Motivation: Research on how primary breast tumours in situ respond to radiotherapy is very limited, though increasingly relevant as neo-adjuvant radiotherapy trials expand, requiring accurate and sensitive monitoring of therapy response. Goal(s): To evaluate MRI response in breast tumours treated with radiotherapy and assess whether ADC values or their changes predict long-term outcomes. Approach: Twenty-five patients underwent radiotherapy to in-situ breast tumours with the aim of long-term control. CE-DW-MRI was performed at baseline and 2W, 6M and 12M post-radiotherapy. Results: Early ADC changes at 2-weeks post-radiotherapy correlated more strongly with long-term response than later ADC changes. Impact: Early assessment of ADC on DW-MRI after radiotherapy treatment could predict long term responses in breast tumours. This could allow future personalisation of radiotherapy doses based on baseline ADC values of tumours.
Durie et al. (Tue,) studied this question.