Predicting breast cancer risk: implications of a "weak" family history.

Published guidelines adopted in many countries recommend that women whose family history of breast cancer places them at a risk>or=1.7 times that of the age-matched general population, should be considered for inclusion in special surveillance programmes. However validation of risk assessment models has been called for as a matter of urgency. The databases of the four Scottish Familial Breast Cancer clinics and the Scottish Cancer Registry have been searched to identify breast cancers occurring among 1,125 women aged 40-56, with family histories placing them below the "moderate" level of genetic risk. The observed incidence over 6 years was compared with age-specific data for the Scottish population. Our findings confirm that when there are two affected relatives (one first degree) the relative risk (RR) exceeds 1.7 regardless of their ages at diagnosis. When only one (first degree) relative was affected at any age from 40 to 55, the RR does not reach 1.7 if that relative was a mother but exceeds it if the relative was a sister. The probable explanation is that sisters are more likely than mother/daughter pairs to share homozygosity for a risk allele. Surveillance programmes might therefore accommodate sisters of women affected before age 55. Evidence that "low penetrance" alleles contributing to breast cancer risk may be recessive should be taken into account in strategies for identifying them.

Risk estimation for familial breast cancer: improving the system of counselling.

Women with a family history of breast cancer dominate referrals for cancer genetic risk counselling across Europe. Given limited health care resources, managing this demand, while achieving good value for money for health services, is a major challenge. The paper reports the benefits and associated costs of moving from a traditional system of deriving family history of cancer during the patient's initial clinic attendance, to a protocol-driven system with pre-counselling assessment of family history. The evaluation was based on retrospective clinical data and a clinical audit. Changes in risk between referral and final risk assessment were ascertained and the cost difference between the two systems estimated. The study results showed that 14% of women assessed as 'low' genetic risk at referral were reassessed as 'moderate' or 'high' genetic risk for breast cancer following verification of family history. Sixteen per cent of those assessed as 'moderate' or 'high' genetic risk at referral were reassessed as 'low' genetic risk for breast cancer. Compared to the traditional system, the new protocol-driven system of risk assessment was more consistent, which reduced the number of return appointments and created time for clinicians to spend with other patients. The estimated cost of family history verification and genetic clinic appointment was calculated as 91.68 pounds (132.53 euro) per family history, compared to 104.00 pounds (150.34 euro) for the traditional system, representing a slight reduction in health service costs. Finally, the protocol-driven system can be used as part of ongoing audit for planning future genetics services in Scotland.