Experience Of Radiotherapy Research Articles

Treatment-related calvarial lesions in pediatric brain tumor survivors.

Despite improved survival, many pediatric brain tumor survivors receiving radiation therapy (RT) experience late effects. To study calvarial lesions in this population, we retrospectively reviewed records of patients undergoing neurosurgical evaluation for calvarial bone lesions detected in posttreatment follow-up imaging at St. Jude Children's Research Hospital. Primary tumor diagnosis, treatment, imaging, surgical intervention, and histopathology from patients with radiographic evidence of lesions followed for ≥2 years post-RT were studied. For 17 patients with 18 index lesions, median time to lesion manifestation was 2.34 years. Medulloblastoma patients developed lesions at a shorter interval from RT than ependymoma patients (P=.05). Twelve of 14 lesions requiring surgery were benign fibro-osseous or sclerotic. Two malignant lesions distinct from the primary tumor had genetic predisposition to malignancy. Most calvarial lesions arising post-RT are benign and fibro-osseous. Serial imaging is recommended, and high index of suspicion for malignant lesions is warranted for patients genetically predisposed to cancer.

Stereotactic body radiotherapy for medically unfit patients with cancers to the head and neck.

A single institutional experience of stereotactic body radiation therapy (SBRT) to medically unfit patients with unresectable head and neck cancers (HNCs). A retrospective review of HNC patients undergoing SBRT was undertaken from 2011 to 2016 for fractionation ranges between 35 and 50 Gy in 4 to 6 fractions. One hundred and fourteen patients with 117 SBRT courses were included with mean follow-up of 10.5 months. The cohort consisted of previously untreated primary HNC (n = 48), recurrent never irradiated HNC (n = 19), oligometastatic (n = 17) non-HNC primaries and previously irradiated HNC (n = 33). Local control (LC) at 12 months and median progression free survival was 85.8%, 78.2%, 85%, 78.9% (P = .86) and 23.7, 14.8, 10.5 and 7.8 months (P = .04) respectively. Only one patient had an acute grade 4 toxicity, two patients had grade 4 late toxicities. HNC SBRT is an effective treatment for frail patients where longer LC is relevant but are unable to tolerate protracted radiation schedules.

Feasibility Study for the Development of an Application for Simulated Virtual Reality Radiation Therapy Experiences Using Android and iOS Devices

Using virtual reality (VR) technology such as head-mounted displays, users can be immersed in a virtual world and perceive it as reality. In radiation therapy departments, pretreatment patients and students rarely observe treatment rooms and treatment devices, making it difficult to understand the overall flow of radiation therapy. In this study, to facilitate the understanding and teaching of radiation therapy, we suggest the implementation of VR technology and develop software compatible with VR to enable a pertinent comprehension of radiation therapy. With versatility and accessibility in mind, the software is developed as an application for Android and iOS devices.Omnidirectional movies in treatment rooms were acquired from both the patient view and a third-person view using an omnidirectional camera. The Android/iOS devices used were AQUOS R (SHARP), iPhone 7 Plus (Apple), and iPad air (Apple). The software was developed using Unity 2018.4.7f (Unity Technologies). The main components of the software were as follows: (i) a home window featuring a user interface with which people can access arbitrarily rooms by tapping on floor maps or a list of treatment rooms, (ii) a snapshot mode providing 2D images of a treatment room as a slide show, and (iii) a movie mode displaying omnidirectional movies from the patient view or a third-person view. The virtual radiation therapy experience was executed by attaching the Android/iOS devices to 3D VR goggles (SAMONIC).The main components of the application operated in good conjunction on the Android/iOS devices, and live viewing in the virtual world ran smoothly with the VR technology. However, there were resolution limitations due to the specs of the camera and the devices. It will therefore be necessary to adjust the resolution and the frame rate according to the performance of the relevant devices. The application is instructive for both patients and students because the virtual radiation therapy experience is immersive when using the VR technology. In addition, the developed software can transfer data in a single package and has the ability to substitute images and omnidirectional movies with those appropriate for diagnostic radiology and nuclear medicine departments. Therefore, the developed application is highly versatile.

