Journal of Radiation Research最新文献

Adult T-cell lymphoma/leukemia (ATL) is an aggressively malignant peripheral T-cell neoplasm. Only a few studies have reported the use of radiotherapy (RT) for ATL. Therefore, the aim of this study was to clarify the efficacy of RT for ATL. We retrospectively reviewed 90 courses of RT administered to 19 consecutive ATL patients between 2008 and 2023. The subtypes included lymphoma (n = 8), acute (n = 7), smoldering (n = 3) and unknown (n = 1). Ninety lesions (cutaneous = 72, extranodal = 10, nodal = 8) were treated at a mean dose of 39.1 Gy/3.2 Gy (range, 24-60 Gy). Administration of RT for ATL lesions resulted in a combined complete response and partial response rate of 92%. At a mean of 47.5 months of follow-up (range, 0-102 months), local recurrence was not observed in 98.9% of the courses. A treatment response in terms of clinical symptoms was observed in 92% of the courses. The median survival time was 918 days. No acute grade ≥3 toxicity or any late toxicity was noted. In conclusion, RT was confirmed to be effective and safe for the treatment of local ATL lesions.

The Japanese Society for Radiation Oncology (JASTRO) Guidelines for Radiotherapy Treatment Planning have been revised every four years to incorporate the latest findings since the publication of the first edition in 2004. This is a review which presents the 2024 JASTRO Guidelines for radiotherapy treatment planning for esophageal cancer in English. Regarding the treatment of esophageal cancer, various new findings have emerged over the past 4 years, leading to significant updates in the 2020 edition, particularly in the following six areas: (i) additional details on indications for superficial cancer, (ii) inclusion of clinical trial results (JCOG1109) for neoadjuvant chemotherapy and chemoradiotherapy in locally advanced cases in Japan, (iii) updated references on prophylactic lymph node irradiation, (iv) updates on IMRT, (v) revisions in accordance with the 5th edition of the Esophageal Cancer Treatment Guidelines, and (vi) additions of FOLFOX to concurrent chemotherapy regimens.

The rare abscopal effect in radiotherapy is thought to result from immune-activating damage-associated molecular patterns, such as high mobility group box-1 protein (HMGB1), released from cancer cells. While external irradiation of cancer cells increases HMGB1 release, it remains unclear whether internal radiotherapy with 131I-meta-iodobenzylguanidine (131I-MIBG) induces similar effects. This study aimed to determine if HMGB1 is released from human-derived cancer and normal cells after 131I-MIBG administration. The number of cells, extracellular lactate dehydrogenase (LDH) and HMGB1 were measured in H441 and human keratinocyte cell line (HaCaT) at 1 day after 2- and 10-Gy X-ray irradiation. Accumulations of 131I-MIBG in SH-SY5Y and HaCaT were measured at 60 min after 131I-MIBG (0.37, 1.85 and 3.7 MBq/well) administration. The number of cells, extracellular LDH and HMGB1 were measured at 1 day after 131I-MIBG treatment. Results: The total number of cells decreased in both H441 and HaCaT at 1 day after 10-Gy X-ray irradiation. Extracellular LDH and HMGB1 from H441 after 10-Gy X-ray irradiation were significantly increased, while no increase was observed in HaCaT after 2- and 10-Gy X-ray irradiation. After 1.85 MBq (~4-Gy by converting of PHITS simulation) and 3.7 MBq 131I-MIBG (8-Gy) administrations, the total number of cells decreased in both SH-SY5Y and HaCaT at 1 day after 131I-MIBG administration. Extracellular LDH and HMGB1 were both significantly increased in SH-SY5Y, but only extracellular LDH was significantly increased in HaCaT. HMGB1 was released from neuroblastoma cells but not from normal cells after 131I-MIBG administration. A combination of 131I-MIBG and immunotherapy may be feasible.

