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Biomedical subjects

J Schildkraut

Publications and source records attributed to J Schildkraut.

8 recordsLinked to original sources
PubMed1999

Ethical ramifications of alternative means of recruiting research participants from cancer registries.

BACKGROUND: The protection of confidentiality and the extent to which voluntary and meaningful informed consent can be obtained from potential participants are critical when recruiting patients for clinical research from cancer registries. In the current study the authors describe the influence of two methods of recruitment from a cancer registry (direct contact by research staff and contact by research staff after physicians alert potential participants) on these issues. METHODS: Enrollment rates were tabulated using each recruitment method and complaints received from potential participants regarding recruitment were reviewed. RESULTS: Of 416 women approached to participate, the first 351 women were recruited by way of direct contact by research staff and the remaining 65 women were recruited by research staff after their physician had sent them an alert letter. There was no difference in the enrollment rate using the two methods. One potential participant believed that her confidentiality had been violated and another hung up the telephone when contacted directly; two potential subjects reported feeling pressure to participate because their physician sent them a letter. CONCLUSIONS: Although concerns regarding violating confidentiality clearly are justified when recruiting research participants from cancer registries, patients also may feel pressure to participate if physician notification is part of the process. It is incumbent on investigators and institutional review boards charged with overseeing this research that they respect confidentiality and avoid pressuring persons to participate in research. It also is critical that persons whose medical information will be entered into cancer registries be informed about this process as well as how the registry will be used for research.

Adult↗
PubMed1999

A Bayesian hierarchical approach for combining case-control and prospective studies.

Motivated by the absolute risk predictions required in medical decision making and patient counseling, we propose an approach for the combined analysis of case-control and prospective studies of disease risk factors. The approach is hierarchical to account for parameter heterogeneity among studies and among sampling units of the same study. It is based on modeling the retrospective distribution of the covariates given the disease outcome, a strategy that greatly simplifies both the combination of prospective and retrospective studies and the computation of Bayesian predictions in the hierarchical case-control context. Retrospective modeling differentiates our approach from most current strategies for inference on risk factors, which are based on the assumption of a specific prospective model. To ensure modeling flexibility, we propose using a mixture model for the retrospective distributions of the covariates. This leads to a general nonlinear regression family for the implied prospective likelihood. After introducing and motivating our proposal, we present simple results that highlight its relationship with existing approaches, develop Markov chain Monte Carlo methods for inference and prediction, and present an illustration using ovarian cancer data.

Bayes Theorem↗
PubMed1999

Attitudes, knowledge, and risk perceptions of women with breast and/or ovarian cancer considering testing for BRCA1 and BRCA2.

PURPOSE: This study examined baseline knowledge, beliefs, and risk perceptions among a group of 200 women with breast and/or ovarian cancer who participated in a trial designed to improve decision making about genetic testing for BRCA1 and BRCA2. PATIENTS AND METHODS: Women were identified by self-referral, physician referral, and tumor registry extraction and invited to participate in a randomized trial in which testing for BRCA1 and BRCA2 was offered free of charge. Subjects completed baseline questionnaires and interviews that assessed knowledge, attitudes, and perceptions of risk of having an alteration in BRCA1 or BRCA2. RESULTS: Sixty percent of women overestimated their chances of having a BRCA1 or BRCA2 mutation compared with estimates from a BRCA1/BRCA2 risk model. Women who have at least three relatives with breast or ovarian cancer were one third (95% confidence interval, 0.2 to 0.6) as likely to overestimate their risk of having a BRCA1 or BRCA2 mutation compared with women who have two or fewer affected relatives. Knowledge was limited about BRCA1 and BRCA2 mutations and cancer risk associated with gene mutations. Eighty-four percent of the women indicated a probable or definite interest in testing. CONCLUSION: A high proportion of the high-risk women in this study had knowledge deficits about BRCA1 and BRCA2 and overestimated their risk of having a mutation. Although some degree of caution should be used in generalizing the results of this study to practice settings, the data provide insight into the challenges clinicians will face in communicating with patients about cancer genetics.

Adult↗
PubMed1998

Effect of BRCA1 and BRCA2 on the association between breast cancer risk and family history.

BACKGROUND: The discovery of BRCA1 and BRCA2 has led to a reassessment of the association between family history of breast/ovarian cancer and breast cancer risk after controlling for carrier status for mutations in the BRCA1 and BRCA2 genes. We examined whether family history of breast cancer remains a predictive risk factor for this disease after carrier status for BRCA1 and/or BRCA2 mutations is taken into consideration. METHODS: The data are from 4730 case subjects with breast cancer and 4688 control subjects enrolled in the Cancer and Steroid Hormone Study. The probability of being a BRCA1 and/or BRCA2 gene carrier was calculated for each woman. Among predicted noncarriers, logistic regression was used to assess the relationship (odds ratios and 95% confidence intervals [CIs]) between case or control status and family history of breast or ovarian cancer. Estimates of age-specific breast cancer risk are presented by predicted carrier status. RESULTS: Among predicted noncarriers, case subjects were 2.06 times (95% CI = 1.69-2.50) and 1.24 times (95% CI = 1.17-1.32) more likely to report a first-degree or second-degree family history of breast cancer, respectively, than were control subjects. Case subjects were 1.99 times (95% CI = 1.63-2.44), 1.66 times (95% CI = 1.18-2.38), and 2.23 times (95% CI = 0.21-24.65) more likely to report an affected mother, sister, or both, respectively, than were control subjects. A family history of ovarian cancer was not statistically significantly associated with breast cancer risk. Noncarriers were predicted to have a lifetime risk of 9% of developing breast cancer compared with a 63% risk for carriers. CONCLUSIONS: Among women with a moderate family history of breast cancer, i.e., predicted noncarriers of BRCA1 and/or BRCA2 mutations, family history remains a factor in predicting breast cancer risk. In families with breast and ovarian cancers, the aggregation of these two cancers appears to be explained by BRCA1/BRCA2 mutation-carrier probability.