Monocentric experiences of stereotactic body radiation therapy (SBRT) for advanced hepatocellular carcinomas (BCLC-C)

Hepatocellular carcinomas (HCCs) are highly malignant primary liver cancers with poor prognosis and limited treatment options in advanced stages of disease. Treatment of HCC requires interdisciplinary discussion and multimodal therapy approaches. Beside established loco-regional and systemic therapies, stereotactic body radiation therapy (SBRT) gained increasing importance over recent years. First results of early clinical studies indicate high rates of local control with a good safety profile. In the present work, we evaluated our single center experiences with SBRT in patients with advanced HCCs.Ten patients with 16 SBRTs were included and retrospectively analyzed in this case collection. All patients presented in advanced tumor stages with vascular invasion and/or metastases, but preserved liver function. Two patients were treated only with SBRT, two after TACE and six patients received SBRT in addition to systemic therapy. In most of the cases SBRT were applied to intrahepatic lesions. Large tumor thromboses, lymph nodes as well as bone metastases were irradiated in one, three and five fractions with a median overall dose of 38 Gy. We observed a good local tumor control with a good safety profile in all cases. No severe complications occurred in combination to sequential as well as additive approach to loco-regional or systemic treatments.In conclusion, our experiences confirm results of early clinical studies indicating safe use and good local control rates also in advanced stages of HCC with preserved liver function.

A quantitative comparative study of medical dosimetry graduates with and without prior radiation therapy certification

All but a small number of formal medical dosimetry programs require radiation therapy certification for admission. The problem is a lingering perception from the radiation oncology community that medical dosimetry students must have a prior radiation therapy certification and/or experience. There is a paucity of evidence in the literature to support the perception that prior radiation therapy certification equates to better job performance as a medical dosimetrist. The purpose of this quantitative comparative study was to investigate outcomes of medical dosimetry graduates with and without prior radiation therapy certification (RTT and non-RTT). The researcher used archival records to examine comparison data of medical dosimetry graduates with and without radiation therapy certification including track of enrollment, admissions cumulative grade point averages (CGPA) and science grade point averages (SGPA), medical dosimetry program GPAs, radiation therapy work experience, Medical Dosimetrist Certification Board (MDCB) exam pass rates, program completion rates, and job placement rates. Surveys were used to collect and analyze data from clinical supervisors at affiliate internship sites and from employers of program graduates. Key findings from the quantitative study revealed that no relevant differences existed between RTT and non-RTT medical dosimetrist graduates with regard to GPA and program effectiveness data. However, for RTT and non-RTT students combined, there were significantly lower GPAs noted for individuals who did not graduate from the program or graduates that did not pass the MDCB exam on first attempt. Thematic findings from the surveys revealed non-RTT medical dosimetrist students/graduates required more initial training and supervision and differences were noticed among the non-RTT medical dosimetrist students/graduates based on their prior degree. Clinical supervisors and employers had no reservations about hiring RTT or non-RTT medical dosimetry graduates from the program.

Side effects of radiotherapy on breast cancer patients in the Department of Radiotherapy, Lagos University Teaching Hospital, Idi-Araba, Lagos, Nigeria

Background: Side effects of radiotherapy (RT) could be temporary or permanent, can be severe, and affect quality of life. An investigation into the side effects of RT on breast cancer patients would help evaluate the incidences and associated risk factors in the low-income countries for patients undergoing RT in order to ensure maximum treatment with very minimal side effects. Objective: To assess the side effects of RT in patients with breast cancer undergoing RT in Lagos University Teaching Hospital. Materials and Methods: This was a descriptive, cross-sectional study. Self-administered questionnaires were distributed to breast cancer patients on RT that have received treatment for at least 2 weeks at the RT Department between March and August 2016. A total of 146 questionnaires were distributed, whereas 139 were completely filled and returned for the evaluation and analysis, given a response rate of 95.2%. Results: The common side effects noticed from the analysis of this research work included skin erythema (87.1%), fatigue (74.1%), telangiectasia (69.1%), pain (89.9%), breast swelling (45.3%), and loss of hair in the armpit and chest area (87.1%), and the less common ones were breast shrinkage (20.1%), lymphedema (41.0%), cardiac complications (30.9%), lung problems (12.9%), sore throat (7.9%), brachial plexopathy (24.5%), and damage to the bones (ribs; 3.6%). Management of the side effects by patients revealed that 30 (21.6%) used analgesics, 28 (20.1%) used steroidal cream, 27 (19.4%) avoided deodorants and antiperspirant, 22 (15.8%) exercised, 15 (10.8%) took antibiotics, 10 (7.2%) took herbs, and 7 (5%) had to stop treatment temporarily for minimum of a week due to severe morbidity. Conclusion: A large percentage of breast cancer patients undergoing RT experience painful side effects (89.9%), of these 87% experience skin erythema, 74% experience fatigue, and 69% experience telangiectasia.