To evaluate the safety of a rotating gantry with scanning beams of carbon-ion radiotherapy (C-ion RT) for choroidal malignant melanoma. A prospective study of C-ion RT using a rotating gantry with scanning beams for choroidal malignant melanoma was initiated at the National Institute for Quantum Science and Technology, QST Hospital in March 2018. The inclusion criteria were as follows: (i) clinically diagnosed ocular/choroidal malignant melanoma; (ii) tumor measurable by imaging tests; (iii) score of 0-2 on the Eastern Cooperative Oncology Group Performance Status scale and (iv) ability to provide consent for treatment. All patients received 68 Gy in four fractions of C-ion RT by a rotating gantry with scanning beams. Between April 2018 and July 2019, 21 patients were enrolled and underwent C-ion RT as planned. All 21 patients completed the treatment schedule and the 3-year follow-up period. The median duration of follow-up was 43 months (range, 35.2-54.6 months). Regarding late normal tissue responses, three of the 21 patients developed grade 2 neovascular glaucoma; however, no other late grade ≥2 acute toxicities were observed. During the 3-year study period, all 21 patients survived with no local recurrence; none of the patients underwent enucleation. Three cases showed liver metastasis. The 3-year local control, overall survival and eye-retention rates were all 100%. The results of this prospective study confirmed that the effectiveness and safety of this method are equivalent to those of conventional passive irradiation methods, although the number of cases was small. The results of this prospective study confirmed that the effectiveness and safety of this method are equivalent to those of conventional passive irradiation methods, although the number of cases was small.

We aimed to compare dose to organs at risk (OARs) and the excess relative risk (ERR) of cardiac mortality among three-dimensional conformal radiotherapy (3D-CRT), volume modulated arc therapy (VMAT) and proton beam therapy (PBT) in craniospinal irradiation (CSI). CSI plans of 3D-CRT, VMAT and PBT were generated. Vertebral body reduced dose (VBR)-CSI according to the International Society of Paediatric Oncology recommendation was used for VMAT and PBT. We delineated two sets of target volumes, i.e. target volume (TV) 1 for brain and thecal sac and TV2 for the vertebral body. Two sets of CSI dose, 23.4 and 36 Gy, were prescribed for TV1, and VBR doses, 18.4 and 20 Gy, were prescribed for TV2. For 3D-CRT, we prescribed a dose only to cover TV1. For VMAT and PBT, 23.4/18.4Gy and 36/20 Gy in 13 and 20 fractions were optimized. To evaluate the ERR of cardiac mortality compared with the normal population, we incorporate the mean heart dose with the linear model. In a total of eight patients, 48 treatment plans were generated (24 plans for each dose set). PBT showed the lowest mean dose to all OARs, i.e. heart, lung, liver, kidney, esophagus, oral cavity, thyroid and vertebral body. PBT showed significantly less ERR of cardiac mortality compared with 3D-CRT and VMAT for both 23.4 and 36 Gy prescriptions. With VBR-CSI, PBT reduced the mean dose to all OARs and significantly reduced the ERR of cardiac mortality compared with 3D-CRT and VMAT. The advantage of PBT was manifest, especially with high-dose CSI.

The brain and spinal cord, which constitute the central nervous system, were historically considered immune-privileged sites, as it was believed they lacked an equivalent to the systemic lymphatic system. However, in 2013, a pathway facilitating the clearance of waste products through the brain parenchyma via the perivascular space was proposed, garnering attention as the 'glymphatic system'. Similar to the systemic lymphatic system, the glymphatic system plays a critical role in immune responses and has been implicated not only in Alzheimer's disease and inflammatory brain disorders but also in conditions such as hydrocephalus and glaucoma, which are associated with cerebrospinal fluid circulation impairments. Recent studies have suggested that dysfunction of the glymphatic system may promote the progression of brain tumors and reduce the efficacy of immune responses and pharmacological therapies targeting tumors. Radiotherapy is a major treatment option for brain tumors; however, while it can enhance immune responses against tumors, it may also suppress these responses at the same time. Additionally, cranial irradiation has been suggested to impair the function of the glymphatic system. This review provides an overview of the structure and functional evaluation methods of the glymphatic system, summarizes the effects of its dysfunction on brain tumor treatment, and explores recent findings on the impact of radiation therapy on glymphatic system functioning. Lastly, it also explores the potential for radiation therapy strategies that account for their effects on the glymphatic system.

