Retrospektive Untersuchung von Komorbiditäten als Risikofaktoren für Brustkrebs und deren Auswirkung auf die Mortalität

The aim of the dissertation was to better understand the interaction of breast cancer with other comorbidities. The work was based on two articles published with first authorship in PubMed-listed journals. The IQVIA Disease Analyzer database formed the data source for both articles. The first article examined the association of thyroid disease and breast cancer incidence. The article was published in Breast Cancer Research and Treatment on May 18, 2020. Methodologically, a retrospective case-control study was designed with 14,816 patients. Existing studies around the link between thyroid dysfunction and breast cancer sometimes did not provide consistent results. Some studies suggested an increased risk of breast cancer in hyperthyroidism. Conversely, other authors claimed an increased risk in hypothyroidism or found no association between these conditions. Similar inconsistent results have been provided so far on thyroiditis and breast cancer. The present analysis did not demonstrate a significant link of hyperthyroidism, hypothyroidism, or goiter with the occurrence of breast cancer. Although a significant association of thyroiditis and breast cancer was shown. The second article focused on the impact of a wide variety of comorbidities on mortality in breast cancer patients. It was published in the Journal of Psychiatric Research on October 27, 2021. Using a retrospective cohort study of 6,656 breast cancer patients, the mortality within five years of the index date was examined among the following comorbidities: thyroid disease, diabetes mellitus, obesity, dyslipidemia, depression, sleep disorders, arterial hypertension, ischemic heart disease, renal insufficiency. Unexpectedly, significantly higher mortality in breast cancer patients was associated with depression or sleep disorder. In addition, increased mortality was also revealed in the comorbidities of diabetes mellitus and renal insufficiency. In conclusion, breast cancer, as the most common form of cancer worldwide, still has many interactions with other comorbidities that urgently need further investigation. Only by understanding the relationships of different diseases can lethal diseases, such as breast cancer, be detected earlier and treated more holistically in an increasingly multimorbid society. This will enable us to further improve the prognosis of those affected in the future.