Strahlentherapie und Onkologie最新文献

Cone-beam computed tomography (CBCT) is a critical imaging modality in various medical fields, yet its repeated use poses radiation risks to patients. Low-dose CBCT image reconstruction aims to mitigate these risks while preserving image quality, which is crucial for clinical diagnosis and treatment. This review paper provides an in-depth analysis of the latest research progress in low-dose CBCT image reconstruction. We explore analytical reconstruction algorithms, iterative reconstruction algorithms, and deep learning approaches, each with distinct characteristics and applications. The paper comprehensively reviews the methods used for dose reduction in CBCT, the evolution of reconstruction algorithms, and their performance evaluations. We also identify challenges and limitations in current techniques, discussing potential future directions for low-dose CBCT reconstruction. Through a systematic literature search and analysis, this review offers a valuable reference for researchers and clinicians alike, aiming to advance the field of CBCT and enhance patient care through reduced radiation exposure and improved imaging outcomes.

Introduction: This study aimed to determine the role of postoperative adjuvant therapy in patients with thymic carcinoma following complete resection.

Methods: We conducted a retrospective analysis of patients with stage I-III or N1+ thymic carcinomas who underwent complete resection at our center between 2006 and 2020. Data on the clinical characteristics and postoperative adjuvant therapies were collected.

Results: One hundred and twenty patients were enrolled. Five (4.2%) patients received only postoperative chemotherapy, 36 (33.0%) received only postoperative radiotherapy, 75 (62.5%) received postoperative chemoradiotherapy, and four (3.3%) did not receive any postoperative therapy. During a median follow-up period of 65 months, disease failure was observed in 46 (38.3%) patients, and 28 (23.3%) patients died. The 5‑year disease-free survival (DFS) and overall survival (OS) rates were 58.7 and 81.4%, respectively. Patients who underwent different postoperative therapies exhibited varying prognoses. Radiotherapy reduced the risks of failure (p < 0.001) and death (p < 0.001), whereas chemotherapy did not (p = 0.198 and 0.260 respectively). Subgroup analyses revealed that stage III/IV patients who received chemotherapy had a lower relapse risk (p = 0.045) and improved OS (p = 0.064). Multivariate analysis demonstrated that radiotherapy alone (hazard ratio [HR], 0.24; p = 0.023) independently predicted OS.

Conclusions: Adjuvant radiotherapy should be recommended for patients with thymic carcinoma who have undergone complete resection. Further exploration is needed to clarify the role of adjuvant chemotherapy.

Introduction: Primary orbital lymphomas are predominantly low-grade subtypes, such as extranodal marginal zone lymphomas (MALT) and follicular lymphomas, which are highly radiosensitive. Mantle cell lymphoma (MCL), although less common, is an aggressive high-grade subtype with an intermediate-to-poor prognosis. While systemic therapies are standard for MCL, data on the efficacy of radiotherapy in localized orbital MCL are limited. This study evaluates the long-term outcomes of radiotherapy for localized orbital MCL using the Surveillance, Epidemiology, and End Results (SEER) database.

Materials and methods: This retrospective study analyzed cases of localized orbital MCL treated with radiotherapy between 2000 and 2021 identified in the SEER database. Demographic, clinical, and survival data were extracted. The primary endpoints were overall (OS) and cancer-specific survival (CSS), estimated using the Kapla-Meier method and Cox proportional hazards models. Statistical analyses were conducted using R software (R Foundation, Vienna, Austria), with a significance threshold set at p < 0.05.

Results: Among 13,662 patients with localized primary orbital lymphomas, 63 (0.5%) cases were histologically confirmed as MCL. Of these, 35 patients (55.6%) received radiotherapy. The age-adjusted incidence rate of orbital MCL was 0.033 per 1,000,000 person-years (95% CI: 0.025-0.042). Patients were predominantly elderly (42.9% were over 80 years old) and male (male-to-female ratio of 2.18 : 1; p = 0.012). With a median follow-up of 91 months (range: 4-237 months), the median OS was 113 months. The 5‑, 10-, and 15-year OS rates were 76.5% (95% CI: 62.7-93.4%), 48.2% (32.9%-70.6%), and 42.8% (27.4%-66.9%), respectively. Median CSS was not reached, with 5‑, 10-, and 15-year CSS rates of 98.0% (95% CI: 78.0-100.0%), 83.4% (69.5%-100.0%), and 83.4% (69.5%-100.0%), respectively. Chemotherapy did not show a significant impact on survival.

Conclusion: Radiotherapy achieves excellent long-term survival outcomes for localized orbital MCL, particularly in elderly and frail patients who may not tolerate systemic therapies. These findings support radiotherapy as an effective therapeutic option for this rare lymphoma subtype. Future multicenter studies are warranted to optimize radiotherapy protocols and improve patient outcomes.

The growing use of reduced-dose radiotherapy in patients with primary cutaneous lymphoma is a promising development. Nevertheless, the absence of controlled clinical trials to ascertain standardized doses for each specific type constitutes a significant impediment to the advancement of this field. This expert opinion strongly advocates for advancements in radiation oncology practice that address the unique complexities of primary cutaneous lymphoma. By refining our methodologies, we can optimize patient care and outcomes in this dynamic field.

