Tolerance of normal tissue to therapeutic irradiation

A cloud-based consultation and collaboration system for radiotherapy: Remote decision support services for community radiotherapy centers

PURPOSE

This study aimed to establish a cloud-based radiotherapy consultation and collaboration system, then investigated the practicability of remote decision support for community radiotherapy centers using the system.

METHODS AND MATERIALS

A cloud-based consultation and collaboration system for radiotherapy, OncoEvidance®, was developed to provide remote services of LINAC modeling, simulation CT data import/export, target volume and organ-at-risk delineation, prescription, and treatment planning. The system was deployed on a hybrid cloud. A federate of public nodes, each corresponding to a medical institution, are managed by a central node where a group of consultants have registered. Users can access the system through network using computing devices. The system has been tested at three community radiotherapy centers. One accelerator was modeled. 12 consultants participated the remote radiotherapy decision support and 77 radiation treatment plans had been evaluated remotely.

RESULTS

All the passing rates of per-beam dose verification are > 94% and all the passing rates of composite beam dose verification are > 99%. The average downloading time for one set of simulation CT data for one patient from Internet was within 1 min under the cloud download bandwidth of 8 Mbps and local network bandwidth of 100 Mbps. The average response time for one consultant to contour target volumes and make prescription was about 24 h. And that for one consultant to design and optimize a IMRT treatment plan was about 36 h. 100% of the remote plans passed the dosimetric criteria and could be imported into the local TPS for further verification.

CONCLUSION

The cloud-based consultation and collaboration system saved the travel time for consultants and provided high quality radiotherapy to patients in community centers. The under-staffed community radiotherapy centers could benefit from the remote system with lower cost and better treatment quality control.

Evaluation of Exposure Doses of Elective Nodal Irradiation in Chemoradiotherapy for Advanced Esophageal Cancer

We evaluated elective nodal irradiation (ENI) doses during radical chemoradiotherapy (CRT) for esophageal cancer (EC). A total of 79 patients (65 men and 14 women) aged 52-80 years with T1-3, N0-3, and M0 (including M1ly) who underwent CRT for EC during November 2012-September 2019 were eligible for this retrospective analysis. Patients were divided into two groups: the high-dose group (HG), including 38 patients who received ≥40 Gy as ENI; and the low-dose group (LG), including 41 patients who received <40 Gy. The median doses were 40.0 and 36.0 Gy in HG and LG, respectively. During the follow-up (median: 36.7 months), no lymph node recurrence was observed in the ENI field in all patients. Lymph node recurrence near the ENI field was observed in six patients. No significant differences were observed between the two groups in median overall survival, progression-free survival, and local control. Grade 3-4 acute and late adverse events were observed in five patients of HG and six patients of LG, respectively. No ulceration or stricture was observed in the ENI field on endoscopy examined with 58 Gy irradiation. In conclusion, an ENI dose of 36 Gy could be considered to control the elective nodes of EC.

Theranostic 64Cu-DOTHA2-PSMA allows low toxicity radioligand therapy in mice prostate cancer model

Introduction

We have previously shown that copper-64 (⁶⁴Cu)-DOTHA₂-PSMA can be used for positron emission tomography (PET) imaging of prostate cancer. Owing to the long-lasting, high tumoral uptake of ⁶⁴Cu-DOTHA₂-PSMA, the objective of the current study was to evaluate the therapeutic potential of ⁶⁴Cu-DOTHA₂-PSMA in vivo.

Methods

LNCaP tumor-bearing NOD-Rag1^nullIL2rg^null (NRG) mice were treated with an intraveinous single-dose of ⁶⁴Cu-DOTHA₂-PSMA at maximal tolerated injected activity, ^natCu-DOTHA₂-PSMA at equimolar amount (control) or lutetium-177 (¹⁷⁷Lu)-PSMA-617 at 120 MBq to assess their impact on survival. Weight, well-being and tumor size were followed until mice reached 62 days post-injection or ethical limits. Toxicity was assessed through weight, red blood cells (RBCs) counts, pathology and dosimetry calculations.

Results

Survival was longer with ⁶⁴Cu-DOTHA₂-PSMA than with ^natCu-DOTHA₂-PSMA (p < 0.001). Likewise, survival was also longer when compared to ¹⁷⁷Lu-PSMA-617, although it did not reach statistical significance (p = 0.09). RBCs counts remained within normal range for the ⁶⁴Cu-DOTHA₂-PSMA group. ⁶⁴Cu-DOTHA₂-PSMA treated mice showed non-pathological fibrosis and no other signs of radiation injury. Human extrapolation of dosimetry yielded an effective dose of 3.14 × 10^-2 mSv/MBq, with highest organs doses to gastrointestinal tract and liver.

Discussion

Collectively, our data showed that ⁶⁴Cu-DOTHA₂-PSMA-directed radioligand therapy was effective for the treatment of LNCaP tumor-bearing NRG mice with acceptable toxicity and dosimetry. The main potential challenge is the hepatic and gastrointestinal irradiation.

Treatment Tolerability and Toxicity of Postoperative Proton Beam Therapy for Gynecologic Malignancies: Results of the Prospective Phase 2 APROVE-trial

PURPOSE

The APROVE study is a prospective one-arm phase-2 study investigating the safety and treatment tolerability of postoperative proton beam therapy in women with uterine cervical or endometrial cancer. In this analysis, we report the primary study endpoint of safety and treatment tolerability as well as toxicity rates and progression-free survival (PFS).

METHODS AND MATERIALS

25 patients were treated with postoperative proton beam therapy with a total dose of 45 to 50.4 Gy (RBE) in 5 to 6 × 1.8 Gy (RBE) fractions weekly using active raster-scanning intensity modulated proton beam therapy (IMPT). Sequential or simultaneous platinum-based chemotherapy was administered if indicated. The primary endpoint was defined as the lack of any acute ≥grade 3 gastrointestinal (GI) or urogenital (GU) toxicity according to the Common Terminology Criteria for Adverse Events v 4.0 or premature treatment abortion. Secondary endpoints were clinical symptoms and toxicity, quality of life, and PFS.

RESULTS

All patients completed IMPT according to the protocol, with a median treatment duration of 43 days (range, 33 to 51 days). No patient developed gastrointestinal or genitourinary toxicity ≥grade 3, and the treatment tolerability rate was 100%. Therefore, the null hypothesis H0: Tolerability Rate ≤80% could be rejected in favor of the alternative hypothesis H1: Tolerability rate >80% using an exact binomial test with a one-sided significance level of α = 10% (one-sided P value P = .0059). The median follow-up time after the end of IMPT was 25.1 months (range, 20.2 to 50.3 months). 18 of 25 (75%) patients completed the study follow-up of 24 months. 7 patients had progressive disease. Kaplan-Meier-estimated mean PFS was 39.9 months (95% confidence interval: 33.37 to 46.5 months).

CONCLUSIONS

Postoperative IMPT is a safe treatment option for cervical and endometrial cancer patients, with only low-grade acute and late toxicities. Larger randomized trials are necessary to further assess the potential of IMPT and improve patient selection.

High-risk patients with locally advanced non-small cell lung cancer treated with stereotactic body radiation therapy to the peripheral primary combined with conventionally fractionated volumetric arc therapy to the mediastinal lymph nodes

Introduction

A very narrow therapeutic window exists when delivering curative chemoradiotherapy for inoperable locally advanced non-small cell lung cancer (NSCLC), particularly when large distances exist between areas of gross disease in the thorax. In the present study, we hypothesize that a novel technique of stereotactic body radiation therapy (SBRT) to the primary tumor in combination with volumetric arc therapy (VMAT) to the mediastinal lymph nodes (MLN) is a suitable approach for high-risk patients with large volume geographically distant locally advanced NSCLC.

Patients and methods

In this single institutional review, we identified high-risk patients treated between 2014 and 2017 with SBRT to the parenchymal lung primary as well as VMAT to the involved MLN using conventional fractionation. Dosimetrically, comparative plans utilizing VMAT conventionally fractionated delivered to both the primary and MLN were analyzed. Clinically, toxicity (CTCAE version 5.0) and oncologic outcomes were analyzed in detail.

Results

A total of 21 patients were identified, 86% (n=18) of which received chemotherapy as a portion of their treatment. As treatment phase was between 2014 and 2017, none of the patients received consolidation immunotherapy. Target volume (PTV) dose coverage (99 vs. 87%) and CTV volume (307 vs. 441 ml) were significantly improved with SBRT+MLN vs. for VMAT alone (p<0.0001). Moreover, low-dose lung (median V5Gy [%]: 71 vs. 77, p<0.0001), heart (median V5Gy [%]: 41 vs. 49, p<0.0001) and esophagus (median V30Gy [%]: 54 vs. 55, p=0.03) dose exposure were all significantly reduced with SBRT+MLN. In contrast, there was no difference observed in high-dose exposure of lungs, heart, and spinal cord. Following SBRT+MLN treatment, we identified only one case of high-grade pneumonitis. As expected, we observed a higher rate of esophagitis with a total of seven patients experience grade 2+ toxicity. Overall, there were no grade 4+ toxicities identified. After a median 3 years follow up, disease progression was observed in 70% of patients irradiated using SBRT+MLN, but never in the spared 'bridging' tissue between pulmonary SBRT and mediastinal VMAT.

Conclusion

For high risk patients, SBRT+MLN is dosimetrically feasible and can provide an alternative to dose reductions necessitated by otherwise very large target volumes.

Health-related quality of life and patient-reported symptoms after postoperative proton beam radiotherapy of cervical and endometrial cancer: 2-year results of the prospective phase II APROVE-trial

INTRODUCTION

The APROVE-trial investigated the tolerability of postoperative proton beam therapy in women with cervical or endometrial cancer. The present analysis evaluated the secondary endpoints of health-related quality of life (HRQOL) and patient-reported symptoms.