Fluoroscopy-guided bronchoscopy is an essential tool for diagnosing and treating lung diseases, particularly lung cancer. However, prolonged fluoroscopic exposure raises concerns regarding radiation-induced lens injuries in physicians, such as radiation cataracts. In response to the International Commission on Radiological Protection lowering the occupational lens dose limit to an average of 20 mSv/year over 5 years, there is an increasing need for effective lens protection during such procedures. This study has aimed to develop a novel lens protection device specifically designed for bronchoscopy physicians and evaluate its protective performance through a phantom study. The device consisted of a 0.175 mm lead (Pb) sheet positioned on the left side of the physician's head, secured with headgear to improve stability and comfort during prolonged use. A phantom study was conducted using a trunk phantom to simulate a patient and a head phantom to simulate a physician. The scattered radiation doses were measured at 15 locations on the phantom head using a radiophotoluminescence glass dosimeter, both with and without a protective device. The device demonstrated a protective effect of more than 80% for the left eye across all tested angles, whereas the right eye showed protection ranging from approximately 40% to 75% depending on the angle. This novel lens protection device has the potential to significantly reduce scattered radiation to the left eye while minimizing vision obstruction and discomfort. This offers a practical solution for radiation protection during bronchoscopy and may be applicable to other interventional procedures requiring fluoroscopic guidance.

Conventional fractionated radiotherapy (CFRT) for hepatocellular carcinoma (HCC) is limited by intrinsic radioresistance. In this study, we investigated the radiosensitizing potential of maraviroc, a chemokine receptor 5 (CCR5) antagonist, and its mechanistic basis in HCC. A murine HCC model was established by subcutaneous implantation of H22 cells into the hind limbs of mice. Tumor-bearing mice received CFRT with or without maraviroc, and tumor growth kinetics were evaluated. Systemic levels of myeloid-derived suppressor cells (MDSCs) in peripheral blood and plasma chemokine ligand 5 (CCL5) were longitudinally monitored post-irradiation. In vitro mechanistic studies utilized maraviroc combined with conditioned media from 2 Gy-irradiated H22 cells to dissect its radiosensitizing effects. H22 cell viability, proliferation and migration were assessed following irradiation with or without maraviroc. Flow cytometry was employed to quantify polymorphonuclear MDSC (PMN-MDSC) proliferation, differentiation and immunosuppressive capacity via T-cell proliferation assays. Compared to monotherapy with either CFRT or maraviroc alone, maraviroc combined with CFRT significantly inhibited HCC growth in the mouse model. In vitro, maraviroc did not directly enhance irradiation-induced H22 cell death or suppress proliferation but reversed PMN-MDSC-mediated immunosuppression by attenuating PMN-MDSC migration and abrogating PMN-MDSC suppression of T-cell proliferation. Maraviroc combined with CFRT significantly inhibited the differentiation of bone marrow cells into PMN-MDSCs. In conclusion, the synergistic application of CCR5 antagonist with CFRT significantly enhanced radiosensitivity in HCC, primarily through suppression of PMN-MDSCs differentiation and migration, coupled with blockade of their T-cell proliferation inhibitory functions.

Cancer stem cell (CSC) radioresistance is a major cause of radiotherapy (RT) failure and tumor recurrence. The molecular target for eradicating CSCs has not been identified despite research efforts to overcome tumor radioresistance. The adenosine monophosphate-activated protein kinase (AMPK) is responsible for transmitting nuclear DNA damage signals to the mitochondria, which in turn generate adenosine triphosphate to execute a DNA damage response. Disruption of this mitochondria-mediated genomic defense mechanism may be an effective strategy to enhance the cytotoxic efficacy of RT. Here, we investigated the potential efficacy of the pan-AMPK inhibitor dorsomorphin (Dor) in preventing CSC radioresistance. Radioresistant cancer stem-like cells were derived from the human liver cancer cell line HepG2 (HepG2 82FR-31NR). The radiosensitizing effect of Dor was then examined in HepG2 82FR-31NR cell cultures by clonogenic assays. Low-dose Dor markedly suppressed the recovery of HepG2 cancer stem-like cells after radiation but had little effect on normal fibroblast proliferation and survival, whether applied alone or in combination with radiation. In conclusion, this study strongly suggests that Dor treatment can radiosensitize cancer stem-like cells at doses that have no significant cytotoxic effects on normal human fibroblasts.