The TARGIT trial compares single dose intra-operative radiotherapy (IORT) with 6-7 week external-beam radiotherapy (EBRT) in women with early breast cancer (EBC) at low risk of local recurrence (LR). We hypothesize that IORT will give a non-inferior risk of LR compared with EBRT. In order to guide women and doctors making choices about radiotherapy, a Patient Preference study was performed to determine what increased risk of LR, without detriment to survival, women with EBC would accept, in return for the increased convenience of IORT.
A cross-sectional study of patient preferences and their determinants in 209 women who had radiotherapy on the TARGIT trial (108 had IORT and 101 had EBRT). Preferences were determined by a self-rated questionnaire using validated trade-off methodology. Disease, treatment, and demographic details were collected and quality of life during radiotherapy.
While 36% of patients were prepared to accept a 4%-6% increase in LR risk for the increased convenience of IORT, 22% would not accept IORT at all. Multivariate Poisson regression identified treatment received as the only significant determinant of preferences (p<0.0001). This is despite significant differences found in two-sample Kolmogorov-Smirnov tests of quality of life scores during treatment all favouring IORT. Comparison of the treatment groups found that 60% of IORT patients would accept IORT at an increased risk of 4%-6% in contrast to 12% of patients in the EBRT group. Only 2% of IORT patients indicated they would not have IORT at all, in contrast to 43% of EBRT patients.
The EBRT group were risk-averse, whilst patients who had IORT valued the convenience of IORT highly. Participants of this study have justified the treatment they were randomly allocated to, which questions the validity of post-treatment patient preference studies. Further research targeting patients who have not yet received radiotherapy will now follow.