METHODS

25 patients were included in this prospective phase-II-trial and treated with postoperative radiotherapy using protons alone or in combination with chemotherapy. To attain general and gynecologic-specific HRQOL measures, the EORTC-QLQ-C30 questionnaires combined with -QLQ-CX24 for cervical and -QLQ-EN24 for endometrial cancer were assessed at baseline, at the end of RT and up to 2 years after radiotherapy. The results were compared to an age-matched norm reference population. Symptoms were assessed using Common Terminology Criteria for Adverse Events (CTCAE) and institutional patient-reported symptoms grading.

RESULTS

Scores regarding global health status were markedly impaired at baseline (mean: 58.0 ± 20.1) compared to reference population data, but significantly (p = 0.036) improved and evened out to comparable norm values 2 years after proton therapy (mean: 69.9 ± 19.3). Treatment caused acute and long-term worsening of pain (p = 0.048) and gastrointestinal symptoms (p = 0.016) for women with endometrial cancer, but no higher-grade CTCAE ≥ 3° toxicity was observed. Dosimetric evaluation of rectum, sigmoid, large and small bowel showed no correlation with the reported gastrointestinal symptoms. After 2 years, fatigue had significantly improved (p = 0.030), whereas patients with cervical cancer experienced more often lymphedema (p = 0.017). Scores for endometrial cancer pertaining to sexual activity (p = 0.048) and body image (p = 0.022) had improved post treatment; in the latter this effect persisted after 2 years.

CONCLUSION

Proton beam therapy in the adjuvant setting was well tolerated with only low-grade side effects concerning gastrointestinal symptoms, lymphedema and pain. Overall quality of life was impaired at baseline, but patients were able to recover to values comparable to norm population 2 years after proton therapy. Larger studies are needed to confirm whether the benefit of proton therapy translates into a clinical effect. Sexual dysfunction remains an important issue.

TRIAL REGISTRATION

The trial was registered at https://clinicaltrials.gov (ClinicalTrials.gov Identifier: NCT03184350, 09th June 2017).

Risk of Myelopathy Following Second Local Treatment after Initial Irradiation of Spine Metastasis

Metastatic lesions of the spine occur in up to 40% of cancer patients and are a frequent source of pain and neurologic deficit due to cord compression. Palliative radiotherapy is the main first-intent local treatment in the form of single-fraction radiotherapy or fractionated courses. Reirradiation is a viable option for inoperable patients where spinal decompression is needed but with an increased risk of radiation-induced myelopathy (RM) and subsequent neurologic damage. This review summarizes reported data on local treatment options after initial irradiation in patients with relapsed spine metastasis and key dosimetric correlations between the risk of spinal cord injury and reirradiation technique, total dose, and time between treatments. The Linear Quadratic (LQ) model was used to convert all the published doses into biologically effective doses and normalize them to EQD2. For 3D radiotherapy, authors used cumulative doses from 55.2 Gy2/2 to 65.5 Gy2/2 EQD2 with no cases of RM mentioned. We found little evidence of RM after SBRT in the papers that met our criteria of inclusion, usually at the median reported dose to critical neural tissue around 93.5 Gy2/2. There is a lack of consistency in reporting the spinal cord dose, which leads to difficulty in pooling data.

Analysis of safety and efficacy of proton radiotherapy for IDH-mutated glioma WHO grade 2 and 3

PURPOSE

Proton beam radiotherapy (PRT) has been demonstrated to improve neurocognitive sequelae particularly. Nevertheless, following PRT, increased rates of radiation-induced contrast enhancements (RICE) are feared. How safe and effective is PRT for IDH-mutated glioma WHO grade 2 and 3?

METHODS

We analyzed 194 patients diagnosed with IDH-mutated WHO grade 2 (n = 128) and WHO grade 3 (n = 66) glioma who were treated with PRT from 2010 to 2020. Serial clinical and imaging follow-up was performed for a median of 5.1 years.

RESULTS

For WHO grade 2, 61% were astrocytoma and 39% oligodendroglioma while for WHO grade 3, 55% were astrocytoma and 45% oligodendroglioma. Median dose for IDH-mutated glioma was 54 Gy(RBE) [range 50.4-60 Gy(RBE)] for WHO grade 2 and 60 Gy(RBE) [range 54-60 Gy(RBE)] for WHO grade 3. Five year overall survival was 85% in patients with WHO grade 2 and 67% in patients with WHO grade 3 tumors. Overall RICE risk was 25%, being higher in patients with WHO grade 2 (29%) versus in patients with WHO grade 3 (17%, p = 0.13). RICE risk increased independent of tumor characteristics with older age (p = 0.017). Overall RICE was symptomatic in 31% of patients with corresponding CTCAE grades as follows: 80% grade 1, 7% grade 2, 13% grade 3, and 0% grade 3 + . Overall need for RICE-directed therapy was 35%.

CONCLUSION

These data demonstrate the effectiveness of PRT for IDH-mutated glioma WHO grade 2 and 3. The RICE risk differs with WHO grading and is higher in older patients with IDH-mutated Glioma WHO grade 2 and 3.

Institutional experience of using active breathing control for paediatric and teenage patients receiving thoraco-abdominal radiotherapy

Introduction

Active Breathing Control (ABC) is a motion management strategy that facilitates reproducible breath-hold for thoracic radiotherapy (RT), which may reduce radiation dose to organs at risk (OARs). Reduction of radiation-induced toxicity is of high importance in younger patients. However, there is little published literature on the feasibility of ABC in this group. The purpose of this study was to report our experience of using ABC for paediatric and teenage patients.

Methods

Patients ≤18 years referred for thoracic RT using ABC at our centre from 2013-2021 were identified. Electronic records were retrospectively reviewed to obtain information on diagnosis, RT dose and technique, OAR dosimetry, tolerability of ABC, post-treatment imaging and early toxicity rates.

Results

12 patients completed RT and were able to comply with ABC during planning and for the duration of RT. Median age was 15.5 years (10-18 years). Diagnoses were: Hodgkin lymphoma (n = 5), mediastinal B-cell lymphoma (n = 1), Ewing sarcoma (n = 5) and rhabdomyosarcoma (n = 1). For mediastinal RT cases (n = 6), median dose delivered was 30.6Gy(19.8-40Gy), median mean heart dose was 11.4Gy(4.8-19.4Gy), median mean lung dose was 9.9Gy(5.7-14.5Gy) and mean lung V20 was 10.9%. For ipsilateral RT cases, (n = 6), median hemithorax and total doses to primary tumour were 18Gy(15-20Gy) and 52.2Gy(36-60Gy) respectively. Median mean heart dose was 19.5Gy(10.6-33.2Gy) and median mean lung dose was 17.7Gy(16.3-30.5Gy). Mean bilateral lung V20 was 39.6%. Median mean contralateral lung dose was 5.2Gy(3.5-11.6Gy) and mean contralateral lung V20 was 1.5%. At a median follow-up of 36 months, only 1 patient had symptomatic radiation pneumonitis having received further thoracic RT following relapse.

Conclusions

ABC is feasible and well tolerated in younger patients receiving RT. Children as young as 10 years are able to comply. Use of ABC results in OAR dosimetry which is comparable to similar data in adults and can facilitate RT for extensive thoracic sarcoma.

Analysis of recurrence probability following radiotherapy in patients with CNS WHO grade 2 meningioma using integrated molecular-morphologic classification

Background

The current World Health Organization (WHO) classification of brain tumors distinguishes 3 malignancy grades in meningiomas, with increasing risk of recurrence from CNS WHO grades 1 to 3. Radiotherapy is recommended by current EANO guidelines for patients not safely amenable to surgery or after incomplete resection in higher grades. Despite adequately predicting recurrence probability for the majority of CNS WHO grade 2 meningioma patients, a considerable subset of patients demonstrates an unexpectedly early tumor recurrence following radiotherapy.

Methods

A retrospective cohort of 44 patients with CNS WHO grade 2 meningiomas were stratified into 3 risk groups (low, intermediate, and high) using an integrated morphological, CNV- and methylation family-based classification. Local progression-free survival (lPFS) following radiotherapy (RT) was analyzed and total dose of radiation was correlated with survival outcome. Radiotherapy treatment plans were correlated with follow-up images to characterize the pattern of relapse. Treatment toxicities were further assessed.

Results

Risk stratification of CNS WHO grade 2 meningioma into integrated risk groups demonstrated a significant difference in 3-year lPFS following radiotherapy between the molecular low- and high-risk groups. Recurrence pattern analysis revealed that 87.5 % of initial relapses occurred within the RT planning target volume or resection cavity.

Conclusions

Integrated risk scoring can identify CNS WHO grade 2 meningioma patients at risk or relapse and dissemination following radiotherapy. Therapeutic management of CNS WHO grade 2 meningiomas and future clinical trials should be adjusted according to the molecular risk-groups, and not rely on conventional CNS WHO grading alone.

Comparison of intensity-modulated proton therapy (IMPT) versus intensity-modulated radiation therapy (IMRT) for the treatment of head and neck cancer based on radiobiological modelling

Aim:

The aim of our study is to retrospectively report the radiobiological aspects for intensity-modulated proton therapy (IMPT) against intensity-modulated radiation therapy (IMRT) for patients with head and neck cancer treated at our institution. A secondary goal is to reinforce current model-based approaches to head and neck cancer patient selection for IMPT.

Materials and Methods:

Eighteen patients were evaluated with prescription doses ranging from 50 to 70 Gy delivered in 2 Gy per fraction. The dose volume histograms (DVH) were used to calculate equivalent uniform dose (EUD), tumour control probability (TCP) and normal tissue complication probability (NTCP) for biophysical comparison using mechanistic mathematical dose response models. Absolute values of TCP and NTCP were then compared between IMPT and IMRT.

Results:

The dose models demonstrate a minimal radiobiological advantage for IMPT compared to IMRT in treating head and neck cancers. Absolute values of TCP were slightly higher, while absolute values of NTCP were slightly lower for IMPT versus IMRT.

Conclusions:

Further studies are needed to determine if the radiobiological advantage indeed translates to a therapeutic advantage for patients.

