Objective: This study aimed to analyze the effect of different gantry angles on portal imaging in terms of isocenter shifts and their dosimetric impact on dose delivery.
Methods: Thirty patients with head and neck cancers were prospectively selected for this study. The reference anterior to posterior (AP) digitally reconstructed reference radiograph image was obtained at a gantry angle of 0°. The AP portal images were acquired at angles of 0°, 0.5°, 1°, 1.5°, and 2.0°. The average deviation of the isocenter shift with respect to the zero-gantry angle was calculated. To check the dosimetric effects, the reference fluence was compared with different fluences measured at different isocenter shifts.
Results: The average isocenter shift differences in the lateral direction were 0.7 mm, 1.3 mm, 1.9 mm, and 2.5 mm. The average difference was <±0.1 mm for isocenter shift in the longitudinal direction. The results of the statistical analysis showed that the average isocenter shift and gamma pass rate with respect to the different isocenter position errors were significant in the lateral direction.
Conclusion: The results of this study showed that as the gantry angle increased, the isocenter shifted and the percentage of deviation in the lateral direction increased.
Temporal bone squamous cell carcinoma (TBSCC) is a rare and invasive malignant tumor. The common predisposing factors include a history of local radiotherapy and chronic suppurative otitis media. The current treatment approach for TBSCC primarily involves surgery, followed by adjuvant radiotherapy and chemotherapy, based on T staging and high-risk factors. Although patients with early-stage TBSCC have a high survival rate after treatment, the majority of patients are diagnosed in the intermediate to advanced stages, with extensive tumor involvement, posing challenges for surgical intervention. Definitive chemoradiotherapy (CRT) serves as a viable alternative for unresectable tumors. Constraints in administering curative radiation doses, due to the tolerance of surrounding organs, can lead to uncontrolled tumor growth. Although programmed cell death 1 inhibitors have demonstrated efficacy in head and neck squamous cell carcinoma and cutaneous squamous cell carcinoma, their application in TBSCC remains underexplored. Herein, we report a case of a 47-year-old man diagnosed with unresectable advanced and localized TBSCC. Following inadequate tumor control with primary chemoradiotherapy, immunotherapy was initiated, resulting in disease remission within a follow-up period of > 4 years.
Esophageal cancer is among the top causes of cancer-related mortality worldwide, and the main treatment modality for locally advanced esophageal cancer is concurrent chemoradiotherapy. The current photon-based radiotherapy modalities and procedures have increased the incidence of treatment-related cardiac and pulmonary complications. Additionally, anatomical changes in the esophagus resulting from diaphragmatic movement, weight loss, and tumor progression present challenges for radiotherapy. These challenges have spurred interest in particle therapies, such as proton beam therapy (PBT) and heavy-ion therapy, for esophageal cancer. This paper comprehensively reviews the dosimetric advantages, clinical efficacy, and limitations of PBT and heavy-ion therapy for esophageal cancer and discusses their prospects. This highlights the unique dosimetric benefits of these therapies, particularly their ability to deliver high-dose radiation precisely to the tumor while sparing the surrounding normal organs and tissues. Although PBT and heavy-ion therapy demonstrate superior clinical efficacy compared to photon therapy, they are not without limitations. Multiple studies are needed to further validate and supplement the existing clinical and preclinical data to better exploit the benefits of PBT and thereby provide improved survival advantages to these patients
Objective: Eye plaque radiation therapy is the treatment of choice for small- and medium-sized choroidal melanomas. This study investigated the dose distribution around eye plaques containing 125I seeds to treat ocular melanoma using Monte Carlo N-Particle eXtended (MCNPX) and Plaque Simulator (PS) software.
Methods: Dosimetry evaluation and comparison of the resulting isodose curves for 125I COMS plaques were performed using the MCNPX code. The isodose curves and dose distributions were calculated using PS treatment planning for a 125I COMS plaque.
Results: In the validation, the maximum relative difference between the results of this study and those reported in other literature was approximately 9%–10% for the COMS plaques. The dose distributions of MCNPX were lower than those of PS with a relative difference of approximately 27.7%–35.4%. The dose distribution may differ depending on the 125I source spectra and seed design used in the two methods. In addition, the dose algorithm used in PS made a major contribution to the relative differences between the results.
Conclusion: The PS did not provide accurate details of dose distribution near the surface of the plaque insert. The source parameters used in each program should be studied more carefully to determine the source of the differences in the estimated dose values.
