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.

Analysis of referrals to a multi-disciplinary breast cancer genetics clinic: practical and economic considerations.

Analysis of activity was undertaken in an established regional clinic providing risk assessment, counselling, screening and management for women with a family history of breast or ovarian cancer. The objectives were to determine: (1) how closely the route and pattern of referrals matched official guidelines (2) whether the previously recorded socio-economic imbalance among clinic clientele persisted and (3) the economic and practical consequences of committing resources to verification and extension of reported family histories. The findings were: (1) after some years of operation, the proportion of referrals direct from primary care had increased from less than 50% to over 75%, with a concomitant slight decrease in overall referral rate; (2) the socio-economic distribution of patients referred had become less selective and (3) extension and verification of reported family histories led to a redistribution of risk categories, increasing the proportion of referrals judged to be in the "low risk" category, from 25% (based on referral letter alone) to 41% (at the end of the process). The costs associated with this approach are offset by the savings generated and it allows specialised counselling and screening services to be targeted more efficiently.

Impact of a cancer registry-based genealogy service to support clinical genetics services.

In collaboration with the network of genetics clinics in Scotland, a brief questionnaire was designed to gather data prospectively about the impact of information arising from pedigree research provided by Scottish Cancer Registry personnel. Pedigree research in Scotland is facilitated by access to public records of births, deaths, marriages, and historic census returns up to 1901, and enables the construction of accurate and extensive family pedigrees encompassing generations beyond the detailed knowledge of the proband. Subject to existing confidentiality guidelines, linkage of these pedigrees to cancer registration records results in a more comprehensive family history including the age at diagnosis of any cancer, multiple primary cancers, and cancers unreported from death certificates. Of 454 requests for pedigree research completed between 1 April 2002 and 31 March 2003, questionnaires were returned for 425 (94%). The information fed back to genetics clinics led to changes in family history, risk categorisation, and management in 41%, 30%, and 23% of cases, respectively. Management advice altered in both directions, that is, to institute active follow-up and surveillance of clinic attendees and their relatives where none was previously envisaged, and viceversa. The interests of current and future generations of patients concerned about their familial risk of cancer will be served by measures which enable cancer registries to collect data that are as accurate and complete as possible.