ORLANDO, Florida-Patients with breast cancer may require screening for thyroid disease, researchers suggested here at the American Society of Breast Surgeons Annual Meeting.
A review of 867 cases of breast cancer found 141 cases of thyroid disease (about 16%), Corrado Chiappa, MD, a surgical resident specializing in breast cancer at the Senology Research Center at the University of Insubria in Italy, said in an interview at his poster presentation.
"From the results of our study, we think that women who are diagnosed with breast cancer should also be screened for thyroid disease. This is a high percentage, and we have started such screening at our institute.
"The possible existence of a correlation between thyroid diseases and breast cancer has been evaluated previously, but the relationship between these two pathological conditions remains controversial," he explained.
"The dependence of breast cancer on hormonal substances and controversial data shown in the literature on the relationship between thyroid function and neoplastic disease suggested that the expression of thyroid hormone receptors could be an important marker in the characterization of breast cancer."
Define Mechanism of Action
Asked for her perspective, Karen Kostroff, MD, Chief of Breast Surgery at North Shore-LIJ Cancer Institute, said: "I believe a pathophysiological mechanism linking breast cancer and thyroid disease needs to be defined before changing screening guidelines."
In the study by Chiappa and his colleagues, histology findings showed that 725 of the breast cancer cases were ductal carcinoma, 71 were lobular carcinoma, and the remaining 71 were made up of less frequent tumoral types.
Regarding the 141 cases of thyroid disease, 138 had benign disease and three had thyroid cancer. Fifty-three patients had autoimmune thyroid disease, more of the women who were premenopausal were diagnosed with autoimmune thyroid disease compared with those who were postmenopausal (44% vs. 25%, respectively).
"We did stratify the women by menopausal status, and the major association was in the postmenopausal women-about 19 percent of the women with thyroid disease were postmenopausal compared with about 11 percent who were premenopausal.
ER Status
The researchers also observed a correlation between estrogen receptor positivity in breast cancer and chronic autoimmune thyroiditis. There were no statistically significant differences regarding the characteristics of breast cancer such as family history, tumor size, lymph node metastasis, distant metastasis, clinical stage, histopathology, grading, estrogen and progesterone receptor profile, and the expression of Ki67, p53, and HER2 genetic markers.
"If we can continue to study these correlations we may be able to find a specific population that can obtain a benefit from the early identification of thyroid disease," Chiappa said.
"It appears to be an association between autoimmune thyroid disease, specifically chronic autoimmune thyroiditis, and the occurrence of breast cancer at young age. However, the pathophysiological mechanism strongly linking the two entities remains to be investigated.
"Multicenter studies are needed to confirm the correlation between these two diseases, in order to accurately identify a subpopulation of high-risk patients."