Prediction of Acute Radiation Mucositis using an Oral Mucosal Dose Surface Model in Carbon Ion Radiotherapy for Head and Neck Tumors

Omega-3 nanoemulgel in prevention of radiation-induced oral mucositis and its associated effect on microbiome: a randomized clinical trial

BACKGROUND

Oral mucositis (OM) is recognized as one of the most frequent debilitating sequelae encountered by head and neck cancer (HNC) patients treated by radiotherapy. This results in severe mucosal tissue inflammation and oral ulcerations that interfere with patient's nutrition, quality of life (QoL) and survival. Omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) have recently gained special interest in dealing with oral diseases owing to its anti-inflammatory, anti-oxidant and wound healing properties. Thus, this study aims to assess topical Omega-3 nanoemulgel efficacy in prevention of radiation-induced oral mucositis and regulation of oral microbial dysbiosis.

MATERIALS AND METHODS

Thirty-four head and neck cancer patients planned to receive radiotherapy were randomly allocated into two groups: Group I: conventional preventive treatment and Group II: topical Omega-3 nanoemulgel. Patients were evaluated at baseline, three and six weeks after treatment using the World Health Organization (WHO) grading system for oral mucositis severity, Visual Analogue Scale (VAS) for perceived pain severity, and MD-Anderson Symptom Inventory for Head and Neck cancer (MDASI-HN) for QoL. Oral swabs were collected to assess oral microbiome changes.

RESULTS

VAS scores and WHO mucositis grades were significantly lower after six weeks of treatment with topical Omega-3 nanoemulgel when compared to the conventional treatment. The total MDASI score was significantly higher in the control group after three weeks of treatment, and the head and neck subscale differed significantly at both three and six weeks. A significant reduction in Firmicutes/Bacteroidetes ratio was observed after six weeks in the test group indicating less microbial dysbiosis.

CONCLUSIONS

Topical Omega-3 nanoemulgel demonstrated a beneficial effect in prevention of radiation-induced oral mucositis with a possibility of regulating oral microbial dysbiosis.

Proton therapy and oral mucositis in oral & oropharyngeal cancers: outcomes, dosimetric and NTCP benefit

INTRODUCTION

Radiation-induced oral mucositis (RIOM), is a common, debilitating, acute side effect of radiotherapy for oral cavity (OC) and oropharyngeal (OPx) cancers; technical innovations for reducing it are seldom discussed. Intensity-modulated-proton-therapy (IMPT) has been reported extensively for treating OPx cancers, and less frequently for OC cancers. We aim to quantify the reduction in the likelihood of RIOM in treating these 2 subsites with IMPT compared to Helical Tomotherapy.

MATERIAL AND METHODS

We report acute toxicities and early outcomes of 22 consecutive patients with OC and OPx cancers treated with IMPT, and compare the dosimetry and normal tissue complication probability (NTCP) of ≥ grade 3 mucositis for IMPT and HT.

RESULTS

Twenty two patients, 77% males, 41% elderly and 73% OC subsite, were reviewed. With comparable target coverage, IMPT significantly reduced the mean dose and D32, D39, D45, and D50, for both the oral mucosa (OM) and spared oral mucosa (sOM). With IMPT, there was a 7% absolute and 16.5% relative reduction in NTCP for grade 3 mucositis for OM, compared to HT. IMPT further reduced NTCP for sOM, and the benefit was maintained in OC, OPx subsites and elderly subgroup. Acute toxicities, grade III dermatitis and mucositis, were noted in 50% and 45.5% patients, respectively, while 22.7% patients had grade 3 dysphagia. Compared with published data, the hospital admission rate, median weight loss, feeding tube insertion, unplanned treatment gaps were lower with IMPT. At a median follow-up of 15 months, 81.8% were alive; 72.7%, alive without disease and 9%, alive with disease.

CONCLUSION

The dosimetric benefit of IMPT translates into NTCP reduction for grade 3 mucositis compared to Helical Tomotherapy for OPx and OC cancers and encourages the use of IMPT in their management.

Dose-volume constraints for head-and-neck cancer in carbon ion radiotherapy: A literature review

BACKGROUND

Carbon ion radiotherapy (CIRT) has been applied in cancer treatment for over 25 years. However, guidelines for dose-volume constraints have not been established yet. The aim of this review is to summarize the dose-volume constraints in CIRT for head-and-neck (HN) cancer that were determined through previous clinical studies based on the Japanese models for relative biological effectiveness (RBE).

