Setup errors analysis in iterative kV CBCT: A clinical study of cervical cancer treated with Volumetric Modulated Arc Therapy.

OBJECTIVE: This study aims to analyze setup errors in pelvic Volumetric Modulated Arc Therapy (VMAT) for patients with non-surgical primary cervical cancer, utilizing the onboard iterative kV cone beam CT (iCBCT) imaging system on the Varian Halcyon 2.0 ring gantry structure accelerator to enhance radiotherapy precision. METHOD: We selected 132 cervical cancer patients who underwent VMAT with daily iCBCT imaging guidance. Before each treatment session, a registration method based on the bony structure was employed to acquire iCBCT images with the corresponding planning CT images. Following verification and adjustment of image registration results along the three axes (but not rotational), setup errors in the lateral (X-axis), longitudinal (Y-axis), and vertical (Z-axis) directions were recorded for each patient. Subsequently, we analyzed 3642 iCBCT image setup errors. RESULTS: The mean setup errors for the X, Y, and Z axes were 4.50 ± 3.79 mm, 6.08 ± 6.30 mm, and 1.48 ± 2.23 mm, respectively. Before correction with iCBCT, setup margins based on the Van Herk formula for the X, Y, and Z axes were 6.28, 12.52, and 3.26 mm, respectively. In individuals aged 60 years and older, setup errors in the X and Y axes were significantly larger than those in the younger group (p < 0.05). Additionally, there is no significant linear correlation between setup errors and treatment fraction numbers. CONCLUSION: Data analysis underscores the importance of precise Y-axis setup for cervical cancer patients undergoing VMAT. Radiotherapy centers without daily iCBCT should appropriately extend the planning target volume (PTV) along the Y-axis for cervical cancer patients receiving pelvic VMAT. Elderly patients exhibit significantly larger setup errors compared to younger counterparts. In conclusion, iCBCT-guided radiotherapy is recommended for cervical cancer patients undergoing VMAT to improve setup precision.

A retrospective study on the effectiveness of intensity modulated radiation therapy for thyroid associated ophthalmopathy at a single institute.

Thyroid-associated ophthalmopathy (TAO) is a hallmark autoimmune condition, and the treatment of TAO requires a multidisciplinary approach. Radiation therapy (RT) is a viable treatment option for active TAO, IMRT is a more precise technology in radiation oncology. This study aims to evaluate the efficacy, feasibility, and safety of orbital intensity-modulated radiation therapy (IMRT) in the treatment of TAO. A single-center retrospective analysis was conducted, including patients diagnosed with moderate to severe active TAO at the Department of Radiation Oncology, Peking University Third Hospital, from October 2020 to October 2023, who had poor responses to corticosteroid treatment. These patients subsequently received IMRT treatment, followed by a period of follow-up and retrospective analysis. The study focused on the outcomes of treatment efficacy, safety, and acute toxic reactions induced by radiation therapy. Improvements in clinical activity score (CAS) at 4 and 12 months were considered as primary and secondary study endpoints, respectively, along with the incidence rate of adverse events. The median follow-up period was 12 months. The median follow-up time after radiation therapy was 12 months. There was no statistically significant difference in CAS between before and 4 months after radiation therapy (CAS: 5.53 ± 2.07 vs.4.68 ± 2.62; R squared: 0.21; 95% CI: - 1.01-0.02; P = 0.054). However, there was a significant reduction in CAS 12 months post-treatment compared to pre-treatment (CAS: 5.53 ± 2.07 vs. 3.06 ± 2.38; R squared: 0.66; 95% CI: 3.42 - 1.52; P < 0.001). The CAS showed a progressively decreasing trend at both 4 months and 12 months post-treatment. In the combined radiotherapy with glucocorticoid treatment group, a statistically significant difference was found between the CAS before treatment and 12 months after radiotherapy (CAS: 6.38 ± 2.00 vs. 3.88 ± 2.85; R squared: 0.66; 95% CI - 4.11 to 0.89; P = 0.008). In the radiotherapy alone group, a statistically significant difference was found between the CAS before treatment and 12 months after radiotherapy (CAS: 4.78 ± 1.92 vs. 2.33 ± 1.73; R squared: 0.66; 95% CI - 3.89 to 1.00; P = 0.005). A few patients experienced Grade I periorbital edema, conjunctival congestion, and dry eye syndrome, but no adverse events such as cataracts, radiation retinopathy, or radiation-induced optic neuropathy were observed by the end of the follow-up period. Orbital IMRT is an effective treatment modality for moderate to severe active TAO, demonstrating significant efficacy even in patients who had not achieved success with previous treatments such as corticosteroids. This retrospective study was approved by the Ethics Committee of Peking University Third Hospital. The permit number was M2024220 and data of registration was April I, 2024.

Identification of MET fusions as novel therapeutic targets sensitive to MET inhibitors in lung cancer.

INTRODUCTION: Alterations in the MET gene, including amplifications and exon 14 skipping mutations, have been identified as actionable oncogenic alterations. However, MET fusions are rarely detected in lung cancer, and their sensitivity to therapeutics has not been systematically analyzed. METHODS: The data from 30876 lung cancer patients from the LAVA database and 7966 patients from cBioPortal database were screened. Basic demographic and clinical information for the patients harboring MET fusions were collected. A lung squamous cell cancer patient harboring a novel EML4-MET fusion was treated with crizotinib. Additionally, a literature review was performed to summarize the cases of patients harboring MET fusions and their treatment information. RESULTS: MET fusions were found in only 0.2% to 0.3% of lung cancer patients and appeared in almost all exons of the MET gene. Intragenic MET fusions were found in 52.6% (41/78) of the included patients. Crizotinib was effective for MET fusions, including a novel identified EML4-MET fusion, even after the failure of multiple lines of treatment. This result suggested that acquired MET fusions become more regionally selective, as they usually occurred in exons encoding the extracellular region. Interestingly, the MET-fused genes in primary MET fusions or acquired MET fusions were very different, which indicated the different functions and influences of the disease. CONCLUSION: MET fusions are rare, and half of the fusion types were intragenic fusions. Lung cancer patients harboring primary or acquired MET fusions could benefit from crizotinib. In addition, EML4-MET was first reported in this study as a novel MET fusion type.