High prevalence of breast cancer in patients with benign thyroid diseases

J Endocrinol Invest. 2011 May;34(5):349-52. doi: 10.1007/BF03347458. Epub 2010 Jul 1.


Background: In patients with breast cancer (BC) a high prevalence of benign thyroid diseases (BTD) has been described, Hashimoto's thyroiditis accounting to a large extent for this association. The aim of this study was to evaluate the prevalence of BC in a large group of patients with BTD.

Patients: Clinical records of 622 consecutive patients with BTD were examined. BC prevalence in BTD patients was compared with BC frequency in general population living in the same country.

Results: BC prevalence in patients with BTD (38/622; 6.11%) was significantly higher (p=0.0002) compared to BC frequency in general population (2.07%). When patients were divided according to the age of menopause, in females older than 49 yr BC frequency in BTD was significantly higher than in age-matched population (7.6 vs 3.3%; p=0.006), while in females aged 30-49 yr BC frequency in BTD was higher, but not statistically significantly, than in agematched population (3.7 vs 0.5%; p=0.06). No significant difference in BC prevalence was found when patients were grouped according to the diagnosis of thyroid disorders: Graves' disease, Hashimoto's thyroiditis, nodular goiter associated or not associated with serum thyroid autoantibodies (TAb). No significant difference in BC frequency was observed between TAb+ (26/377; 6.9%) and TAb- (12/245; 4.9%) patients. The distribution of known risk factors for breast malignancies was similar in patients with or without BC.

Conclusion: In patients with BTD the prevalence of BC is significantly higher than the expected, showing the usefulness of screening for breast malignancy of patients with BTD.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Breast Neoplasms / diagnosis
  • Breast Neoplasms / epidemiology*
  • Breast Neoplasms / pathology
  • Comorbidity
  • Female
  • Humans
  • Middle Aged
  • Thyroid Diseases / diagnosis
  • Thyroid Diseases / epidemiology*
  • Thyroid Diseases / pathology
  • Thyroid Gland / pathology