The First Linac-based Stereotactic Body Radiation Therapy (SBRT) in Iran: A Case Study

Introduction: In this paper, we present the first experience of linac-based stereotactic body radiation therapy (SBRT) in Iran to treat a single liver metastasis. Case Presentation: A 23-year-old girl with a history of visceral melanoma of the uterine was treated for liver metastasis. Stereotactic body radiotherapy was selected as the treatment of choice after tumor recurrence following surgical removal and radiofrequency ablation. The treatment was delivered in five fractions to a total dose of 50 Gy. The patient tolerated the treatment without any considerable side effect and the lesion remained progression-free twelve months after treatment. Conclusions: It can be presumed that SBRT can be safely applied using IGRT-equipped conventional linear accelerators with a few but no adverse events if it is delivered with due consideration.

Nephron-Sparing Robotic Radiosurgical Therapy for Primary Renal Cell Carcinoma: Single-Institution Experience and Review of the Literature

PurposeWe report our single-institution stereotactic body radiation therapy (SBRT) experience on stage I renal cancer with prospectively collected toxicity and efficacy data. Methods and MaterialsA total of 21 patients with solitary renal tumors, including 14 surgical candidates who refused surgery (66%), were treated with SBRT. Histologic confirmation was obtained on all patients before treatment; 2 had transitional cell carcinoma and 19 had renal cell carcinoma. The median age was 71 years (range, 58-88). Nearly all patients received 48 Gy in 3 fractions. ResultsThe median follow-up was 78 months (range, 5-107). At 5 years post treatment, the local tumor control rate was 100%. Tumor size decreased by a median value of 5.3% at 1 year post treatment, 15.6% at 2 years post treatment, and 15.4% at 5 years post treatment. Glomerular filtration rate had decreased by a median value of 1.5% at 1 year post treatment, 7.0% at 2 years post treatment, and 14.2% at 5 years post treatment. Three patients experienced grade 1 toxicity; no other treatment-related adverse effects were reported. ConclusionsSBRT is a promising noninvasive treatment in the management of primary renal cell carcinoma, with evolving clinical evidence demonstrating encouraging results with respect to local control and toxicity.

CN76 - Understanding the patients’ experiences of radiation therapy: A qualitative study on prostate cancer patients

BackgroundRadiotherapy involves many short visits to the hospital during several weeks. Side effects may occur after a few weeks of daily treatment. This includes problems with urination, urgency, bowel problems, and often a disturbed sleep. A research team at Karolinska University Hospital in Sweden attempted to understand how the patients with prostate cancer experience the radiation therapy, as well as how the therapy affects their daily life. MethodsTen prostate cancer patients from two different hospitals in Stockholm were asked to keep diaries, and subsequently interviewed about their experiences of radiation treatment. Data were analyzed with Framework content analysis. ResultsThree themes emerged after analysis: Changed life situation because of radiation treatment and its side effects and cancer diagnosis; Guidance by oncology nurses, oncologist and close relatives and own reflection the patients got; New Perspectives after weeks of treatment. With New perspectives they could find routines for their daily life and cope with side effects and cancer diagnosis. ConclusionsDespite the stressful situation caused by side effects affecting daily life, patients with prostate cancer receiving radiation therapy generally describe their treatment period as positive. In the beginning, the treatment period is perceived as a journey with a sense of uncertainty, which gradually turns into a sense of increased certainty and stability as the treatment proceeds. The patients describe their partner as the most important support and guide through the journey of radiation therapy. Legal entity responsible for the studyThe author. FundingHas not received any funding. DisclosureThe author has declared no conflicts of interest.

Practical Heart Sparing Breast Cancer Radiation Therapy Using Continuous Positive Airway Pressure (CPAP) in Resource-Limited Radiation Oncology Clinics.

