Implications for cancer genetics practice of pro-actively assessing family history in a General Practice cohort in North West London.

At present cancer genetics referrals are reactive to individuals asking for a referral and providing a family history thereafter. A previous pilot study in a single General Practice (GP) catchment area in North London showed a 1.5-fold increase in breast cancer risk in the Ashkenazi Jewish population compared with the non-Ashkenazi mixed population. The breast cancer incidence was equal in the Ashkenazim in both pre- and postmenopausal groups. We wanted to investigate the effect of proactively seeking family history data from the entire female population of the practice to determine the effect on cancer genetics referral. Objectives To determine the need for cancer genetics intervention for women in a single GP catchment area. (1) to determine the incidence and strength of family history of cancer in women aged over 18 in the practice, (2) to offer cancer genetics advice and determine the uptake of counselling in those with a positive family history, (3) to identify potential BRCA1/BRCA2 gene mutation carriers who can be offered clinical follow up with appropriate translational research studies. Design Population-based cohort study of one General Practice female population. Participants Three hundred and eighty-three women over the age of 18 from one General Practice who responded to a questionnaire about family history of cancer. The whole female adult GP population was the target and the total number sampled was 3,820. Results 10% of patients completed the questionnaire (n = 383). A family history of cancer was present in 338 cases, 95 went on to have genetic counselling or had previously had counselling and 47 were genetically tested. We identified three carriers of an Ashkenazi Jewish founder mutation in BRCA1. Conclusions Response rate to a family history questionnaire such as that used in genetics centres was low (10%) and other approaches will be needed to proactively assess family history. Although the Ashkenazim are present in 39% of the GP catchment area, 62% of those who returned a family history questionnaire were from this ethnic group and of those returned, 44% warranted referral to a cancer genetics unit. In the non Ashkenazim, the questionnaire return rate was 38% and 18% of those warranted referral to cancer genetics.

A population-based audit of ethnicity and breast cancer risk in one general practice catchment area in North London, UK: implications for practice.

OBJECTIVES: To conduct a pilot population-based study within a general practice catchment area to determine whether the incidence of breast cancer was increased in the Ashkenazi population. DESIGN: Population-based cohort study. SETTING: A single general practice catchment area in North London. PARTICIPANTS: 1947 women over the age of 16 who responded to a questionnaire about ethnicity and breast cancer. MAIN OUTCOME MEASURES: Incidence of breast cancer, ethnicity. RESULTS: This study showed a 1.5-fold (95% CI 0.93-2.39) increase in breast cancer risk in the Ashkenazim compared with the non-Ashkenazi white population. The increased incidence was for both premenopausal and postmenopausal breast cancer (expected incidence pre:post is 1:4 whereas in the Ashkenazim it was 1:1; 51 and 52% of cases respectively). This increase was not shown in the Sephardim. Asians had a reduction in incidence (OR = 0.44; 95% CI 0.10-1.89). Results were adjusted for other risk factors for breast cancer. CONCLUSION: This study showed a 1.5-fold increase in breast cancer rates in Ashkenazim compared with the non-Jewish white population when adjusted for age (i.e. corrections were made to allow comparison of age groups) and this is not observed in the Sephardic population. The proportion of premenopausal breast cancer was just over double that of the general population. This is the first general practice population-based study in the UK to address this issue and has implications for general practitioners who care for patients from the Ashkenazi community.