Practical Radiation Oncology最新文献

Purpose: To compare the outcomes of 2 standard radiation therapy (RT) doses for limited-stage gastric extranodal marginal zone lymphoma (EMZL) of the mucosa-associated lymphoid tissues.

Methods and materials: A database search was performed to identify articles published from database inception to August 31, 2023. Based on the current standard dose of 24.0 to 30.0 Gy, doses of approximately 30.0 Gy were classified as standard dose (SD), while those of approximately 24.0 Gy were classified as low dose (LD). Pooled estimates of the complete remission (CR) and local recurrence (LR) rates were calculated and compared.

Results: Data from 1072 patients across 30 included studies were analyzed. SD was used in 28 studies (n = 987), while LD was used in 6 studies (n = 85), and both regimens were used in 4 studies. In all included studies, the CR rate was 0.96 (95% CI, 0.94-0.97), and the LR rate was 0.05 (95% CI, 0.04-0.06), showing no significant between-study heterogeneity (τ² = 0 and I² = 0% for both; P = .8447 and .9998, respectively). SD and LD resulted in no significant differences in the CR rates (0.96 [95% CI, 0.94-0.97] vs 0.96 [95% CI, 0.89-0.99]; P = .9174) or LR rates (0.05 [95% CI, 0.04-0.06] vs 0.03 [95% CI, 0.01-0.10]; P = .5495).

Conclusions: Both the SD and LD groups achieved excellent CR and LR rates. These results indicate that the RT dose for limited-stage gastric EMZL may be safely de-escalated without compromising local tumor control.

Patients with locally advanced, bulky, and unresectable tumors frequently exhibit frailty and endure symptomatic burdens arising from the mass effect of their tumors. Conservative approaches may often fail to provide symptomatic benefits in relatively radioresistant, slower-growing tumors such as sarcomas. A novel technique termed partially ablative body radiation therapy (PABR) administers a highly centralized ablative dose through the utilization of a simultaneous integrated boost while delivering a low and safe palliative dose to the peripheral regions of tumors. The purpose of this paper was to describe a widely applicable radiation therapy protocol in detail for the PABR technique, of which clinical results are available in previous work.⁷ In summary, a PABR prescription of 20 Gy in 5 fractions is applied to the planning target volume and is planned for 95% of the volume to be covered by 95% of the prescribed dose. A dose of 50 Gy is planned to the boost target volume, with an allowed maximum dose of up to 65 to 70 Gy, using volumetric modulated arc therapy. Daily Cone-Beam Computed Tomography images are used for delivery verification and imaging study. The centrally located volume exceeding 50 Gy effectively achieved the desired outcomes of symptom relief and tumor size reduction. The PABR approach is widely accessible and can be readily implemented in a routine clinical setting to address a pressing need for the challenging palliative patient cohort.

Purpose: A digital visual communication tool was recently developed by MyCareGorithm which incorporates explanations of treatments and procedures for cancer patients. This study will evaluate if this novel tool can enhance both patient and provider satisfaction.

Methods: In an IRB approved, prospective, pilot study, patients and caregivers at a single institution receiving head and neck cancer radiation underwent an initial consult using this digital tool and completed a survey of 6 questions to evaluate their understanding of their disease. Providers completed a 7-question survey to rate their satisfaction. Patients and caregivers with 4 or more "Yes" answers and providers with 5 or more "Yes" answers were defined as "Satisfied". In order to obtain 90% power to detect that the proportion of "Satisfied" patients (assumed 75%) is greater than 50% with a significance level 5% using a one-sided Z test, we planned to enroll 30 patients.

Results: Thirty patients enrolled and completed all surveys. Most patients were male (66%), white (60%) and spoke English as a primary language (93%). Patients most commonly had oropharyngeal cancer (23%). Overall, 27 out of 30 of patients (90%; one sided 95%CI: 76.1%) were satisfied (z = 4.38, p < 0.05), 16 of the 17 caregivers (94%; one sided 95% CI: 74.8%) were satisfied and 100% of providers were satisfied with the digital tool. Most patients (90%) and caregivers (94%) felt that the tool improved their understanding of the disease. One male answered "No" for all 6 questions commenting that it was only marginally helpful. One female also answered "No" for all questions commenting that she did not find it helpful on its own without the provider explanation. Out of the 30 patients, 26 (87%) stayed at our institution to receive treatment.

