Tissue tolerance to reirradiation

Tumor volume instead of recurrent T category predicts clinical outcome of patients with locally recurrent nasopharyngeal carcinoma salvaged by carbon ion radiation therapy

BACKGROUND

Although carbon ion radiation therapy (CIRT) substantially improves the overall survival (OS) of patients with LR-NPC, approximately 40% of the patients may develop local recurrence. The purpose of study is to assess the value of tumor volume (TV) as a predictive tool to guide individualized CIRT.

METHODS

Consecutive patients with LR-NPC treated using CIRT at Shanghai Proton and Heavy Ion Center between April 2015 and May 2019 were included. TV before CIRT was delineated and calculated. The generalized additive Cox model was used to examine the relationship between TV and OS and local progression-free survival (LPFS). A cutoff value of tumor volume was identified to best discriminate patients with different 2-year OS rates, using receiver operating characteristic (ROC) analysis.

RESULTS

A total of 157 patients were enrolled. The median tumor volume was 22.49 (2.52-90.13) ml. In the univariable analyses, tumor volume was significantly associated with OS (p < 0.001) and LPFS (p = 0.01). The relationships with OS (p = 0.009) and LPFS (p = 0.020) remained significant in multivariable analyses. Using ROC analysis, a TV of 26.69 ml was identified to predict the 2-year OS rate. To facilitate potential clinical use, 25 ml was designated as the final cutoff value. The 2-year OS and LPFS rates were 88.6 % vs 62.3 %, and 54.7 % vs 35.5 %, for patients with a TV ≤ 25 ml and > 25 ml, respectively.

CONCLUSION

Tumor volume could predict the OS and LPFS of patients. We propose that tumor volume should be considered in the risk stratification and CIRT-based treatment for patients with LR-NPC.

A protocol for a randomized trial evaluating the role of carbon-ion radiation therapy plus camrelizumab for patients with locoregionally recurrent nasopharyngeal carcinoma

PURPOSE

Management of locoregionally recurrent nasopharyngeal carcinoma (LR NPC) is difficult. Although carbon-ion radiation therapy (CIRT) could substantially improve the overall survival (OS) of those patients, around 40% of the patients may still develop local failure. Further improvement of the disease control is necessary. Immunotherapy, such as immune checkpoint inhibitors (ICIs) becomes a promising antitumor treatment. The role of ICIs was proved in head and neck cancers including recurrent/metastatic NPC. Preclinical studies indicated potential synergistic effects between radiation therapy and ICIs. Therefore, we conduct a randomized phase 2 trial to evaluate the efficacy and safety of camrelizumab, an anti-PD-1 monoclonal antibody, along with CIRT in patients with LR NPC.

METHODS

Patients will be randomly assigned at 1:1 to receive either standard CIRT with 63 Gy (relatively biological effectiveness, [RBE]) in 21 fractions, or standard CIRT plus concurrent camrelizumab. Camrelizumab will be administered intravenously with a dose of 200 mg, every 2 week, for a maximum of 1 year. We estimate addition of camrelizumab will improve the 2-year progression-free survival (PFS) from 45% to 60%. A total of 146 patients (with a 5% lost to follow-up rate) is required to yield a type I error of 0.2, and a power of 0.8.

RESULTS AND CONCLUSION

The results of the trial may shed insights on the combined therapy with ICIs and CIRT.

Automated planning of stereotactic spine re-irradiation using cumulative dose limits

Background and Purpose

The lack of dedicated tools in commercial planning systems currently restricts efficient review and planning for re-irradiation. The aim of this study was to develop an automated re-irradiation planning framework based on cumulative doses.

Materials and Methods

We performed a retrospective study of 14 patients who received spine SBRT re-irradiation near a previously irradiated treatment site. A fully-automated workflow, DART (Dose Accumulation-based Re-irradiation Tool), was implemented within Eclipse by leveraging a combination of a dose accumulation script and a proprietary automated optimization algorithm. First, we converted the prior treatment dose into equivalent dose in 2 Gy fractions (EQD2) and mapped it to the current anatomy, utilizing deformable image registration. Subsequently, the intersection of EQD2 isodose lines with relevant organs at risk defines a series of optimization structures. During plan optimization, the residual allowable dose at a specified tissue tolerance was treated as a hard constraint.

Results

All DART plans met institutional physical and cumulative constraints and passed plan checks by qualified medical physicists. DART demonstrated significant improvements in target coverage over clinical plans, with an average increase in PTV D99% and V100% of 2.3 Gy [range -0.3-7.7 Gy] and 3.4 % [range -0.4 %-7.6 %] (p < 0.01, paired t-test), respectively. Moreover, high-dose spillage (>105 %) outside the PTV was reduced by up to 7 cm3. The homogeneity index for DART plans was improved by 19 % (p < 0.001).

Conclusions

DART provides a powerful framework to achieve more tailored re-irradiation plans by accounting for dose distributions from the previous treatments. The superior plan quality could improve the therapeutic ratio for re-irradiation patients.

Breast Cancer and Mediastinal Hodgkin's Lymphomas: Multidisciplinary Discussion

Treatment for Hodgkin's lymphoma (HL) has evolved, with modern treatments combining less toxic chemotherapy and radiation, leading to improved long-term disease-free survival. However, there is a higher chance of second cancer, especially breast cancer, following effective HL treatment. The impact of reduced radiation doses and volumes, as well as the use of advanced irradiation techniques, on the risk of second malignancy is not clear. According to medical organizations, the history of chest irradiation is a relative contraindication to breast preservation therapy for women with initial breast cancer, leading to a paradigm of mastectomy. This article proposes a discussion between radiation oncologists and surgeons to review major trials and recent developments on the prevalence of breast cancer following HL therapy, the risk of contralateral cancer, the feasibility of breast conserving surgery (BCS), as well as breast reconstruction modalities.

Spinal Reirradiation-Mediated Myelopathy: A Systematic Review and Meta-Analysis

Reirradiation of the spine is carried out in 42% of patients who do not respond to treatment or have recurrent pain. However, there are few studies and data on the effect of reirradiation of the spine and the occurrence of acute and chronic side-effects caused by reirradiation, such as myelopathy, in these patients. This meta-analysis aimed to determine the safe dose in terms of biological effective dose (BED), cumulative dose and dose interval between BED1 and BED2 to decrease or prevent myelopathy and pain control in patients undergoing radiation therapy in the spinal cord. A search was carried out using EMBASE, MEDLINE, PUBMED, Google Scholar, Cochrane Collaboration library electronic databases, Magiran, and SID from 2000 to 2022 to recognise qualified studies. In total, 17 primary studies were applied to estimate the pooled effect size. The random effects model showed that the pooled BED in the first stage, the BED in the second stage and the cumulative BED1 and BED2 were estimated at 77.63, 58.35 and 115.34 Gy, respectively. Studies reported on dose interval. The results of a random effects model showed that the pooled interval was estimated at 13.86 months. The meta-analysis revealed that using appropriate BED1 and/or BED2 in a safe interval between the first and second phases of treatment can have an influential role in preventing or reducing the effects of myelopathy and regional control pain in spinal reirradiation.

Brain Re-Irradiation Robustly Accounting for Previously Delivered Dose

(1) Background: The STRIDeR (Support Tool for Re-Irradiation Decisions guided by Radiobiology) planning pathway aims to facilitate anatomically appropriate and radiobiologically meaningful re-irradiation (reRT). This work evaluated the STRIDeR pathway for robustness compared to a more conservative manual pathway. (2) Methods: For ten high-grade glioma reRT patient cases, uncertainties were applied and cumulative doses re-summed. Geometric uncertainties of 3, 6 and 9 mm were applied to the background dose, and LQ model robustness was tested using α/β variations (values 1, 2 and 5 Gy) and the linear quadratic linear (LQL) model δ variations (values 0.1 and 0.2). STRIDeR robust optimised plans, incorporating the geometric and α/β uncertainties during optimisation, were also generated. (3) Results: The STRIDeR and manual pathways both achieved clinically acceptable plans in 8/10 cases but with statistically significant improvements in the PTV D98% (p < 0.01) for STRIDeR. Geometric and LQ robustness tests showed comparable robustness within both pathways. STRIDeR plans generated to incorporate uncertainties during optimisation resulted in a superior plan robustness with a minimal impact on PTV dose benefits. (4) Conclusions: Our results indicate that STRIDeR pathway plans achieved a similar robustness to manual pathways with improved PTV doses. Geometric and LQ model uncertainties can be incorporated into the STRIDeR pathway to facilitate robust optimisation.

