RADIOTHERAPY- INDUCED THYROID DYSFUNCTION
Keywords:
breast cancer, radiotherapy, thyroid disorder, supraclavicular nodal irradiationAbstract
Aim:The aim of this paper was to evaluate the effects of radiotherapy on thyroid function in breast cancer patients, comparing those treated only on the chest wall with those who also received supraclavicular (SCV) nodal irradiation.
Material and Methods: A total of 100 women with breast cancer treated with radiotherapy were analyzed. Blood samples were taken before radiotherapy and evaluated by measuring serum thyroid stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) levels. None of the women were on thyroid substitution therapy. Thyroid function, including TSH, fT3 and fT4 levels, was monitored in patients every 6 months after the completion of radiation.
Results: The results revealed a significant impact on thyroid function, particularly an increased incidence of hypothyroidism in the SCV irradiation group. The study reported that after six months of radiotherapy, 35% of patients developed hypothyroidism, and this percentage decreased to 27% after twelve months. This suggests that while many patients may experience immediate thyroid dysfunction following radiotherapy, some may recover over time, though a substantial portion remains affected.
Conclusions: The data presented highlight a concerning trend of increased hypothyroidism among breast cancer patients undergoing radiotherapy, particularly those receiving SCV irradiation. The study's findings indicate that a substantial proportion of patients may experience lasting thyroid dysfunction, necessitating vigilant monitoring and management.
References
Beatson GT. On the treatment of inoperable cases of carcinoma of the mamma: Suggestions for a new method of treatment, with illustrative cases. Trans Medico-Chir Soc Edinb 1896;15:153-179.PMID: 29584099.
Park J, Kim C, Ki Y, Kim W, Nam J, Kim D,et al. Incidence of hypothyroidism after treatment for breast cancer: A Korean population-based study. Andaloro C, ed. PLOS ONE 2022;17(6):e0269893. doi:10.1371/journal.pone.0269893.
Ung KA, Portillo M, Moran B, Kron T, Sawyer B, Herschtal A, et al. The dosimetric impact of supraclavicular nodal irradiation on the thyroid gland in patients with breast cancer. Pract Radiat Oncol. 2013;3(4):e131-e137. doi:10.1016/j.prro.2012.12.007.
Smith GL, Smith BD, Giordano SH, Shih YC, Woodward WA, Strom EA, et al. Risk of hypothyroidism in older breast cancer patients treated with radiation. Cancer 2008;112(6):1371-1379. doi:10.1002/cncr.23307.
Bruning P, Bonfrèr J, De Jong-Bakker M, Nooyen W, Burgers M. Primary hypothyroidism in breast cancer patients with irradiated supraclavicular lymph nodes. Br J Cancer 1985;51(5):659-663. doi:10.1038/bjc.1985.99.
Reinertsen KV, Cvancarova M, Wist E, Bjøro T, Dahl AA, Danielsen T, et al. Thyroid function in women after multimodal treatment for breast cancer stage II/III: Comparison with controls from a population sample. Int J Radiat Oncol Biol Phys 2009;75(3):764-770. doi:10.1016/j.ijrobp.2008.11.037.
Joensuu H, Viikari J. Thyroid function after postoperative radiation therapy in patients with breast cancer. Acta Radiol Oncol 1986;25(3):167-170. doi:10.3109/02841868609136397.
Jereczek-Fossa BA, Alterio D, Jassem J, Gibelli B, Tradati N, Orecchia R. Radiotherapy-induced thyroid disorders. Cancer Treat Rev 2004;30(4):369-384. doi:10.1016/j.ctrv.2003.12.003.
Tunio M, Al Asiri M, Bayoumi Y, Stanciu LG, Al Johani N, Al Saeed EF. Is thyroid gland an organ at risk in breast cancer patients treated with locoregional radiotherapy? Results of a pilot study. J Cancer Res Ther 2015;11(4):684-689. doi:10.4103/0973-1482.167613.
