Technological advances in DNA sequencing have made gene testing fast and more 
affordable. Evidence of effectiveness and cost-effectiveness of genetic service 
models is essential for the successful translation of sequencing improvements 
for patient benefit, but remain sparse in the genetics literature. In 
particular, there is a lack of detailed cost data related to genetic services. A 
detailed micro-costing of 28 possible pathways relating to breast and/or ovarian 
cancer and BRCA testing was carried out by defining service activities and 
establishing associated costs. These data were combined with patient-level data 
from a Royal Marsden Cancer Genetics Service audit over a 6-month period during 
which BRCA testing was offered to individuals at ≥10 % risk of having a 
mutation, in line with current NICE guidance. The average cost across all 
patient pathways was £2227.39 (range £376.51 to £13,553.10). The average cost 
per pathway for an affected person was £1897.75 compared to £2410.53 for an 
unaffected person. Of the women seen in the Cancer Genetics Service during the 
audit, 38 % were affected with breast and/or ovarian cancer, and 62 % were 
unaffected but concerned about their family history. The most efficient service 
strategy is to identify unaffected relatives from an affected individual with an 
identified BRCA mutation. Implementation of this strategy would require more 
comprehensive testing of all eligible cancer patients, which could be achieved 
by integrating BRCA testing into oncology services. Such integration would be 
also more time-efficient and deliver greater equity of access to BRCA testing 
than the standard service model.