The purpose of this study was to report experiences of practical heart sparing breast radiation therapy (RT) using continuous positive airway pressure (CPAP) in resource-limited radiation oncology clinics. Twelve patients underwent computed tomography-simulations with both free-breathing (FB) and CPAP under the individual maximum tolerable air pressure. For each patient, left-sided breast RT plans (9 with breast only, 3 with breast and regional nodal stations) with FB and CPAP were created using 3-dimensional conformal RT (supine tangential or wide tangential RT fields) according to RTOG 1304. For daily RT, patients started CPAP in the patients waiting area for 15 minutes before entering the treatment room and continued CPAP during RT. Treatment setup times between breast RT with and without CPAP were compared. All patients tolerated CPAP well with 8 to 15 cm H2O of air pressure. Compared with FB, CPAP inflated the thorax and increased total lung volume by 35±16% (CPAP: 3136±751 vs. FB: 2354±657 cm, P<0.01); caudally displaced the heart by 1.8 cm (P<0.01); and decreased heart volume within tangential RT fields on computed tomography-simulation scans by 96±4% (1.4±2.5 vs. 21±17 cm, P=0.02) in all patients. Planning target volume coverage was acceptable in all RT plans. CPAP lowered mean dose (Dmean) to heart by 47±22% (2.5±1.5 vs. 5.4±3.3 Gy, P<0.01); heart volume receiving ≥25 Gy (V25) by 82±18% (2.2±2.6 vs. 9.1±7.1%, P<0.01); Dmean to left anterior descending coronary artery by 68±8% (4.7±1.9 vs. 14.8±3.3 Gy, P<0.01). CPAP decreased radiation dose to ipsilateral lung compared with FB: 9.1±5.8 versus 11.2±8 Gy (20% reduction, P=0.03) of Dmean; 15.7±12.5 vs. 20.5±17.5% (25% reduction, P=0.03) of V20. RT with CPAP did not increase treatment setup time compared with FB (week 1: 362±63 vs. 352±77 s; week 2 to 5: 217±13 vs. 201±14 s, all P>0.25). Novel use of CPAP allowed efficient and practical heart sparing breast RT without increasing infrastructural requirements in resource-limited radiation oncology clinics.

IBS19.02 Novel Radiotherapy Approaches in Small Cell Lung Carcinoma – Has SABR and Radionuclide Therapy Got a Role to Play?

Thoracic radiotherapy has been shown in to increase overall survival when added to systemic therapy in patients with small cell lung carcinoma (SCLC) and M0 stage. The dose, fractionation, treatment time and timing issues have not been fully resolved. A recent study did not show the superiority of 66Gy in 33 daily fractions over 6.5 weeks over twice-daily radiotherapy to a dose of 45 Gy in 30 fractions over 3 weeks twice daily [1]. For stage I non-small cell lung carcinoma (NSCLC), stereotactic ablative body radiotherapy (SABR) has been clearly shown to be superior to conventional fractionation [2]. Given the clear benefit seen in early stage NSCLC, it is postulated that SABR may have a role to play in early stage SCLC. A recent multi-institutional cohort study has reported favourable outcomes in this setting [3]. However, randomised data of equivalence or indeed superiority are lacking. Furthermore, questions remain as the timing and role of systemic therapy and prophylactic cranial irradiation when SABR is used in this setting. In advanced SCLC, many tumors display neuroendocrine clinical and cytological features and many SCLC tumors express somatostatin receptor and this can be imaged using radiolabeled somatostatin analogs such as 68Ga-DOTATATE [4]. Given the uptake by some SCLC tumors of 68Ga-DOTATATE, higher doses of the tracer have been used in an attempt to provide radiolabelled radiotherapy treatment in metastatic disease in what has been described as peptide receptor radionuclide therapy (PRRT) [5]. This molecularly target radiotherapy is a potentially exciting therapeutic approach, but the ideal positioning of such therapy in tumors which are suitable for treatment with PRRT and the safety of PRRT with systemic therapy have yet to be determined. 1. Faivre-Finn C, Snee M, Ashcroft L, et al. Concurrent once-daily versus twice-daily chemoradiotherapy in patients with limited-stage small-cell lung cancer (CONVERT): an open-label, phase 3, randomised, superiority trial. Lancet Oncol. 2017;18(8):1116–1125. https://doi.org/10.1016/S1470-2045(1730318-2) 2. Ball D, Mai GT, Vinod S, et al. Stereotactic ablative radiotherapy versus standard radiotherapy in stage 1 non-small cell lung cancer (TROG 09.02. CHISEL): a phase 3, open-label, randomised controlled trial. The Lancet. 2019; 20: 494-503 3. Verma V, Simone CB, 2nd, Allen PK, et al. Multi-Institutional Experience of Stereotactic Ablative Radiation Therapy for Stage I Small Cell Lung Cancer. Int J Radiat Oncol Biol Phys 2017;97:362-71 4. Sollini M, Farioli D, Froio A, et al. Brief Report on the Use of Radiolabeled Somatostatin Analogs for the Diagnosis and Treatment of Metastatic Small-Cell Lung Cancer Patients. J Thor Oncol 2013;8(8):1095-1101. 5. Lapa C, Hänscheid H, Wild V, et al. Somatostatin receptor expression in small cell lung cancer as a prognostic marker and a target for peptide receptor radionuclide therapy. Oncotarget. 2016 Apr 12;7(15):20033-40. SCLC, SABR, radiotherapy

