Understanding breast cancer screening: should the intellectually non-disabled make decisions for the intellectually disabled?

Abstract

In the USA, 70% of women without a cervix have cervicalcancer screening (Sirovich & Welch 2004). According to arecent survey most individuals would overrule a physicianwho recommended against cancer screening, 60% want tobe tested even for cancers that would never cause problemsduring the person’s lifetime if untreated, and 40% believethat an 80-year old woman who chose not to have a screen-ing mammogram was irresponsible (Schwartz et al. 2004).In another recent survey in the US, UK, Italy, and Switzer-land widespread misconceptions about mammographyscreening were found: 60 to 70% of women believed thatscreening prevents or reduces the risk of contracting breastcancer and that screening at least halves breast cancer mor-tality (Domenighetti 2003). Evidence is overwhelming thatunderstanding of cancer screening is poor among the intel-lectually non-disabled.“All screening programmes do harm; some can do good aswell. The harm from a screening programme starts immedi-ately; the good takes longer to appear. Therefore, the firststep of any programme, even an effective one, is to impairthe health of the population.” (Muir-Gray 1997) As to breastcancer screening the scientific controversy about the benefit-harm ratio has not been resolved (Olsen & Gotzsche 2001).But, even if effective, breast cancer screening will benefitvery few and many more will be harmed.Under such circumstances informed decision making by theindividual becomes an ethical issue. Criteria have been defined for consumer information on screening interven-tions (General Medical Council 1999). The informationshould be evidence-based. It should communicate prognosiswithout intervention, probability of benefit, risk of failureand harm, likelihood of positive and negative findings andpossibility of false test results. Since framing of data has animportant influence on risk perception results should be presented in natural frequencies (Hoffrage et al. 2000). Theinformation must not be withheld because of the possibilitythat the person might refuse the screening test (General Medical Council 1999). Information on breast cancer screening does not fulfil thesecriteria. The material is poor and severely biased in favourof screening (Slaytor & Ward 1998; Jorgensen & Gotzsche2004). Public health officials, physicians and disease advo-cacy groups use powerful campaigns to convince individualsof the importance of cancer screening. The messages are unbalanced, misleading and prescriptive (Schwartz et al.2004). From a public health perspective screening pro-grammes are cost effective only at high participation rates.Hence, increasing awareness and attendance rates are considered good practice whereas a woman who declines is a failure. Sullivan et al. (2004) investigated why women with intellec-tual disabilities are among the least frequent users of mam-mography screening services. Barriers identified by carersincluded a need to motivate people to attend, the belief thatwomen with intellectual disability would not understand whythe procedure needs to be done and therefore would experi-ence fear and anxiety, and severe medical problems.Motivating women with learning disabilities to participate in breast cancer screening raises particular ethical concerns.A proactive and persuasive approach is not justified in caseof preventive interventions that target healthy people andthat may do more harm than good to the individual. Goodpractice guidelines on breast screening for women withlearning disabilities have been issued (NHSBPS 2000). One