Lung oligometastases represent an intermediate state of cancer dissemination between localized and widespread metastases. Stereotactic body radiation therapy (SBRT) has emerged as an effective treatment option, with an efficacy comparable to that of surgical resection. This review aimed to provide a comprehensive summary of the latest advancements and controversial issues regarding SBRT for lung oligometastases. It focuses on four crucial perspectives: efficacy of SBRT, optimal patient selection criteria, technological innovations, and synergistic effects of SBRT combined with systemic therapy. Relevant clinical trials investigating SBRT for lung oligometastases have been conducted, with median 1- and 5-year local control rates of 90% and 79%, respectively. The origin of the primary tumor, size and number of lesions, and biomarker profiles were highlighted as pivotal considerations in patient selection. The precise dose delivery was enhanced using robotic SBRT and optimized dose fractionation schemes. Evidence suggests that dose escalation above 100 Gy biologically effective dose may improve tumor control. Combined immunotherapy and SBRT have demonstrated synergistic effects in prolonging progression-free survival and overall survival. This review provides valuable insights into the precise treatment of oligometastatic lung diseases using SBRT. Further multicenter randomized trials are warranted to develop definitive patient selection criteria and optimize the integration with systemic therapies.
The superior physical and biological properties of high linear energy transfer (LET), as opposed to traditional low-LET rays, underscore the advantage of proton therapy (PRT) and carbon ion radiotherapy (CIRT) are better than traditional photon radiotherapy (XRT). With the advancements in science, an increasing number of hospitals have introduced new technologies. However, radiotherapy is primarily used for local treatment, which means that if the tumor has metastasized to distant sites, it is often necessary to combine it with systemic therapies such as immunotherapy. In recent years, the combination of high-LET radiotherapy and immunotherapy has emerged as a promising treatment option in oncology and many studies have confirmed its efficacy for both local and distant metastases. In this review, we summarize the effects of PRT and CIRT on the immune system in detail, followed by an introduction to preclinical and clinical studies of PRT and CIRT in combination with immune checkpoint inhibitor (ICIs) therapy. We also briefly introduce some preclinical studies on CIRT in combination with dendritic cells (DCs) and Treg inhibitor therapies.
Background and purpose: This study aimed to summarize the clinical outcomes of patients with metastatic melanoma who received high-dose radiation prior to or during systemic therapy at a single academic institution.
Methods: We identified patients with metastatic melanoma who underwent high-dose radiation therapy (HDRT) for extracranial metastases prior to or during systemic therapy from 2010 to 2018. Treatment indications included oligometastases, oligoprogression, and local control. Using the Kaplan-Meier method, we plotted overall survival (OS), progression-free survival-1 (PFS1), and PFS2. Competing risk analysis determined the cumulative incidence of local failure (LF) and the time to start or change systemic therapy (SCST). Univariate and multivariable analyses were used to identify predictive factors.
Results: We analyzed 34 patients with 79 lesions, with a median follow-up of 17.4 months. Sixty-eight percent of patients received systemic therapy after the first HDRT. The median OS was 22 months, with brain metastases before HDRT being a significant predictor in multivariable analysis. The median PFS1 for first-line HDRT was 4.1 months, and the median PFS2 was 3.9 months. Rates of LF were 10.3% at 12 months and 11.7% at 24 months. The incidence of SCST following HDRT was 59.8% at 12 months and 76.1% at 24 months, with radiation targeted at the lung associated with a lower incidence of SCST.
Conclusion: HDRT for treating metastatic lesions in melanoma demonstrated excellent local control and may play a role in delaying SCST. Additional courses of HDRT may provide cumulative benefits.
Objective: This study assessed the outcomes of elderly patients with limited-stage small cell lung cancer (LS-SCLC), which may be linked to the timing of thoracic radiotherapy (TRT) following chemotherapy.
Methods: Elderly patients (n = 78) with LS-SCLC were divided into three groups depending on the timing of radiotherapy. The patients in the TRT group were stratified into early (TRT after 1–2 cycles of chemotherapy, n = 29), medium-term (TRT after 3–4 cycles of chemotherapy, n = 33), and late (TRT after 5–6 cycles of chemotherapy, n = 16) TRT groups. The overall survival (OS) and progression-free survival (PFS) were assessed and compared.
Results: The medium-term TRT group demonstrated significantly longer mPFS (20.12 months) and better mOS (35.97 months) than those in the other groups (PFS: P = 0.021;OS: P = 0.035). A pairwise comparison of the three groups revealed that those who received medium-term TRT exhibited significantly improved PFS than the early (mPFS: 20.12 vs. 10.36 mouths, P = 0.018) and late (mPFS: 20.12 vs. 9.17 months, P = 0.016) TRT. The medium-term TRT group demonstrated significantly improved OS than the early TRT (mOS: 35.97 vs. 25.22 months, P = 0.007) but not in comparison with the late TRT (mOS: 35.97 vs. 21.63 months, P = 0.100).