Single institutional experience of radiation therapy for angiosarcoma of the scalp without cervical lymph node metastases: Impact of concurrent chemoradiation with maintenance chemotherapy using taxanes on patient prognosis.

Cutaneous angiosarcoma is a rare aggressive malignant tumor. Concurrent chemoradiation (CCRT) with maintenance chemotherapy using taxanes is one of the primary treatments. The aim of the present study was to retrospectively analyze the efficacy of CCRT with maintenance chemotherapy using taxanes in localized angiosarcoma of the scalp without cervical lymph node metastases. A total of 19 patients treated with radiation therapy for localized angiosarcomas of the scalp without cervical lymph node metastases were enrolled. The overall survival (OS), progression-free survival (PFS), and local control (LC) rates were calculated using Kaplan-Meier analysis. Univariate analyses were performed for various potential prognostic factors for OS, PFS, and LC. The median radiation dose was 70 Gy (range, 60-70 Gy), and the fractional dose was 2 Gy. Radiation therapy alone, radiation therapy + interleukin-2, surgery + CCRT with maintenance chemotherapy, CCRT with maintenance chemotherapy, and CCRT without maintenance chemotherapy were administered to 2, 4, 2, 9 and 2 patients, respectively. The 1- and 3-year OS, PFS, and LC rates were 88 and 52%, 47 and 33%, and 74 and 56%, respectively. CCRT with maintenance chemotherapy and surgery were significant prognostic factors for PFS (P=0.036 and 0.025, respectively). Therefore, CCRT with maintenance chemotherapy using taxanes might be effective in treating localized angiosarcomas of the scalp without cervical lymph node metastases.

Local Therapy for a Systemic Disease: Indications and Impact of Radiation Therapy to the Pancreatic Primary in Metastatic Pancreatic Cancer

