ESTRO 2024 - Abstract Book

S541

Clinical - Breast

ESTRO 2024

Results:

63 patients underwent 152 CCA scans. Median follow-up from primary diagnosis to last follow-up or death was 77 months (range 10-366). Median age at primary diagnosis was 45 years (range 24-81). 41 patients (65%) received SRS as their initial brain directed therapy, while 10 (16%) had surgical resection followed by SRS to the tumour bed. The most common SRS dose/fractionation schedule was 21Gy in 3 fractions with doses ranging from 16Gy to 27Gy in 1-3 fractions. Patients received a median of 2 (range 0-12) lines of SACT. All patients had received cranial radiotherapy (SRS in 95%) before their first CCA, with a median of 16 months (range 3-73) between SRS to the first CCA. 30 patients (48%) were symptomatic, the most common symptom being headache. CCA findings included disease (42%), treatment-related changes (25%), mixed-changes (23%) and equivocal changes (13%). Initial CCA scans provided a diagnosis in 54 patients (86%) of patients with equivocal findings on standard-MRI. Among the 9 patients for whom the initial CCA did not identify a diagnosis, 7 were subsequently diagnosed through serial CCA analysis. When initial CCA reported disease, treatment recommendations included SRS (16 patients), surgical resection (2 patients), SACT changes (4 patients), WBRT (2 patients) and further monitoring (2 patients). For treatment-related changes recommendations were surveillance (4 patients), continuing SACT (4 patients) and steroids (2 patients). 4/10 patients who had treatment-related changes reported on initial CCA developed neurological disease progression within a median of 2.5 months (range 0-13). The median time from the first CCA scan to treatment initiation was 4 weeks (range 0-11). Histology was available for 8/63 (13%) of patients for whom surgical resection was offered, throughout the entire study, based on the CCA reports. In 6/8 cases histology was concordant with the CCA report. In the 2/8 non concordant cases, CCA had suggested disease, but histology showed treatment-related changes only.

Conclusion:

CCA appears to add value to standard contrast-enhanced MRI in terms of distinguishing residual viable tumour from treatment-related effects. It therefore has the potential to reduce the need for serial scanning and biopsies in