Adult↗
PubMed1998

Genetic counseling and testing for breast-ovarian cancer susceptibility: what do women want?

PURPOSE: To assess preferences for the content and process of genetic counseling and testing for breast-ovarian cancer susceptibility among women at high risk for breast cancer. METHODS: Ninety-eight healthy women who had a family history of breast cancer in at least two first-degree relatives participated in a structured telephone survey that evaluated preferences for type of provider and the content and process of pretest education and posttest genetic counseling. RESULTS: Forty-two percent of women preferred that pretest education be delivered by a genetic counselor, while 22% preferred an oncologist. This preference was positively associated with a desire to discuss psychosocial issues during the session (P = .001). For posttest counseling, 38% of women preferred an oncologist, while 20% preferred a genetic counselor. However, women who desired supportive counseling during this session were significantly more likely to prefer a genetic counselor to an oncologist (P = .02). Fewer women wished to see a primary care physician or gynecologist for pretest education (11%) or posttest counseling (22%). With regard to the counseling process, 82% of women wished to self-refer for genetic counseling, but 63% desired advice and recommendations about whether to be tested. CONCLUSION: When feasible, the optimal approach may be for oncologists to work with genetic counselors to provide pretest education and medical recommendations. Elicitation of patients' preferences may be useful to determine the level of counseling services needed.

Adult↗
PubMed1997

Probability of carrying a mutation of breast-ovarian cancer gene BRCA1 based on family history.

BACKGROUND: Heritable mutations of the breast cancer gene BRCA1 are rare, occurring in fewer than 1% of women in the general population, and therefore account for a small proportion of cases of breast and ovarian cancers. Nevertheless, the presence of such mutations is highly predictive of the development of these cancers. PURPOSE: We developed and applied a mathematic model for calculating the probability that a woman with a family history of breast and/or ovarian cancer carries a mutation of BRCA1. METHODS AND RESULTS: As a basis for the model, we use Mendelian genetics and apply Bayes' theorem to information on the family history of these diseases. Of importance are the exact relationships of all family members, including both affected and unaffected members, and ages at diagnosis of the affected members and current ages of the unaffected members. We used available estimates of BRCA1 mutation frequencies in the general population and age-specific incidence rates of breast and ovarian cancers in carriers and noncarriers of mutations to estimate the probability that a particular member of the family carries a mutation. This probability is based on cancer statuses of all first- and second-degree relatives. We first describe the model by considering single individuals: a woman diagnosed with breast and/or ovarian cancer and also a woman free of cancer. We next considered two artificial and two actual family histories and addressed the sensitivity of our calculations to various assumptions. Particular relationships of family members with and without cancer can have a substantial impact on the probability of carrying a susceptibility gene. Ages at diagnosis of affected family members and their types of cancer are also important. A woman with two primary cancers can have a probability of carrying a mutation in excess of 80%, even with no other information about family history. The number and relationships of unaffected members, along with their current ages or ages at death, are critical determinants of one's carrier probability. An affected woman with several cancers in her family can have a probability of carrying a mutation that ranges from close to 100% to less than 5%. CONCLUSION: Our model gives informative and specific probabilities that a particular woman carries a mutation. IMPLICATIONS: This model focuses on mutations in BRCA1 and assumes that all other breast cancer is sporadic. With the cloning of BRCA2, we now know that this assumption is incorrect. We have adjusted the model to include BRCA2, but the use of this version must await publication of penetrance data for BRCA2, including those for male breast cancer that are apparently associated with BRCA2 but not with BRCA1. The current model is, nevertheless, appropriate and useful. Of principal importance is its potential and that of improved versions for aiding women and their health care providers in assessing the need for genetic testing.

Adult↗
PubMedDate not supplied

High expression of insulin-like growth factor binding protein-2 messenger RNA in epithelial ovarian cancers produces elevated preoperative serum levels.

The molecular etiology of epithelial ovarian cancer remains unclear. Using microarray expression analysis, we recently reported that expression of the insulin-like growth factor binding protein-2 (IGFBP-2) gene is elevated in advanced epithelial ovarian cancers. The aim of this study was to further delineate the role of IGFBP-2 in the pathoetiology of epithelial ovarian cancer and determine if elevated ovarian cancer IGFBP-2 gene expression is reflected in serum. Relative IGFBP-2 expression was measured using quantitative real-time polymerase chain reaction in 113 epithelial ovarian cancers and 6 normal ovarian surface epithelial samples. Preoperative serum IGFBP-2 levels were measured by radioimmunoassay in 84 women (42 ovarian cancers, 26 benign gynecological conditions, and 10 healthy female controls). Ovarian cancers demonstrated 38-fold higher mean IGFBP-2 expression than normal ovarian epithelium (P < 0.01). Serum IGFBP-2 levels were elevated in women with early- and advanced-stage ovarian cancer compared to controls and patients with benign gynecological conditions (P = 0.05 and P < 0.01, respectively). Epithelial ovarian cancers express high levels of IGFBP-2 relative to normal ovarian epithelium, and this is associated with elevated serum IGFBP-2 levels compared to both normal controls and patients with benign gynecological disease. Our findings provide further support that the insulin-like growth factor pathway plays a significant role in epithelial ovarian cancer pathogenesis. Further, IGFBP-2 may represent an additional serum biomarker with utility in detection and monitoring of epithelial ovarian cancer.

Adenocarcinoma, Clear Cell↗