Re-irradiation for recurrent/progressive pediatric brain tumors: from radiobiology to clinical outcomes

INTRODUCTION

Brain tumors are the most common solid tumors in children. Neurosurgical excision, radiotherapy, and/or chemotherapy represent the standard of care in most histopathological types of pediatric central nervous system (CNS) tumors. Even though the successful cure rate is reasonable, some patients may develop recurrence locally or within the neuroaxis.

AREA COVERED

The management of these recurrences is not easy; however, significant advances in neurosurgery, radiation techniques, radiobiology, and the introduction of newer biological therapies, have improved the results of their salvage treatment. In many cases, salvage re-irradiation is feasible and has achieved encouraging results. The results of re-irradiation depend upon several factors. These factors include tumor type, extent of the second surgery, tumor volume, location of the recurrence, time that elapses between the initial treatment, the combination with other treatment agents, relapse, and the initial response to radiotherapy.

EXPERT OPINION

Reviewing the radiobiological basis and clinical outcome of pediatric brain re-irradiation revealed that re-irradiation is safe, feasible, and indicated for recurrent/progressive different tumor types such as; ependymoma, medulloblastoma, diffuse intrinsic pontine glioma (DIPG) and glioblastoma. It is now considered part of the treatment armamentarium for these patients. The challenges and clinical results in treating recurrent pediatric brain tumors were highly documented.

Magnetic resonance guided SBRT reirradiation in locally recurrent prostate cancer: a multicentric retrospective analysis

AIMS

Reirradiation of prostate cancer (PC) local recurrences represents an emerging challenge for current radiotherapy. In this context, stereotactic body radiation therapy (SBRT) allows the delivery of high doses, with curative intent. Magnetic Resonance guided Radiation Therapy (MRgRT) has shown promising results in terms of safety, feasibility and efficacy of delivering SBRT thanks to the enhanced soft tissue contrast and the online adaptive workflow. This multicentric retrospective analysis evaluates the feasibility and efficacy of PC reirradiation, using a 0.35 T hybrid MR delivery unit.

METHODS

Patients affected by local recurrences of PC and treated in five institutions between 2019 and 2022 were retrospectively collected. All patients had undergone previous Radiation Therapy (RT) in definitive or adjuvant setting. Re-treatment MRgSBRT was delivered with a total dose ranging from 25 to 40 Gy in 5 fractions. Toxicity according to CTCAE v 5.0 and treatment response were assessed at the end of the treatment and at follow-up.

RESULTS

Eighteen patients were included in this analysis. All patients had previously undergone external beam radiation therapy (EBRT) up to a total dose of 59.36 to 80 Gy. Median cumulative biologically effective dose (BED) of SBRT re-treatment was 213,3 Gy (103,1-560), considering an α/β of 1.5. Complete response was achieved in 4 patients (22.2%). No grade ≥ 2 acute genitourinary (GU) toxicity events were recorded, while gastrointestinal (GI) acute toxicity events occurred in 4 patients (22.2%).

CONCLUSION

The low rates of acute toxicity of this experience encourages considering MRgSBRT a feasibile therapeutic approach for the treatment of clinically relapsed PC. Accurate gating of target volumes, the online adaptive planning workflow and the high definition of MRI treatment images allow delivering high doses to the PTV while efficiently sparing organs at risk (OARs).

Treatment plan optimisation for reirradiation

BACKGROUND

The STRIDeR (Support Tool for Re-Irradiation Decisions guided by Radiobiology) project aims to create a clinically viable re-irradiation planning pathway within a commercial treatment planning system (TPS). Such a pathway should account for previously delivered dose, voxel-by-voxel, taking fractionation effects, tissue recovery and anatomical changes into account. This work presents the workflow and technical solutions in the STRIDeR pathway.

METHODS

The pathway was implemented in RayStation (version 9B DTK) to allow an original dose distribution to be used as background dose to guide optimisation of re-irradiation plans. Organ at risk (OAR) planning objectives in equivalent dose in 2 Gy fractions (EQD2) were applied cumulatively across the original and re-irradiation treatments, with optimisation of the re-irradiation plan performed voxel-by-voxel in EQD2. Different approaches to image registration were employed to account for anatomical change. Data from 21 patients who received pelvic Stereotactic Ablative Radiotherapy (SABR) re-irradiation were used to illustrate the use of the STRIDeR workflow. STRIDeR plans were compared to those produced using a standard manual method.

RESULTS

The STRIDeR pathway resulted in clinically acceptable plans in 20/21 cases. Compared to plans produced using the laborious manual method, less constraint relaxation was required or higher re-irradiation doses could be prescribed in 3/21.

CONCLUSION

The STRIDeR pathway used background dose to guide radiobiologically meaningful, anatomically-appropriate re-irradiation treatment planning within a commercial TPS. This provides a standardised and transparent approach, offering more informed re-irradiation and improved cumulative OAR dose evaluation.

Efficacy and toxicity of primary re-irradiation for malignant spinal cord compression based on radiobiological modelling: a phase II clinical trial

BACKGROUND

The efficacy and safety of primary re-irradiation for MSCC are not known. Our aim was to establish the efficacy and safety of biologically effective dose-based re-irradiation.

METHODS

Patients presenting with MSCC at a previously irradiated spine segment, and not proceeding with surgical decompression, were eligible. A 3 Gray per fraction experimental schedule (minimum 18 Gy/6 fractions, maximum 30 Gy/10 fractions) was used, delivering a maximum cumulative spinal dose of 100 Gy2 if the interval since the last radiotherapy was within 6 months, or 130 Gy2 if longer. The primary outcome was a change in mobility from week 1 to week 5 post-treatment, as assessed by the Tomita score. The RTOG SOMA score was used to screen for spinal toxicity, and an MRI performed to assess for radiation-induced myelopathy (RIM).

RESULTS

Twenty-two patients were enroled, of whom eleven were evaluable for the primary outcome. Nine of eleven (81.8%) had stable or improved Tomita scores at 5 weeks. One of eight (12.5%) evaluable for late toxicity developed RIM.

CONCLUSIONS

Re-irradiation is an efficacious treatment for MSCC. There is a risk of RIM with a cumulative dose of 120 Gy2.

CLINICAL TRIAL REGISTRATION

Cancer Trials Ireland (ICORG 07-11); NCT00974168.

European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer consensus on re-irradiation: definition, reporting, and clinical decision making

Re-irradiation can be considered for local recurrence or new tumours adjacent to a previously irradiated site to achieve durable local control for patients with cancer who have otherwise few therapeutic options. With the use of new radiotherapy techniques, which allow for conformal treatment plans, image guidance, and short fractionation schemes, the use of re-irradiation for different sites is increasing in clinical settings. Yet, prospective evidence on re-irradiation is scarce and our understanding of the underlying radiobiology is poor. Our consensus on re-irradiation aims to assist in re-irradiation decision making, and to standardise the classification of different forms of re-irradiation and reporting. The consensus has been endorsed by the European Society for Radiotherapy and Oncology and the European Organisation for Research and Treatment of Cancer. The use of this classification in daily clinical practice and research will facilitate accurate understanding of the clinical implications of re-irradiation and allow for cross-study comparisons. Data gathered in a uniform manner could be used in the future to make recommendations for re-irradiation on the basis of clinical evidence. The consensus document is based on an adapted Delphi process and a systematic review of the literature was done according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

Re-Irradiation for Recurrent Cervical Cancer: A State-of-the-Art Review

The recurrence rate of cervical cancer after primary treatment can reach 60%, and a poor prognosis is reported in most cases. Treatment options for the recurrence of cervical cancer mainly depend on the prior treatment regimen and the location of recurrent lesions. Re-irradiation is still considered as a clinical challenge, owing to a high incidence of toxicity, especially in in-field recurrence within a short period of time. Recent advances in radiotherapy have preliminarily revealed encouraging outcomes of re-irradiation. Several centers have concentrasted on stereotactic body radiation therapy (SBRT) for the treatment of well-selected cases. Meanwhile, as the image-guiding techniques become more precise, a better dose profile can also be achieved in brachytherapy, including high-dose-rate interstitial brachytherapy (HDR-ISBT) and permanent radioactive seed implantation (PRSI). These treatment modalities have shown promising efficacy with a tolerable toxicity, providing further treatment options for recurrent cervical cancer. However, it is highly unlikely to draw a definite conclusion from all of those studies due to the large heterogeneity among them and the lack of large-scale prospective studies. This study mainly reviews and summarizes the progress of re-irradiation for recurrent cervical cancer in recent years, in order to provide potential treatment regimens for the management of re-irradiation.

Emerging Role of Carbon Ion Radiotherapy in Reirradiation of Recurrent Head and Neck Cancers: What Have We Achieved So Far?