Conclusion: In elderly patients with LS-SCLC, the addition of TRT after 3–4 cycles of chemotherapy appears to be a viable and potentially beneficial treatment approach.
Stereotactic radiotherapy is a term collectively used to describe the radiation treatment techniques that allow for the delivery of highly precise ionizing radiation. It is usually a high dose per session in single or few fractions. This treatment approach has been in medical use for over six decades and has primarily evolved in the last two decades. Many patients benefit from this unique non-conventional radiotherapy approach. Its indications include various malignant, benign and functional problems in cranial and body sites. This technique is not widespread in developing countries compared to developed countries. This work is an educational narrative review for learners in radiation oncology. We aim to share the knowledge of this practice to improve precision radiation oncology globally. This review summarizes the basics of stereotactic radiotherapy, the technical prerequisites, the clinical considerations, the practical recommendations and the learning points from each site-specific region.
Objective: We retrospectively analyzed breast cancer patients who received adjuvant radiotherapy to determine the incidence of lymphocytopenia and its risk factors.
Methods: We reviewed 812 patients with breast cancer who received postoperative radiotherapy. Patients were divided into two groups based on the use of chemotherapy, and a generalized linear regression model was used to explore predictive factors for grade 2 or higher lymphocytopenia. We also examined the effect of lymphocytopenia on overall survival.
Results: Grade 2 or higher lymphocytopenia was observed in 19.4% of patients who did not receive chemotherapy and 45.1% of patients who received chemotherapy. In multivariate analysis, bilateral disease, regional lymph node irradiation, and baseline lymphocytopenia were associated with lymphocytopenia in patients who did not receive cytotoxic chemotherapy. Regional lymph node irradiation, baseline lymphocytopenia, use of antimetabolites, and use of molecular-targeted agents were associated with lymphocytopenia in patients treated with chemotherapy. In the survival analysis, lymphocytopenia was associated with worse overall survival only in patients treated with cytotoxic chemotherapy (p = 0.039), and not in patients who did not receive chemotherapy (p = 0.77).
Conclusion: The analysis revealed the incidence and risk factors of lymphocytopenia after postoperative radiotherapy in patients with breast cancer.
Introduction: This study evaluated the clinical outcomes of stereotactic body radiotherapy (SBRT) for both pathologically diagnosed (PD) and clinically diagnosed (CD) early-stage non-small cell lung cancer (NSCLC) and explored the significance of accurate expert computed tomography (CT) interpretation.
Methods: We retrospectively analyzed 95 patients with early-stage NSCLC who received SBRT at our institution. Patients were classified into CD and PD groups. Two chest radiologists retrospectively interpreted the pre-SBRT CT images to determine the tumor subtype and probability of malignancy (PM). Clinical findings, CT features, and treatment outcomes were compared between the two groups. The survival rate of the CD group was analyzed separately according to the PM grade.
Results: Median overall survival for the CD and PD groups was 6.0 and 5.4 years (P = 0.57), respectively. Median cause-specific survival was 10.2 years in the CD group and not reached in the PD group (P = 0.76). In the CD group, lung cancer mortality was lower in the low PM group (25% [1 of 4]) than in the high PM group (47.4% [9 of 19]).
Conclusion: It may be desirable to evaluate the PM of the nodule using expert CT interpretation to decide whether SBRT is indicated in CD early-stage NSCLC.
Nasopharyngeal carcinoma(NPC) occurs frequently in Southern China, and radiotherapy is the main treatment method. At present, intensity-modulated radiotherapy is widely used, which has improved efficacy in patients with NPC and reduced toxicity and side effects. Recently, helical tomography radiotherapy, proton radiotherapy, carbon particle radiotherapy, and other radiotherapy techniques have been used for the clinical treatment of NPC. Individualized nasopharyngeal cancer targets have also been explored. This paper reviews the research progress in radiotherapy techniques and target volume for NPC
Radiation-induced bladder injury is a common complication after pelvic radiotherapy. Few studies exist on diagnosing and treating radiation-induced bladder injury, with no established guidelines or consensus in China or internationally. Clinical physicians' diagnosis and treatment of radiation-induced bladder injury are primarily based on their own clinical experience, and there is an urgent need for unified guidelines to standardize clinical diagnosis and treatment. Therefore, the Chinese Radiation Therapy Oncology Group, China Anti-Cancer Association Tumor Support Therapy Committee, and China Anti-Cancer Association Tumor Radiation Protection Committee gathered experts to develop Chinese clinical practice guidelines, guiding diagnosing and treating radiation-induced bladder injury. The development of these guidelines adopted the grading system of evidence quality and recommendation strength (GRADE).