May Up Breast Cancer
YORK (Reuters Health) - Women who undergo treatment for thyroid
cancer may be at increased risk of developing breast cancer up
to 20 years later, according to US researchers.
study found that, overall, women with thyroid cancer had an 18%
higher-than-average risk of developing breast cancer. Premenopausal
white women were 42% more likely to develop breast cancer, the
researchers report in the July 15th issue of the journal Cancer.
a history of thyroid carcinoma have a greater than expected risk
of developing breast carcinoma. This risk is most pronounced in
premenopausal white women,'' write Dr. Amy Y. Chen and colleagues
from University of Texas M.D. Anderson Cancer Center in Houston.
with breast cancer were not found to have a higher risk of developing
thyroid cancer, and black women with thyroid cancer were not found
to have a higher risk of breast cancer, the investigators note.
findings support earlier research linking the two cancers, it
is not clear why thyroid cancer might increase the risk of malignant
breast tumors. One possibility is that radioactive iodine (RAI)
treatment for thyroid tumors may contribute to the development
of breast cancer.
of the radioactive iodine, although low, by the breast may influence
the susceptibility of the premenopausal breast tissue to the development
of cancer,'' the study authors explain.
In an interview
with Reuters Health, Dr. Rena Vassilopoulou-Sellin, the study's
senior author, stressed that RAI remains an important and effective
therapy for thyroid cancer.
``We are not
suggesting that it be omitted or replaced--rather, that the possible
late effect described in the paper be taken into consideration
when deciding how to use RAI in the patient's care plan,'' she
are based on data from nearly 300,000 cases of breast cancer and
more than 23,000 cases of thyroid cancer reported to the National
Cancer Institute's Surveillance, Epidemiology and End Results
(SEER) database from 1973 to 1994. Of those cases, 612 women had
diagnoses of both thyroid and breast cancer, and the researchers
included 365 of these women in the study.
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