Administering reirradiation for the treatment of recurrent head and neck cancers is extremely challenging. These tumors are hypoxic and radioresistant and require escalated radiation doses for adequate control. The obstacle to delivering this escalated dose of radiation to the target is its proximity to critical organs at risk (OARs) and possible development of consequent severe late toxicities. With the emergence of highly sophisticated technologies, intensity-modulated radiotherapy (IMRT) and stereotactic body radiotherapy have shown promising outcomes. Proton beam radiotherapy has been used for locally recurrent head and neck cancers because of its excellent physical dose distribution, exploring sharp Bragg peak properties with negligible entrance and exit doses. To further improve these results, carbon ion radiotherapy (CIRT) has been explored in several countries across Europe and Asia because of its favorable physical properties with minimal entrance and exit doses, sharper lateral penumbra, and much higher and variable relative biological efficacy, which cannot be currently achieved with any other form of radiation. Few studies have described the role of CIRT in recurrent head and neck cancers. In this article, we have discussed the different aspects of carbon ions in reirradiation of recurrent head and neck cancers, including European and Asian experiences, different dose schedules, dose constraints of OARs, outcomes, and toxicities, and a brief comparison with proton beam radiotherapy and IMRT.

Dose summation and image registration strategies for radiobiologically and anatomically corrected dose accumulation in pelvic re-irradiation

BACKGROUND

Re-irradiation (reRT) is a promising technique for patients with localized recurrence in a previously irradiated area but presents major challenges. These include how to deal with anatomical change between two courses of radiotherapy and integration of radiobiology when summating original and re-irradiation doses. The Support Tool for Re-Irradiation Decisions guided by Radiobiology (STRIDeR) project aims to develop a software tool for use in a commercial treatment planning system to facilitate more informed reRT by accounting for anatomical changes and incorporating radiobiology. We evaluated three approaches to dose summation, incorporating anatomical change and radiobiology to differing extents.

METHODS

In a cohort of 21 patients who previously received pelvic re-irradiation the following dose summation strategies were compared: (1) Rigid registration (RIR) and physical dose summation, to reflect the current clinical approach, (2) RIR and radiobiological dose summation in equivalent dose in 2 Gy fractions (EQD2), and (3) Patient-specific deformable image registration (DIR) with EQD2 dose summation.

RESULTS

RIR and physical dose summation (Strategy 1) resulted in high cumulative organ at risk (OAR) doses being 'missed' in 14% of cases, which were highlighted by EQD2 dose summation (Strategy 2). DIR (with EQD2 dose summation; Strategy 3) resulted in improved OAR overlap and distance to agreement metrics compared to RIR (with EQD2 dose summation; Strategy 2) and was consistently preferred in terms of clinical utility. DIR was considered to have a clinically important impact on dose summation in 38% of cases.

CONCLUSION

Re-irradiation cases require individualized assessment when considering dose summation with the previous treatment plan. Fractionation correction is necessary to meaningfully assess cumulative doses and reduce the risk of unintentional OAR overdose. DIR can add clinically relevant information in selected cases, especially for significant anatomical change. Robust solutions for cumulative dose assessment offer the potential for future improved understanding of cumulative OAR tolerances.

A treatment planning comparison of photon stereotactic ablative radiotherapy and proton beam therapy for the re-irradiation of pelvic cancer recurrence

BACKGROUND

Patients who experience a pelvic cancer recurrence in or near a region that received initial radiotherapy, typically have few options for treatment. Organs at risk (OAR) have often reached their dose constraint limits leaving minimal dose remaining for standard re-irradiation (reRT). However, photon based stereotactic ablative radiotherapy (SABR) has been utilised for reRT with promising initial results although meeting OAR constraints can be challenging. Proton beam therapy (PBT) could offer an advantage.

MATERIALS AND METHODS

SABR plans used for treatment for ten pelvic reRT patients were dosimetrically compared to PBT plans retrospectively planned using the same CT and contour data. PBT plans were created to match the CTV dose coverage of SABR treatment plans with V100% ≥95%. An 'as low as reasonably achievable' approach was taken to OAR tolerances with consideration of OAR dose from the initial radiation (using equivalent dose in 2 Gy fractions).

RESULTS

Dosimetric comparison of relevant OAR statistics showed a decrease in OAR dose using PBT over SABR in all patients, with equivalent target coverage. The largest statistically significant reduction was seen for the colon D0.5 cm3 with a median reduction from 13.1 Gy to 5.9 Gy. There were statistically significant dose reductions in the median dose to small bowel, sacral plexus and cauda equina.

CONCLUSION

PBT has the potential for significant dose reductions for OARs in the pelvic reRT setting compared to SABR. However, it remains unclear if the magnitude of these OAR dose reductions will translate into clinical benefit.

An international Delphi consensus for pelvic stereotactic ablative radiotherapy re-irradiation

INTRODUCTION

Stereotactic Ablative Radiotherapy (SABR) is increasingly used to treat metastatic oligorecurrence and locoregional recurrences but limited evidence/guidance exists in the setting of pelvic re-irradiation. An international Delphi study was performed to develop statements to guide practice regarding patient selection, pre-treatment investigations, treatment planning, delivery and cumulative organs at risk (OARs) constraints.

MATERIALS AND METHODS

Forty-one radiation oncologists were invited to participate in three online surveys. In Round 1, information and opinion was sought regarding participants' practice. Guidance statements were developed using this information and in Round 2 participants were asked to indicate their level of agreement with each statement. Consensus was defined as ≥75% agreement. In Round 3, any statements without consensus were re-presented unmodified, alongside a summary of comments from Round 2.

RESULTS

Twenty-three radiation oncologists participated in Round 1 and, of these, 21 (91%) and 22 (96%) completed Rounds 2 and 3 respectively. Twenty-nine of 44 statements (66%) achieved consensus in Round 2. The remaining 15 statements (34%) did not achieve further consensus in Round 3. Consensus was achieved for 10 of 17 statements (59%) regarding patient selection/pre-treatment investigations; 12 of 13 statements (92%) concerning treatment planning and delivery; and 7 of 14 statements (50%) relating to OARs. Lack of agreement remained regarding the minimum time interval between irradiation courses, the number/size of pelvic lesions that can be treated and the most appropriate cumulative OAR constraints.

CONCLUSIONS

This study has established consensus, where possible, in areas of patient selection, pre-treatment investigations, treatment planning and delivery for pelvic SABR re-irradiation for metastatic oligorecurrence and locoregional recurrences. Further research into this technique is required, especially regarding aspects of practice where consensus was not achieved.

Ultra hypofractionated extended nodal irradiation using volumetric modulated arc therapy for oligorecurrent pelvic nodal prostate cancer

Prostate cancer (PCa) may recur after primary treatment but no standard of care exists for patients with pelvic nodal relapse. Based on obervational data, Extended Nodal Irradiation (ENI) might be associated with fewer treatment failures than Stereotactic Ablative Radiotherapy (SABR) to the involved node(s) alone. Ultra hypofractionated ENI is yet to be evaluated in this setting, but it could provide a therapeutic advantage if PCa has a low α/β ratio in addition to patient convenience/resource benefits. This volumetric modulated arc therapy (VMAT) planning study developed a class solution for 5-fraction Extended Nodal Irradiation (ENI) plus a simultaneous integrated boost (SIB) to involved node(s). Ten patients with oligorecurrent nodal disease after radical prostatectomy/post-operative prostate bed radiotherapy were selected. Three plans were produced for each dataset to deliver 25 Gy in 5 fractions ENI plus SIBs of 40, 35 and 30 Gy. The biologically effective dose (BED) formula was used to determine the remaining dose in 5 fractions that could be delivered to re-irradiated segments of organs at risk (OARs). Tumour control probability (TCP) and normal tissue complication probability (NTCP) were calculated using the LQ-Poisson Marsden and Lyman-Kutcher-Burman models respectively. Six patients had an OAR positioned within planning target volume node (PTVn), which resulted in reduced target coverage to PTV node in six, five and four instances for 40, 35 and 30 Gy SIB plans respectively. In these instances, only 30 Gy SIB plans had a median PTV coverage >90% (inter-quartile range 90-95). No OAR constraint was exceeded for 30 Gy SIB plans, including where segments of OARs were re-irradiated. Gross tumour volume node (GTVn) median TCP was 95.7% (94.4-96), 90.7% (87.1-91.2) and 78.6% (75.8-81.1) for 40, 35 and 30 Gy SIB plans respectively, where an α/β ratio of 1.5 was assumed. SacralPlex median NTCP was 43.2% (0.7-61.2), 12.1% (0.6-29.7) and 2.5% (0.5-5.1) for 40, 35 and 30 Gy SIB plans respectively. NTCP for Bowel_Small was <0.3% and zero for other OARs for all three plan types. Ultra hypofractionated ENI planning for pelvic nodal relapsed PCa appears feasible with encouraging estimates of nodal TCP and low estimates of NTCP, especially where a low α/β ratio is assumed and a 30 Gy SIB is delivered. This solution should be further evaluated within a clinical trial and compared against SABR to involved node(s) alone.

