ESTRO 2023 - Abstract Book

S1174

Digital Posters

ESTRO 2023

Scores of episodic and semantic memories tests were significantly lower in G1 and correlated with mean absolute values of perfusion in hippocampi (0.30< r <0.35, p<0.04). No significant differences were found between G1 & G2 (MRSI or ASL values) or between G2 & G3 (ASL values). Neither MRSI nor perfusion values were correlated to total dose or doses in structures. Conclusion In this study, we showed changes in cerebellar metabolic values in PFT survivors and in perfusion values in other brain structures in the RT group. These values have been correlated with memory deficits suggesting that it could be used as a biomarker of cognitive decline, but this will require validation on a larger sample . Further statistical analysis, including structural, diffusion (DTI), and functional (rs-fMRI) imaging results, is ongoing.

PO-1449 The effect of ADT on ADC change in intermediate-risk prostate cancer patients receiving radiotherapy

C. Onal 1 , G. Erbay 2 , E. Oymak 3 , O.C. Guler 4

1 Baskent University, Department of Radiation Oncology, Adana, Turkey; 2 Baskent University , Department of Radiology, Adana, Turkey; 3 Iskenderun Gelisim Hospital, Radiation Oncology Clinic, Hatay, Turkey; 4 Baskent University, Department of Radiology, Adana, Turkey Purpose or Objective The therapeutic effect of radiotherapy RT is monitored using serum prostate-specific antigen (PSA) levels; however, PSA monitoring may not be useful in determining the true treatment response due to the late onset of PSA response after definitive RT or false negative or positive results. To investigate the effects of androgen deprivation therapy (ADT) on primary tumor apparent diffusion coefficient (ADC) values from diffusion-weighted magnetic resonance image (DW-MRI) parametric maps, as well as their associations with established measures of treatment response in intermediate-risk prostate cancer (PC) patients treated with radiotherapy (RT) with or without ADT. Materials and Methods The clinical and radiological parameters of 123 PC patients treated with RT alone (RT, 34%), concurrent ADT and RT (C, 31%), or neoadjuvant ADT and RT (N, 35%) were evaluated. Before treatment, ADC values were measured using DW-MRI, and four months after treatment, ADC values were measured again. According to treatment modality, pre- and post treatment ADC values were compared using one-way ANOVA test. Results The median serum PSA level at initial diagnosis was 11.0 ng/mL (range: 2.9 – 19.9 ng/mL) and post-treatment PSA value was 2.9 ng/mL (range: 0–12.6 ng/mL) for entire cohort. All patients had a significant decline in serum PSA value measured in a median of 3.9 months (range: 3.7–4.9 months) after completion of RT (p < 0.001). The post-treatment ADC value in primary tumor was significantly higher than the pre-treatment ADC value in the entire cohort (0.73 ± 0.17 vs. 1.09 ± 0.22 × 10 ˗ ³ mm ² /sec; p < 0.001), and also for each treatment arm. An increase in tumor ADC value was seen in 116 patients (94.3%), with a median of 35% (range: 4–65%), while 7 patients (5.7%) showed a decrease in ADC value, with a median of 9% (range: 1–30%) .There was no significant correlation between post-treatment tumor ADC change and serum PSA value change (Pearson r = 0.11; p = 0.29). The overall cohort's mean ADC increase was 33.8 ± 14.2%, while the RT, N, and C arms increased by 36.4 ± 12.1%, 32.3. ± 16.3 and 32.5 ± 14.3%, respectively, with no statistically significant difference (p = 0.35). The ADC response following concurrent ADT and RT was significantly greater in patients with GS 7 disease compared to patients with GS 6 disease (34.8% vs. 18.6%; p = 0.003). Patients with GS 3 + 4 disease had significantly higher post treatment tumor ADC values than those with GS 4 + 3 disease (1.23 ± 0.22 vs. 0.99 ± 0.14 × 10 ˗ ³ mm ² /sec; p = 0.007) in patients treated with RT only. Conclusion We found that RT with or without ADT changes serum PSA and tumor ADC values; early change in ADC values may be useful in assessing therapeutic response in intermediate-risk PC patients. Patients with GS 4 + 3 disease had a poorer response to RT alone, as measured by tumor ADC, highlighting the need for ADT in this patient population. E. Ruznic 1 , B. Zellinger 2,3 , U. Bodenhofer 4,5 , I.A. Engländer 6,6 , C. Kronberger 3 , B. Grambozov 1 , M. Stana 1 , J. Karner 1 , G. Fastner 1 , K. Sotlar 3 , F. Sedlmayer 1,1 , F. Zehentmayr 1,6 1 Paracelsus Medical University Salzburg, Department of Radiation Oncology, Salzburg, Austria; 2 Paracelsus Medical University Salzburg, radART - Institute for Research and Development on Advanced Radiation Technologies, Salzburg, Austria; 3 Paracelsus Medical University Salzburg, Department of Pathology, Salzburg, Austria; 4 University of Applied Sciences Upper Austria, School of Informatics, Communications and Media, Hagenberg, Austria; 5 Johannes Kepler University, Institute for Machine Learning, Linz, Austria; 6 Paracelsus Medical University Salzburg, radART—Institute for Research and Development on Advanced Radiation Technologies, Salzburg, Austria Purpose or Objective MicroRNAs are small non-coding RNAs with pivotal regulatory functions in multiple cellular processes. Their significance as molecular predictors for breast cancer was demonstrated in the past 15 years. The aim of this study was to elucidate the role of hsa-miR-3651 for predicting of local control (LC) in early breast cancer. PO-1450 Hsa-miR-3651 could serve as a novel predictor for in-breast recurrence via FRMD3

Materials and Methods