Clinical Radiobiology for Radiation Oncology

This chapter is focused on radiobiological aspects at the molecular, cellular, and tissue level which are relevant for the clinical use of ionizing radiation (IR) in cancer therapy. For radiation oncology, it is critical to find a balance, i.e., the therapeutic window, between the probability of tumor control and the probability of side effects caused by radiation injury to the healthy tissues and organs. An overview is given about modern precision radiotherapy (RT) techniques, which allow optimal sparing of healthy tissues. Biological factors determining the width of the therapeutic window are explained. The role of the six typical radiobiological phenomena determining the response of both malignant and normal tissues in the clinic, the 6R’s, which are Reoxygenation, Redistribution, Repopulation, Repair, Radiosensitivity, and Reactivation of the immune system, is discussed. Information is provided on tumor characteristics, for example, tumor type, growth kinetics, hypoxia, aberrant molecular signaling pathways, cancer stem cells and their impact on the response to RT. The role of the tumor microenvironment and microbiota is described and the effects of radiation on the immune system including the abscopal effect phenomenon are outlined. A summary is given on tumor diagnosis, response prediction via biomarkers, genetics, and radiomics, and ways to selectively enhance the RT response in tumors. Furthermore, we describe acute and late normal tissue reactions following exposure to radiation: cellular aspects, tissue kinetics, latency periods, permanent or transient injury, and histopathology. Details are also given on the differential effect on tumor and late responding healthy tissues following fractionated and low dose rate irradiation as well as the effect of whole-body exposure.

A web-based nomogram model for predicting the overall survival of hepatocellular carcinoma patients with external beam radiation therapy: A population study based on SEER database and a Chinese cohort

BACKGROUND

External beam radiation therapy (EBRT) for hepatocellular carcinoma (HCC) is rarely used in clinical practice. This study aims to develop and validate a prognostic nomogram model to predict overall survival (OS) in HCC patients treated with EBRT.

METHOD

We extracted eligible data of HCC patients between 2004 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database. Those patients were randomly divided into a training cohort (n=1004) and an internal validation cohort (n=429), and an external validation cohort composed of a Chinese cohort (n=95). A nomogram was established based on the independent prognostic variables identified from univariate and multivariate Cox regression analyses. The effective performance of the nomogram was evaluated using the concordance index (C-index), receiver operating characteristic curve (ROC), and calibration curves. The clinical practicability was evaluated using decision curve analysis (DCA).

RESULTS

T stage, N stage, M stage, AFP, tumor size, surgery, and chemotherapy were independent prognostic risk factors that were all included in the nomogram to predict OS in HCC patients with EBRT. In the training cohort, internal validation cohort, and external validation cohort, the C-index of the prediction model was 0.728 (95% confidence interval (CI): 0.716-0.740), 0.725 (95% CI:0.701-0.750), and 0.696 (95% CI:0.629-0.763), respectively. The 6-, 12-,18- and 24- month areas under the curves (AUC) of ROC in the training cohort were 0.835 、0.823 、0.810, and 0.801, respectively; and 0.821 、0.809 、0.813 and 0.804 in the internal validation cohort, respectively; and 0.749 、0.754 、0.791 and 0.798 in the external validation cohort, respectively. The calibration curves indicated that the predicted value of the prediction model performed well. The DCA curves showed better clinical practicability. In addition, based on the nomogram, we established a web-based nomogram to predict the OS of these patients visually.

CONCLUSION

Based on the SEER database and an independent external cohort from China, we established and validated a nomogram to predict OS in HCC patients treated with EBRT. In addition, for the first time, a web-based nomogram model can help clinicians judge the prognoses of these patients and make better clinical decisions.

The "Combo" radiotherapy treatment for high-risk grade 2 meningiomas: dose escalation and initial safety and efficacy analysis

PURPOSE

The subgroup "high-risk" WHO grade 2 (hRG2) meningiomas may benefit from adjuvant radiation therapy (RT), but results are still suboptimal with high rates of local progression. A dose escalation using high-conformal RT techniques needs to be evaluated in terms of efficacy and safety. We report the results of a dose-escalation study, named "Combo-RT", combining Intensity Modulated Radiotherapy (IMRT) or Volumetric Arc Therapy (VMAT) with Hypofractionated Stereotactic Radiotherapy (hSRT) boost.

PATIENTS AND METHODS

From November 2015 to January 2019, we prospectively enrolled 16 patients with hRG2. Seven patients had subtotal resection (STR) and 9 patients had a recurrent tumor. All patients received Combo-RT: LINAC-IMRT/ VMAT on the surgical bed and CyberKnife-hSRT boost on residual/recurrent meningioma Toxicity and initial efficacy were evaluated.

RESULTS

The median age was 62 years (range, 31-80 years). The median cumulative dose delivered was 46 Gy For IMRT or VMAT and 15 Gy in 3 fractions at a median isodose line of 77% for hSRT. The median cumulative BED and EQD2 were 108.75 Gy and 72.5 Gy respectively. 3-year-PFS was 75% for the whole cohort,100% for patients with STR, and 55.5% for recurrent patients. Negligible toxicities, and stable or improved symptoms during long-term follow-up were observed. Salvage treatment for recurrence was an independent predictor of treatment failure (P = 0.025).

CONCLUSIONS

With the limitation of a small series of patients, our results suggest that a dose escalation for hRG2 meningiomas, using a Combo-RT approach, is safe and particularly effective in the subgroup of patients with STR. Further studies are warranted.

Volumetric Intensity-Modulated Arc Stereotactic Radiosurgery Boost in Oligometastatic Patients with Spine Metastases: a Dose-escalation Study

AIMS

To report the final results of a dose-escalation study of volumetric intensity-modulated arc stereotactic radiosurgery (VMAT-SRS) boost after three-dimensional conformal radiation therapy in patients with spine metastases.

MATERIALS AND METHODS

Oligometastatic cancer patients bearing up to five synchronous metastases (visceral or bone, including vertebral ones) and candidates for surgery or radiosurgery were considered for inclusion. 25 Gy was delivered in 10 daily fractions (2 weeks) to the metastatic lesion, affected vertebrae and adjacent ones (one cranial and one caudal vertebra). Sequentially, the dose to spinal metastases was progressively increased (8 Gy, 10 Gy, 12 Gy) in the patient cohorts. Dose-limiting toxicities were defined as any treatment-related non-hematologic acute adverse effects rated as grade ≥3 or any acute haematological toxicity rated as ≥ 4 by the Radiation Therapy Oncology Group scale.

RESULTS

Fifty-two lesions accounting for 40 consecutive patients (male/female: 29/11; median age: 71 years; range 40-85) were treated from April 2011 to September 2020. Most patients had a primary prostate (65.0%) or breast cancer (22.5%). Thirty-two patients received 8 Gy VMAT-SRS boost (total BED _α/β10: 45.6 Gy), 14 patients received 10 Gy (total BED _α/β10: 51.2 Gy) and six patients received 12 Gy (total BED _α/β10: 57.6 Gy). The median follow-up time was over 70 months (range 2-240 months). No acute toxicities > grade 2 and no late toxicities > grade 1 were recorded. The overall response rate based on computed tomography/positron emission tomography-computed tomography/magnetic resonance was 78.8%. The 24-month actuarial local control, distant metastases-free survival and overall survival rates were 88.5%, 27.1% and 90.3%, respectively.

CONCLUSION

A 12 Gy spine metastasis SRS boost following 25 Gy to the affected and adjacent vertebrae was feasible with an excellent local control rate and toxicity profile.

Dose-volume parameters comparison of organs at risk between the prone and supine positions in pelvic tumors using 3D-CRT

AIMS

Cancer is a major public health problem worldwide, the leading cause of death in developed countries. Radiotherapy is an important treatment for many malignancies. The main purpose of this study was to compare the two techniques of supine and prone in prostate and rectal cancers using DVH extraction parameters.

METHODS AND MATERIAL

Clinical and dosimetry data of 41 rectal and prostate cancer patients were evaluated in both the supine and prone positions with belly board. Administered dose was daily 180 cGy. The four box fields in the first phase and two lateral fields in the second phase with 18 MV photon fields were used. Each patient underwent CT scan, at both the positions using a contrast agent with a full bladder.

STATISTICAL ANALYSIS USED

By using IBM SPSS software v23, all the data were described. The normal distribution of the data was performed using the KS sample statistical test. For data analysis, paired t test was used in the normal data and the Wilcoxon test was used in the non-normal data.

RESULTS

In patients with rectal cancer, there is no change in the received minimum dose by organs at risk. A significant decrease in received maximum dose, except for the prostate organ, could be due to the spatial proximity of the two organs to each other. Also, the received average dose in the small intestine was significantly reduced (P = 0.005). But in other organs, the dose reduction was not significant. In patients with prostate cancer, there is no change in the received minimum dose by OARs, except for the bladder organ (P = 0.003). Except the bladder organs (P = 0.011), there is no significant decrease in the received average dose by OARs. The maximum dose of the OARs is significantly reduced, except for the colon where there was not much overlap in the PTV, in addition to receiving the dose in the range. There was no significant relationship between CI in the rectal field and UI in the prostate field (P > 0.05), but there was a significant relationship between CI in the prostate field and UI in the rectal field with change in patient position.

CONCLUSIONS

In the prone position, in both patients' groups, the OARs receive an optimal and better dose than the supine position, especially the small intestine organ in the rectal field and the bladder and rectum organs in the prostate field. However, it seems that this change in the position of rectal cancer patients is ineffective in reducing the dose of prostate and needs further investigation.

Three-dimensional conformal radiotherapy (3D-CRT) vs. volumetric modulated arc therapy (VMAT) in deep inspiration breath-hold (DIBH) technique in left-sided breast cancer patients-comparative analysis of dose distribution and estimation of projected secondary cancer risk

PURPOSE

The purpose of this study was to compare two techniques of irradiation of left-sided breast cancer patients who underwent breast-conserving surgery, three-dimensional conformal radiotherapy technique (3D-CRT) and volumetric modulated arc therapy (VMAT), in terms of dose distribution in the planning target volume (PTV) and organs at risk (OARs). The second aim of the study was estimation of the projected risk of radiation-induced secondary cancer for both radiotherapy techniques.