METHODS

A literature review was conducted to identify all constraints determined for HN cancer CIRT that are based on the Japanese RBE models.

RESULTS

Dose-volume constraints are reported for 17 organs at risk (OARs), including the brainstem, ocular structures, masticatory muscles, and skin. Various treatment planning strategies are also presented for reducing the dose delivered to OARs.

CONCLUSIONS

The reported constraints will provide assistance during treatment planning to ensure that radiation to OARs is minimized, and thus adverse effects are reduced. Although the constraints are given based on the Japanese RBE models, applying the necessary conversion factors will potentially enable their application by institutions worldwide that use the local effect model for RBE.

Delineation of Oral Mucosa as a Pseudo-Organ-at-Risk May Lead to a Decrease in the Incidence of Oral Mucositis: A Dosimetric Analysis of Intensity-Modulated Radiation Therapy Plans in Head and Neck Cancers

Introduction

Oral mucositis is a common and potentially serious complication of radiation in head and neck cancer treatment. Severe mucositis causes pain, difficulty in chewing and swallowing that can cause treatment breaks and can cause treatment failures leading to local recurrence or a decrease in overall survival. The contouring of the planning target volume (PTV) and organ at risk (OAR) leaves some undefined regions on computed tomography imaging. The treatment planning system uses these regions as dumping sites for the dose in order to achieve the optimum plan. The present study was done to assess the dose going to these unspecified regions termed as pseudo-OARs and whether delineation of these structures and prescribing a dose constraint will reduce the dose to the oral mucosa without compromising the quality of the treatment plan.

Methods

Twenty patients of head and neck cancer were selected and were randomly placed in two arms. One was intensity-modulated radiation therapy (IMRT) arm I, which included the initial plans with which the patients were treated where the pseudo-OAR was not delineated and hence was not considered in the planning process. After giving treatment, the pseudo-OAR was delineated to see the dose dumped into the area outside the PTV. The other was IMRT arm II, where another virtual plan of the same patients of arm I was made wherein the delineation of the pseudo-OAR was done before planning and dose constraint prescribed. The pseudo-OAR consisted of anterior oral mucosa, part of mandible and maxilla, which was adjacent to the PTV in oropharynx and contralateral buccal mucosa patients. The dose constraint given to the pseudo-OAR was Dmean ≤30 Gy. Statistical significance was calculated by using a paired t-test. A p-value of <0.05 was considered as statistically significant.

Results

The dosimetric parameters of PTV were comparable in both the IMRT arms. The pre-specified objective was fulfilled with both the study arms. The dose homogeneity and conformity was also similar. The dosimetric parameters of other OARs were within the prescribed dose constraints. The Dmean value of the pseudo-OAR in arm I was 31.28 Gy ± 3.55 Gy and 7.87 Gy ± 9.11 Gy in arm II and the p-value was significant (p=0.001), whereas the Dmax in arm I was 61.82 Gy ± 5.91 Gy and 61.23 Gy ± 5.54 Gy in arm II (p=0.6). The dose to the pseudo-OAR in IMRT arm II was reduced drastically by 75%, which was statistically significant.

Conclusion

The delineation of oral mucosa as a pseudo-OAR should routinely be done. The dose constraints need to be optimized by clinical studies, which might probably decrease the incidence and severity of oral mucositis.

Relationship between oral mucositis and the oral bacterial count in patients with head and neck cancer undergoing carbon ion radiotherapy: A prospective study

BACKGROUND AND PURPOSE

Acute adverse events, such as oral mucositis, can affect treatment success in patients undergoing head and neck radiotherapy. In this study, we aimed to identify the relationship between oral mucositis and oral bacterial counts during carbon ion radiotherapy (C-ion RT) in patients with head and neck cancer.

MATERIALS AND METHODS

This prospective study included patients with head and neck tumors treated with C-ion RT between 2017 and 2019. C-ion RT consisted of treatment at 57.6, 64.0, or 70.4 Gy (relative biological effectiveness) in 16 fractions. Bacterial counts in the saliva and the back of the tongue were measured using a rapid oral bacteria quantification system. The relationship between the oral bacterial count and oral mucositis was subsequently analyzed.

