Racial differences in the familial aggregation of breast cancer and other female cancers.
Although breast cancer familial aggregation has been studied in Caucasians, information for African-Americans is scant. We used family cancer history from the Women's Contraceptive and Reproductive Experiences study to assess the aggregation of breast and gynecological cancers in African-American and Caucasian families. Information was available on 41,825 first and second-degree relatives of Caucasian and 28,956 relatives of African-American participants. We used a cohort approach in which the relative's cancer status was the outcome in unconditional logistic regression and adjusted for correlated data using generalized estimating equations. Race-specific models included a family history indicator, the relative's age, and type. Relative risk (RR) estimates for breast cancer were highest for first-degree relatives, and the overall RR for breast cancer among case relatives was 1.96 (95% CI = 1.68-2.30) for Caucasian and 1.78 (95% CI = 1.41-2.25) for African-Americans. The effect of CARE participants' reference age on their relatives' breast cancer risk was greatest among first-degree relatives of African-American patients with RRs (95% CI) for ages <45 and > or =45 of 2.97 (1.86-4.74) and 1.48 (1.14-1.92), respectively. Among Caucasians, first-degree relatives of case subjects were at greater risk for ovarian cancer, particularly relatives younger than 45 years (RR (95% CI) = 2.06 (1.02-4.12)), whereas African-American first-degree relatives of case subjects were at increased cervical cancer risk (RR (95% CI) = 2.17 (1.22-3.85). In conclusion, these racially distinct aggregation patterns may reflect different modes of inheritance and/or environmental factors that impact cancer risk.
Simon
Michael S
MS
Division of Haematology and Oncology, Barbara Ann Karmanos Cancer Institute, 4100 John R, 4221 Hudson, Weber Cancer Research Building, Detroit, M1 48201, USA. Simonm@karmanos.org
Korczak
Jeannette F
JF
Yee
Cecilia L
CL
Daling
Janet R
JR
Malone
Kathleen E
KE
Bernstein
Leslie
L
Marchbanks
Polly A
PA
Folger
Suzanne G
SG
McDonald
Jill A
JA
Norman
Sandra A
SA
Strom
Brian L
BL
Deapen
Dennis
D
Ursin
Giske
G
Burkman
Ronald T
RT
Press
Michael F
MF
Schwartz
Ann G
AG
Spirtas
Robert
R
D000328:Adult; D044383:Black People; D001943:Breast Neoplasms / Q000208:ethnology* / Q000473:pathology / Q000628:therapy; D016022:Case-Control Studies; D018572:Disease-Free Survival; D005190:Family; D005260:Female; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D010051:Ovarian Neoplasms / Q000208:ethnology* / Q000473:pathology / Q000628:therapy; D014594:Uterine Neoplasms / Q000208:ethnology* / Q000473:pathology / Q000628:therapy; D044465:White People; D001741:Black or African American