Purpose: Population-based cancer incidence rates of the corpus uteri, cervix uteri, and ovaries are underestimated if they fail to remove women not at risk for developing the cancers from the denominator in the race calculation. This study compares incidence rates among selected racial groups for these cancers before and after correction for prevalence of hysterectomy and bilateral oophorectomy.
Methods: The study covers 1998 through 2002 and involves Surveillance, Epidemiology, and End Results Program; Behavior Risk Factor Surveillance System; and National Health Interview Survey data. Prevalence data were obtained by using survey and life-table methods. Four racial groups are considered: whites, blacks, American Indians/Alaska Natives, and Asians/Pacific Islanders.
Results: Risk correction significantly increased rates of corpus uterine cancer by 73.1% for whites, 93.0% for blacks, 86.3% for American Indians/Alaska Natives, and 41.0% for Asians/Pacific Islanders. Corresponding percentages among these racial groups for cervical cancer were 37.7%, 60.2%, 45.6%, and 33.0%, and for ovarian cancer, 32.5%, 31.1%, 35.0%, and 23.6%, respectively. Risk correction had large influences on the comparison of rates among racial groups. For example, for uterine corpus cancer, Asians/Pacific Islanders had 32.9% lower rates than whites before correction, but 45.3% lower rates after correction. For cervical cancer, blacks had 27.6% higher rates than whites before correction, but 48.5% higher rates after correction; and for ovarian cancer, Asians/Pacific Islanders had 31.2% lower rates than whites before correction and 35.8% lower rates after correction.
Conclusions: Corrected rates of corpus uteri, cervix uteri, and ovarian cancers have a large, but differential, impact on the racial groups considered.