MATERIALS AND METHODS

For 25 patients who underwent CT simulation in deep inspiration breath-hold (DIBH), three treatment plans were generated: one using a three-dimensional conformal radiotherapy technique and two using volumetric modulated arc therapy. First VMAT-DIBH geometry consisted of three partial arcs (ARC-DIBH 3A) and second consisted of four partial arcs (ARC-DIBH 4A). Cumulative dose-volume histograms (DVHs) were used to compare dose distributions within the PTV and OARs (heart, left anterior descending coronary artery [LAD], ipsilateral and contralateral lung [IL, CL], and contralateral breast [CB]). Normal tissue complication probabilities (NTCPs) and organ equivalent doses (OEDs) were calculated using the differential DVHs. Excess absolute risks (EARs) for second cancers were estimated using Schneider's full mechanistic dose-response model.

RESULTS

All plans fulfilled the criterium for PTV V95% ≥ 95%. The PTV coverage, homogeneity, and conformity indices were significantly better for VMAT-DIBH. VMAT showed a significantly increased mean dose and V5Gy for all OARs, but reduced LAD D_max by 15 Gy. For IL, CL, and CB, the 3D-CRT DIBH method achieved the lowest values of EAR: 28.38 per 10,000 PYs, 2.55 per 10,000 PYs, and 4.48 per 10,000 PYs (p < 0.001), compared to 40.29 per 10,000 PYs, 15.62 per 10,000 PYs, and 23.44 per 10,000 PYs for ARC-DIBH 3A plans and 41.12 per 10,000 PYs, 15.59 per 10,000 PYs, and 22.73 per 10,000 PYs for ARC-DIBH 4A plans. Both techniques provided negligibly low NTCPs for all OARs.

CONCLUSION

The study shows that VMAT-DIBH provides better OAR sparing against high doses. However, the large low-dose-bath (≤ 5 Gy) is still a concern due to the fact that a larger volume of normal tissues exposed to lower doses may increase a radiation-induced risk of secondary cancer.

Phase 1 Study of No-Carrier Added 177Lu-DOTATATE (SNU-KB-01) in Patients with Somatostatin Receptor-Positive Neuroendocrine Tumors: The First Clinical Trial of Peptide Receptor Radionuclide Therapy in Korea

PURPOSE

To provide a wider choice of treatment opportunities for patients with neuroendocrine tumor (NET) in Korea, we have conducted a phase 1, open-label, single-arm, dose-escalation study of SNU-KB-01, a no-carrier added (NCA) 177Lu-labeled DOTATATE.

MATERIALS AND METHODS

Seven patients with inoperable, progressive, metastatic, or locally advanced, somatostatin receptor-positive NET with Ki67 index ≤ 20% were enrolled according to the rolling six design. The study consisted of two cohorts to receive 4 cycles of SNU-KB-01 every 8 weeks for the first dose of 5.55 GBq (n=3) and 7.40 GBq (n=4). We assessed the incidence of dose-limiting toxicity (DLT) and adverse event, absorbed dose of kidneys and bone marrow, and objective tumor response.

RESULTS

Seven patients completed 4 cycles (21.3-30.1 GBq total dose) of SNU-KB-01. The mean absorbed doses to kidneys and bone marrow were 0.500 mGy/MBq and 0.053 mGy/MBq, respectively, and the total body effective dose was 0.115 mSv/MBq. No DLT was observed and the maximum tolerated dose was 7.40 GBq/cycle. Grade 3 thrombocytopenia occurred in one patient, but no other grade 3 or 4 major hematologic or renal toxicity was observed. The best objective response to SNU-KB-01 was partial response. Overall response rate was 42.9% and disease control rate was 85.7%.

CONCLUSION

Treatment with 4 cycles of SNU-KB-01 was well tolerated and resulted in control of disease in most of the patients. Our results indicate SNU-KB-01, an NCA 177Lu-labeled DOTATATE, as a potentially safe and efficacious treatment option for NET patients in Korea.

Clinical course and treatment of radiation-induced hemorrhagic gastritis: a case series study

Radiation-induced hemorrhagic gastritis is a relatively uncommon complication of irradiation that can be severe. However, appropriate treatment guidelines have not yet been established because of the small number of known cases. At our hospital, we encountered nine cases of radiation-induced hemorrhagic gastritis between July 2005 and July 2018. All patients initially underwent argon plasma coagulation (APC) for hemostasis. The treatment was highly effective, and hemostasis was successfully achieved in eight of the cases. Hemostasis could not be achieved in one case treated with APC; therefore, surgical resection was required. This patient had risk factors, such as liver cirrhosis and a history of abdominal surgery. Our case series suggests that APC is an effective hemostatic method that should be considered as the initial treatment option for radiation-induced hemorrhagic gastritis; however, surgical resection may be considered when the patient is at high risk for rebleeding.

Contralateral esophageal sparing technique in definitive radiotherapy for non-small cell lung cancer: dosimetric parameters and normal tissue complication probability modeling

Background

The purpose of this study was to assess the benefit of the contralateral esophageal sparing technique (CEST) in definitive radiotherapy of non-small cell lung cancer (NSCLC).

Materials and methods

We retrospectively reviewed radiation plans for 13 patients who underwent definitive chemoradiation for locally advanced NSCLC. Alternative plans were prepared with the use of CEST, with an additional margin of 5 mm from planning treatment volume (PTV). Normal tissue complication probability (NTCP) analyses for the esophagus and tumor control probability (TCP) for the PTV were performed for original and CEST plans using the equivalent uniform dose (EUD)-based mathematical model.

Results

In all cases, the CEST plan allowed for the reduction of esophageal dose, with a mean of 3.8 Gy (range, 0.7 to 8.7 Gy). The mean reductions of V40 and V60 to the esophagus were 6.4 Gy (range, 2.1 to 17.2 Gy) and 1.9 Gy (range, 3.4 to 10.0 Gy), respectively. There was no substantial decrease in the maximal dose to the esophagus. Reduction of NTCP was achieved for all patients (range, 5-73%), and TCP was not affected (-1.8 to +6.7%).

Conclusions

The application of CEST in definitive radiotherapy of locally advanced NSCLC allows for reducing selected dosimetric parameters to the esophagus without compromising TCP.

Relationship between absorbed dose and changes in liver volume after chemoradiotherapy for esophageal cancer

PURPOSE

The liver is the largest organ in the abdomen and is often irradiated in radiotherapy for non-hepatic malignancies. As most of the studies on changes in liver volume are on hepatocellular carcinoma based on liver dysfunction, there are few studies on healthy liver. In this study, we investigated the relationship between absorbed dose and changes in liver volume after chemoradiotherapy for esophageal cancer in patients without apparent pre-treatment liver dysfunction.

MATERIALS AND METHODS

Liver volume was compared between pre-treatment, acute (< 4 months) and late post-treatment (≥ 4 and < 13 months) phases in 12 patients using abdominal plain CT images. Volume changes were evaluated separately for the right and left lobes. We investigated the relationship between the volume change and V_xGy (percentage of volume received x Gy or more dose). In addition, volume change for each absorbed dose was investigated using deformable image registration.

RESULTS

The volume of the left lobe showed a significant decrease between pre-treatment and acute post-treatment phases (p < 0.001), while the volume of right lobe and between acute and late post-treatment phase of left lobe did not. The mean value of the volume reduction rate of the left lobe was 51.1% and equivalent to the mean value of V_30Gy. As a result of the volume change for each absorbed dose, the volume reduction rate increased as the absorbed dose increased, and a significant volume loss was observed at doses above 11 Gy.

CONCLUSION

Volume of the liver significantly decreased only in the acute phase after chemoradiotherapy for esophageal cancer. The tolerable dose for a healthy liver is generally considered to be 30 Gy, but attention should be paid to lower doses to avoid radiation-induced liver injury.

The Normal, the Radiosensitive, and the Ataxic in the Era of Precision Radiotherapy: A Narrative Review

(1) Background: radiotherapy is a cornerstone of cancer treatment. When delivering a tumoricidal dose, the risk of severe late toxicities is usually kept below 5% using dose-volume constraints. However, individual radiation sensitivity (iRS) is responsible (with other technical factors) for unexpected toxicities after exposure to a dose that induces no toxicity in the general population. Diagnosing iRS before radiotherapy could avoid unnecessary toxicities in patients with a grossly normal phenotype. Thus, we reviewed iRS diagnostic data and their impact on decision-making processes and the RT workflow; (2) Methods: following a description of radiation toxicities, we conducted a critical review of the current state of the knowledge on individual determinants of cellular/tissue radiation; (3) Results: tremendous advances in technology now allow minimally-invasive genomic, epigenetic and functional testing and a better understanding of iRS. Ongoing large translational studies implement various tests and enriched NTCP models designed to improve the prediction of toxicities. iRS testing could better support informed radiotherapy decisions for individuals with a normal phenotype who experience unusual toxicities. Ethics of medical decisions with an accurate prediction of personalized radiotherapy's risk/benefits and its health economics impact are at stake; (4) Conclusions: iRS testing represents a critical unmet need to design personalized radiotherapy protocols relying on extended NTCP models integrating iRS.

Use of imaging-based dosimetry for personalising radiopharmaceutical therapy of cancer

Theranostics - i.e., the combination of molecular imaging and radiopharmaceutical therapy of cancer targeting a common biological feature - is a rapidly expanding field owing the recent successes of novel radiopharmaceutical therapies, such as ¹⁷⁷Lu-based prostate-specific membrane antigen radioligand therapy of prostate cancer and peptide receptor radionuclide therapy of neuroendocrine tumours. Despite the ongoing technical developments in imaging-based dosimetry, the existence of tumour absorbed dose-efficacy and organ absorbed dose-toxicity relationships, as well as the high interpatient variability in absorbed doses per unit activity, radiopharmaceutical therapies are still mostly administered in a fixed-activity, one-size-fits-all fashion. This is at odds with the principles of radiation oncology, where the absorbed doses to tissues are prescribed and their delivery is carefully planned and controlled for each individual patient to maximise the clinical benefits. There is a growing body of clinical evidence that dosimetry-based radiopharmaceutical therapy allows to safely optimise tumour irradiation, which translates into improved clinical outcomes. In this narrative review, we will present the reported prospective clinical experience to date on the use of imaging-based dosimetry to personalise radiopharmaceutical therapies.

