Scalp Irradiation with 3D-Milled Bolus: Initial Dosimetric and Clinical Experience.

BACKGROUND AND PURPOSE: A bolus is required when treating scalp lesions with photon radiation therapy. Traditional bolus materials face several issues, including air gaps and setup difficulty due to irregular, convex scalp geometry. A 3D-milled bolus is custom-formed to match individual patient anatomy, allowing improved dose coverage and homogeneity. Here, we describe the creation process of a 3D-milled bolus and report the outcomes for patients with scalp malignancies treated with Volumetric Modulated Arc Therapy (VMAT) utilizing a 3D-milled bolus. MATERIALS AND METHODS: Twenty-two patients treated from 2016 to 2022 using a 3D-milled bolus and VMAT were included. Histologies included squamous cell carcinoma (n = 14, 64%) and angiosarcoma (n = 8, 36%). A total of 7 (32%) patients were treated in the intact and 15 (68%) in the postoperative setting. The median prescription dose was 66.0 Gy (range: 60.0-69.96). RESULTS: The target included the entire scalp for 8 (36%) patients; in the remaining 14 (64%), the median ratio of planning target volume to scalp volume was 35% (range: 25-90%). The median dose homogeneity index was 1.07 (range: 1.03-1.15). Six (27%) patients experienced acute grade 3 dermatitis and one (5%) patient experienced late grade 3 skin ulceration. With a median follow-up of 21.4 months (range: 4.0-75.4), the 18-month rates of locoregional control and overall survival were 75% and 79%, respectively. CONCLUSIONS: To our knowledge, this is the first study to report the clinical outcomes for patients with scalp malignancies treated with the combination of VMAT and a 3D-milled bolus. This technique resulted in favorable clinical outcomes and an acceptable toxicity profile in comparison with historic controls and warrants further investigation in a larger prospective study.

Volumetric Modulated Arc Therapy Craniospinal Irradiation Utilizing a Vertebral Body Sparing Approach: An Alternative Approach to Improve Access and Minimize Toxicity.

Introduction: Craniospinal irradiation (CSI) is indicated for adult patients diagnosed with leptomeningeal disease (LMD). Proton-based vertebral body sparing (VBS) CSI has been explored with pediatric patients to minimize hematologic toxicity; however, utilization of VBS in an adult population is limited. A recent phase II trial has shown efficacy of proton-based CSI to treat non-small cell lung and breast cancer with LMD. We hypothesize that VBS CSI using volumetric modulated arc therapy (VMAT) could also effectively reduce dose to vertebral bodies and surrounding organs at risk, minimizing toxicity for adult patients with LMD and comparing favorably to proton-based CSI. Methods and Materials: Consecutive patients with LMD received VMAT VBS CSI, 30 Gy in 10 fractions, as a part of a prospective registry. Full VMAT arcs for the brain fields matched to 2 spine isocenters for the upper and lower spine were created using limited posterior arcs. To further decrease the vertebral body dose, an avoid entry and exit contour was created. Acute toxicity data were collected using Common Terminology Criteria for Adverse Events v5. Results: Ten adult patients were treated in this cohort. One patient experienced grade 2 neutropenia with the remaining 9 experiencing grade 1 hematologic toxicity. Three patients experienced grade 2 gastrointestinal toxicity with the remaining 7 experiencing grade 1 nausea. No patient experienced grade 3+ toxicities in this cohort. One patient experienced a 5-day delay in systemic therapy initiation due to neutropenia; otherwise, all patients planned for systemic therapy started without delay. Conclusions: In this study, VMAT VBS CSI led to acceptable toxicity compared with patients treated with proton CSI on a phase 2 clinical trial. Given its promising early results, future prospective evaluation of the technique is warranted.

Clinical outcomes and efficacy of stereotactic body radiation therapy in children, adolescents, and young adults with metastatic solid tumors.

OBJECTIVE: The objective of this study is to report disease outcomes and toxicity with the use of stereotactic body radiation therapy (SBRT) in the treatment of pediatric metastatic disease. METHODS: All pediatric and adolescent young adult (AYA) patients' who received SBRT were included between the years 2000 and 2020. Study endpoints included local control (LC), progression-free survival (PFS), overall survival (OS), cumulative incidence (CI) of death or local failure and toxicity. The end points with respect to survival and LC were calculated using the Kaplan-Meier estimate. The cumulative incidence of local failure was calculated using death as a competing risk. RESULTS: 16 patients with 36 lesions irradiated met inclusion criteria and formed the study cohort. The median OS and PFS for the entire cohort were 17 months and 15.7 months, respectively. The 1 year OS for the entire cohort was 75%. The 6- and 12 month local control was 85 and 78%, respectively. There were no local failures in irradiated lesions for patients who received a BED10≥100 Gy. Patients who were treated with SBRT who had ≤5 metastatic lesions at first recurrence had a superior 1 year OS of 100 vs 50% for those with >5 lesions. One patient (6.3%) experienced a Grade 3 central nervous system toxicity. CONCLUSION: LC was excellent with SBRT delivered to metastatic disease, particularly for lesions receiving a BED10≥100 Gy. High-grade toxicity was rare in our patient population. Patients with five or fewer metastatic sites have a significantly better OS compared to >5 sites. ADVANCES IN KNOWLEDGE: This study demonstrates that SBRT is safe and efficacious in the treatment of pediatric oligometastatic disease.