Preclinical Studies and Clinical Prospects of Wharton's Jelly-Derived MSC for Treatment of Acute Radiation Syndrome

Purpose of Review

Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs) have received widespread attention from researchers owing to the remarkable benefits offered by these cells over other stem cells. The primitive nature of WJ-MSCs, ease of isolation, differentiation ability, and immuno-modulatory nature make these cells superior to bone marrow MSCs and ideal to treat various human ailments. This review explores ability of WJ-MSCs to mitigate acute radiation syndrome caused by planned or unplanned radiation exposure.

Recent Findings

Recent reports suggest that WJ-MSCs home to damaged tissues in irradiated host and mitigate radiation induced damage to radiosensitive tissues such as hematopoietic and gastrointestinal systems. WJ-MSCs and conditioned media were found to protect mice from radiation induced mortality and also prevent radiation dermatitis. Local irradiation-induced lung toxicity in mice was significantly reduced by CXCR4 over-expressing WJ-MSCs.

Summary

Emerging evidences support safety and effectiveness of WJ-MSCs for treatment of acute radiation syndrome and lung injury after planned or accidental exposure. Additionally, conditioned media collected after culturing WJ-MSCs can also be used for mitigation of radiation dermatitis. Clinical translation of these findings would be possible after careful evaluation of resilience, effectiveness, and molecular mechanism of action of xenogeneic WJ-MSCs in non-human primates.

Re-Irradiation of Recurrent Non-Small Cell Lung Cancer

Locoregional recurrence occurs in 10%-30% of non-small cell lung cancer (NSCLC) after treatment with definitive (chemo)radiotherapy. Re-irradiation is the main curative-intent treatment option for these patients; however, it represents a therapeutic challenge for thoracic radiation oncologists. Re-irradiation practices are variable worldwide with lack of agreement on the optimal dose or the cumulative maximum dose acceptable for critical organs. The role of re-irradiation in NSCLC is also not clearly defined in the era of immunotherapy. In this review, we will present published and on-going re-irradiation studies for recurrent NSCLC. We will appraise available evidence for critical organ dose constraints and provide a framework for future therapeutic approaches and trials.

RBE-weighted dose conversions for patients with recurrent nasopharyngeal carcinoma receiving carbon-ion radiotherapy from the local effect model to the microdosimetric kinetic model

Background

We sought to establish a conversion curve to convert the RBE-weighted doses calculated by local effect model I (LEM) (LEM RBE-weighted doses) in patients with locally recurrent nasopharyngeal carcinoma (rNPC) to the RBE-weighted doses calculated by microdosimetric kinetic model (MKM) (MKM RBE-weighted doses). We also converted the LEM dose constraints (RBE-weighted dose constraints in LEM plans) for the brain stem, spinal cord, and optic nerve based on this curve.

Methods

Data from 20 patients with rNPC receiving carbon-ion radiotherapy (CIRT) in our hospital were collected. LEM in Raystation (V8A, Raystation, Sweden) was used to generate treatment plans. The clinical target volume CTV1 (GTV + 5 mm) was given 3 Gy (RBE) per fraction. Ninety-nine percent of target volumes should be covered by 95% of the prescriptions; the maximum doses of the brainstem and spinal cord were < 45 Gy (RBE) and < 30 Gy (RBE), respectively. The doses covering 20% volumes of optical nerves/chiasms D20 were < 30 Gy (RBE). Then physical doses of the LEM plans were recalculated by using MKM in Raystation to generate MKM plans. A series of conversion factors (i.e., the ratio of LEM RBE-weighted dose to MKM RBE-weighted dose) was then obtained by using an isovolumetric dose method. The LEM plan prescriptions (LEM prescription) and dose constraints of the organs at risk (OARs) (OAR constraints) were converted to the corresponding MKM prescriptions and dose constraints using this conversion curve.

Results

For the CTV1 fractional RBE-weighted dose prescription of 3.00 Gy (RBE) and CTV2 of 2.70 Gy (RBE) in LEM plans, the conversion factors (LEM RBE-weighted dose/MKM RBE-weighted dose) were 1.37 (CI 95% 1.35–1.39) and 1.46 (1.41–1.51), respectively. The average conversion factors from 1.37 (CI 95% 1.33–1.41) to 3.09 (2.94–3.24) corresponded to the LEM fractionated doses from 2.86 Gy (RBE) to 0.24 Gy (RBE), including the doses constraining upon OARs. LEM RBE-weighted doses of 30 Gy (RBE) and 45 Gy (RBE) in 21 fractions were converted to MKM RBE-weighted doses of 16.64 Gy (RBE) and 30.72 Gy (RBE) in 16 fractions.

Conclusions

This conversion curve could be used to convert LEM RBE-weighted doses to MKM RBE-weighted doses for patients with rNPC receiving CIRT, providing dose references for re-irradiation therapy.

Management of recurrent or progressive spinal metastases: reirradiation techniques and surgical principles

With the growing incidence of new cases and the increasing prevalence of patients living longer with spine metastasis, a methodological approach to the management of patients with recurrent or progressive disease is increasing in relevance and importance in clinical practice. As a result, disease management has evolved in these patients using advanced surgical and radiotherapy technologies. Five key goals in the management of patients with spine metastases include providing pain relief, controlling metastatic disease at the treated site, improving neurologic deficits, maintaining or improving functional status, and minimizing further mechanical instability. The focus of this review is on advanced reirradiation techniques, given that the majority of patients will be treated with upfront conventional radiotherapy and further treatment on progression is often limited by the cumulative tolerance of nearby organs at risk. This review will also discuss novel surgical approaches such as separation surgery, minimally invasive percutaneous instrumentation, and laser interstitial thermal therapy, which is increasingly being coupled with spine reirradiation to maximize outcomes in this patient population. Lastly, given the complexities of managing recurrent spinal disease, this review emphasizes the importance of multidisciplinary care from neurosurgery, radiation oncology, medical oncology, neuro-oncology, rehabilitation medicine, and palliative care.

Repeat Thoracic Stereotactic Body Radiation Therapy (SBRT) for Nonsmall Cell Lung Cancer: Long-Term Outcomes, Toxicity, and Dosimetric Considerations

Purpose

Lung reirradiation for nonsmall cell lung cancer (NSCLC) is common for either recurrent disease or new primary cancer. Dose volume tolerance of the lung after multiple courses of radiation therapy (RT) is unknown. We review our experience with lung reirradiation for patients with NSCLC in a single community setting using stereotactic body radiation therapy (SBRT) to report lung cumulative doses, survival, and toxicity.

Methods and Materials

Forty-four patients who received at least 2 curative courses of lung RT with the second course delivered between January 2012 and December 2017 were eligible. All patients had NSCLC and were treated with SBRT for reirradiation. Cumulative lung dose volume histograms for all courses were generated, summated, and converted into cumulative equivalent dose in 2 Gy fractions (EQD2). Actuarial overall survival (OS), local control, and toxicity is reported, including a subset of patients who received more than 2 courses of SBRT.

Results

Median age of the group was 71 years (range, 51-87). Median survival of the entire group from diagnosis, first, and second courses of RT was 3.94, 3.03, and 2.03 years. Three-year actuarial OS for the entire group was 34.1% from second course of RT. The mean EQD2 Gy₃ mean lung dose for all courses was 12.35 Gy (range, 2.7-26.52). The mean EQD2 Gy₃ V5Gy, V10Gy, V20Gy, V30Gy, and V40Gy were 40.9%, 25.5%, 14.7%, 10.2%, and 7.7%. Six-year actuarial freedom from grade ≥3 complications was 86.3%. The rate of grade ≥3 lung toxicity was 4.5% (2 of 44). Other late toxicities included grade 3 recurrent laryngeal nerve damage (n = 1) and grade 3 chest wall pain/rib fracture (n = 1). Overall, 32% of patients had more than 2 courses of RT to the lung (range, 3-7).

Conclusions

Long-term OS is possible with multiple RT courses to the lung for NSCLC with low toxicity.

Particle Beam Radiation Therapy for Skull Base Sarcomas

Background: To report the clinical experience of carbon-ion and proton radiation therapy for skull base sarcomas.