RESULTS

In total, 46 patients were included in the analysis. The bacterial count in the saliva gradually increased from the commencement of C-ion RT and peaked at 16 fractions. Bacterial counts at the back of the tongue were already high at the beginning of C-ion RT; however, they decreased with continued treatment, peaked at 16 fractions, and subsequently decreased again. Patients with bacterial counts exceeding the mean before C-ion RT (high-count group) did not experience more severe mucositis than those with counts below the mean (low-count group). However, patients in the high-count group tended to experience faster-onset mucositis and slower healing than those in the low-count group.

CONCLUSION

Bacterial counts may aid in the development of clinical strategies for C-ion RT-induced oral mucositis.

Dose-Effects Models for Space Radiobiology: An Overview on Dose-Effect Relationships

Space radiobiology is an interdisciplinary science that examines the biological effects of ionizing radiation on humans involved in aerospace missions. The dose-effect models are one of the relevant topics of space radiobiology. Their knowledge is crucial for optimizing radioprotection strategies (e.g., spaceship and lunar space station-shielding and lunar/Mars village design), the risk assessment of the health hazard related to human space exploration, and reducing damages induced to astronauts from galactic cosmic radiation. Dose-effect relationships describe the observed damages to normal tissues or cancer induction during and after space flights. They are developed for the various dose ranges and radiation qualities characterizing the actual and the forecast space missions [International Space Station (ISS) and solar system exploration]. Based on a Pubmed search including 53 papers reporting the collected dose-effect relationships after space missions or in ground simulations, 7 significant dose-effect relationships (e.g., eye flashes, cataract, central nervous systems, cardiovascular disease, cancer, chromosomal aberrations, and biomarkers) have been identified. For each considered effect, the absorbed dose thresholds and the uncertainties/limitations of the developed relationships are summarized and discussed. The current knowledge on this topic can benefit from further in vitro and in vivo radiobiological studies, an accurate characterization of the quality of space radiation, and the numerous experimental dose-effects data derived from the experience in the clinical use of ionizing radiation for diagnostic or treatments with doses similar to those foreseen for the future space missions. The growing number of pooled studies could improve the prediction ability of dose-effect relationships for space exposure and reduce their uncertainty level. Novel research in the field is of paramount importance to reduce damages to astronauts from cosmic radiation before Beyond Low Earth Orbit exploration in the next future. The study aims at providing an overview of the published dose-effect relationships and illustrates novel perspectives to inspire future research.

Multicenter Study of Carbon-ion Radiotherapy for Oropharyngeal Non-squamous Cell Carcinoma

BACKGROUND/AIM

To evaluate treatment outcomes of carbon-ion radiotherapy for oropharyngeal non-squamous cell carcinoma at four carbon-ion facilities in Japan.

PATIENTS AND METHODS

We retrospectively analyzed the cases of 33 patients with oropharyngeal non-squamous cell carcinoma who were treated with carbon-ion radiotherapy between November 2003 and December 2014.

RESULTS

The histology included adenoid cystic carcinoma (n=25) and mucosal malignant melanoma (n=4). No patients had T1 tumors; 23 had T4 tumors. The most-commonly prescribed dose was 57.6 Gy (RBE) in 16 fractions. The median follow-up period was 34.8 months (range=4.2-122.8 months). The 3-year local control and overall survival rates were 94.7% and 90.7%, respectively. There were no grade ≥4 acute adverse events. Only one patient experienced a grade ≥4 late adverse event. No patients experienced late adverse events related to swallowing or salivary function.

CONCLUSION

Carbon-ion radiotherapy appears to be a promising treatment option for oropharyngeal non-squamous cell carcinoma.

Clinical features and dosimetric evaluation of carbon ion radiation-induced osteoradionecrosis of mandible in head and neck tumors

BACKGROUND AND PURPOSE

Osteoradionecrosis (ORN) affects the patient's quality of life by making eating and maintaining oral hygiene painful. This study aimed to analyze carbon ion radiotherapy (C-ion RT)-induced ORN of the mandible.

MATERIALS AND METHODS

A retrospective study of 199 patients with head and neck tumors treated with C-ion RT was performed from 2010 to 2019. Only 11 patients with tumors located in the oropharynx and floor of the mouth were analyzed. C-ion RT consisted of 57.6 Gy or 64.0 Gy (relative biological effectiveness) in 16 fractions. The mandible was analyzed for magnetic resonance imaging (MRI) changes and bone exposure. The relationship between the radiation dose and ORN of the mandible was analyzed.