Conclusions: These findings showed high rates of patient, caregiver and provider satisfaction with their initial consult when incorporating a digital visual tool. Its routine use in clinical practice should be strongly considered.

Purpose: Online adaptive radiation therapy (oART) has high resource costs especially for head and neck (H&N) cancer, which requires recontouring complex targets and numerous organs-at-risk (OARs). Adaptive radiation therapy systems provide autocontours to help. We aimed to explore the optimal level of editing automatic contours to maintain plan quality in a cone beam computed tomography-based oART system for H&N cancer. In this system, influencer OAR contours are generated and reviewed first, which then drives the autocontouring of the remaining OARs and targets.

Methods and materials: Three-hundred-forty-nine adapted fractions of 44 patients with H&N cancer were retrospectively analyzed, with physician-edited OARs and targets. These contours and associated online-adapted plans served as the gold standard for comparison. We simulated 3 contour editing workflows: (1) no editing of contours; (2) only editing the influencers; and (3) editing the influencers and targets. The geometric difference was quantified using the Dice similarity coefficient (DSC) and Hausdorff distance (HD). The dosimetric differences in target coverage and OAR doses were calculated between the gold standard and these 3 simulated workflows.

Results: Workflow 1 resulted in significantly inferior contour quality for all OARs (mean DSC, 0.85 ± 0.17 and HD95, 3.10 ± 5.80mm); hence, dosimetric data was not calculated for workflow 1. In workflow 2, the frequency of physician editing targets and remaining OARs were 80.8% to 95.7% and 2.3% (brachial plexus) to 67.7% (oral cavity), respectively, where the OAR differences were geometrically minor (mean DSC >0.95 with std ≤0.09). However, because of the unedited target contours of workflow 2 (mean DSC, 0.86-0.92 and mean HD95, 2.56-3.30 mm vs the ground-truth targets), plans were inadequate with insufficient coverage. In workflow 3, when both targets and influencers were edited (noninfluencer OARs were unedited), >95.5% of the adapted plans achieved the patient-specific dosimetry goals.

Conclusions: The cone beam computed tomography-based H&N oART workflow can be meaningfully accelerated by only editing the influencers and targets while omitting the remaining OARs without compromising the quality of the adaptive plans.

Purpose: The optimal extent of regional nodal irradiation (RNI) in postoperative radiation therapy for breast cancer, particularly regarding axillary level 1 (AXL1), remains uncertain. This study aimed to compare clinical outcomes between extensive RNI including the entire axilla and limited RNI excluding the upper AXL1 in patients with breast cancer.

Methods and materials: A retrospective analysis included 1780 women with nonmetastatic unilateral breast cancer who underwent RNI during postoperative radiation therapy between 2007 and 2018. Patients were classified into extensive and limited RNI groups based on the upper AXL1 inclusion in the radiation field. Propensity-score matching yielded a cohort of 1020 patients. Noninferiority of limited RNI compared with extensive RNI was assessed with a defined margin of ≤2% in the 5-year axillary recurrence rate.

Results: After a median follow-up of 67.9 months, the 5-year axillary recurrence rates were similar between extensive and limited RNI groups (1.2% vs 1.6%; P_log-rank= .790). Limited RNI demonstrated noninferiority with a 0.4% difference (95% confidence interval, -1.1% to 1.9%; P_{noninferiority}= .019). Disease-free survival (87.9% vs 91.5%; P_log-rank= .122) and overall survival (94.1% vs 96.9%; P_log-rank= .260) at 5 years were not significantly different between extensive and limited RNI groups. Multivariable analysis revealed that lymphovascular invasion (hazard ratio [HR], 5.17; P = .02) and negative hormone receptor status (HR, 11.73; P = .002) were associated with a higher risk of axillary recurrence, whereas limited RNI showed no significant association (HR, 1.35; P = .652). Subgroup analysis demonstrated that extensive RNI did not improve axillary control in patients with lymphovascular invasion, hormone receptor negativity, positive lymph node metastasis, or a small number of nodes removed.