Machine learning-based normal tissue complication probability model for predicting albumin-bilirubin (ALBI) grade increase in hepatocellular carcinoma patients

PURPOSE

The aim of this study was to develop a normal tissue complication probability model using a machine learning approach (ML-based NTCP) to predict the risk of radiation-induced liver disease in hepatocellular carcinoma (HCC) patients.

MATERIALS AND METHODS

The study population included 201 HCC patients treated with radiotherapy. The patients' medical records were retrospectively reviewed to obtain the clinical and radiotherapy data. Toxicity was defined by albumin-bilirubin (ALBI) grade increase. The normal liver dose-volume histogram was reduced to mean liver dose (MLD) based on the fraction size-adjusted equivalent uniform dose (2 Gy/fraction and α/β = 2). Three types of ML-based classification models were used, a penalized logistic regression (PLR), random forest (RF), and gradient-boosted tree (GBT) model. Model performance was compared using the area under the receiver operating characteristic curve (AUROC). Internal validation was performed by 5-fold cross validation and external validation was done in 44 new patients.

RESULTS

Liver toxicity occurred in 87 patients (43.1%). The best individual model was the GBT model using baseline liver function, liver volume, and MLD as inputs and the best overall model was an ensemble of the PLR and GBT models. An AUROC of 0.82 with a standard deviation of 0.06 was achieved for the internal validation. An AUROC of 0.78 with a standard deviation of 0.03 was achieved for the external validation. The behaviors of the best GBT model were also in good agreement with the domain knowledge on NTCP.

CONCLUSION

We propose the methodology to develop an ML-based NTCP model to estimate the risk of ALBI grade increase.

Preclinical Evaluation of 225Ac-Labeled Single-Domain Antibody for the Treatment of HER2pos Cancer

Human epidermal growth factor receptor type 2 (HER2) is overexpressed in various cancers; thus, HER2-targeting single-domain antibodies (sdAb) could offer a useful platform for radioimmunotherapy. In this study, we optimized the labeling of an anti-HER2-sdAb with the α-particle-emitter 225Ac through a DOTA-derivative. The formed radioconjugate was tested for binding affinity, specificity and internalization properties, whereas cytotoxicity was evaluated by clonogenic and DNA double-strand-breaks assays. Biodistribution studies were performed in mice bearing subcutaneous HER2pos tumors to estimate absorbed doses delivered to organs and tissues. Therapeutic efficacy and potential toxicity were assessed in HER2pos intraperitoneal ovarian cancer model and in healthy C57Bl/6 mice. [225Ac]Ac-DOTA-2Rs15d exhibited specific cell uptake and cell-killing capacity in HER2pos cells (EC50 = 3.9 ± 1.1 kBq/mL). Uptake in HER2pos lesions peaked at 3 hours (9.64 ± 1.69% IA/g), with very low accumulation in other organs (<1% IA/g) except for kidneys (11.69 ± 1.10% IA/g). α-camera imaging presented homogeneous uptake of radioactivity in tumors, although heterogeneous in kidneys, with a higher signal density in cortex versus medulla. In mice with HER2pos disseminated tumors, repeated administration of [225Ac]Ac-DOTA-2Rs15d significantly prolonged survival (143 days) compared to control groups (56 and 61 days) and to the group treated with HER2-targeting mAb trastuzumab (100 days). Histopathologic evaluation revealed signs of kidney toxicity after repeated administration of [225Ac]Ac-DOTA-2Rs15d. [225Ac]Ac-DOTA-2Rs15d efficiently targeted HER2pos cells and was effective in treatment of intraperitoneal disseminated tumors, both alone and as an add-on combination with trastuzumab, albeit with substantial signs of inflammation in kidneys. This study warrants further development of [225Ac]Ac-DOTA-2Rs15d.

Dosimetric predictors of toxicity in a randomized study of short-course vs conventional radiotherapy for glioblastoma

PURPOSE

There is no consensus on appropriate organ at risk (OAR) constraints for short-course radiotherapy for patients with glioblastoma. Using dosimetry and prospectively-collected toxicity data from a trial of short-course radiotherapy for glioblastoma, this study aims to empirically examine the OAR constraints, with particular attention to left hippocampus dosimetry and impact on neuro-cognitive decline.

METHODS AND MATERIALS

Data was taken from a randomized control trial of 133 adults (age 18-70 years; ECOG performance score 0-2) with newly diagnosed glioblastoma treated with 60 Gy in 30 (conventional arm) versus 20 (short-course arm) fractions of adjuvant chemoradiotherapy (ClinicalTrials.gov Identifier: NCT02206230). The delivered plan's dosimetry to the OARs was correlated to prospective-collected toxicity and Mini-Mental State Examination (MMSE) data.

RESULTS

Toxicity events were not significantly increased in the short-course arm versus the conventional arm. Across all OARs, delivered radiation doses within protocol-allowable maximum doses correlated with lack of grade ≥ 2 toxicities in both arms (p < 0.001), while patients with OAR doses at or above protocol limits correlated with increased grade ≥ 2 toxicities across all examined OARs in both arms (p-values 0.063-0.250). Mean left hippocampus dose was significantly associated with post-radiotherapy decline in MMSE scores (p = 0.005), while the right hippocampus mean dose did not reach statistical significance (p = 0.277). Compared to the original clinical plan, RapidPlan left hippocampus sparing model decreased left hippocampus mean dose by 43 % (p < 0.001), without compromising planning target volume coverage.

CONCLUSIONS

In this trial, protocol OAR constraints were appropriate for limiting grade ≥ 2 toxicities in conventional and short-course adjuvant chemoradiotherapy for glioblastoma. Higher left hippocampal mean doses were predictive for neuro-cognitive decline post-radiotherapy. Routine contouring and use of dose constraints to limit hippocampal dose is recommended to minimize neuro-cognitive decline in patients with glioblastoma treated with chemoradiotherapy.

Lymphocyte sparing normal tissue effects in the clinic (LymphoTEC): A systematic review of dose constraint considerations to mitigate radiation-related lymphopenia in the era of immunotherapy

BACKGROUND

Radiation-related lymphopenia has been associated with suboptimal tumor control rates leading to inferior survival outcomes. To date, no standardized dose constraints are available to limit radiation dose to resident and circulating lymphocyte populations. We undertook this systemic review of the literature to provide a synopsis of the dosimetric predictors of radiation-related lymphopenia in solid malignancies.

METHODOLOGY

A systematic literature review of PubMed (National Institutes of Health), Cochrane Central (Cochrane collaboration), and Google Scholar was conducted with the following keywords: "radiation", "lymphopenia", "cancer", "dosimetric predictors" with an inclusion deadline of May 31, 2022. Studies that met prespecified inclusion criteria were designated either Good, Fair, or Poor Quality based on the Newcastle-Ottawa quality assessment. The dosimetric parameters derived from Good Quality studies were tabulated as LymphoTEC dose constraints. Dosimetric parameters derived from Fair and Poor-quality studies were grouped as optional.

RESULTS

An initial systematic search of the literature yielded 1,632 articles. After screening, a total of 48 studies met inclusion criteria and were divided into the following categories: central nervous system (CNS, 6), thoracic (11), gastrointestinal (26), gynecologic (2), head and neck, breast, and genitourinary (one each) cancers. Lung mean dose, heart mean dose, brain V25, spleen mean dose, estimated dose to immune cells, and bone marrow V10 were among the strongest predictors for severe lymphopenia related to radiotherapy.

CONCLUSION

Optimizing the delivery of radiation therapy to limit dose to lymphocyte-rich structures may curb the negative oncologic impact of lymphocyte depletion. The dose constraints described herein may be considered for prospective validation and future use in clinical trials to limit risk of radiation-related lymphopenia and possibly improve cancer-associated outcomes.

Radiation-induced optic neuropathy: a review

Radiation is a commonly used treatment modality for head and neck as well as CNS tumours, both benign and malignant. As newer oncology treatments such as immunotherapies allow for longer survival, complications from radiation therapy are becoming more common. Radiation-induced optic neuropathy is a feared complication due to rapid onset and potential for severe and bilateral vision loss. Careful monitoring of high-risk patients and early recognition are crucial for initiating treatment to prevent severe vision loss due to a narrow therapeutic window. This review discusses presentation, aetiology, recent advances in diagnosis using innovative MRI techniques and best practice treatment options based on the most recent evidence-based medicine.

Determining the Occurrence of Hypothyroidism Following Treatment With Radiation Therapy in Head and Neck Carcinoma Patients and the Associated Role of Risk Factors and Dose-Volume Histograms: A Prospective Study

Background

Head and neck carcinomas are one of the most common malignancies in developing countries including India. Most patients are treated with radiotherapy. Although post-radiotherapy hypothyroidism is a known complication, data regarding its incidence and factors influencing it are scarce. This study aimed to determine the incidence of post-radiotherapy hypothyroidism in head and neck carcinoma patients treated with radiotherapy and the factors influencing it.

Methodology

Patients with head and neck carcinomas treated with radiotherapy as one of the modalities were included in this study. Thyroid function tests were done, and quality of life questionnaires were completed before treatment and during follow-up. Dose-volume histogram (DVH), demographic data, and disease-related parameters were compared.

Results

Out of the 95 patients screened, 14 were found to be hypothyroid prior to the commencement of radiotherapy and were excluded. With a median follow-up duration of 34 weeks, 29.6% developed hypothyroidism, with 19% developing it in the first year. On univariate and multivariate analysis of the DVH of the thyroid gland, volume receiving 50 Gy (V50), dose received to 50% volume (D50), and the mean dose (more than 50 Gy) were found to be significantly associated with hypothyroidism.

