{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T14:17:10Z","timestamp":1784557030906,"version":"3.55.0"},"reference-count":6,"publisher":"Bioscientifica","issue":"2","license":[{"start":{"date-parts":[[2023,4,1]],"date-time":"2023-04-01T00:00:00Z","timestamp":1680307200000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["edm.bioscientifica.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2023,4,1]]},"abstract":"\n Summary<\/jats:title>\n We report a case of a woman with a diagnosis of breast cancer who unintentionally started gaining weight, feeling tired, and constipated 44 weeks after the initiation of trastuzumab. Hypothyroidism secondary to an autoimmune thyroiditis associated with trastuzumab was diagnosed, the first case described in Portugal and the fourth case described worldwide. Our intention regarding the publication of this case report is to alert the clinicians treating people with trastuzumab that they should ask the patients about symptoms of hypothyroidism and should screen the thyroid function of the patients before, during, and after the initiation of trastuzumab.<\/jats:p>\n <\/jats:sec>\n \n Learning points<\/jats:title>\n \n \n Trastuzumab is a humanized MAB used in HER2-positive breast and gastric cancer.<\/jats:p>\n <\/jats:list-item>\n \n Trastuzumab-associated autoimmune thyroid disease (AITD) is rare (incidence rate in an RCT of 0.3%).<\/jats:p>\n <\/jats:list-item>\n \n Manifestations of autoimmune thyroiditis associated with trastuzumab resemble those of hypothyroidism in other clinical contexts, but the presence of goiter is highlighted as a reason for medical evaluation. Biochemically, it is characterized by an increased thyroid-stimulating hormone (TSH) with or without a low FT4\/FT3, and sonographically with a pattern of thyroiditis.<\/jats:p>\n <\/jats:list-item>\n \n The treatment consists of levothyroxine, in a dose of 1.6\u20131.8 \u00b5g\/kg\/day, with re-evaluation of the thyroid function in 4\u20136 weeks.<\/jats:p>\n <\/jats:list-item>\n \n We report the first case of autoimmune thyroiditis secondary to trastuzumab in Portugal.<\/jats:p>\n <\/jats:list-item>\n \n It is important to evaluate the thyroid function before, during, and after the initiation of this therapeutic agent.<\/jats:p>\n <\/jats:list-item>\n <\/jats:list>\n <\/jats:sec>","DOI":"10.1530\/edm-22-0412","type":"journal-article","created":{"date-parts":[[2023,4,25]],"date-time":"2023-04-25T08:29:18Z","timestamp":1682411358000},"update-policy":"https:\/\/doi.org\/10.1530\/crossmarkpolicy-2","source":"Crossref","is-referenced-by-count":2,"title":["Autoimmune hypothyroidism and trastuzumab therapy: a rare association"],"prefix":"10.1530","volume":"2023","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2835-7709","authenticated-orcid":true,"given":"Valentim","family":"Lopes","sequence":"first","affiliation":[{"name":"Hospital de Braga, EPE, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Catarina","family":"Machado","sequence":"additional","affiliation":[{"name":"Hospital de Braga, EPE, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0499-9790","authenticated-orcid":true,"given":"Adriana","family":"De Sousa Lages","sequence":"additional","affiliation":[{"name":"Hospital de Braga, EPE, Portugal"},{"name":"Faculdade de Medicina, Universidade de Coimbra, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"416","reference":[{"key":"bib1","series-title":"Nature Reviews. Clinical Oncology","first-page":"33","article-title":"HER2-targeted therapies \u2013 a role beyond breast cancer","volume":"17","author":"Oh","year":"2020","unstructured":"Oh DY & Bang YJ. HER2-targeted therapies \u2013 a role beyond breast cancer. Nature Reviews. Clinical Oncology20201733\u201348. (https:\/\/doi.org\/10.1038\/s41571-019-0268-3)"},{"key":"bib2","series-title":"Korean Journal of Internal Medicine","first-page":"608","article-title":"Trastuzumab-associated autoimmune thyroid disease in a patient with metastatic breast cancer","volume":"31","author":"Min","year":"2016","unstructured":"Min HKKim IHKim JYBan THKim KHHa J & Kim JH. Trastuzumab-associated autoimmune thyroid disease in a patient with metastatic breast cancer. Korean Journal of Internal Medicine201631608\u2013611. (https:\/\/doi.org\/10.3904\/kjim.2014.031)"},{"key":"bib3","series-title":"Journal of Cancer Research and Therapeutics","first-page":"1183","article-title":"Trastuzumab and thyroid dysfunction: an association to be aware of","volume":"18","author":"S\u00e1nchez-Bayona","year":"2022","unstructured":"S\u00e1nchez-Bayona RGarcia del Barrio MAAlegre EFernandez-Hidalgo OA & Eslava MS. Trastuzumab and thyroid dysfunction: an association to be aware of. Journal of Cancer Research and Therapeutics2022181183\u20131185. (https:\/\/doi.org\/10.4103\/jcrt.JCRT_66_19)"},{"key":"bib4","series-title":"Best Practice and Research. Clinical Endocrinology and Metabolism","first-page":"693","article-title":"Immune reconstitution syndrome and the thyroid","volume":"23","author":"Weetman","year":"2009","unstructured":"Weetman A. Immune reconstitution syndrome and the thyroid. Best Practice and Research. Clinical Endocrinology and Metabolism200923693\u2013702. (https:\/\/doi.org\/10.1016\/j.beem.2009.07.003)"},{"key":"bib5","series-title":"AAPS Journal","first-page":"1144","article-title":"Clinical immunogenicity of rHuPH20, a hyaluronidase enabling subcutaneous drug administration","volume":"17","author":"Rosengren","year":"2015","unstructured":"Rosengren SDychter SSPrintz MAHuang LSchiff RISchwarz HPMcVey JKDrake FHManeval DCKennard DAClinical immunogenicity of rHuPH20, a hyaluronidase enabling subcutaneous drug administration. AAPS Journal2015171144\u20131156. (https:\/\/doi.org\/10.1208\/s12248-015-9782-0)"},{"key":"bib6","series-title":"Cancer Letters","first-page":"9","article-title":"Low molecular weight hyaluronan inhibits colorectal carcinoma growth by decreasing tumor cell proliferation and stimulating immune response","volume":"278","author":"Alaniz","year":"2009","unstructured":"Alaniz LRizzo MMalvicini MJaunarena JAvella DAtorrasagasti CAquino JBGarcia MMatar PSilva MLow molecular weight hyaluronan inhibits colorectal carcinoma growth by decreasing tumor cell proliferation and stimulating immune response. Cancer Letters20092789\u201316. 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