Temporal trends in incidence and mortality of molecular subtypes of breast cancer to inform public health, policy and prevention

Numerous molecular markers have been identified as having treatment and prognostic value for breast cancer, but their distribution and potential translation into cancer prevention or clinical interventions remains to be determined. Oestrogen receptor (ER) expression in tumours is a marker of aetiological and treatment differences, and preliminary data from more than 73,000 cases in Scotland show ER-positive breast cancers rising and ER-negative breast cancers declining from 1997-2014. The underlying reasons for these divergent trends are lacking and we do not know the differences in population trends, such as age, socioeconomic status and screening. Advances in ’omics technologies have changed breast cancer treatment regimens beyond ER, identifying subgroups of cases that might benefit from different chemotherapy, radiotherapy and hormonal treatment regimens.

We will use the electronic medical record datasets from cases of breast cancer in Scotland to develop a high-dimensional ‘omics dataset through a proof-of-principle study using 1,600 tissue samples from Lothian Bioresource from two five-year periods.

This proposal will quantify how many women might benefit from new ’omics-defined molecular subtypes of breast cancer, with the goal of defining the populations that might most benefit from prevention, screening or treatment interventions.