RESULTS

Five patients (45.5%) had ORN of the mandible. The median follow-up time was 68 months. The median onset times based on MRI changes and bone exposure were 9 and 15 months, respectively. Doses of 30 Gy (relative biological effectiveness) to the mandible and teeth showed the most significant effect, causing ORN at 29.5 ± 6.7 cc and 3.9 ± 1.8 cc, respectively, with cut-off values at 16.5 cc (p = 0.002) and 1.8 cc (p = 0.0059), respectively.

CONCLUSION

This is the first study reporting the incidence, onset time, and risk-predictive dosimetry parameters of C-ion RT-induced ORN of the mandible. Our study will be useful for establishing clinical strategies for C-ion RT to the head and neck near the mandible.

Individualized 3D-Printed Tissue Retraction Devices for Head and Neck Radiotherapy

Background

Radiotherapy for head and neck cancer may cause various oral sequelae, such as radiation-induced mucositis. To protect healthy tissue from irradiation, intraoral devices can be used. Current tissue retraction devices (TRDs) have to be either individually manufactured at considerable cost and time expenditure or they are limited in their variability. In this context, a 3D-printed, tooth-borne TRD might further facilitate clinical use.

Methods

A novel approach for the manufacturing of TRDs is described and its clinical application is analysed retrospectively. The devices were virtually designed for fabrication by 3D-printing technology, enabling—in only a single printing design—caudal or bi-lateral tongue displacement, as well as stabilization of a tongue-out position. For a total of 10 patients undergoing radiotherapy of head and neck tumors, the devices were individually adapted after pre-fabrication. Technical and clinical feasibility was assessed along with patient adherence. Tissue spacing was calculated by volumetric analysis of tongue retraction. In one exemplary case, radiotherapy treatment plans before and after tissue displacement were generated and compared. The reproducibility of maxillomandibular relation at device re-positioning was quantified by repeated intraoral optical scanning in a voluntary participant.

Results

3D-printing was useful for the simplification of TRD manufacture, resulting in a total patient treatment time of less than 30 min. The devices were tolerated well by all tested patients over the entire radiation treatment period. No technical complications occurred with the devices. The TRDs caused an effective spacing of the healthy adjacent tissue, e.g., the tongue. Position changes of maxillomandibular relation were limited to a mean value of 98.1 µm ± 29.4 µm root mean square deviation between initial reference and follow-up positions.

Conclusions

The presented method allows a resource-efficient fabrication of individualized, tooth-bourne TRDs. A high reproducibility of maxillomandibular relation was found and the first clinical experiences underline the high potential of such devices for radiotherapy in the head and neck area.

Dosimetric parameters predict radiation-induced choanal stenosis in patients with nasopharyngeal carcinoma

BACKGROUND

Radiation-induced choanal stenosis (RICS) severely decreases life quality of patients with nasopharyngeal carcinoma (NPC) and originates from nasal mucositis, which depends on radiation dose. This self-controlled study aimed to find the correlations between dosimetric parameters and RICS.

METHODS

Totally 49 NPC patients treated with intensity-modulated radiotherapy from May 2010 to Aug. 2013 and diagnosed with RICS during follow-up were enrolled into this study. Minimum point dose, maximum point dose, mean dose (Dmean), dose covering ≥33% volume (D33), dose covering ≥66% volume (D66), and volume receiving ≥60 Gy (V60) were compared between the nasal cavities with and without RICS, through paired t-test. The parameters with difference would enter receiver operating characteristic analysis to determine their cutoff values. Then predicting abilities of the cutoff values were tested by Chi-square test.

RESULT

The nasal cavities with RICS appeared to have higher Dmean, D33, D66 and V60, compared with those without RICS (P values were 0.014, 0.003, 0.006 and 0.010). Dmean ≥54.22 Gy, D33 ≥ 61.96 Gy, D66 ≥ 46.50 Gy and V60 ≥ 48.13% were demonstrated to be related with a higher risk of RICS.

CONCLUSION

Dmean, D33, D66 and V60 of nasal cavity might be used as predictors of RICS. Their values needed to be controlled whenever possible, for ameliorating life quality of NPC patients.

