Table 1

Characteristics of breast cancer cases, women with benign breast disease (BBD) and unaffected control women tested for BRCA1 and BRCA2 mutation

Breast Cancer (n = 645) No. (%)BBD (n = 342) No. (%)Controls (n = 319) No. (%)P valueaP valueb
Agec
 <45 years256 (39.7)234 (68.4)126 (39.5)
 ≥45 years389 (60.3)108 (31.6)193 (60.5)0.95<.001
Family history of breast cancer
 None594d (94.7)329e (96.8)300f (96.2)
 First degreeg28 (4.7)8 (2.3)7 (2.2)0.080.70
 Grandmother only4 (0.6)3 (0.9)5 (1.6)
 Unknown1827
  • a P for differences between breast cancer cases and controls based on standard χ2 tests.

  • b P for differences between women with BBD and controls based on standard χ2 tests.

  • c Age is age at diagnosis for cases and age at blood draw and interview for women with BBD and for controls.

  • d Includes 112 women with no history of cancer in first-degree female relatives, but history was incomplete for one or both grandmothers; also includes 4 women with no history of cancer in either grandmother, but history was incomplete for 1 or more first-degree female relatives.

  • e Includes 31 women with no history of cancer in first-degree female relatives, but history was incomplete for one or both grandmothers; also includes one woman with no history of cancer in grandmothers or sisters, but mother’s history was unknown.

  • f Includes 139 women with no history of cancer in first-degree female relatives, but history was incomplete for one or both grandmothers.

  • g One case has both maternal grandmother and mother with history of breast cancer.