Daniela-Elena Oprea-Lager

Suppl. Fig. 4. Relationship between the various quantitative parameters and ESR1 mutation status. Overall, data shows that quantitative parameters were not affected significantly by ESR1 mutations (Mann-Whitney U test). However, a trend could be observed showing higher tracer uptake in patients with an ESR1 mutation than in patients with an ESR1 WT.

Suppl. Fig. 1. The number of lesions included in the quantitative lesion-based analysis using the [18F]FDG and [18F]FES PET/CT scans. Lesions have been classified per organ type for each patient.

Suppl. Table 2. Various clinicopathological features of the 16 patients.

Suppl. Table 5. Median change in [18F]FES uptake (%) between the baseline vs on-treatment [18F]FES scan for each patient and the received doses of rintodestrant. Change in uptake was unrelated to the dose (Spearman's rho, p = 0.65) and PFS (Spearman's rho, p = 0.98).

Suppl. Table 4. Mutation profile of each patient with their corresponding PFS. Data shows that almost all patients with a prolonged PFS (>5 months) harbor an ESR1 mutation

Suppl. Fig. 3. Relationship between the various quantitative parameters and PFS. Data shows that patients with a PFS ≥2.0 months have lesions that are metabolically more active and have higher ER expression than patients with a PFS of <2.0 months (Mann-Whitney U test).

Suppl. Table 3. Best clinical response and cause of progression for all patients. NE = not evaluable. SD = stable disease. PD = progressive disease. CR = clinical response. PR = partial response.

Suppl. Fig. 2. The correspondence between the SUVmax values and the SUVpeak values of [18F]FDG and [18F]FES for the lesions with the highest uptake. Lesions have been indicated per patient.

Suppl. Table 6. Various [18F]FDG uptake parameters, representing the median values with their interquartile range.