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Reviewed research
Authors Mai PL, Garceau AO, Graubard BI, et al
Review Date Aug 2011
Citation Journal of the National Cancer Institute 2011; 103: 788-797. (See page 776 for the accompanying editorial)
Background
Knowledge of family cancer history is essential for estimating an individual’s cancer risk and making clinical recommendations regarding screening and referral to a specialty cancer genetics clinic.
There are two potential barriers to gaining optimal value from family history information: 1) the doctor, usually in the primary care setting, may not elicit or accurately record family history information and ii) the information given by the patient may not be accurate.
Attempts have been made to measure the quality of patient reporting but it is still not clear if reported family cancer history is sufficiently accurate for use in risk estimation. Alerting doctors to the issue of accuracy of reporting may encourage the use of tools to improve the collection and use of family history data in cancer screening and prevention.
Aim
To assess the accuracy of patient reporting of family history of cancer for four major cancers: breast, colorectal, prostate and lung.
Methods
In the population-based 2001 Connecticut Family Health Study, 1019 participants reported on 20,578 first-degree relatives (FDR) and second-degree relatives (SDR). Of those, 2,605 relatives were sampled for confirmation of cancer reports on breast, colorectal, prostate, and lung cancer. Confirmation sources included state cancer registries, Medicare databases, the National Death Index, death certificates, and health-care facility records. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for reports on lung, colorectal, breast, and prostate cancer and after stratification by sex, age, education, and degree of relatedness and used to estimate report accuracy. Pairwise t tests were used to evaluate differences between the two strata in each stratified analysis. All statistical tests were two-sided.
Results
Overall, sensitivity and positive predictive value were low to moderate and varied by cancer type: 60.2% and 40.0%, respectively, for lung cancer reports, 27.3% and 53.5% for colorectal cancer reports, 61.1% and 61.3% for breast cancer reports, and 32.0% and 53.4% for prostate cancer reports.
Specificity and negative predictive value were more than 95% for all four cancer types. Cancer history reports on FDR were more accurate than reports on SDR, with reports on FDR having statistically significantly higher sensitivity for prostate cancer than reports on SDR (58.9% vs 21.5%, P = .002) and higher positive predictive value for lung (78.1% vs 31.7%, P < .001), colorectal (85.8% vs 43.5%, P = .004), and breast cancer (79.9% vs 53.6%, P = .02).
Conclusion
General population reports on family history for the four major adult cancers were not highly accurate. Efforts to improve accuracy are needed in primary care and other health-care settings in which family history is collected to ensure appropriate risk assessment and clinical care recommendations.
Points to Note
- An individual’s risk of prostate cancer (and the other cancers in the study) is partly dependent on family history of cancer and an accurate report of family history is important to determine risk and screening recommendations.
- This American study, of a general population sample of adults aged 25-64 years, showed a low sensitivity (ability to identify all the cancers present amongst relatives) and moderate positive predictive value (proportion of cancers reported by the individual that prove to be confirmed cancers) for prostate cancer suggesting that risk calculated from these reports would be inaccurate. These figures were lower than those reported in other studies.
- The authors suggest that the relatively high false negative rate (non-reporting of cancers in the family) in prostate cancer might be due to the reluctance of men to discuss or disseminate information about their prostate cancer in the family.
- Although the study used several sources to attempt to confirm reported cancers in relatives, the authors could not be sure that they had not missed some cancers, thus inaccurately raising the false positive rate and lowering the positive predictive value.
- Given the importance of family history in determining cancer risk, this study highlights the problems that may arise from patient report of cancers in the family. Promoting awareness, encouraging discussion of cancer in families and using family history tools can all contribute to increasing the quality of family history information.
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