Tuesday, May 29, 2018

is there a link between RAI use in treating thyroid cancer and the development of breast cancer?

i have been interested in this question for some time now. well, for 3 years, anyway. i was diagnosed with stage three, papillary with follicular variant thyroid cancer in 2010. after surgery to remove my entire thyroid and two parathyroids, i received a high dose ( 155 millicuries) of RAI. in 2015, i was diagnosed with invasive lobular breast cancer, stage 2b. i have no history of breast cancer in my family, and i did not have any other risk factors associated with developing breast cancer. did the large dose of RAI have anything to do with my breast cancer, or was it something else?

when i was making the decision to have or not to have the RAI, i did read that some scientists thought that perhaps a high dose of RAI could be linked to developing breast cancer. my " gold standard" book on thyroid cancer is " thyroid cancer" by m. sara rosenthal. she is a thyroid cancer survivor herself, and her book presents the pros and cons of the disease and treatment in a way that is informative, but readable. her take on the RAI issue, was that perhaps the RAI might slightly increase the incidence of breast cancer, but getting the RAI- in her case- was worth the risk. she recommended that if the physician in charge of your thyroid cancer treatment  thought the RAI was necessary, then it would be wise to get the RAI. but she also said that patients should have all diagnostic tests necessary, especially yearly mammograms.

adding to the confusion, is the fact  that according to a study in taiwan, which covered the entire population, if a patient has had thyroid cancer, they have a 33% increased risk of developing a second primary cancer. i have read this statistic in other studies, as well. to make matters even more complicated, according to research published in " Cancer Epidemiology, biomarkers and prevention", thyroid and breast cancer survivors are at risk of having  the other cancer. in a study conducted by dr. raymon h. grogan, an assistant professor of surgery and director of the endocrine surgery research program at the university of chicago medicine and biological sciences in illinois, researchers found that a breast cancer survivor was " 1.55 times more likely to develop thyroid cancer ( compared to a woman with no history of breast cancer)". and " a woman who had had thyroid cancer was 1.18 times more likely to develop breast cancer than one with no history of thyroid cancer. "

i found one study that said that a large dose of RAI had very little  impact on the development of breast cancer. for a patient like me though," very little" might be more significant. i have read that only 5 to 10% of all thyroid nodules are cancerous. sounds pretty good, but if you happen to be in that 5 to 10 % group, the statistic takes on a whole new meaning. in the above mentioned study about the breast cancer and thyroid cancer link, the authors came to this conclusion: " the use of RAI in the treatment of thyroid cancer may have a very small impact on the development of other cancers at a later date, including breast cancer. how great the risk is remains unclear."

so, basically, after researching this topic ( this continues to be a hot topic on many thyroid cancer forums), i did not find any conclusive studies or evidence that RAI and breast cancer are linked. could they be? yes. it could also be the breast cancer- thyroid cancer ( in women) link. then there is the 33% risk of developing a second primary cancer. what should you do if you are considering RAI therapy after surgery for thyroid cancer? good question.

 i will tell you why i decided to get the RAI. as i said, i had read that there could be some link to breast cancer. BUT, my thyroid cancer had an aggressive area of follicular variant, along with the papillary area. i had three tumors which had burst and infiltrated into  my surrounding tissues. two of my parathyroids were also cancerous. my endocrinologist said that even the most brilliant surgeon can not possibly get all of the cancer. some of the cancer had escaped, you might say, and was in my neck. luckily, even though i had positive TG ( a thyroid cancer marker) for three and one-half years after my surgery and RAI, the cancer did not move to my lungs or bones. would i have the RAI again after knowing that i would develop breast cancer five years after my thyroid cancer? absolutely. i had yearly mammograms- i might have had them every six months, but hind sight is always 20/20. that was my decision. this is an individual decision. what i decided to do may not be the best course of action for someone else.

my best advice, and the take away from this blog, is that when deciding about the RAI consider all sides of the story. read up on the type of thyroid cancer that you have and what additional treatments are recommended. if you are a woman, BE SURE to get regular mammograms. we should all get regular screening tests as recommended by our physicians. i wish that there was a definitive answer to the question of RAI use and breast cancer. i will keep researching, and hopefully we will have an answer soon.

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