Methods: An analysis of the retrospective data registry from the Shanghai Proton and Heavy Ion Center for patients with skull base sarcomas was conducted. The 1-/2-year local relapse-free, distant metastasis-free, progression-free, and overall survival (LRFS, DMFS, PFS, OS) rates as well as associated prognostic indicators were analyzed. Radiotherapy-induced acute and late toxicities were summarized.

Results: Between 7/2014 and 5/2019, 62 patients with skull base sarcomas of various subtypes received carbon-ion radiation therapy (53), proton radiation therapy (5), or proton radiation therapy + carbon-ion boost (4). With a median follow-up of 20.4 (range 2.73–91.67) months, the 1-/2-year OS, LRFS, DMFS, and PFS rates were 91.2%/80.2%, 89.2%/80.2%, 86.0%/81.1%, and 75.8%/62.9%, respectively. Grade 3 mucositis and grade 4 hemorrhage were observed in 1 patient for each. Only grade 1 and grade 2 toxicities were observed except for the same patient with grade 4 acute toxicity died of severe hemorrhage (grade 5). Multivariate analyses revealed the lack of prior RT was an independent favorable prognostic factor for OS, PFS, and LRFS, age under 40 was associated with improved OS, early T-disease (T1/2) showed a significant association with better PFS.

Conclusion: With few observed acute and late toxicities, particle beam radiation therapy provided effective tumor control and overall survival for patients with skull base sarcomas.

Clinical outcomes of carbon-ion radiotherapy for patients with locoregionally recurrent nasopharyngeal carcinoma

BACKGROUND

Reirradiation for locoregionally recurrent nasopharyngeal carcinoma (LR-NPC) after high-dose radiotherapy (RT) is challenging and usually is associated with poor survival and severe toxicities. Because of its physical and biological advantages over photon-beam RT, carbon-ion RT (CIRT) could be a potential treatment option for patients with LR-NPC.

METHODS

Patients with LR-NPC who underwent salvage therapy using CIRT at the Shanghai Proton and Heavy Ion Center between May 2015 and June 2019 were analyzed. CIRT doses were 50 to 69 gray equivalent (GyE) (2.0-3.0 GyE per fraction). Overall survival (OS), local control, regional control, distant control, and acute and late toxicities were analyzed. Univariable and multivariable analyses of OS and local control were performed using the Cox regression model.

RESULTS

Among the 206 patients included, 139 patients (67.5%) had recurrent American Joint Committee on Cancer stage III or stage IV disease. With a median follow-up of 22.8 months, the 2-year OS, local control, regional control, and distant control rates were 83.7%, 58.0%, 87.3%, and 94.7%, respectively. Multivariable analysis revealed that older age (P = .017) was predictive of worse OS, whereas a larger tumor volume (P = .049) and a lower biological equivalent dose (P = .029) were associated with inferior local control. No patient developed an acute toxicity of ≥grade 3 during CIRT. Severe (≥grade 3) late toxicities included temporal lobe necrosis (0.97%), cranial neuropathy (0.49%), hearing loss (1.46%), xerostomia (0.49%), and mucosal necrosis (16.02%) (toxicities were graded using the Radiation Therapy Oncology Group and European Organization for Research and Treatment of Cancer criteria).

CONCLUSIONS

Salvage treatment using CIRT is efficacious for patients with LR-NPC and its toxicities are acceptable. CIRT may improve the survival and toxicity profiles substantially for patients with LR-NPC compared with the reported results after photon-based intensity-modulated RT.

A national surveillance study of the current status of reirradiation using brachytherapy in Japan

PURPOSE

This study aimed to explore the current status and pattern of practice for reirradiation using brachytherapy (ReRT-BT) through a survey in Japan.

MATERIALS AND METHODS

We distributed an e-mail-based questionnaire to 153 institutions equipped with high-dose-rate brachytherapy facilities.

RESULTS

We received responses from 76 institutions (49.7%). Forty-three of these institutions performed ReRT-BT and 42 institutions (55%) performed ReRT-BT during 2009-2018. However, 29 of the 42 institutions (69%) reported difficulty in obtaining ReRT-BT case information from their respective databases. Almost all the institutions encountered insufficient database system to extract details about the ReRT-BT cases. Responses from 33 institutions included the number of ReRT-BT cases; this increased from 90 in the period 2009-2013 (institution median = 0.5; 0-16) to 172 in the period 2014-2018 (institution median = 2; 0-26). Nine institutions had to perform ReRT-BT for more than one case per year. The major location for cancer treatment was the pelvis (94%), followed by the head and neck (5%) and others (1%). In six site-specific scenarios, barring uterine corpus cancer recurrence, more than 90% of radiation oncologists agreed to perform ReRT-BT, whereas other areas (head and neck, prostate, and rectal cancer) gained 16-37% agreement.

CONCLUSIONS

This decade saw an increase in the number of ReRT-BT cases in Japan and radiation oncologists' interest in ReRT-BT as a viable therapeutic option. However, scarce availability, immature education system, and insufficient database system are barriers to further consensus building.

Stereotactic Body Radiation Therapy Reirradiation for Locally Recurrent Rectal Cancer: Outcomes and Toxicity

Purpose

Stereotactic body radiation therapy (SBRT) has emerged as a potential therapeutic option for locally recurrent rectal cancer (LRRC) but contemporaneous clinical data are limited. We aimed to evaluate the local control, toxicity, and survival outcomes in a cohort of patients previously treated with neoadjuvant pelvic radiation therapy for nonmetastatic locally recurrent rectal cancer, now treated with SBRT.

Methods and Materials

Inoperable rectal cancer patients with ≤3 sites of pelvic recurrence and >6 months since prior pelvic radiation therapy were identified from a prospective registry over 4 years. SBRT dose was 30 Gy in 5 fractions, daily or alternate days, using cumulative organ at risk dose constraints. Primary outcome was local control (LC). Secondary outcomes were progression free survival, overall survival, toxicity, and patient reported quality of life scores using the EQ visual analog scale (EQ-VAS) tool.

Results

Thirty patients (35 targets) were included. Median gross tumor volume size was 14.3 cm³. In addition, 27 of 30 (90%) previously received 45 to 50.4 Gy in 25 of 28 fractions, with 10% receiving an alternative prescription. All patients received the planned reirradiation SBRT dose. The median follow-up was 24.5 months (interquartile range, 17.8-28.8). The 1-year LC was 84.9% (95% confidence interval [CI], 70.6-99) and a 2-year LC was 69% (95% CI, 51.8-91.9). The median progression free survival was 12.1 months (95% CI, 8.6-17.66), and median overall survival was 28.3 months (95% CI, 17.88-39.5 months). No patient experienced >G2 acute toxicity and only 1 patient experienced late G3 toxicity. Patient-reported QoL outcomes were improved at 3 months after SBRT (Δ EQ-VAS, +10 points, Wilcoxon signed-rank, P = .009).

Conclusions

Our study demonstrates that, for small volume pelvic disease relapses from rectal cancer, reirradiation with 30 Gy in 5 fractions is well tolerated and achieves an excellent balance between high local control rates with limited toxicity.

The preliminary results of proton and carbon ion therapy for chordoma and chondrosarcoma of the skull base and cervical spine

Purpose

To evaluate the short-term outcomes in terms of tumor control and toxicity of patients with skull base or cervical spine chordoma and chondrosarcoma treated with intensity-modulated proton or carbon-ion radiation therapy.

Methods

Between 6/2014 and 7/2018, a total of 91 patients were treated in our Center. The median age was 38 (range, 4–70) years. Forty-six (50.5%) patients were treated definitively for their conditions as initial diagnosis, 45 (49.5%) patients had recurrent tumors including 14 had prior radiotherapy. The median gross tumor volume was 37.0 (range, 1.6–231.7) cc. Eight patients received proton therapy alone, 28 patients received combined proton and carbon ion therapy, 55 patients received carbon-ion therapy alone.

Results

With a median follow-up time of 28 (range, 8–59) months, the 2-year local control (LC), progression free (PFS) and overall survival (OS) rates was 86.2, 76.8, and 87.2%, respectively. Those rates for patients received definitive proton or carbon-ion therapy were 86.7, 82.8, and 93.8%, respectively. On multivariate analyses, tumor volume of > 60 cc was the only significant factor for predicting PFS (p = 0.045), while re-irradiation (p = 0.012) and tumor volume (> vs < 60 cc) (p = 0.005) were significant prognosticators for OS. Grade 1–2 late toxicities were observed in 11 patients, and one patient developed Grade 3 acute mucositis.

Conclusions

Larger tumor volume and re-irradiation were related to inferior survival for this group of patients. Further follow-up is needed for long-term efficacy and safety.