Metastatic pancreatic ductal adenocarcinoma (mPDAC) carries a poor prognosis, with median survival (MS) of 6-11 months. However, with more effective multi-agent chemotherapy (CTX) regimens, there has been increasing debate regarding potential role of local therapy. We aim to report our experience of radiation therapy (RT) delivered to the primary in the setting of mPDAC, hypothesizing that in select patients, RT may offer improved survival and time off chemotherapy (TOC). An IRB-approved retrospective analysis of 44 patients with mPDAC who received pancreas RT between November 2007 and August 2018 was performed. Indications for RT were: “symptom palliation” (n=13, 30%), “consolidative RT” after response in metastases (n=29, 66%), or both (n=2, 5%). Of “consolidative RT” patients, 21 (48%) were treated after response of primary and metastases, and 10 (23%) for local progression. 38 patients (86%) received CTX prior to RT (median 1 line, 76% FOLFOX/FOLFIRINOX, 27% gemcitabine); 6 received upfront RT for symptom palliation. Median RT dose was 50.4 Gy (range: 25-58.8 Gy) with concurrent 5-FU/capecitabine; 2 patients received SBRT. Clinical and treatment characteristics were reviewed. Statistical analyses were performed using JMP 14.0 (SAS Institute Inc., Cary, NC). Kaplan-Meier calculations and univariate (UVA) and multivariate (MVA) Cox proportional hazards models were used to evaluate TOC and survival after RT. Median follow-up was 18 months (Range: 1-66). Median age was 61 (range: 40-81) with 55% male and 77% ECOG 0-1. 77% had 1 metastatic site; 57% had liver metastases, with liver as only site in 43%. Median time from diagnosis to RT start was 8.5 months (range: 0-49 months). 5 patients (11%) underwent surgical resection of primary after RT. MS from diagnosis was 20 (CI: 15-27) months; MS from RT completion was 7.6 (CI: 5.1–10.8) months. 68% had local control of primary. Median TOC was 3.9 (CI 2.1 – 10.4) months, with 27% off for 6 months. On UVA, better performance status, FOLFIRINOX, surgery, CTX-responsive metastases at RT start, CTX-responsive primary at RT start, normal CA 19-9 at RT start and consolidative RT indication were associated with improved survival from RT. On MVA, only CA19-9 elevation at RT start was predictive of survival (HR 5.13; CI 1.60-22.14, p=0.0062). On UVA for TOC, prior FOLFIRINOX, CTX-responsive primary at RT start, and consolidative RT indication were associated with TOC. On MVA, only CTX-responsive primary at RT start was associated with more TOC (HR 0.38; CI 0.15-0.96, p=0.0408). Despite the systemic nature of metastatic PDAC, RT to the pancreatic primary may offer benefit in highly selected patients with chemo-responsive disease and normal pretreatment CA 19-9. This work suggests a potential role of local RT in selected patients with metastatic PDAC, and warrants further study.

Initial Clinical Experience of Stereotactic Body Radiation Therapy (SBRT) For Liver Metastases, Primary Liver Malignancy, and Pancreatic Abdominal Nodal Recurrence with 4D-MRI based Online Adaptation and Real-Time MRI Monitoring using a 1.5 Tesla MR-Linac

The commercial introduction of a 1.5 MR equipped linear accelerator presents an opportunity to acquire MR images while simultaneously treating with external beam radiation therapy. We present the first in human experience treating patients for both liver and abdominal tumors using a 1.5 MR Linac. A commercially available 1.5 MR Linac was used to treat a total of 4 patients with abdominal tumors in our institution. Each patient consented to enroll in an advanced imaging protocol. A treatment checklist was followed during each fraction, with tasks time-stamped upon completion. Adaptive plans were based on pre-beam motion-averaged or mid-position images derived from respiratory-correlated 4D-MRI. Methodology applied included either adapt-to-position, or adapt-to-shape workflows. A parallel contouring strategy was employed using independent delineation software. Quantitative diffusion-weighted images, T2 mapping, and B0 maps were acquired during plan adaptation. Real-time motion monitoring was performed during beam-on. A comparison between the doses to normal organs at risk on the reference plan and the daily delivered plan was conducted. The median patient age was 70.5, two patients were male and two were female. Primary tumors treated (doses prescribed/fractions) included 1 liver melanoma metastatic lesion (45 Gy/3), 2 primary hepatocellular carcinomas (40-45 Gy/5), 1 upper abdominal nodal (pancreatic) recurrence (30 Gy/6). Two patients were treated with the adapt-to-position work flow, two patients were treated with the adapt-to-shape workflow. The median treatment time duration was approximately 50 minutes. For the liver lesions treated, the liver mean radiation dose was found to be lower on the adaptive plan as compared to the reference plan. In addition, for the abdominal nodal recurrence,accumulated dose to at risk GI structures was sufficiently below the reference plan dose, which permitted administration of an additional treatment fraction. We present a successful first in human experience of treating both an upper abdominal (pancreatic) nodal recurrence along with primary and secondary liver malignancies with a 1.5 MR Linear accelerator using adapt-to-position and adapt-to-shape strategies. Treatments were well tolerated by all patients. Fully quantitative MR imaging was acquired during the treatment course. Unique work flow elements and custom MR sequence utilization will be presented.