Smart Targeting To Improve Cancer Therapeutics

Cancer is the second largest cause of death worldwide with the number of new cancer cases predicted to grow significantly in the next decades. Biotechnology and medicine can and should work hand-in-hand to improve cancer diagnosis and treatment efficacy. However, success has been frequently limited, in particular when treating late-stage solid tumors. There still is the need to develop smart and synergistic therapeutic approaches to achieve the synthesis of strong and effective drugs and delivery systems. Much interest has been paid to the development of smart drug delivery systems (drug-loaded particles) that utilize passive targeting, active targeting, and/or stimulus responsiveness strategies. This review will summarize some main ideas about the effect of each strategy and how the combination of some or all of them has shown to be effective. After a brief introduction of current cancer therapies and their limitations, we describe the biological barriers that nanoparticles need to overcome, followed by presenting different types of drug delivery systems to improve drug accumulation in tumors. Then, we describe cancer cell membrane targets that increase cellular drug uptake through active targeting mechanisms. Stimulus-responsive targeting is also discussed by looking at the intra- and extracellular conditions for specific drug release. We include a significant amount of information summarized in tables and figures on nanoparticle-based therapeutics, PEGylated drugs, different ligands for the design of active-targeted systems, and targeting of different organs. We also discuss some still prevailing fundamental limitations of these approaches, eg, by occlusion of targeting ligands.

Dosimetric parameters predictive of nasolacrimal duct obstruction after carbon-ion radiotherapy for head and neck carcinoma

BACKGROUND AND PURPOSE

Little information is available on the risk factors for nasolacrimal duct obstruction after radiotherapy for head and neck tumors. We investigated the incidence and predictive dosimetric parameters for nasolacrimal duct obstruction following carbon-ion radiotherapy for head and neck tumors.

MATERIALS AND METHODS

Twenty-eight patients with head and neck non-squamous cell carcinoma were analyzed in this single-institution prospective study. More than half of the tumors were located in the nasal cavity and maxillary sinus. Carbon-ion radiotherapy consisting of 57.6 or 64.0 Gy(relative biological effectiveness; RBE) in 16 fractions was administered. Nasolacrimal duct obstruction was recorded according to Common Terminology Criteria for Adverse Events version 4.0. Cutoff values were determined using receiver operating characteristic (ROC) curve analysis. VX indicates the volume irradiated with X Gy(RBE).

RESULTS

The median follow-up period was 60.3 months. Incidences of Grade 1 and 2 nasolacrimal duct obstructions were 46% (13/28) and 7% (2/28), respectively; no Grade 3 or greater toxicities were recorded. Throughout the dose range, the volumes of the irradiated nasolacrimal ducts were significantly higher in the obstruction-positive patients than in the obstruction-negative patients (p < 0.001 for V10, V20, V30, V40, V50, and V60). Cutoff values determined by the ROC curve analysis classified the obstruction-positive patients with an accuracy of >96% over the entire range of V10-V60.

CONCLUSION

The incidence and predictive dosimetric parameters for nasolacrimal duct obstruction after carbon-ion radiotherapy were demonstrated in a prospective cohort. These data should help optimize carbon-ion radiotherapy treatments for patients with head and neck tumors.

Optic nerve constraints for carbon ion RT at CNAO - Reporting and relating outcome to European and Japanese RBE

BACKGROUND AND PURPOSE

Until now, carbon ion RT (CIRT) dose constraints for the optic nerve (ON) have only been validated and reported in the NIRS RBE-weighted dose (D_NIRS). The aim of this work is to improve CNAO's RBE-weighted dose (D_LEM) constraints by analyzing institutional toxicity data and by relating it to D_NIRS.

MATERIAL AND METHODS

A total of 65 ONs from 38 patients treated with CIRT to the head and neck region in the period 2013-14 were analyzed. The absorbed dose (D_Abs) of the treatment plans was reproduced and subsequently both D_LEM and D_NIRS were applied, thus relating CNAO clinical toxicity to D_NIRS.