Normal tissue complication probability (NTCP) models for modern radiation therapy

Mathematical models of normal tissue complication probability (NTCP) able to robustly predict radiation-induced morbidities (RIM) play an essential role in the identification of a personalized optimal plan, and represent the key to maximizing the benefits of technological advances in radiation therapy (RT). Most modern RT techniques pose, however, new challenges in estimating the risk of RIM. The aim of this report is to schematically review NTCP models in the framework of advanced radiation therapy techniques. Issues relevant to hypofractionated stereotactic body RT and ion beam therapy are critically reviewed. Reirradiation scenarios for new or recurrent malignances and NTCP are also illustrated. A new phenomenological approach to predict RIM is suggested.

Outcomes of orbital malignancies treated with eye-sparing surgery and adjuvant particle radiotherapy: a retrospective study

Background

To report the clinical experience of eye sparing surgery (ESS) and adjuvant carbon-ion or proton radiotherapy (CIRT or PRT) for orbital malignancies.

Methods

An analysis of the retrospective data registry from the Shanghai Proton and Heavy Ion Center for patients with orbital tumors was conducted. The 2-year local progression-free, regional recurrence-free, distant metastasis-free, progression-free, and overall survival (LPFS, RRFS, DMFS, PFS, OS) rates as well as associated prognostic indicators were analyzed. Radiotherapy-induced acute and late toxicities were summarized.

Results

Between 7/2014 to 5/2018, 22 patients with orbital malignancies of various pathologies received ESS followed by CIRT (18), PRT (1), or PRT + CIRT boost (3). With a median follow-up of 20.25 (range 3.8–38.8) months, the 2-year OS, PFS, LPFS, RRFS, and DMFS rates were 100, 57.9, 92.9, 93.3, and 72.8%, respectively. No acute severe (i.e., ≥grade 3) toxicity was observed. Two patients experienced severe visual impairment as late toxicities.

Conclusion

With few observed acute and late toxicities, particle radiotherapy following ESS provided effective local control with infrequent severe toxicities for patients with orbital malignancies.

Re-Irradiation of Brain Metastases and Metastatic Spinal Cord Compression: Clinical Practice Suggestions

The recent improvements of therapeutic approaches in oncology have allowed a certain number of patients with advanced disease to survive much longer than in the past. So, the number of cases with brain metastases and metastatic spinal cord compression has increased, as has the possibility of developing a recurrence in areas of the central nervous system already treated with radiotherapy.

Clinicians are reluctant to perform re-irradiation of the brain, because of the risk of severe side effects. The tolerance dose for the brain to a single course of radiotherapy is 50–60 Gy in 2 Gy daily fractions. New metastases appear in 22–73% of the cases after whole brain radiotherapy, but the percentage of re-irradiated patients is 3–10%. An accurate selection must be made before giving an indication to re-irradiation. Patients with Karnofsky performance status >70, age <65 years, controlled primary and no extracranial metastases are those with the best prognosis. The absence of extracranial disease was the most significant factor in conditioning survival, and maximum tumor diameter was the only variable associated with an increased risk of unacceptable acute and/or chronic neurotoxicity. Re-treatment of brain metastases can be done with whole brain radiotherapy, stereotactic radiosurgery or fractionated stereotactic radiotherapy. Most patients had no relevant radiation-induced toxicity after a second course of whole brain radiotherapy or stereotactic radiosurgery. There are few data on fractionated stereotactic radiotherapy in the re-irradiation of brain metastases.

In general, the incidence of an “in-field” recurrence of spinal metastasis varies from 2.5–11% of cases and can occur 2–40 months after the first radiotherapy cycle. Radiation-induced myelopathy can occur months or years (6 months-7 years) after radiotherapy, and the pathogenesis remains obscure. Higher radiotherapy doses, larger doses per fraction, and previous exposure to radiation could be associated with a higher probability of developing radiation-induced myelopathy. Experimental data indicate that also the total dose of the first and second radiotherapy, interval to re-treatment, length of the irradiated spinal cord, and age of the treated animals influence the risk of radiation-induced myelopathy. An α/β ratio of 1.9–3 Gy could be generally the reference value for fractionated radiotherapy. However, when fraction sizes are up to 5 Gy, the linear-quadratic equation become a less valid model. The early diagnosis of relapse is crucial in conditioning response to re-treatment.

Dosimetric comparison of protons vs photons in re-irradiation of intracranial meningioma

OBJECTIVES

Re-irradiation of recurrent intracranial meningiomas represents a major challenge due to dose limits of critical structures and the necessity of sufficient dose coverage of the recurrent tumor for local control. The aim of this study was to investigate dosimetric differences between pencil beam scanning protons (PBS) and volumetric modulated arc therapy (VMAT) photons for intracranial re-irradiation of meningiomas.

METHODS

Nine patients who received an initial dose >50 Gy for intracranial meningioma and who were re-irradiated for recurrence were selected for plan comparison. A volumetric modulated arc therapy photon and a pencil beam scanning proton plan were generated (prescription dose: 15 × 3 Gy) based on the targets used in the re-irradiation treatment.

RESULTS

In all cases, where the cumulative dose exceeded 100 or 90 Gy, these high dose volumes were larger for the proton plans. The integral doses were significantly higher in all photon plans (reduction with protons: 48.6%, p < 0.01). In two cases (22.2%), organ at risk (OAR) sparing was superior with the proton plan. In one case (11.1%), the photon plan showed a dosimetric advantage. In the remaining six cases (66.7%), we found no clinically relevant differences in dose to the OARs.

CONCLUSIONS

The dosimetric results of the accumulated dose for a re-irradiation with protons and with photons were very similar. The photon plans had a steeper dose falloff directly outside the target and were superior in minimizing the high dose volumes. The proton plans achieved a lower integral dose. Clinically relevant OAR sparing was extremely case specific. The optimal treatment modality should be assessed individually.

ADVANCES IN KNOWLEDGE

Dose sparing in re-irradiation of intracranial meningiomas with protons or photons is highly case specific and the optimal treatment modality needs to be assessed on an individual basis.

Intensity-Modulated Proton and Carbon-Ion Radiation Therapy in the Management of Head and Neck Sarcomas

PURPOSE

We report our experience of intensity-modulated proton and carbon-ion radiotherapy (IMPT/IMCT) for head and neck sarcomas (HNS).

METHODS AND MATERIALS

An analysis of the ongoing prospective data registry from the Shanghai Proton and Heavy Ion Center (SPHIC) for patients with HNS was conducted. The 12- and 24-month rates of local recurrence-free, overall, distant metastasis-free, progression-free survival (LRFS, OS, DMFS, and PFS), and acute/late toxicities were calculated. The prognostic factors for the effectiveness of the treatment were also analyzed.

RESULTS

Between 7/2014 and 5/2018, 51 consecutive patients with HNS received definitive doses of IMCT (41 cases), IMPT (two cases), or their combination (eight cases). One patient had R0 resection and another treated on the Chinese Food and Drug Administration registration trial received IMPT only. Twenty-seven patients were treated according to various dose escalation trials or institutional protocols using IMCT or IMPT + IMCT boost. Twenty-two patients with locoregional recurrence (10 and four patients failed surgery or surgery followed by radiotherapy, respectively) or radiation-induced second primary sarcomas (eight patients) received salvage particle radiotherapy. With a median follow-up time of 15.7 months, four patients with second primary sarcoma died. The 1- and 2-year OS, PFS, LRFS, and DMFS rates for the entire cohort were 92.9% vs 90%, 73.6% vs 57.4%, 88.4% vs 78.9%, and 84.6% vs 76.5%, respectively. Those rates for patients without prior radiotherapy were 100% vs 100%, 82.1% vs 65.8%, 93.6% vs 85.3%, and 88.4% vs 79.5%, respectively. Multivariate analyses revealed that re-irradiation was an independent prognostic factor for both LRFS and PFS (P = 0.015 and 0.037, respectively). In addition, gross tumor volume (GTV) was an independent prognostic factor for PFS (P = 0.048). One patient experienced Grade 3 acute toxicity (oral mucositis); another experienced Grade 4 acute event (hemorrhage) which required embolization. He lately died from hemorrhage (Grade 5) at 3.4 months after the completion of treatment. No patient experienced radiation-induced acute/late toxicity of ≥ Grade 2 otherwise.

CONCLUSION

With few observed acute/late toxicities, IMPT/IMCT provided effective short-term tumor control in our patients with HNS. Further investigations, preferably in a prospective fashion, will be required to confirm the efficacy and toxicities of IMPT/IMCT in this group of patients.

Practical effectiveness of re-irradiation with or without surgery for locoregional recurrence of rectal cancer: A meta-analysis and systematic review

BACKGROUND AND PURPOSE

Re-irradiation might yield local control (LC) or palliation for locoregionally recurrent rectal cancer (LRRC), but iatrogenic complications are a possible hindrance. We aimed to evaluate the efficacy of re-irradiation to determine optimal treatment of LRRC.