Radiation Therapy Without Anesthesia for a 2-Year-Old Child Using Audio-Visual Assisted Therapeutic Ambience in Radiation Therapy (AVATAR).

PURPOSE: Radiation therapy (RT) is essential to managing many pediatric malignancies but can provoke anxiety, fear, and discomfort for children owing to prolonged treatment time, extended course, and restrictive immobilization. Patients younger than 10 years frequently require daily general anesthesia (GA), which is resource intensive, expensive, potentially toxic, and anxiety and fear provoking. Audio-Visual Assisted Therapeutic Ambience in Radiation Therapy (AVATAR), a video streaming device, has been proposed as an alternative to anesthesia in patients aged 3 to 10 years. A pilot study evaluating the efficacy of this novel innovation is accruing, but patients younger than 3 years are ineligible. METHODS AND MATERIALS: We simulated a 2-year-old with stage IV Wilms tumor for bilateral whole-lung and left-flank irradiation without GA. Using AVATAR, we attempted to deliver RT to this patient without sedation. Patient anxiety at the time of simulation and at the beginning, middle, and end of the treatment course was characterized using the validated Modified Yale Preoperative Anxiety Score (mYPAS) measurement tool. RESULTS: Although the patient tolerated computed tomography simulation without GA or AVATAR use, his mYPAS of 14 out of 18 indicated significant anxiety. Using AVATAR, all treatments were delivered without GA; his mYPASs were 5 and 4 (the lowest possible) and 4 at the first, midcourse, and final treatments, indicating no significant anxiety and a decrease from the pre-AVATAR baseline. Without GA, the time to deliver RT decreased by 66% from 90 to 30 minutes. CONCLUSIONS: We describe an expanded, previously unreported indication for AVATAR by demonstrating the feasibility of this approach to reduce or omit anesthesia in appropriate younger patients currently excluded from ongoing trials. The financial and quality-of-life benefits (including decreased stress, anxiety, toxic effects, cost, and appointment time) of AVATAR use may be extendable to a younger patient population than previously thought. In older children, prospective validation is ongoing, but additional study in patients younger than 3 years is needed.

Thyroid-optimized and thyroid-sparing radiotherapy in oral cavity and oropharyngeal carcinoma: A dosimetric study.

BACKGROUND: Radiation-induced hypothyroidism is a common toxicity of head and neck radiation. Our re-planning study aimed to reduce thyroid dose while maintaining target coverage with IMRT. METHODS: We retrospectively identified patients with oral-cavity (n = 5) and oropharyngeal cancer (n = 5). Treatment plans were re-optimized with 45 Gy thyroid mean dose constraint, then we cropped the thyroid out of PTVs and further reduced thyroid dose. Target coverage was delivering 100% dose to ≥ 93% of PTV and 95% of dose to > 99% of PTV. RESULTS: Originally, average mean dose to thyroid was 5580 cGy. In model I, this dropped to 4325 cGy (p < 0.0001). In model II, average mean dose was reduced to 3154 cGy (p < 0.0001). For PTV low and PTV int, all had acceptable target coverage. CONCLUSION: In patients with oral-cavity and oropharyngeal cancers, mean dose could be significantly reduced using a thyroid-optimized or thyroid-sparing IMRT technique with adequate coverage.

Synchronous Supraglottic and Esophageal Squamous Cell Carcinomas Treated with a Monoisocentric Hybrid Intensity-Modulated Radiation Technique.

Risk factors for squamous cell carcinomas (SCCs) of the head and neck (HN) and esophagus are similar. As such, synchronous primary tumors in these areas are not entirely uncommon. Definitive chemoradiation (CRT) is standard care for locally advanced HNSCC and is a preferred option for inoperable esophageal SCC. Simultaneous treatment of both primaries with CRT can present technical challenges. We report a case of synchronous supraglottic and esophageal SCC primary tumors, highlighting treatment with a monoisocentric hybrid radiation technique and normal tissue toxicity considerations.