Conclusions: Limited RNI, excluding the upper AXL1 from the radiation field, demonstrated axillary recurrence rates comparable with those of extensive RNI in patients with breast cancer. The study suggests that extensive RNI may not provide additional therapeutic benefits, whereas limited RNI appears to be a valid option for regional control.

Treatment plan quality is a crucial component for a successful outcome of radiation therapy treatments. As the complexity of radiation therapy planning and delivery techniques increases, the role of the medical physicist in assessing treatment plan quality becomes more critical. Integrating plan quality review throughout the treatment planning process allows improvements without delaying treatment or rushing to produce changes at the last minute. In this work, we aim to provide practical check items for physicists to reference when assessing treatment plan quality with a critical eye, asking questions such as "is this the best dose distribution feasible for this patient?," "could we change any planning parameters to improve plan quality?," and "could we change the planning strategy for this particular patient or for future patients?"; and to work with planners and physicians to create a multidisciplinary collaborative culture that achieves the best plan feasible for every patient. We tabulate the features that affect plan quality in each process step and check details for individual items. This report is aimed at medical physicists, planners, radiation oncologists, and other professionals who are involved in treatment planning.

Purpose: Radiation therapy (RT) is a critical treatment modality for both primary and metastatic brain tumors, yet ∼30% of patients experience cognitive decline post-RT. This cognitive toxicity is linked to low radiation doses affecting the hippocampal dentate gyrus. Hippocampal avoidance-whole brain RT combined with memantine has shown promising outcomes in preserving cognitive function and quality of life in patients with brain metastases. Nowadays, it is the standard of care for those with good performance status and no hippocampal metastases.

Methods and materials: We conducted a prospective trial approved by the institutional review board (SMC0307-23), including patients aged ≥18 years with primary brain tumors postresection or biopsy. Exclusion criteria included multifocal glioma crossing to the other hemisphere. RT was delivered to a total dose of 54 Gy in 30 fractions. Diffusion tensor imaging was performed to map hippocampal-associated white matter tracts. Using Eclipse treatment planning software, memory fiber tracts and hippocampi were contoured and integrated into RT planning. Dosimetric analyses compared 2 plans with memory fiber constraints and 1 without. The primary endpoints were safety and dosimetric feasibility.

Results: Twelve patients with low-grade gliomas were included, and the contouring of memory fibers and hippocampi was successful. Volumetric modulated arc therapy (VMAT) treatment plans met-dose constraints for memory fibers, with an average mean dose of 10.1 Gy. The average Montreal Cognitive Assessment score before RT was 27.1 and 26.4 at 8 months post-treatment, with a P value of .07. Excluding 1 patient, the scores were 27.1 and 26.6, respectively (P = .13).

Conclusions: Magnetic resonance imaging planning using diffusion tensor imaging for memory fiber detection and incorporation into RT planning via VMAT techniques enables hippocampal and associated white fiber sparing, potentially preserving cognitive function. Preliminary cognitive data are promising, supporting the need for further validation in a larger cohort.

