Abstract
Background
The objective was to compare women’s personal estimates of their risk with objective breast cancer risk estimates and to describe the risk factors for breast cancer identified by women.
Methods
Telephone survey of a random sample of 761 rural and urban women with no history of breast cancer. Survey instrument included measures of perceptions of lifetime risk for breast cancer for themselves and for the average woman, perceptions of risk factors that influenced their risk and the average woman’s risk for breast cancer. Objective estimates of breast cancer risk were calculated using the Gail et al. algorithm. Descriptive statistics and multiple linear regression were used to analyze the data.
Results
Women’s estimates of their own lifetime risk for breast cancer were significantly higher than their Gail model risk estimates (mean difference=19%, p<0.001). The women’s personal breast cancer risk estimates were lower than estimates of risk for a hypothetical average woman (mean difference=-8%, p<0.001). Fifty percent of the sample reported a perceived risk estimate at least 15% above their Gail risk estimate. The risk factors for breast cancer most frequently identified included family history, nutrition/diet, smoking, lifestyle, environment, stress and age. Although the risk factors used to calculate the Gail model risk estimates were reported by some study participants, these women consistently identified only family history as their personal risk factor.
Conclusion
Women have difficulty accurately estimating their breast cancer risk and identifying known risk factors for breast cancer. Individual risk information may be more useful in enhancing accurate risk perceptions than the “1 in 9” message.
Résumé
Objectif
Le but de cette étude était de comparer l’opinion des femmes sur leur risque personnel et le risque objectif de cancer du sein et de décrire les facteurs associés au cancer du sein signalés par les femmes.
Méthodes
Sondage téléphonique avec un échantillon aléatoire composé de 761 femmes de milieux urbains et ruraux, sans antécédents familiaux de cancer du sein. Le sondage comportait des instruments de mesure des perceptions du risque individuel et collectif à long terme, ainsi que des perceptions des facteurs associés au risque. Les estimations objectives du risque de cancer du sein ont été calculées par l’algorithme de Gail et al. Les données ont été analysées au moyen de statistiques descriptives et par régression linéaire multiple.
Résultats
Les estimations des femmes quant à leur propre risque de cancer du sein étaient considérablement plus élevées que le risque estimé par le modèle de Gail (différence moyenne = 19 %, p<0,001). Les estimations des femmes quant à leur risque personnel à long terme étaient inférieures à leurs estimations du risque collectif (différence moyenne = -8 %, p<0,001). Pour la moitié de l’échantillon, l’estimation du risque était de 15 % supérieure à celle obtenue par le modèle de Gail. Les facteurs les plus fréquemment associés étaient les antécédents familiaux, l’alimentation, le tabac, le mode de vie, l’environnement, le stress et l’âge. Bien que certaines répondantes aient signalé les facteurs de risque utilisés dans le calcul du modèle de Gail, ces femmes ont uniformément cité les antécédents familiaux comme seul facteur de risque personnel.
Conclusion
On constate que les femmes estiment difficilement leur risque de cancer du sein, ainsi que les facteurs associés. Plus que le message «une sur neuf», le fait de présenter des informations individuelles sur le risque pourrait peut-être créer une perception plus juste du risque.
Footnotes
Source of Funding: Medical Research Council
References
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