Multiple primary breast and thyroid cancer
1984

Breast and Thyroid Cancer Risk

Sample size: 1487 publication Evidence: moderate

Author Information

Author(s): E. Ron, R. Curtis, D.A. Hoffman, J.T. Flannery

Primary Institution: Chaim Sheba Medical Center

Hypothesis

Is there an increased risk of developing breast cancer after thyroid cancer and vice versa?

Conclusion

The study found a significantly elevated risk of thyroid cancer following breast cancer and breast cancer following thyroid cancer, especially in women under 40 years of age.

Supporting Evidence

  • A significantly elevated risk of thyroid cancer following breast cancer was observed (SIR=1.68).
  • A significantly elevated risk of breast cancer following thyroid cancer was observed (SIR=1.89).
  • The highest risk of developing breast cancer was found among patients with follicular or mixed papillary-follicular thyroid cancer.
  • Women under age 40 with follicular carcinoma had a 10-fold risk of developing breast cancer.
  • An enhanced risk of second primary tumors was evident for the entire period after treatment of the first primary.

Takeaway

Women who have had thyroid cancer are more likely to get breast cancer, and women who have had breast cancer are more likely to get thyroid cancer, especially if they are younger than 40.

Methodology

Data from the Connecticut Tumor Registry was analyzed for women diagnosed with primary thyroid and breast cancer between 1935 and 1978.

Potential Biases

Potential bias due to incomplete treatment data and reliance on registry records.

Limitations

The study only included treatment data for the first 4 months post-diagnosis, and some treatment types were not consistently recorded.

Participant Demographics

The study included 1487 women with primary thyroid cancer and 36,542 women with primary breast cancer.

Statistical Information

Confidence Interval

1.51-14.22

Statistical Significance

p<0.05

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