Conclusions

Hypothyroidism is a significant comorbid factor in Indian patients with head and neck carcinomas. The incidence of post-radiotherapy hypothyroidism is significant and occurs early compared to the western population leading to significant deterioration in the quality of life. Parameters such as the volume of the thyroid gland, V50, D50, and mean dose to the thyroid gland influence the incidence of hypothyroidism. The use of appropriate constraints can significantly prevent radiotherapy-induced hypothyroidism.

Technical note: rtdsm-An open-source software for radiotherapy dose-surface map generation and analysis

BACKGROUND

Dose-outcome studies in radiation oncology have historically excluded spatial information due to dose-volume histograms being the most dominant source of dosimetric information. In recent years, dose-surface maps (DSMs) have become increasingly popular for characterization of spatial dose distributions and identification of radiosensitive subregions for hollow organs. However, methodological variations and lack of open-source, publicly offered code-sharing between research groups have limited reproducibility and wider adoption.

PURPOSE

This paper presents rtdsm, an open-source software for DSM calculation with the intent to improve the reproducibility of and the access to DSM-based research in medical physics and radiation oncology.

METHODS

A literature review was conducted to identify essential functionalities and prevailing calculation approaches to guide development. The described software has been designed to calculate DSMs from DICOM data with a high degree of user customizability and to facilitate DSM feature analysis. Core functionalities include DSM calculation, equivalent dose conversions, common DSM feature extraction, and simple DSM accumulation.

RESULTS

A number of use cases were used to qualitatively and quantitatively demonstrate the use and usefulness of rtdsm. Specifically, two DSM slicing methods, planar and noncoplanar, were implemented and tested, and the effects of method choice on output DSMs were demonstrated. An example comparison of DSMs from two different treatments was used to highlight the use cases of various built-in analysis functions for equivalent dose conversion and DSM feature extraction.

CONCLUSIONS

We developed and implemented rtdsm as a standalone software that provides all essential functionalities required to perform a DSM-based study. It has been made freely accessible under an open-source license on Github to encourage collaboration and community use.

Sex-based differences in the severity of radiation-induced arthrofibrosis

As cancer survivorship increases, so does the number of patients that suffer from the late effects of radiation therapy. This includes arthrofibrosis, the development of stiff joints near the field of radiation. Previous reports have concentrated on skin fibrosis around the joint but largely ignored the deeper tissues of the joint. We hypothesized that fat, muscle, and the joint tissues themselves would play a more significant role in joint contracture after radiation than the skin surrounding the joint. To address this hypothesis, we irradiated the right hind flanks of mice with fractionated and unfractionated dose schedules, then monitored the mice for 3 months postradiotherapy. Mice were euthanized and physiological indications of arthrofibrosis including limb contracture and joint resting position were assessed. Stifle (knee) joints demonstrated significant arthrofibrosis, but none was observed in the hock (ankle) joints. During these studies, we were surprised to find that male and female mice showed a significantly different response to radiation injury. Female mice developed more injuries, had significantly worse contracture, and showed a greater difference in the expression of all markers studied. These results suggest that women undergoing radiation therapy might be at significantly greater risk for developing arthrofibrosis and may require specific adjustments to their care.

Surface guided 3DCRT in deep-inspiration breath-hold for left sided breast cancer radiotherapy: implementation and first clinical experience in Iran

Background

The aim of the study is to evaluate the overall accuracy of the surface-guided radiotherapy (SGRT) workflow through a comprehensive commissioning and quality assurance procedures and assess the potential benefits of deep-inspiration breath-hold (DIBH) radiotherapy as a cardiac and lung dose reduction approach for left-sided breast cancer irradiation.

Materials and methods

Accuracy and reproducibility of the optical surface scanner used for DIBH treatment were evaluated using different phantoms. Patient positioning accuracy and reproducibility of DIBH treatment were evaluated. Twenty patients were studied for treatment plan quality in target dose coverage and healthy organ sparing for the two different treatment techniques.

Results

Reproducibility tests for the surface scanner showed good stability within 1 mm in all directions. The maximum position variation between applied shifts on the couch and the scanner measured offsets is 1 mm in all directions. The clinical study of 200 fractions showed good agreement between the surface scanner and portal imaging with the isocenter position deviation of less than 3 mm in each lateral, longitudinal, and vertical direction. The standard deviation of the DIBH level showed a value of < 2 mm during all evaluated DIBHs. Compared to the free breathing (FB) technique, DIBH showed significant reduction of 48% for heart mean dose, 43% for heart V25, and 20% for ipsilateral lung V20.

Conclusion

Surface-guided radiotherapy can be regarded as an accurate tool for patient positioning and monitoring in breast radiotherapy. DIBH treatment are considered to be effective techniques in heart and ipsilateral lung dose reductions for left breast radiotherapy.

New Directions in the Therapy of Glioblastoma

Glioblastoma is the most common histologic type of all gliomas and contributes to 57.3% of all cases. Despite the standard management based on surgical resection and radiotherapy, it is related to poor outcome, with a 5-year relative survival rate below 6.9%. In order to improve the overall outcome for patients, the new therapeutic strategies are needed. Herein, we describe the current state of knowledge on novel targeted therapies in glioblastoma. Based on recent studies, we compared treatment efficacy measured by overall survival and progression-free survival in patients treated with selected potential antitumor drugs. The results of the application of the analyzed inhibitors are highly variable despite the encouraging conclusions of previous preclinical studies. This paper focused on drugs that target major glioblastoma kinases. As far, the results of some BRAF inhibitors are favorable. Vemurafenib demonstrated a long-term efficacy in clinical trials while the combination of dabrafenib and trametinib improves PFS compared with both vemurafenib and dabrafenib alone. There is no evidence that any MEK inhibitor is effective in monotherapy. According to the current state of knowledge, BRAF and MEK inhibition are more advantageous than BRAF inhibitor monotherapy. Moreover, mTOR inhibitors (especially paxalisib) may be considered a particularly important group. Everolimus demonstrated a partial response in a significant proportion of patients when combined with bevacizumab, however its actual role in the treatment is unclear. Neither nintedanib nor pemigatinib were efficient in treatment of GBM. Among the anti-VEGF drugs, bevacizumab monotherapy was a well-tolerated option, significantly associated with anti-GBM activity in patients with recurrent GBM. The efficacy of aflibercept and pazopanib in monotherapy has not been demonstrated. Apatinib has been proven to be effective and tolerable by a single clinical trial, but more research is needed. Lenvatinib is under trial. Finally, promising results from a study with regorafenib may be confirmed by the ongoing randomized AGILE trial. The studies conducted so far have provided a relatively wide range of drugs, which are at least well tolerated and demonstrated some efficacy in the randomized clinical trials. The comprehensive understanding of the molecular biology of gliomas promises to further improve the treatment outcomes of patients.

Impact of fiducial markers placement on the delineation of target volumes in radiation therapy for oesophageal cancer: FIDUCOR study

Purpose

This prospective monocentric phase II study (FIDUCOR-study, NCT02526134) aimed to assess the impact of fiducial markers (FMs) implantation on conformal chemo-radiation therapy (CRT) planning in oesophageal carcinoma (EC) patients.

Methods/materials

Fifteen EC patients were enrolled in the study. Each patient underwent two simulation CT-scans before (CT1) and after (CT2) FMs implantation, in the same position. FMs (3 mm length gold markers, preloaded in a 22G needle) were implanted after sedation, under endoscopic ultrasound (EUS) and X-Ray guidance, and were placed at the tumor’s extremities, and in the visible lymph nodes. Target delineation and treatment plan were both performed first on CT1 with the assistance of diagnosis CT, gastroscopy and EUS details, and second on CT2 using FMs and CT-data. The value of FMs implantation was assessed by the difference of growth-tumor-volume (GTV) and clinical-target-volume (CTV) between CT1-based and CT2-based delineation. A significant difference was defined as a ≥5 mm-difference on axial(x) or coronal(y) slices, a ≥10mm-difference on sagittal slices, or a ≥20%-difference in GTV. The impact on dose distribution in organs at risk (OAR) (lung, heart, liver) was also studied.

Results

Between 09/2014 and 12/2015, 15 patients could achieve fiducial procedures, without any complication. One FM migration occurred. We observed a significant modification of the GTV-dimension in 100% of the cases (15/15, 95%CI: [78.2;100.0]), mainly due to a difference in sagittal dimension with a mean variation of 11.2 mm and a difference&gt; 10 mm for 8/15 patients (53.3%). One patient had a significant isocenter displacement as high as 20 mm. The oesophagus tumor was not seen on the CT-scan in one patient due to its small size. One patient had a distant lymph node metastasis not visible on CT-scan. We observed no significant impact on OAR distribution.

Conclusion

In our study, FMs-implantation under EUS had a positive impact on accurate volume definition in EC-patients (modification of GTV in 15/15 patients). Close cooperation between gastroenterologist and radiation oncologist has the potential to improve local treatment of oesophageal carcinoma.

Point Shear Wave Elastography in Diagnosis and Follow-Up of Salivary Gland Affection after Head and Neck Cancer Treatment

Therapies of head and neck squamous cell carcinoma (HNSCC), particularly irradiation and chemotherapy (C/RT), can affect salivary glands to some extent. Recent studies suggest that point shear wave elastography (pSWE) is well suited for the diagnosis and rating of homogenous damage to parenchymatous organs. The purpose of this study was to assess the value of this sonographic modality as a tool for the evaluation both of salivary gland affection after HNSCC therapy and the effect of a salivary replacement therapy based on liposomes. A total of 69 HNSCC patients were included in this study. All patients had finished cancer treatment and attended regular follow-up. pSWE values of ipsi- and contralateral parotid (PG) and submandibular glands (SMG) were obtained in a standardized manner and compared to those of a healthy control (HC) group. After a two months treatment with a liposomal saliva replacement therapy pSWE quantification was performed again. Ipsi- and contralateral salivary glands suffer under standard HNSCC tumor therapy. Here, the ipsilateral parotid gland (PG) is primarily affected. Therefore, a sequence of manifestation (surgery < surgery plus adjuvant C/RT < primary C/RT) is comprehensible, evaluated by pSWE measurements. The examination of all glands and statistical analysis of the values compared to controls resulted in an pSWE cutoff value for affected glandular tissue of >2 m/s. Using a liposomal saliva replacement therapy, pSWE values of the ipsilateral PG can be improved, although the level of HC could not be restored.