METHODS

We performed a systematic review of PubMed, MEDLINE, Cochrane Library, and Embase.

RESULTS

A total of 17 studies involving 744 patients with LRRC were included; median OS ranging from 10 to 45 months (median: 24.5 months). Pooled 1-, 2-, and 3-year OS rates for all patients were 76.1%, 49.1%, and 38.3%, respectively. For patients who underwent re-irradiation and surgery (OP group), these pooled rates were 85.9%, 71.8%, and 51.7%, respectively. For patients who underwent re-irradiation but not surgery (non-OP group), pooled 1-, 2-, and 3-year OS rates were 63.5%, 34.2%, and 23.8%, respectively. The OS difference between both groups was significant for all 3 years (P < 0.05). Pooled 1-, 2-, and 3-year LC rates for the OP group were 84.4%, 63.8%, and 46.9%, and for the non-OP group were 72.0%, 54.8%, and 44.6%, respectively, without significant differences. Pooled grade ≥3 acute and late complication rates were 11.7% and 25.5% in the OP and non-OP groups, respectively. Patients who underwent surgery had a higher risk of grade ≥3 late complications (odds ratio: 6.39). Pooled symptomatic palliation rate was 75.2%.

CONCLUSIONS

Re-irradiation with or without surgery for LRRC showed oncologic and palliative efficacy. Salvage treatment including re-irradiation and surgery showed higher survival, but the late complication was significantly increased with concomitant surgery.

Palliative Radiation Therapy for Head and Neck Cancers

Patients with advanced head and neck cancers who are not eligible for curative treatment represent a challenging cohort of patients to manage given the complexity and severity of their presenting symptoms. Palliative radiation therapy, along with other systemic and surgical measures, has the potential to significantly improve the quality of life of such patients. There is little high-level evidence and a lack of consensus to direct the selection of an optimal palliative radiation regimen. An ideal palliative radiation regimen should alleviate symptoms secondary to the cancer with minimal treatment toxicity and side effects while improving a patient's quality of life. This review presents the treatment approaches, outcomes, and toxicities associated with different radiation regimens and proposes a multidisciplinary framework for the selection of an individualized treatment regimen for patients that centers around patient prognosis, goals of care, logistics of treatment, and the availability of other surgical and systemic therapies.

Iatrogenic Disease of the Genitourinary Tract

Iatrogenic disease is defined as illness caused by diagnostic procedures or treatment given by health care professionals. More recently described treatment complications involving the genitourinary tract include newly recognized variants of renal carcinoma in the setting of dialysis/end-stage renal disease, treatment effect in genitourinary carcinomas, and medical renal disease caused by drug therapies, including immunotherapy. The objective of this review is to cover iatrogenic inflammatory diseases, pseudotumors and tumors of the kidney, bladder, prostate, testis and paratestis of most interest to surgical pathologists. For this reason, disease caused by the following will not be covered: iatrogenic glomerulonephritis, self-inflicted injury including the introduction of foreign bodies, surgical error, drugs of abuse and herbal medications, and iatrogenic disease in the transplant setting including ischemia/reperfusion injury. Emphasis is placed upon commonly encountered diseases in order to ensure that the review is of utility to practicing pathologists. The clinical context, pathophysiology and histopathology of each disease entity are covered.

Salvage Carbon-Ion Radiation Therapy For Locoregionally Recurrent Head and Neck Malignancies

To investigate the safety and efficacy of salvage carbon-ion radiation therapy (CIRT) in patients with locoregionally recurrent head and neck malignancies. One hundred and forty-one patients with locally recurrent head and neck malignancies previously treated with radiotherapy were salvaged using intensity-modulated carbon-ion radiation therapy (CIRT). The median dose was 60 Gray-Equivalent (GyE) (range 50–69 GyE, 2.0~3.5 GyE/daily fraction). All patients completed planned CIRT except for one. With a median follow-up time of 14.7 (range 1.6–36.4) months, the 1-year overall survival rate was 95.9%. Local, regional, and distant progression free survival rates were 84.9% and 97.7%, and 96%, respectively. Grade 3 or higher acute and late toxicities were observed in 7.1% of the patients. Ten patients developed mucosal necrosis and 4 of these patients deceased. Due to its physical and biological characteristics, CIRT appeared to be an acceptable treatment option for patients with locoregionally recurrent head and neck malignancies after previous radiotherapy. Treatment-induced adverse effects and early response to CIRT were both favorable. Longer follow-up is needed to evaluate the long-term outcome in terms of disease control, survival, as well as potential late effects.

Re-irradiation of recurrent glioblastoma as part of a sequential multimodality treatment concept

PURPOSE

The aim of this retrospective study was to evaluate survival outcomes in well-performing, mainly, young patients receiving a sequence of all available therapeutic options for relapsed glioblastoma, including re-irradiation.

METHODS

We performed a retrospective analysis of 27 patients irradiated twice for glioblastoma between 2008 and 2016. In the first line, all had surgical treatment of the tumor followed by radiotherapy with a total dose of 60 Gy and temozolomide. All re-irradiated patients were treated with a total dose of 36 Gy in 12 fractions. The endpoints were death from glioblastoma or any cause, and toxicity after re-irradiation.

RESULTS

The median follow-up of survivors was 35.6 months. At the time of analysis, 25 patients had died. The median time between first and second radiotherapy was 18.9 months (6.1-58.4). Re-irradiation was performed at different time points of first, second and third progression. The median overall survival after first diagnosis was 39.2 months. Five years after first surgery, nearly 20% of the patients were alive.

CONCLUSION

Carefully planned re-irradiation of the brain is a safe therapy for recurrent glioblastoma. Younger and well-performing patients benefit from all available therapy options. Every patient should be discussed in a multidisciplinary setting at each time point of tumor progression. Further prospective studies are needed to define the optimal time, dose and volume of re-irradiation.

Repeat stereotactic body radiotherapy (SBRT) for local recurrence of non-small cell lung cancer and lung metastasis after first SBRT

BACKGROUND

This study evaluated the safety and efficacy of repeat SBRT for local recurrence of stage I non-small-cell lung cancer (NSCLC) and solitary lung metastasis.

METHODS

Thirty-one patients with in-field local relapse of NSCLC (n = 23) or lung metastasis (n = 8) underwent repeat SBRT. All patients had grade 2 or lower radiation pneumonitis after the first SBRT. Local recurrence was diagnosed with CT and FDG-PET in 17 patients and by biopsy in 14. The median interval between the first and second SBRT was 18 months (range, 4-80). The first SBRT dose was mainly 48-52 Gy in 4 fractions (n = 25) according to the institutional protocols. Second SBRT doses were determined based on the tumor size and distance to organs at risk, and were mostly 48-52 Gy in 4 fractions (n = 13) or 60 Gy in 8 fractions (n = 13).

RESULTS

At 3 years, overall survival and local control rates were 36 and 53%, respectively, for all 31 patients. Four patients showed no further recurrence for > 5 years (63-111 months) after the second SBRT. Radiation pneumonitis after the second SBRT was grade 2 in 4 patients, and no grade 3 pneumonitis was observed.

CONCLUSION

Repeat SBRT was safe. Local control and survival rates were higher than expected. SBRT should be an important treatment option for local recurrence of NSCLC or lung metastasis after previous local SBRT.

TRIAL REGISTRATION

This retrospective study was approved by the ethics committee of our institution (September, 2017; approval number: 27-10).

Salvage Carbon Ion Radiation Therapy for Locally Recurrent or Radiation-Induced Second Primary Sarcoma of the Head and Neck

Purpose: Salvage radiation therapy (RT) is a potentially curative treatment option for head and neck sarcomas (HNS) that did not respond to previous treatment(s). We report the first clinical experience of carbon ion radiotherapy (CIRT) for salvage treatment of locally recurrent (LR) or RT-induced secondary HNS after surgery and/or radiotherapy.

Methods and Materials: A retrospective analysis of the ongoing prospective data registries from the Shanghai Proton and Heavy Ion Center was conducted. Patients with LR-HNS who underwent surgery and/or RT and those with RT-induced second primary HNS were included. Acute and late toxicities were evaluated using the Common Terminology Criteria for Adverse Events version 4.0 and the Radiation Therapy Oncology Group late radiation toxicity scoring system, respectively. The actuarial 12-month local progression-free and overall survival rates (LPFS and OS) were calculated using the Kaplan-Meier method.