Targeted Intervention to Improve the Quality of Head and Neck Radiation Therapy Treatment Planning in the Netherlands: Short and Long-Term Impact

To benchmark and improve, through means of a targeted intervention, the quality of intensity modulated radiation therapy treatment planning for locally advanced head and neck cancer (HNC) in the Netherlands. The short and long-term impact of this intervention was assessed. A delineated computed tomography-scan of an oropharynx HNC case was sent to all 15 Dutch radiation therapy centers treating HNC. Aims for planning target volume and organ-at-risk (OAR) dosimetry were established by consensus. Each center generated a treatment plan. In a targeted intervention, OAR sparing of all plans was discussed, and centers with the best OAR sparing shared their planning strategies. Impact of the intervention was assessed by (1) short-term (half a year after intervention) replanning of the original case and (2) long-term (1 and 3 years after intervention) planning of new cases. Benchmarking revealed substantial difference in OAR doses. Initial mean doses were 22 Gy (range, 15-31 Gy), 35 Gy (18-49 Gy), and 37 Gy (20-46 Gy) for the contralateral parotid gland, contralateral submandibular gland, and combined swallowing structures, respectively. Replanning after targeted intervention significantly reduced mean doses and variation, but clinically relevant differences still remained: 18 Gy (14-22 Gy), 28 Gy (17-45 Gy), and 29 Gy (18-39 Gy), respectively. One and 3 years later the variation remained stable. Despite many years of HNC intensity modulated radiation therapy experience, initial treatment plans showed surprisingly large variations. The simple targeted intervention used in this analysis improved OAR sparing, and its impact was durable; however, fairly large dose differences still continue to exist. Additional work is needed to understand these variations and to minimize them. A national radiation oncology platform can be instrumental for developing and maintaining high-quality planning protocols.

A preliminary experience of moderate-intensity stereotactic body radiation therapy for ultra-central lung tumor

Purpose: Administration of stereotactic body radiation therapy (SBRT) to ultra-central (UC) lung tumors, generally defined as those abutting the proximal bronchial trees, is difficult due to concerns about serious toxicities. Therefore, our institution has performed moderate-intensity SBRT.Patients and methods: Patients with UC tumors underwent SBRT at a dose of 50–60 Gy in 10 fractions, with Dmax in the target volume not exceeding 110% of the prescribed dose. The primary outcomes were tumor response and overall survival (OS).Results: From January 2017 to September 2018, we treated eight patients who had been diagnosed with UC tumors. The median follow-up time was 8.6 months (range: 2.7–14.9). Five of the eight patients (62.5%) showed a complete response (CR), two (25%) had a partial response (PR), and one (12.5%) had stable disease (SD); the response and disease control rates were 87.5% and 100%, respectively. Seven patients were alive with no evidence of disease or with controlled disease until the last follow-ups, except for one patient who died due to a non-RT cause at 3 months after SBRT. One patient experienced grade 2 esophageal pain and another had grade 1 cough. No grade 3 or higher toxicities were reported.Conclusion: Moderate-intensity SBRT might aid in achieving good control of UC tumors without excessive toxicities. Future studies involving larger numbers of patients and longer follow-up times are warranted to confirm the efficacy and feasibility.

The systemic immunostimulatory effects of radiation therapy producing overall tumor control through the abscopal effect

Emerging studies show that radiation therapy produces an important out of field (distant) effect known as the ‘‘abscopal effect” in nonirradiated tumor sites. The objective of this study was to provide an overview of the current state of knowledge and clinical experience of radiation therapy producing abscopal effects in the management of different types of malignant diseases. Peer-reviewed published clinical evidence on the abscopal effect of radiation therapy was collected using electronic databases such as Medline via PubMed and Google Scholar. The reference lists were searched in the publications that we obtained in an attempt to find additional relevant publications. Non-indexed peer-reviewed journals were manually searched and relevant information was extracted. The search was restricted to English language articles. The clinical data on the abscopal effect of radiation therapy were reviewed and the outcomes have been summarized. Currently, only clinical case reports and anecdotes have slowly converted into solid clinical data and interest is building in the field of radiation therapy, specifically on how local radiation can produce the abscopal effects for the management of different types of malignant tumors. Extensive clinical evidence suggests that the radiation therapy induced abscopal antitumor effects are mediated by immune cells such as the T-lymphocytes. This forms a basis for using radiation therapy in combination with immunotherapy to augment the abscopal response rates in cancer patients. Current evidence demonstrates that radiation therapy induces abscopal responses across many tumor types. Together, the clinical outcomes from published reports suggest that localized radiation therapy is capable of inducing abscopal effects in a wide variety of malignant tumors. With the advent of novel immunotherapies, the potential for immune activation by radiation defines a novel role for radiation therapy in the treatment of systemic disease. A clinical consideration of the abscopal effects produced by radiation therapy could lead to a revolutionary change in the current management of patients including radiation treatment strategies and immunotherapies for various malignant tumors.

