Thyroid Dysfunction is Common in Women With Breast Cancer Following Radiation Therapy

Thyroid and parathyroid dysfunction is common among women with breast cancer (BC) following radiotherapy (RT), according to a study published in the Canadian Oncology Nursing Journal.

“The current advances in (RT) have improved the outcome of breast cancer (BC) patients. Despite its therapeutic benefits, the iatrogenic toxicities of RT and its impact on BC survivors are still debated, and further evaluations should be considered,” the researchers noted.

In this cross-sectional study, researchers analyzed 70 women with BC undergoing RT. They analyzed thyroid function by assessing thyroid stimulating hormone (TSH), free thyroxine (fT4), and free triiodothyronine (fT3) levels. They noted that parathyroid function was evaluated by measuring serum levels of Calcium (Ca), Phosphorus (P), and parathyroid hormone (PTH) at baseline, six and 12 months after RT.

There were no cases of hypothyroidism before radiotherapy. However, the researchers observed that nine patients developed hypothyroidism in the six months following radiotherapy (one clinical and eight subclinical, 13% in total), and six patients were identified with hypothyroidism in the 12 months after radiotherapy (one clinical and five subclinical, 8.7% in total). They noted that there was a significant relationship between hypothyroidism rate at both six months (p = 0.003) and 12 months (p = 0.028) after RT compared with the baseline.

Given the results, the researchers concluded that “routine thyroid function monitoring should be recommended to improve the quality of life in BC survivors.”