilled about, but says it's acceptable.  Now the question is whether I should or shouldn't do radiation.  I read that some in the mediacl field call DCIS stage 0 cancer, and some say it's not cancer.  I'm curious to know what is the prevalent view of it in the European oncological community, and what's your personal opinion on this type of situation.  

On a somewhat unrelated note, I was just diagnosed with Hypothyroidism (TSH of 7), and when my family MD and I took a look at my past blood tests, we found that my TSH was perfect up until my mammosite radiation and from then on kept going up rapidly (I should have been diagnosed a couple of years ago, somehow he missed it). Can radiation, especially mammosite, cause Hypothyroidism?  Should this alter my cancer treatment or affect my medication choices?

Thanks in advance!

Answer
In my opinion a DCIS is an EARLY cancer and that is also what I have been taught. In my opinion a lumpectomy without radiation is NOT lege artis (= proper) therapy! If for some reason radiation can not be used the surgical treatment of choice should be a mastectomy! So I must recommend radiation also on your other side. While I can not rule out a radiation effect on your thyroid with a 100% certainty I still think it is highly unlikely that it is the cause of your hypothyroidism. Your thyroid should have been well outside any radiation field for example. Luckily it is easy to compensate for hypothyroidism by medication (my mother did it for almost 40 years after treatment with radioactive iodine for hyperthyroidism, she died in 1990, 91 years old - strangely enough her dr. who treated her, professor J. Einhorn, later became my boss). So yes radiation can cause hypothyroidism but I do not think it is the cause in your case. It is probably just a coincidence.
Good luck!