Radiation Therapy Dose Escalation to Clinically Involved Pelvic Sidewall Lymph Nodes in Locally Advanced Rectal Cancer

PurposeLateral pelvic sidewall lymph nodes (PSW LN) may be involved in up to 24% of locoregionally advanced rectal cancers. PSW LN are not resected in total mesorectal excision (TME), and no standard of care regarding the management of PSW LN exists in the United States. We assessed our institutional experience of preoperative radiation therapy (RT) boost to clinically involved PSW LN that were not planned for resection. Methods and materialsData from all patients with rectal adenocarcinoma treated between 2006 and 2018 were reviewed to identify those who received a cumulative dose of >50.4 Gy to suspicious PSW LN during neoadjuvant chemoradiation therapy (nCRT). Demographic, cancer characteristic, treatment, and toxicity data were derived from the chart. ResultsOf a total of 261 patients, 12 patients met the inclusion criteria. The median age was 47.5 years, and 83% of patients were men. All patients had T3/4 disease, 17% of patients had N1b disease and the remainder had N2 disease, and 33% had M1 disease (all ≤2 metastases). Seventy-five percent of patients had moderately or poorly differentiated histology. The mean distance from the anal verge was 4.85 cm (range, 2-8.9 cm), and 58% had ≥2 PSW LN with an average short axis diameter of 1.11 cm (range, 0.4-3.2 cm). Boost doses ranged from 53.48 Gy to 60.2 Gy in 27 to 30 fractions (1.8-2.15 Gy/fraction). The median follow-up time was 18 months. One patient who received concurrent capecitabine and irinotecan had grade 3 perineal dermatitis and anemia during nCRT. The median hospitalization time for TME was 6.5 days. Within 90 days of TME, 1 patient required surgical exploration for perineal wound breakdown, and another required a blood transfusion for anemia. At the time of the last follow up, 75% of patients were alive. Local control at 12 months was 90%. ConclusionsRT dose escalation to nonresected PSW LN during nCRT was well tolerated with a low risk of acute toxicity and perioperative complications and has a high rate of local control at 12 months. RT boost warrants further study in patients with clinically involved nonresected PSW LN.

SP-0112 First clinical experience and future directions of MR-guided radiation therapy

SP-0112 First clinical experience and future directions of MR-guided radiation therapy

Intraoperative radiotherapy with electrons as partial breast irradiation in limited stage breast cancer: Early term clinical and cosmetic outcomes.

We aimed to report the experience of intraoperative electron radiation therapy (IOERT) with Mobetron (Intraop Medical Incorporated, Santa Clara, CA, USA) as a partial breast irradiation (PBI) for patients with early-stage breast cancer and explanation of IOERT application and present early clinical and cosmetic result. Between November 2012 and February 2014, in Ankara Oncology Hospital, Radiation Oncology Clinic, was performed IOERT as a PBI with a single dose of 21 Gy for 21selected patients. Median tumor size was 1.5 cm (range, 0.6-2.8 cm). Median treatment duration was 2.04 min (range, 1.26-2.44 min). According to final pathology, two patients were found to have close margin and mastectomy was applied. Three cases (two were N1 mic and one case had perineural invasion and tumor size was >2 cm) received whole breast irradiation. Median follow-up time was 3 years (range, 26-42 months). One patient died because of nonbreast cancer reason, all of the other patients (except one) alive without disease. There was no Grade 3 or 4 toxicities related to the IOERT. Good or excellent cosmesis was revealed 79% (15/19) and 95% (18/19), by physician and patient, respectively. IOERT, for patients with early-stage breast cancer as a part of breast-conserving treatment, offer patients better cosmetic results with less skin toxicity and increases comfort of patients by shortening duration of treatment time.