Purpose: Modern involved-site radiotherapy (ISRT) for Hodgkin lymphoma decreases toxicity through reduced field sizes and radiation doses. However, in pregnancy, the therapeutic benefit has to be weighed against putative harm to the mother and the fetus, as even small doses may have deleterious effects. We conducted a phantom-based simulation to analyze uterine dose exposure from cervical and mediastinal ISRT.

Methods: Cervical and mediastinal ISRT target volumes were contoured to calculate three comparison plans (3D-conformal radiotherapy [3D-CRT], intensity-modulated radiotherapy [IMRT], volumetric intensity-modulated arc therapy [VMAT]). Thermoluminescent dosimeters (TLD) were placed within a humanoid Alderson phantom to simulate early and late pregnancy. Overall, six measurements (two for every radiotherapy plan) with 38 TLD were conducted.

Results: In early pregnancy, cervical ISRT treatment of 19.8 Gray (Gy) resulted in median fetal exposures of 8.8 mGy, 15.4 mGy, and 9.9 mGy for 3D-CRT, IMRT, and VMAT, respectively, with significant differences between the three techniques (p < 0.001) and increased doses in late pregnancy (p < 0.001). For mediastinal ISRT (19.8 Gy), early pregnancy doses were 44 mGy, 63.8 mGy, and 60.5 mGy for 3D-CRT, IMRT, and VMAT, respectively, again with significant differences (p < 0.001) and a significant increase (p < 0.001) in late pregnancy. In comparison, values of 214.2 mGy (3D-CRT), 249.9 mGy (IMRT), and 249.9 mGy (VMAT) were reached using 30.6 Gy, with significant differences between 3D-CRT and VMAT (p < 0.001), 3D-CRT and IMRT (p < 0.001), and IMRT and VMAT (p = 0.004).

Conclusion: Using RT during pregnancy may have deleterious effects on the fetus and should be deferred until after birth whenever possible. Theoretical uterine RT doses are low overall and only exceeded safety thresholds with higher-dose intensity-modulated plans. The indication for RT in pregnancy always requires careful risk-benefit consideration and individualized planning.

Background and purpose: Stereotactic body radiotherapy (SBRT) is associated with good local control and symptom relief in the management of spinal metastases. Delivery of ablative doses and re-irradiation is challenged by spinal cord toxicity. We hypothesized that lower spinal cord doses as well as better target coverage could be yielded with stereotactic magnetic resonance-guided adaptive radiotherapy (SMART).

Materials and methods: Institutional records were reviewed to retrieve patients who received online MR-guided SBRT for spinal metastases. Each fraction was reviewed to determine the necessity of adaptive planning, to identify reasons for violations that required adaptive planning, and to assess the spinal cord dose. The study also evaluated how adaptive planning contributed to reducing spinal cord doses.

Results: A total of 34 patients with 61 lesions were included. The treatment intent was definitive for 47 (77.1%), palliative for 12 (19.7%), and postoperative for two (3.3%) lesions. The median prescribed Biological Equivalent Dose (BED)₁₀ was 51.3 Gy. Treatment plans often required adaptive adjustments (81.8%). Adaptive planning significantly improved target coverage (median PTV coverage 92.75% vs. 95%; p < 0.001) and reduced spinal cord D_max (median spinal cord D_max constraint: 7.3 Gy, median predicted spinal cord D_max: 7.76, and median adaptive spinal cord D_max 6.18; p < 0.001). Lesion-based median follow-up from irradiation was 7.5 months (range: 1-46 months). One-year LPFS was 94.3%. Six lesions progressed and none of the progressed lesions received a dose above the median BED₁₀ of 51.3 Gy.

Conclusion: Herein we present our institutional experience with SMART for spinal bone metastases. According to our results, adaptive planning yields better target coverage as well as lower spinal cord doses compared to the predicted plan, which translates into a feasible method for delivering SBRT. Future prospective studies evaluating spinal SMART are awaited.

Purpose: Proton beam therapy (PBT) has a promising local control rate, but clinical data supporting its use for intermediate-stage hepatocellular carcinoma (HCC) remains insufficient, and its survival benefit over transarterial chemoembolization (TACE) has yet to be established. This study aimed to compare the two modalities by evaluating real-world survival outcomes.

Methods: The propensity score-matched (PSM) cohort study used data from a multi-institutional medical research database. Treatment-naïve patients with Barcelona Clinic Liver Cancer (BCLC) stage B HCC who underwent PBT or TACE as monotherapy were enrolled. Baseline patient and tumor characteristics were used for matching. Overall survival (OS) and post-treatment albumin-bilirubin (ALBI) grade were assessed, and stratified analyses were performed to evaluate the heterogeneity.

Results: Between January 2007 and December 2022, 4349 patients with BCLC‑B HCC were identified, 1172 of whom met the inclusion criteria (PBT: 68; TACE: 1104). The PSM cohort matched 340 patients (PBT: 68; TACE: 272). Cox regression analysis revealed a significant survival benefit in the PBT group (p = 0.032, hazard ratio (HR) 0.64, 95% CI 0.42-0.97). Liver function was assessed in terms of ALBI grade every 3 months for 12 months after treatment, and the proportion of patients who maintained better liver function was greater in the PBT group than in the TACE group (p = 0.006).

Conclusion: For patients with BCLC‑B HCC who are suitable candidates for PBT, PBT preserves better liver function than TACE and provides superior OS.