Hunting down NLRP3 inflammasome: An executioner of radiation-induced injury

Radiotherapy is one of the mainstream treatment modalities for several malignancies. However, radiation-induced injury to surrounding normal tissues limits its efficacy. The NLRP3 inflammasome is an essential mechanism of innate immunity that reacts to challenges from endogenous danger signals and pathological microbes. A growing body of evidence has demonstrated a key role of NLRP3 inflammasome in the pathogenesis of radiation-induced tissue injury. Despite accumulating evidence, the potential value of the NLRP3 inflammasome in the management of radiation-induced tissue injury is not adequately recognized. We conducted a literature review to characterize the relationship between NLRP3 inflammasome and radiation injury. By analyzing recent evidence, we identify NLRP3 inflammasome as one of the executioners of radiation-induced injury, since it responds to the challenges of radiation, induces cell pyroptosis and tissue dysfunction, and initiates non-resolving inflammation and fibrosis. Based on these concepts, we propose early intervention/prevention strategies targeting NLRP3 inflammasome in a radiation context, which may help resolve imperative clinical problems.

Adaptive radiation therapy (art) for patients with limited-stage small cell lung cancer (LS-SCLC): A dosimetric evaluation

Background

Adaptive radiation therapy (ART) refers to redesigning of radiation therapy (RT) treatment plans with respect to dynamic changes in tumor size and location throughout the treatment course. In this study, we performed a comparative volumetric and dosimetric analysis to investigate the impact of ART for patients with limited-stage small cell lung cancer (LS-SCLC).

Methods

Twenty-four patients with LS-SCLC receiving ART and concomitant chemotherapy were included in the study. ART was performed by replanning of patients based on a mid-treatment computed tomography (CT)-simulation which was routinely scheduled for all patients 20-25 days after the initial CT-simulation. While the first 15 RT fractions were planned using the initial CT-simulation images, the latter 15 RT fractions were planned using the mid-treatment CT-simulation images acquired 20-25 days after the initial CT-simulation. In order to document the impact of ART, target and critical organ dose-volume parameters acquired from this adaptive radiation treatment planning (RTP) were compared with the RTP based solely on the initial CT-simulation to deliver the whole RT dose of 60 Gy.

Results

Statistically significant reduction was detected in gross tumor volume (GTV) and planning target volume (PTV) during the conventionally fractionated RT course along with statistically significant reduction in critical organ doses with incorporation of ART.

Conclusion

One-third of the patients in our study who were otherwise ineligible for curative intent RT due to violation of critical organ dose constraints could be treated with full dose irradiation by use of ART. Our results suggest significant benefit of ART for patients with LS-SCLC.

Long-Term Follow-Up Results of Adjuvant Intensity-Modulated Radiotherapy with Concurrent Paclitaxel and Cisplatin in High-Risk Endometrial Cancer Patients

Purpose. The purpose of this study was to retrospectively review the outcomes of patients with high-risk endometrial cancer treated with adjuvant radiotherapy with concurrent paclitaxel and cisplatin (TP). Methods. Patients with endometrial cancer who underwent radical surgery were screened between Jan 2005 and Dec 2018. Patients with high-risk factors who received adjuvant chemoradiotherapy were included in the study. High risks included stage I, endometrioid-type grade 3 with deep myometrial invasion or lymphovascular space invasion (or both), endometrioid-type stage II to IVa, or stage I to III with serous or clear cell histology. The adjuvant treatment regimen included one cycle of TP chemotherapy, followed by pelvic intensity-modulated radiotherapy (IMRT) with concurrent TP, followed by an additional one cycle of TP. Failure free survival (FFS) and overall survival (OS) were estimated. Patterns of recurrence and occurrence of adverse events were described. Results. A total of 450 patients with high-risk endometrial cancer were screened, 231 of whom were included in this study. After a median follow-up of 70 months, the 5-year OS was 94.7%, and the 6-year OS was 91.8%. The 5-y and 6-y FFS were 90.8% and 87.9%, respectively, which were related to stage ( $P<0.05$ ). A total of 14 patients experienced tumor recurrence, including 7 pelvic recurrence and 7 distant metastases. Seven patients died, all due to tumor progression. A total of 164 patients (71%) completed the prescribed course of treatment. A total of 205 patients had adverse events, 46 patients (20%) had grade 1, 92 patients (40%) had grade 2, 49 patients (21%) had grade 3, and 18 patients (8%) had grade 4. There were 83 nonhematologic and 122 hematologic toxicities (26 grade 3 and 18 grade 4). Conclusion. Adjuvant pelvic radiotherapy combined with synchronous TP chemotherapy can achieve excellent long-term survival for high-risk endometrial cancer patients. Moreover, this combination therapy has good safety and feasibility, which is worthy of further study and verification.

Dosimetric analysis and biological evaluation between proton radiotherapy and photon radiotherapy for the long target of total esophageal squamous cell carcinoma

Objective

The purpose of this study is to compare the dosimetric and biological evaluation differences between photon and proton radiation therapy.

Methods

Thirty esophageal squamous cell carcinoma (ESCC) patients were generated for volumetric modulated arc therapy (VMAT) planning and intensity-modulated proton therapy (IMPT) planning to compare with intensity-modulated radiation therapy (IMRT) planning. According to dose–volume histogram (DVH), dose–volume parameters of the plan target volume (PTV) and homogeneity index (HI), conformity index (CI), and gradient index (GI) were used to analyze the differences between the various plans. For the organs at risk (OARS), dosimetric parameters were compared. Tumor control probability (TCP) and normal tissue complication probability (NTCP) was also used to evaluate the biological effectiveness of different plannings.

Results

CI, HI, and GI of IMPT planning were significantly superior in the three types of planning (p < 0.001, p < 0.001, and p < 0.001, respectively). Compared to IMRT and VMAT planning, IMPT planning improved the TCP (p<0.001, p<0.001, respectively). As for OARs, IMPT reduced the bilateral lung and heart accepted irradiation dose and volume. The dosimetric parameters, such as mean lung dose (MLD), mean heart dose (MHD), V₅, V₁₀, and V₂₀, were significantly lower than IMRT or VMAT. IMPT afforded a lower maximum dose (D_max) of the spinal cord than the other two-photon plans. What’s more, the radiation pneumonia of the left lung, which was caused by IMPT, was lower than IMRT and VMAT. IMPT achieved the pericarditis probability of heart is only 1.73% ± 0.24%. For spinal cord myelitis necrosis, there was no significant difference between the three different technologies.

Conclusion

Proton radiotherapy is an effective technology to relieve esophageal cancer, which could improve the TCP and spare the heart, lungs, and spinal cord. Our study provides a prediction of radiotherapy outcomes and further guides the individual treatment.

Comparison of PSMA-TO-1 and PSMA-617 labeled with gallium-68, lutetium-177 and actinium-225

BACKGROUND

PSMA-TO-1 ("Tumor-Optimized-1") is a novel PSMA ligand with longer circulation time than PSMA-617. We compared the biodistribution in subcutaneous tumor-bearing mice of PSMA-TO-1, PSMA-617 and PSMA-11 when labeled with ⁶⁸Ga and ¹⁷⁷Lu, and the survival after treatment with ²²⁵Ac-PSMA-TO-1/-617 in a murine model of disseminated prostate cancer. We also report dosimetry data of ¹⁷⁷Lu-PSMA-TO1/-617 in prostate cancer patients.

METHODS

First, PET images of ⁶⁸Ga-PSMA-TO-1/-617/-11 were acquired on consecutive days in three mice bearing subcutaneous C4-2 xenografts. Second, 50 subcutaneous tumor-bearing mice received either 30 MBq of ¹⁷⁷Lu-PSMA-617 or ¹⁷⁷Lu-PSMA-TO-1 and were sacrificed at 1, 4, 24, 48 and 168 h for ex vivo gamma counting and biodistribution. Third, mice bearing disseminated lesions via intracardiac inoculation were treated with either 40 kBq of ²²⁵Ac-PSMA-617, ²²⁵Ac-PSMA-TO-1, or remained untreated and followed for survival. Additionally, 3 metastatic castration-resistant prostate cancer patients received 500 MBq of ¹⁷⁷Lu-PSMA-TO-1 under compassionate use for dosimetry purposes. Planar images with an additional SPECT/CT acquisition were acquired for dosimetry calculations.

RESULTS

Tumor uptake measured by PET imaging of ⁶⁸Ga-labeled agents in mice was highest using PSMA-617, followed by PSMA-TO-1 and PSMA-11. ¹⁷⁷Lu-PSMA tumor uptake measured by ex vivo gamma counting at subsequent time points tended to be greater for PSMA-TO-1 up to 1 week following treatment (p > 0.13 at all time points). This was, however, accompanied by increased kidney uptake and a 26-fold higher kidney dose of PSMA-TO-1 compared with PSMA-617 in mice. Mice treated with a single-cycle ²²⁵Ac-PSMA-TO-1 survived longer than those treated with ²²⁵Ac-PSMA-617 and untreated mice, respectively (17.8, 14.5 and 7.7 weeks, respectively; p < 0.0001). Kidney, salivary gland, bone marrow and mean ± SD tumor dose coefficients (Gy/GBq) for ¹⁷⁷Lu-PSMA-TO-1 in patients #01/#02/#03 were 2.5/2.4/3.0, 1.0/2.5/2.3, 0.14/0.11/0.10 and 0.42 ± 0.03/4.45 ± 0.07/1.8 ± 0.57, respectively.

