ESTRO 2023 - Abstract Book

S1282

Digital Posters

ESTRO 2023

Conclusion Stereotactic boost within 4 months after previous radiotherapy seems to be feasible with a safe toxicity profile. The end of the study is awaited in order to draw definite conclusions about the safety and efficacy of SBRT boost.

PO-1579 Interim analysis after radiotherapy using MR-LINAC for the patients with locally advanced HCC

C. Kay 1 , M. Kim 2 , Y. Kwak 3

1 Jeju Halla general hospital, radiation onology, Jeju, Korea Republic of; 2 Incheon St. Mary's Hospital, College of medicine, The Catholic University of Korea, radiation oncology, Incheon, Korea Republic of; 3 Incheon St. Mary's hospital, College of medicine, The Catholic University of Korea , radiation oncology, Incheon, Korea Republic of Purpose or Objective In the treatment of hepatocellular carcinoma, the role of radiation therapy is gradually expanding. The reason is that the spread of precision radiation therapy techniques such as intensity-modulated and image-guided radiation therapy is becoming more common. However, in image-guided radiotherapy, images using cone beam CT equipped in a radiotherapy machine are most commonly used in real clinical situations. To improve this, our research team performed image-guided and intensity-modulated radiotherapy using real-time MRI images using the MR-LINAC system for patients with locally advanced HCC, Materials and Methods We retrospectively reviewed the treatment outcomes of twenty-one patients with locally advanced hepatocellular carcinoma (HCC) after radiotherapy using real-time MRI tumor tracking image-guided radiotherapy. The radiotherapy was performed with conventionally radiotherapy (total tumor dose 45 ∼ 60 Gy with 25 ∼ 30 fractions), hypofractionated radiotherapy (total tumor dose 30 ∼ 60 Gy with 10 ∼ 20 fractions), and stereotactic body radiotherapy (35 ∼ 36 Gy with 4 ∼ 5 fractions) after concerning about tumor stage, liver function, and the patient's performance status. The median biological effective dose (BED) with an alpha-beta ratio of 10 was 75 Gy10 (range 39 ∼ 96 Gy). Of the total 21 patients, 17 patients who completed radiotherapy were included. The follow-up period ranged from 1 month to 12 months. The response rate after radiotherapy was 70.6% (CR & PR & SD). The median survival time was 339 days (mean survival time 297 days), and the 1-year survival rate was 35.8% (6-month survival rate 85.9%). Results We retrospectively reviewed the treatment outcomes of twenty-one patients with locally advanced hepatocellular carcinoma (HCC) after radiotherapy using real-time MRI tumor tracking image-guided radiotherapy. The radiotherapy was performed with conventionally radiotherapy (total tumor dose 45 ∼ 60 Gy with 25 ∼ 30 fractions), hypofractionated radiotherapy (total tumor dose 30 ∼ 60 Gy with 10 ∼ 20 fractions), and stereotactic body radiotherapy (35 ∼ 36 Gy with 4 ∼ 5 fractions) after concerning about tumor stage, liver function, and the patient's performance status. The median biological effective dose (BED) with an alpha-beta ratio of 10 was 75 Gy10 (range 39 ∼ 96 Gy). Of the total 21 patients, 17 patients who completed radiotherapy were included. The follow-up period ranged from 1 month to 12 months. The response rate after radiotherapy was 70.6% (CR & PR & SD). The median survival time was 339 days (mean survival time 297 days), and the 1-year survival rate was 35.8% (6-month survival rate 85.9%). Conclusion Real-time tumor tracking image-guided intensity-modulated radiation therapy using MRI-LINAC system was performed relatively effectively in patients with locally advanced HCC. However, systematic clinical investigations will continue to be needed for more effective and safe methodological development.

PO-1580 Association of upfront treatment and survival of SVC syndrome in advanced non-small cell lung cancer

A. Berpan 1 , K. Trikhirhisthit 2