Page 54 - ARNM-2-4

Advances in Radiotherapy
& Nuclear Medicine Efficacy of stereotactic radiotherapy

factor affecting treatment failure and the quality of life The inclusion criteria were as follows: oligometastases
of patients. Active systemic therapy is usually used to confirmed by pathology and imaging, no prior systemic
control the increase in tumor load caused by distant treatment for metastatic diseases, measurable lesions on
metastasis. However, the survival benefits of first-line imaging, age ≥18 years, physical status (PS) score of 0
chemotherapy remain limited. For instance, in patients – 2, expected survival time of >3 months, and complete
with advanced non-small cell lung cancer, platinum- clinical and imaging data. The exclusion criteria were as
based chemotherapy results in a median overall survival follows: serious complications, pregnancy or lactation, and
(OS) of only 9.1 months, with a 1-year OS rate of 37%. expected survival time of <3 months.
1
In recent years, in-depth studies on targeted therapy and
This study was approved by the Ethics Committee of the
immunotherapy have demonstrated significant clinical First Affiliated Hospital of Guangxi Medical University (2023-
benefits of their combination for advanced tumors. For E257-01). Patient confidentiality was strictly maintained.
instance, the median OS of patients with metastatic liver
cancer receiving first-line targeted therapy is 10.7 months. 2.2. Treatment process
2
Similarly, in patients with metastatic colorectal cancer,
combining targeted therapy or immunotherapy with Patients were treated in the supine position and subjected to
chemotherapy has significantly extended OS compared with 4D computed tomography (CT) scanning across 10 phases,
chemotherapy alone. However, targeted therapy has some with a slice thickness of 3 mm. The gross tumor target area
3
limitations, including restricted effectiveness to tumors (GTV) was defined as the tumor location identified on
with specific biomarkers, emergence of drug resistance, imaging and was delineated across 10 phases using 4D-CT
and new mutations resulting from target inhibition. scans. The internal target volume (ITV) included the
4
Immunotherapy also faces certain challenges, such as GTV and any associated fusion volume. The clinical target
low response rates and the development of resistance. volume (CTV) was derived by expanding the ITV by 5 mm
5
Although surgery and local ablation have proven effective in all directions, and the planned target volume (PTV) was
in treating oligometastatic colorectal cancer, these invasive determined by expanding the CTV by an additional 5 mm
6
treatments carry the risk of complications. Consequently, in all directions. Treatment plans were developed using the
there is a need for non-invasive, effective, and less toxic Monaco 5.11.03 planning system, ensuring that the PTV
therapies for managing recurrent and oligometastatic prescription dose exceeded 95%. The dose to organs-at-
tumors. risk was managed in strict accordance with the standards
outlined by Timmerman 2021.8. Expert guidelines were
Stereotactic radiotherapy (SRT), including stereotactic
radiosurgery and stereotactic body radiation therapy, followed to determine appropriate treatment doses based
on the tumor type. Dose ranges and fractionations were
has emerged as a promising approach. Unlike traditional defined as follows: brain oligometastases (30 – 55 Gy/5 –
radiotherapy, SRT delivers highly conformal, high-dose 10f), lung oligometastases (24 – 60 Gy/3 – 12f), and liver
radiation of ≥5.0 Gy, achieving similar outcomes with
7
equal or reduced toxicity. SRT has demonstrated efficacy oligometastases (24 – 60 Gy/3 – 12f).
8
not only in early non-small cell lung cancer, hepatocellular Positioning accuracy was verified through KV
carcinoma, pancreatic cancer, and prostate cancer but cone-beam CT (CBCT) imaging, and treatment was
9
10
11
also in managing oligometastatic tumors. 12-15 administered using the Elekta Versa HD linear accelerator.
This study evaluates the efficacy and safety of SRT in Of the 96 patients in the study, 51 (53.13%) received
treating oligometastatic tumors based on data collected chemotherapy, 55 (57.29%) received targeted therapy, and
from a single center data and compares the findings of the 35 (36.46%) received immunotherapy.
present study with those of previous studies to explore the
efficacy and safety of SRT. 2.3. Follow-up and response evaluation
After SRT, hematologic toxicity was assessed through
2. Methods monthly blood tests, including liver and kidney function
2.1. Data collection tests. Imaging follow-ups, using either CT or magnetic
resonance imaging, were performed every 3 months. The
This retrospective study analyzed data from 96 patients
with oligometastatic solid organ tumors (defined as 1 – 5 follow-up period concluded on September 30, 2023, or
distant metastases in a single organ) treated with SRT at the with the patient’s death.
Department of Radiotherapy of the First Affiliated Hospital The efficacy of tumor response after SRT was evaluated
of Guangxi Medical University between September 2019 based on the Response Evaluation Criteria in Solid Tumors
and March 2023. version 1.1. Tumor response was classified as complete

Volume 2 Issue 4 (2024) 2 doi: 10.36922/arnm.3391