CONCLUSIONS

PSMA-TO-1 tumor uptake tended to be greater than that of PSMA-617 in both preclinical and clinical settings. Mice treated with ²²⁵Ac-PSMA-TO-1 conferred a significant survival benefit compared to ²²⁵Ac-PSMA-617 despite the accompanying increased kidney uptake. In humans, PSMA-TO-1 dosimetry estimates suggest increased tumor absorbed doses; however, the kidneys, salivary glands and bone marrow are also exposed to higher radiation doses. Thus, additional preclinical studies are needed before further clinical use.

Laparoscopic spacer placement for bulky lymph node metastasis of cervical cancer: A case report

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Spacers focus high-dose radiotherapy towards the target lesion.

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Laparoscopic insertion of spacers allows for rapid initiation of radiotherapy.

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Spacers may be applied to patients requiring multidisciplinary treatment beyond standard therapy.

Dose-Volume Constraints fOr oRganS At risk In Radiotherapy (CORSAIR): An "All-in-One" Multicenter-Multidisciplinary Practical Summary

BACKGROUND

The safe use of radiotherapy (RT) requires compliance with dose/volume constraints (DVCs) for organs at risk (OaRs). However, the available recommendations are sometimes conflicting and scattered across a number of different documents. Therefore, the aim of this work is to provide, in a single document, practical indications on DVCs for OaRs in external beam RT available in the literature.

MATERIAL AND METHODS

A multidisciplinary team collected bibliographic information on the anatomical definition of OaRs, on the imaging methods needed for their definition, and on DVCs in general and in specific settings (curative RT of Hodgkin's lymphomas, postoperative RT of breast tumors, curative RT of pediatric cancers, stereotactic ablative RT of ventricular arrythmia). The information provided in terms of DVCs was graded based on levels of evidence.

RESULTS

Over 650 papers/documents/websites were examined. The search results, together with the levels of evidence, are presented in tabular form.

CONCLUSIONS

A working tool, based on collected guidelines on DVCs in different settings, is provided to help in daily clinical practice of RT departments. This could be a first step for further optimizations.

Concepts and methods for the dosimetry of radioembolisation of the liver with Y-90-loaded microspheres

This article aims at presenting in a didactic way, dosimetry concepts and methods that are relevant for radio-embolization of the liver with 90Y-microspheres. The application of the medical internal radiation dose formalism to radio-embolization is introduced. This formalism enables a simplified dosimetry, where the absorbed dose in a given tissue depends on only its mass and initial activity. This is applied in the single-compartment method, partition model, for the liver, tumour and lung dosimetry, and multi-compartment method, allowing identification of multiple tumours. Voxel-based dosimetry approaches are also discussed. This allows taking into account the non-uniform uptake within a compartment, which translates into a non-uniform dose distribution, represented as a dose-volume histogram. For this purpose, dose-kernel convolution allows propagating the energy deposition around voxel-sources in a computationally efficient manner. Alternatively, local-energy deposition is preferable when the spatial resolution is comparable or larger than the beta-particle path. Statistical tools may be relevant in establishing dose-effect relationships in a given population. These include tools such as the logistic regression or receiver operator characteristic analysis. Examples are given for illustration purpose. Moreover, tumour control probability modelling can be assessed through the linear-quadratic model of Lea and Catcheside and its counterpart, the normal-tissue complication probability model of Lyman, which is suitable to the parallel structure of the liver. The selectivity of microsphere administration allows tissue sparing, which can be considered with the concept of equivalent uniform dose, for which examples are also given. The implication of microscopic deposition of microspheres is also illustrated through a liver toxicity model, even though it is not clinically validated. Finally, we propose a reflection around the concept of therapeutic index (TI), which could help tailor treatment planning by determining the treatment safety through the evaluation of TI based on treatment-specific parameters.

Dosimetry of [212Pb]VMT01, a MC1R-Targeted Alpha Therapeutic Compound, and Effect of Free 208Tl on Tissue Absorbed Doses

[²¹²Pb]VMT01 is a melanocortin 1 receptor (MC1R) targeted theranostic ligand in clinical development for alpha particle therapy for melanoma. ²¹²Pb has an elementally matched gamma-emitting isotope ²⁰³Pb; thus, [²⁰³Pb]VMT01 can be used as an imaging surrogate for [²¹²Pb]VMT01. [²¹²Pb]VMT01 human serum stability studies have demonstrated retention of the ²¹²Bi daughter within the chelator following beta emission of parent ²¹²Pb. However, the subsequent alpha emission from the decay of ²¹²Bi into ²⁰⁸Tl results in the generation of free ²⁰⁸Tl. Due to the 10.64-hour half-life of ²¹²Pb, accumulation of free ²⁰⁸Tl in the injectate will occur. The goal of this work is to estimate the human dosimetry for [²¹²Pb]VMT01 and the impact of free ²⁰⁸Tl in the injectate on human tissue absorbed doses. Human [²¹²Pb]VMT01 tissue absorbed doses were estimated from murine [²⁰³Pb]VMT01 biodistribution data, and human biodistribution values for ²⁰¹Tl chloride (a cardiac imaging agent) from published data were used to estimate the dosimetry of free ²⁰⁸Tl. Results indicate that the dose-limiting tissues for [²¹²Pb]VMT01 are the red marrow and the kidneys, with estimated absorbed doses of 1.06 and 8.27 mGy_{RBE = 5}/MBq. The estimated percent increase in absorbed doses from free ²⁰⁸Tl in the injectate is 0.03% and 0.09% to the red marrow and the kidneys, respectively. Absorbed doses from free ²⁰⁸Tl result in a percent increase of no more than 1.2% over [²¹²Pb]VMT01 in any organ or tissue. This latter finding indicates that free ²⁰⁸Tl in the [²¹²Pb]VMT01 injectate will not substantially impact estimated tissue absorbed doses in humans.

DEGRO practical guideline for central nervous system radiation necrosis part 1: classification and a multistep approach for diagnosis

PURPOSE

The Working Group for Neuro-Oncology of the German Society for Radiation Oncology in cooperation with members of the Neuro-Oncology Working Group of the German Cancer Society aimed to define a practical guideline for the diagnosis and treatment of radiation-induced necrosis (RN) of the central nervous system (CNS).

METHODS

Panel members of the DEGRO working group invited experts, participated in a series of conferences, supplemented their clinical experience, performed a literature review, and formulated recommendations for medical treatment of RN including bevacizumab in clinical routine.

CONCLUSION

Diagnosis and treatment of RN requires multidisciplinary structures of care and defined processes. Diagnosis has to be made on an interdisciplinary level with the joint knowledge of a neuroradiologist, radiation oncologist, neurosurgeon, neuropathologist, and neuro-oncologist. A multistep approach as an opportunity to review as many characteristics as possible to improve diagnostic confidence is recommended. Additional information about radiotherapy (RT) techniques is crucial for the diagnosis of RN. Misdiagnosis of untreated and progressive RN can lead to severe neurological deficits. In this practice guideline, we propose a detailed nomenclature of treatment-related changes and a multistep approach for their diagnosis.

Radiation and the nervous system

Radiation therapy is widely used for benign and malignant brain tumours as it is effective and well tolerated. However, damage to the surrounding healthy nervous system tissue leads to a variety of complications both in the short term and long term, ranging from mild and self-limiting to irreversible and fatal. Radiation neurotoxicity is due to a combination of early inflammation and oligodendroglial damage followed later by brain tissue necrosis, white matter damage, accelerated vascular disease and the development of secondary tumours. This article explains the basic principles of radiation physics, the different modalities used in clinical practice, how radiotherapy is planned and delivered and the scientific basis of radiation damage. The main body of the article focuses on the clinical features of radiation toxicity in the brain, spinal cord, cranial and peripheral nerves with an emphasis on the distinction between early and delayed complications.

[Radiation induced brachial plexopathy: Diagnosis, risk factors, principles of care]

Radiation plexitis, also known as radiation-induced brachial neuropathy is a rare toxicity following axillary, breast, cervical or thoracic radiotherapy, first described in 1966 by Stoll and Andrew. Although improvements in radiotherapy techniques have greatly reduced its risk over the past seventy years, its severe form remains a dreaded complication that is difficult to manage in patients with increased life expectancy. This article summarizes the epidemiological elements, risk factors, diagnostic methods, doses and constraints to be respected in radiotherapy and the treatment strategies of radiation plexitis.

Radiation Oncology: Future Vision for Quality Assurance and Data Management in Clinical Trials and Translational Science

The future of radiation oncology is exceptionally strong as we are increasingly involved in nearly all oncology disease sites due to extraordinary advances in radiation oncology treatment management platforms and improvements in treatment execution. Due to our technology and consistent accuracy, compressed radiation oncology treatment strategies are becoming more commonplace secondary to our ability to successfully treat tumor targets with increased normal tissue avoidance. In many disease sites including the central nervous system, pulmonary parenchyma, liver, and other areas, our service is redefining the standards of care. Targeting of disease has improved due to advances in tumor imaging and application of integrated imaging datasets into sophisticated planning systems which can optimize volume driven plans created by talented personnel. Treatment times have significantly decreased due to volume driven arc therapy and positioning is secured by real time imaging and optical tracking. Normal tissue exclusion has permitted compressed treatment schedules making treatment more convenient for the patient. These changes require additional study to further optimize care. Because data exchange worldwide have evolved through digital platforms and prisms, images and radiation datasets worldwide can be shared/reviewed on a same day basis using established de-identification and anonymization methods. Data storage post-trial completion can co-exist with digital pathomic and radiomic information in a single database coupled with patient specific outcome information and serve to move our translational science forward with nimble query elements and artificial intelligence to ask better questions of the data we collect and collate. This will be important moving forward to validate our process improvements at an enterprise level and support our science. We have to be thorough and complete in our data acquisition processes, however if we remain disciplined in our data management plan, our field can grow further and become more successful generating new standards of care from validated datasets.