ESTRO 2023 - Abstract Book

S1098

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ESTRO 2023

free survival (DMFS), overall survival (OS), and treatment-associated toxicities according to CTCAE criteria v5.0 were analyzed, and parameters determining patient outcomes were assessed. Results Thirty-three patients (38%) were treated with neoadjuvant chemoradiation followed by surgery, while the remaining patients received definitive (chemo)radiation. The delivery of radiotherapy without dose reduction was possible in 80 patients (93 %). In 66 patients (77%), concomitant chemotherapy was initially prescribed; however, during the course of therapy, 50 % of patients (n = 33) required chemotherapy de-escalation due to treatment-related toxicities and comorbidities. Twenty-nine patients (34%) experienced higher-grade acute toxicities and 14 patients (16%) higher-grade late toxicities. The 2-year LRC, DMFS, PFS, and OS rates amounted to 72%, 49%, 46%, and 52%, respectively. On multivariate analysis, neoadjuvant chemoradiation followed by surgery was shown to significantly improve PFS (p = 0.006), DMFS (p = 0.006), and OS (p = 0.004) compared with definitive (chemo)radiation. We could not identify any clinico-pathological factor that was significantly associated with LRC. The majority of patients receiving neoadjuvant therapy received standard chemoradiotherapy without dose reduction (n = 32/33, 97%). In contrast, concurrent chemotherapy was only possible in 62% of definitive irradiated patients (n=33/53), and most of these patients required dose-reduction or modification of chemotherapy (n=32/33, 97%). Conclusion In our analysis, half of the chemotherapy-eligible patients required adjustment of chemotherapy due to comorbidities or toxicities. De-escalation of therapy was mainly performed in the subgroup of patients who received definitive radiation. Therefore, the survival benefit shown for patients receiving neoadjuvant therapy is most likely due to a selection bias. Therefore, the identification of potential predictive factors for safe administration of concurrent chemotherapy in elderly EACA and AEG patients requires further exploration to optimize treatment in this vulnerable patient cohort. 1 Pusan National University School of Medicine, Department of Radiation Oncology, Yangsan-si, Korea Republic of; 2 Pusan National University Hospital, Department of Radiation Oncology, Busan, Korea Republic of; 3 Pusan National University Yangsan Hospital, Department of Radiation Oncology, Yangsan-si, Korea Republic of; 4 School of Medicine, Kyungpook National University , Department of Radiation Oncology, Daegu, Korea Republic of Purpose or Objective Unlike other cancer, assessment of underlying liver function plays a key role in predicting treatment outcomes of hepatocellular carcinoma (HCC). As an alternative to Child-Turcotte-Pugh (CTP) classification, a measure of liver function based on albumin and bilirubin has been proposed, the albumin-bilirubin (ALBI) score. We evaluated prognostic performance of ALBI score and determined optimal cutoff point as a potential predictor of hepatotoxicity after stereotactic body radiation therapy (SBRT). Materials and Methods We retrospectively evaluated 121 HCC cases treated between 2018 and 2020. Raw ALBI scores and CTP scores were calculated. The occurrence of hepatotoxicity was defined as post-SBRT CTP score increase ≥ 2. To compare ALBI and CTP scores, receiver operating characteristic (ROC) curves were calculated and DeLong’s test was used for statistical analysis. The optimal cutoff of ALBI score was calculated. By mean radiation dose to the whole liver, patients were subgrouped and tested. Results Median follow-up time was 15.5 months. There were 93 patients of CTP score 5, 19 of CTP 6, 4 of CTP 7, and 5 of CTP 8. Median ALBI score was -2.6 ± 0.4. Hepatotoxicity occurred in 7 patients (5%). Both baseline CTP score and ALBI score predicted the post-SBRT CTP score change. Correlation coefficient was 0.316 for CTP score (P<0.001) and 0.336 for ALBI score (P<0.001). The area under ROC curve predicting hepatotoxicity for ALBI score was 0.77, and for CTP score was 0.71 (P = 0.5019, fig. 1). The optimal cutoff value of the ALBI score was -2.47, with a sensitivity of 85.7% and a specificity of 71.1%. Of the patients with ALBI score >-2.47, 15.38% (6 of 39) developed toxicity, compared to 1.22% (1 of 82) in patients with score ≤ -2.47. In the multivariable analysis, ALBI score and PTV were significant factors (odds ratio [OR] of 29.51 for ALBI score, P = 0.003; OR of 1.05 for PTV, P = 0.004). Patients were divided into the following four groups based on ALBI score of 2.47 and PTV of 65 mL; Group 1, ALBI score ≤ -2.47 & PTV<65mL; Group 2, ALBI score ≤ -2.47 & PTV ≥ 65; Group 3, ALBI score>-2.47 & PTV<65; Group 4, ALBI score>-2.47 & PTV ≥ 65. The incidence of hepatotoxicity in groups 1, 2, 3, and 4 was 1.47% (1 of 68), 6.25% (1 of 16), 6.25% (2 of 32), and 60% (3 of 5), respectively (P<0.001). In subgroup analysis, area under curve was larger in ALBI than CTP when mean liver dose was higher than 9 Gy, 11 Gy, 12 Gy. PO-1368 Albumin-Bilirubin (ALBI) score predicts hepatotoxicity after stereotactic ablative radiation therapy J.H. Joo 1 , W. Kim 1 , J. Nam 2 , Y. Ki 1 , D. Kim 1 , D. Park 2 , H. Jeon 3 , D.W. Kim 3 , J. Park 4