Radiation therapy is the standard treatment for localized gastric mucosa-associated lymphoid tissue (MALT) lymphoma. The ETHOS system (Varian Medical System) has enabled us to perform cone beam computed tomography (CBCT)-guided online adaptive radiation therapy (oART). This study presents a retrospective dosimetric analysis for interfractional and intrafractional change and treatment time in oART for gastric MALT lymphoma. We included 3 male patients with gastric MALT lymphoma who underwent exhalation breath-hold fasting oART using the SpiroDynr'X system. Treatment details and plans (3 reference [REF] plans, 51 scheduled [SCH] plans, and adapted [ADP] plans) were retrospectively analyzed. Doses to the clinical target volume in planning CT (CTV_REF), CTV1, and CTV2 (representing the stomach in planning and preirradiation CBCT, respectively) and planning target volume (PTV) in the planning CBCT were estimated. D_2%, D_98%, D_50%, and D_mean for these volumes, along with organ-at-risk doses, were examined across the 3 plans. The PTV dose coverage of CTV2 on preirradiation CBCT was calculated. CBCT-guided oART was completed within the scheduled period, using the ADP plans instead of the SCH plans on each treatment day in all cases. The average treatment time was approximately 45 minutes. CTV1 and CTV2 exhibited intrafractional and interfractional variations, fluctuating above and below CTV_REF. Some ADP plans resulted in incomplete PTV coverage of CTV2, but the unincluded volume was <1% of CTV2. D_50%, D_98%, and D_mean of CTV1, CTV2, and PTV were significantly improved in the ADP plans than in the SCH plans. Moreover, the D_mean to the liver and kidneys was reduced in the ADP plans. CBCT-guided oART in patients with gastric MALT lymphoma demonstrated that ADP plans improved CTV1, CTV2, and PTV doses and reduced the mean bilateral kidney and liver doses, suggesting that it may offer enhanced treatment precision for gastric MALT lymphoma.

Radiation therapy plays a critical role in the management of locally advanced vulvar cancers but can lead to a unique spectrum of side effects, with >25% of patients experiencing high-grade toxicities. The treatment phase requires meticulous perineal skincare and may require pharmacologic management of dysuria and cystitis, diarrhea, nausea, and dermatitis/mucositis. The addition of chemotherapy warrants close laboratory monitoring for hematologic and metabolic derangements.

Purpose: The optimal SABR treatment delivery schedule in stage I non-small cell lung cancer (NSCLC) remains unclear. This population-based study investigated grade ≥2 toxicity rates, local failure (LF), and overall survival (OS) in patients treated with 48 Gy in 4 fractions scheduled every other day versus daily with weekends and consecutive daily without weekends.

Methods and materials: Between January 2019 and June 2022, treatment records using 48 Gy in 4 fractions were extracted from a provincial cancer registry and grouped by delivery as every other day, daily with weekends, or consecutive daily without weekends. Toxicity events were recorded using National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0. The Kaplan-Meier method was used to compute OS and LF was calculated using cumulative incidence methods with death as a competing risk. Cox regression analyses and Fine-Gray modeling was used to assess for variables associated with OS and LF, respectively.

Results: Of 404 patients meeting study criteria, 190, 111, and 103 received SABR every other day, daily with weekends, and consecutive daily without weekends, respectively. More patients receiving SABR daily with weekends were medically inoperable and more patients receiving SABR consecutive daily without weekends had tumors abutting the chest wall. Median follow-up time was 29.5 months (IQR, 19.2-38.4 months). Overall toxicity was low, with crude rates of acute and late grade ≥2 toxicity not being statistically different among the groups. No grade 4 or 5 toxicities were recorded. LF rates at 24 months were not different at 7.5% (95% CI, 3.7-11.3), 9.5% (95% CI, 3.9-15.1), and 11.0% (95% CI, 4.9-17.2) for the every other day, daily with weekends, and consecutive daily without weekends groups, respectively (P = .60). Schedules of daily with weekends and consecutive daily without weekends were not associated with LF. Similarly, no significant differences in median OS were found among the every other day, daily with weekends, and consecutive daily without weekends groups at 47.5 months (95% CI, 39.26-55.74), 52.7 months (95% CI, 34.7-70.7), and 49.0 months (95% CI, 31.6-66.4), respectively. Schedules of daily with weekends and consecutive daily without weekends were not associated with OS.

Conclusions: This population-based study demonstrated no statistically significant differences in grade ≥2 toxicity rates, LF, and OS for patients with stage I NSCLC treated with lung SABR using 48 Gy in 4 fractions delivered every other day, daily with weekends, and consecutive daily without weekends. Patient convenience and optimization of resources may be considered when choosing a lung SABR treatment delivery schedule.