NCI Abstract related to Thyca & Breast Cancer

[Guest guest]

I know the question about a link between Breast Cancer and Thyroid

Cancer gets revisited on occasion, so I thought I'd post info from a

recent NCI Cancerlit Abstract. Just think of it as a reminder to do

your monthly breast exam and to have mammograms as suggested by your own

physicians.

Marilyn

Multiple primary breast and thyroid cancers: role of age at diagnosis

and cancer treatments (United States).

Unique Identifier: 20525127

Author: Li CI; Rossing MA; Voigt LF; Daling JR

Source: Cancer Causes Control 2000 Oct;11(9):805-11

Address: Fred Hutchinson Cancer Research Center, Program in

Epidemiology, Division of Public Health Sciences, Seattle, Washington

98104, USA. cili@...

ABSTRACT:

BACKGROUND: Breast and thyroid cancer have been observed to occur more

frequently than expected as multiple primary tumors in women. The study

presented herein focuses on the effects of age at diagnosis and

treatment for the first cancer on the development of the second cancer.

METHODS: This retrospective cohort study used a study population

consisting of 38,632 women diagnosed with primary invasive breast cancer

and 2189 women diagnosed with primary invasive thyroid cancer between

1974 and 1994. Cases were identified from records of the Cancer

Surveillance System of western Washington and followed for subsequent

cancer development through 1995.

RESULTS: Seventy-one women were diagnosed during their lives with both

breast and thyroid cancers. Including cancers diagnosed during the same

month as or after the initial cancer, the relative risk (RR) of breast

cancer among women with thyroid cancer was 1.5 (95% confidence interval

[CI] 1.1-2.0), and the RR of thyroid cancer among women with breast

cancer was 1.5 (95% CI 1.1-2.2). Among women with thyroid cancer, risk

of breast cancer was greatest when the latter cancer was diagnosed under

45 years of age (RR = 2.3, 95% CI 1.1-4.4). First course of treatment,

including radiation or hormonal therapy to

treat thyroid cancer, and radiation, chemotherapy, or hormonal therapy

to treat breast cancer, did not alter a woman's risk of developing the

second cancer.

CONCLUSIONS: The data suggest that the incidence of breast and thyroid

cancer may be related, and that in particular women with thyroid cancer

may be at a moderately increased risk of developing breast cancer before

age 45.