{
  "abstract": "Despite advances in screening and treatment for breast cancer and a substantial decline in the disease’s mortality, breast cancer continues to show increased incidence and remains a major global health burden. A major factor in these trends is breast cancer’s heterogeneity, as reflected by distinct subtypes. Central thyroid hormone sensitivity can be assessed using the thyroid feedback quantile-based index (TFQI), thyroid-stimulating hormone (TSH) index (TSHI), TSH T4 resistance index (TT4RI), and the free triiodothyronine/free thyroxine (fT3/fT4) ratio, an indirect proxy of peripheral thyroid hormone conversion. We investigated associations between surrogate clinicopathologic subtypes of breast cancer and central thyroid hormone sensitivity indices and the fT3/fT4 ratio. We retrospectively analyzed 109 patients with preoperative thyroid function tests who underwent surgery for breast cancer between 2017 and 2022 at Gülhane Training and Research Hospital, Department of Surgical Oncology. We investigated associations of surrogate clinicopathologic subtypes with TFQI, TT4RI, TSHI, and the fT3/fT4 ratio. Associations with receptor and Ki-67 status were additionally evaluated using separate age- and BMI-adjusted Firth’s penalized logistic regression models, each including 1 thyroid index. No statistically significant differences emerged in the distribution of central thyroid hormone sensitivity indices across surrogate clinicopathologic subtypes (P = .349 for TFQI, P = .867 for TT4RI, P = .645 for TSHI). The fT3/fT4 ratio differed significantly across subtypes (P < .001). In separate age- and BMI-adjusted Firth’s models, a higher fT3/fT4 ratio was associated with lower odds of HER2 positivity (adjusted OR = 0.226, 95% CI: 0.088–0.579; P = .002) but higher odds of being in the high Ki-67 group (adjusted OR = 2.096, 95% CI: 1.219–3.603; P = .007). No statistically significant associations were observed between these outcomes and central thyroid hormone sensitivity indices. The fT3/fT4 ratio differed significantly across breast cancer subtypes, with higher values in the triple-negative breast cancer group than in several other subtypes, whereas central thyroid hormone sensitivity indices showed no significant differences. These findings suggest a possible association between peripheral thyroid hormone conversion and clinicopathologic tumor phenotype.",
  "abstract_shown": true,
  "affiliations": [
    "Department of General Surgery, Health Sciences University, Faculty of Medicine, Gülhane Research and Training Hospital, Ankara, Turkey",
    "Department of Surgical Oncology, Health Sciences University, Faculty of Medicine, Gülhane Research and Training Hospital, Ankara, Turkey",
    "Department of Endocrinology and Metabolism, Health Sciences University, Faculty of Medicine, Gülhane Research and Training Hospital, Ankara, Turkey."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Mehmet Mert Hidiroglu",
      "orcid": "0009-0009-1137-8803"
    },
    {
      "affs": [
        1
      ],
      "name": "Sevket Baris Morkavuk",
      "orcid": "0000-0003-0441-0333"
    },
    {
      "affs": [
        2
      ],
      "name": "Safak Akin"
    },
    {
      "affs": [
        1
      ],
      "name": "Ibrahim Burak Bahcecioglu"
    },
    {
      "affs": [
        2
      ],
      "name": "Nese Ersoz Gulcelik"
    },
    {
      "affs": [
        1
      ],
      "name": "Mehmet Ali Gulcelik"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dyemhgmk77vw9.bib",
  "cited_by": 0,
  "doi": "10.1097/md.0000000000051340",
  "fulltext_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13727159/?tool=EBI",
  "id": "dyemhgmk77vw9",
  "issns": [
    "0304-5412",
    "1536-5964",
    "0025-7974"
  ],
  "landing_url": "https://europepmc.org/article/PMC/PMC13727159",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "4300"
    ],
    [
      "heading",
      "Observational Study"
    ],
    [
      "heading",
      "Research Article"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13727159/pdf/?tool=EBI",
  "pmcid": "PMC13727159",
  "pmid": null,
  "published": "2026-10-30",
  "publisher": "Wolters Kluwer Health",
  "ris": "https://research.draconitic.com/paper/dyemhgmk77vw9.ris",
  "sources": [
    {
      "first_seen": "2026-11-03T15:20:51Z",
      "native_id": "PMC:PMC13727159",
      "source": "europepmc",
      "url": "https://europepmc.org/article/PMC/PMC13727159"
    },
    {
      "first_seen": "2026-11-05T12:23:17Z",
      "native_id": "PMC13727159",
      "source": "pmc",
      "url": "https://doi.org/10.1097/md.0000000000051340"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "journal-openalex:F27",
      "subfield": "general"
    }
  ],
  "title": "Association between thyroid hormone sensitivity indices and surrogate clinicopathologic subtypes of breast cancer : A retrospective single-center study",
  "title_text": "Association between thyroid hormone sensitivity indices and surrogate clinicopathologic subtypes of breast cancer : A retrospective single-center study",
  "type": "peer-reviewed",
  "updated_at": "2026-11-06T12:22:53Z",
  "url": "https://research.draconitic.com/paper/dyemhgmk77vw9",
  "venue": "Medicine",
  "versions": []
}