Harvey A. Risch

An application of capture-recapture methods to the estimation of completeness of cancer registration

Completeness of cancer registration has not been consistently ascertained across different registries. This report describes how capture-recapture methods have been used to estimate completeness at the Ontario Cancer Registry. The method was applied in two fashions; first, using three data sources in a modeling approach: and second, using two data sources and standard, simple capture-recapture methods. The modeling approach is more flexible, since several variables that influence cancer registration can be considered and can be used to identify reporting patterns of different data sources. In the present analysis, estimates of completeness of the registry as a whole were remarkably similar using either two or three data sources, and site-specific comparisons differed by at most 7%. Because of the advantages of capture-recapture methods-estimation of level of completeness, possible comparability of estimates across different registries, and versatility to consider other determinants of cancer registration-a plea for greater use of these methods in cancer registration is made.

Progesterone receptor variant increases ovarian cancer risk in BRCA1 and BRCA2 mutation carriers who were never exposed to oral contraceptives.

Oral contraceptives have been shown to be protective against hereditary ovarian cancer. The variant progesterone receptor allele named PROGINS is characterized by an Alu insertion into intron G and two additional mutations in exons 4 and 5. The PROGINS allele codes for a progesterone receptor with increased stability and increased hormone-induced transcriptional activity. We studied the role of the PROGINS allele as a modifying gene in hereditary breast and ovarian cancer. The study included 195 BRCA1 and BRCA2 carriers with a prior diagnosis of ovarian cancer, 392 carriers with a diagnosis of breast cancer and 249 carriers with neither cancer. Fifty-eight women had both forms of cancer. Five hundred and ninety-five women had a BRCA1 mutation and 183 women had a BRCA2 mutation. Overall, there was no association between disease status and the presence of the PROGINS allele. Information on oral contraception use was available for 663 of the 778 carriers of BRCA1 or BRCA2 mutations. Among the 449 subjects with a history of oral contraceptive use (74 cases and 365 controls), no modifying effect of PROGINS was observed [odds ratio (OR) 0.8; 95% confidence interval (CI) 0.5-1.3]. Among the 214 carriers with no past exposure to oral contraceptives, the presence of one or more PROGINS alleles was associated with an OR of 2.4 for ovarian cancer, compared to women without ovarian cancer and with no PROGINS allele (P = 0.004; 95% CI 1.4-4.3). The association was present after adjustment for ethnic group and for year of birth.

Changes in breast self-examination behavior in a cohort of 8214 women in the Canadian National Breast Screening Study.

A study cohort of 8214 women was formed from all participants in the Canadian National Breast Screening Study who attended their first three screens after the introduction of a structured evaluation protocol involving eight criteria for breast self‐examination (BSE). Self‐reported BSE frequency was collected by questionnaire at all three screens. Breast self‐examination instruction preceded breast exam at each screen but BSE evaluation occurred only at the second and third screen. Reported monthly BSE frequency increased from 18% to 51% to 55% on first, second, and third screens, respectively. The proportion claiming to do no BSE fell correspondingly: 52%, 16%, and 11%. Compliance with each of the seven other BSE criteria was significantly greater at the third screen than at the second. The mean number of these criteria performed at screen 3 was 5.1 compared with 4.4 at screen 2; older women performed as well as younger. The mean number of criteria performed was associated with BSE frequency at screen 3. The authors conclude that womens BSE behavior can be altered, and that integration of BSE evaluation and instruction into routine medical exams seems feasible and potentially useful.