Results: Between 10/2015 and 7/2017, 19 consecutive and non-selected patients with LR-HNS or RT-induced secondary HNS received definitive doses of CIRT delivered with pencil beam scanning technology for salvage. Six patients had locally recurrent soft-tissue sarcoma, and another 6 had chondrosarcoma. Among these 12 patients, 4 had received one prior course of RT. Seven additional patients had an RT-induced second primary soft tissue sarcoma (STS)/osteosarcoma after RT. The median time between the completion of initial treatment (either surgery only or surgery followed by adjuvant RT) and salvage CIRT was 30.6 months.

The median follow-up time was 13.1 (range 1.6-41.1) months. All patients except one (for re-irradiation) completed the planned CIRT for salvage. The median dose of salvage CIRT was 60 GyE. Three patients developed local progression, and another 3 developed distant metastasis after salvage CIRT. Deaths occurred (3 patients) only in patients with radiation-induced second primary sarcoma at the time of analysis. The actuarial 12-month LPFS, DMFS and OS rates were 74.6%, 82.6% and 86.5%, respectively.

Two patients irradiated for a second primary sarcoma had Grade 4 bleeding during CIRT, including one who experienced the rupture of an optic artery aneurysm unrelated to his disease or the salvage treatment. No patient had Grade 5 toxicity during treatment. Except for one patient who died of hemorrhage 3.5 months after the completion of CIRT, no moderate or severe late toxicities were observed.

Conclusions: With few observed acute and late toxicities, salvage CIRT can provide effective short-term tumor control. Further research, preferably in a prospective fashion, will be required to confirm the efficacy and safety of salvage CIRT in this patient population.

Salvage treatment using carbon ion radiation in patients with locoregionally recurrent nasopharyngeal carcinoma: Initial results

BACKGROUND

Reirradiation for locoregionally recurrent nasopharyngeal carcinoma (NPC) after a definitive dose of radiotherapy (RT) is challenging and usually associated with severe toxicities. Intensity‐modulated carbon ion RT (IMCT) offers physical/biologic advantages over photon‐based intensity‐modulated RT. Herein, the authors report their initial experience of IMCT in previously irradiated patients with locoregionally recurrent NPC.

METHODS

Patients with locoregionally recurrent, poorly differentiated or undifferentiated NPC who underwent salvage therapy with IMCT at the Shanghai Proton and Heavy Ion Center between May 2015 and August 2017 were included in the current study. The IMCT doses were 50 to 66 Gray equivalent (GyE) (2.0‐3.0 GyE/daily fraction), delivered via raster scanning technology. The 1‐year overall survival, disease‐specific survival, progression‐free survival (PFS), local recurrence‐free survival, regional recurrence‐free survival, and distant metastasis‐free survival were calculated. Univariate and multivariate analyses of PFS were performed to identify possible predictive factors.

RESULTS

Among the 75 patients included, 4 patients, 14 patients, 29 patients, and 28 patients, respectively, had recurrent American Joint Committee on Cancer stage I, stage II, stage III, and stage IVA/B disease. With a median follow‐up of 15.4 months (range, 2.6‐29.7 months), the 1‐year overall survival, disease‐specific survival, PFS, local recurrence‐free survival, regional recurrence‐free survival, and distant metastasis‐free survival rates were 98.1%, 98.1%, 82.2%, 86.6%, 97.9%, and 96.2%, respectively. A higher fraction size of 3 GyE (vs <3 GyE) or a higher biological equivalent dose significantly improved the PFS rate on univariate analysis, but not on multivariate analysis. No patient developed acute toxicity of grade ≥2 during IMCT. Late treatment‐induced severe (grade 3 or 4) toxicities were infrequent, but included mucosal necrosis (9.3%), xerostomia (1.3%), and temporal lobe necrosis (1.3%).

CONCLUSIONS

This initial experience in the first 75 patients with locoregionally recurrent NPC was encouraging. Carbon ion RT could provide promising survival rates with infrequent severe toxicities for patients with locoregionally recurrent NPC. Cancer 2018;124:2427‐37. © 2018 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society.

Reirradiation for locoregionally recurrent nasopharyngeal carcinoma after a definitive dose of radiotherapy is challenging and usually associated with severe toxicities. Carbon ion radiotherapy provides promising short‐term survival rates for patients with locoregionally recurrent nasopharyngeal carcinoma, with few treatment‐induced severe adverse effects noted.

Local Control and Toxicity of External Beam Reirradiation With a Pulsed Low-dose-rate Technique

PURPOSE

To evaluate the efficacy and toxicity of external beam reirradiation using a pulsed low-dose-rate (PLDR) technique.

METHODS AND MATERIALS

We evaluated patients treated with PLDR reirradiation from 2009 to 2016 at a single institution. Toxicity was graded using the Common Terminology Criteria for Adverse Events, version 4.0, and local control was assessed using the Response Evaluation Criteria In Solid Tumors, version 1.1. On univariate analysis (UVA), the χ2 and Fisher exact tests were used to assess the toxicity outcomes. Competing risk analysis using cumulative incidence function estimates were used to assess local progression.

RESULTS

A total of 39 patients were treated to 41 disease sites with PLDR reirradiation. These patients had a median follow-up time of 8.8 months (range 0.5-64.7). The targets were the thorax, abdomen, and pelvis, including 36 symptomatic sites. The median interval from the first radiation course and reirradiation was 26.2 months; the median dose of the first and second course of radiation was 50.4 Gy and 50 Gy, respectively. Five patients (13%) received concurrent systemic therapy. Of the 39 patients, 9 (23%) developed grade ≥2 acute toxicity, most commonly radiation dermatitis (5 of 9). None developed grade ≥4 acute or subacute toxicity. The only grade ≥2 late toxicity was late skin toxicity in 1 patient. On UVA, toxicity was not significantly associated with the dose of the first course of radiation or reirradiation, the interval to reirradiation, or the reirradiation site. Of the 41 disease sites treated with PLDR reirradiation, 32 had pre- and post-PLDR scans to evaluate for local control. The local progression rate was 16.5% at 6 months and 23.8% at 12 months and was not associated with the dose of reirradiation, the reirradiation site, or concurrent systemic therapy on UVA. Of the 36 symptomatic disease sites, 25 sites (69%) achieved a symptomatic response after PLDR, including 6 (17%) with complete symptomatic relief.

CONCLUSION

Reirradiation with PLDR is effective and well-tolerated. The risk of late toxicity and the durability of local control were limited by the relatively short follow-up duration in the present cohort.

Pelvic re-irradiation using stereotactic ablative radiotherapy (SABR): A systematic review

BACKGROUND AND PURPOSE

To perform a systematic review regarding the use of stereotactic ablative radiotherapy (SABR) for the re-irradiation of recurrent malignant disease within the pelvis, to guide the clinical implementation of this technique.

MATERIAL AND METHODS

A systematic search strategy was adopted using the MEDLINE, EMBASE and Cochrane Library databases.

RESULTS

195 articles were identified, of which 17 were appropriate for inclusion. Studies were small and data largely retrospective. In total, 205 patients are reported to have received pelvic SABR re-irradiation. Dose and fractionation schedules and re-irradiated volumes are highly variable. Little information is provided regarding organ at risk constraints adopted in the re-irradiation setting. Treatment appears well-tolerated overall, with nine grade 3 and six grade 4 toxicities amongst thirteen re-irradiated patients. Local control at one year ranged from 51% to 100%. Symptomatic improvements were also noted.

CONCLUSIONS

For previously irradiated patients with recurrent pelvic disease, SABR re-irradiation could be a feasible intervention for those who otherwise have limited options. Evidence to support this technique is limited but shows initial promise. Based on the available literature, suggestions for a more formal SABR re-irradiation pathway are proposed. Prospective studies and a multidisciplinary approach are required to optimise future treatment.

Re-irradiation of cervical and endometrial cancer

PURPOSE OF REVIEW

Re-irradiation historically has been associated with unacceptable toxicity and limited benefit. Recent advances in radiotherapy can change the treatment paradigm to provide new salvage treatments for recurrences of cervical and endometrial cancer.

RECENT FINDINGS

Image-guided brachytherapy is an effective method for salvaging central pelvic recurrence, although it has resulted in 20-25% severe late toxicity. Pelvic sidewall disease is not accessible to brachytherapy, so a combined modality approach with radical surgery and intraoperative radiotherapy is an alternative approach. Stereotactic body radiotherapy (SBRT) now provides the option of radical re-irradiation with local control rates of 50-80% and a low incidence of severe late complications.

SUMMARY

Initial outcomes using SBRT and image-guided brachytherapy for re-irradiation of gynaecological cancer are encouraging. There has been good local control and acceptable toxicity. Further, large-scale studies are required to define optimal target doses and OAR limits.