RESULTS

Median FU was 47 (26-67) months. Visual acuity was preserved for the 56 ONs in which the old constraints were respected. Three ONs developed visual decline at D_LEM|1% ≥71 Gy(RBE)/D_LEM|20% ≥68 Gy(RBE), corresponding to D_NIRS|1% ≥68 Gy(RBE)/D_NIRS|20% ≥62 Gy(RBE). Dose recalculation revealed that NIRS constraints of D_NIRS|1% ≤40 Gy(RBE)/D_NIRS|20% ≤28 Gy(RBE) corresponded to D_LEM|1% ≤50 Gy(RBE)/D_LEM|20% ≤40 Gy(RBE). Reoptimization of treatment plans with these new D_LEM constraints showed that the dose distribution still complied with NIRS constraints when evaluated in D_NIRS. However, due to uncertainties in the method, and to comply with the EQD2-based constraints used at GSI/HIT, a more moderate constraint relaxation to D_LEM|1% ≤45 Gy(RBE)/D_LEM|20% ≤37 Gy(RBE) has been implemented in CNAO clinical routine since October 2018.

CONCLUSION

New D_LEM constraints for the ON were derived by analyzing CNAO toxicity data and by linking our results to the experience of NIRS and GSI/HIT. This work demonstrates the value of recalculating and reporting results in both D_LEM and D_NIRS.

Tongue surface model can predict radiation tongue mucositis due to intensity-modulated radiation therapy for head and neck cancer

Acute radiation tongue mucositis has a profound effect on talking and eating. We examined whether the dose-volume histogram obtained from the tongue surface model correlates with mucositis severity, and whether it is useful for predicting acute radiation tongue mucositis in patients with head and neck cancer treated with intensity-modulated radiation therapy. Thirty-six patients who received intensity-modulated radiation therapy for head and neck cancer were analysed for acute radiation tongue mucositis according to the Common Terminology Criteria for Adverse Events, version 4.0, as well as the Radiation Therapy Oncology Group scoring systems. The corresponding high-dose locations in anatomical sub-regions in the tongue surface model and the development of high-grade acute radiation tongue mucositis were compared. The mucositis sites coincided with the high-dose anatomical sub-regions in the tongue surface model. There was a clear dose-response relationship between the mean dose to the tongue and the acute radiation tongue mucositis Radiation Therapy Oncology Group grade. According to the dose-volume histogram, patients receiving 16.0-73.0 Gy to the tongue were susceptible to grade 2-3 toxicity. The tongue surface model can predict the site and severity of acute radiation tongue mucositis. In future, radiation treatment plans ccould be optimized using this model.

Metformin as a Radiation Modifier; Implications to Normal Tissue Protection and Tumor Sensitization

BACKGROUND

Nowadays, ionizing radiation is used for several applications in medicine, industry, agriculture, and nuclear power generation. Besides the beneficial roles of ionizing radiation, there are some concerns about accidental exposure to radioactive sources. The threat posed by its use in terrorism is of global concern. Furthermore, there are several side effects to normal organs for patients who had undergone radiation treatment for cancer. Hence, the modulation of radiation response in normal tissues was one of the most important aims of radiobiology. Although, so far, several agents have been investigated for protection and mitigation of radiation injury. Agents such as amifostine may lead to severe toxicity, while others may interfere with radiation therapy outcomes as a result of tumor protection. Metformin is a natural agent that is well known as an antidiabetic drug. It has shown some antioxidant effects and enhances DNA repair capacity, thereby ameliorating cell death following exposure to radiation. Moreover, through targeting endogenous ROS production within cells, it can mitigate radiation injury. This could potentially make it an effective radiation countermeasure. In contrast to other radioprotectors, metformin has shown modulatory effects through induction of several genes such as AMPK, which suppresses reduction/ oxidation (redox) reactions, protects cells from accumulation of unrepaired DNA, and attenuates initiation of inflammation as well as fibrotic pathways. Interestingly, these properties of metformin can sensitize cancer cells to radiotherapy.

CONCLUSION

In this article, we aimed to review the interesting properties of metformin such as radioprotection, radiomitigation and radiosensitization, which could make it an interesting adjuvant for clinical radiotherapy, as well as an interesting candidate for mitigation of radiation injury after a radiation disaster.

A multi-institutional retrospective study of carbon-ion radiotherapy for non-squamous cell malignant tumors of the nasopharynx: Subanalysis of Japan Carbon-Ion Radiation Oncology Study Group study 1402 HN

Background

This multi‐institutional retrospective study focused on the clinical outcome of carbon‐ion radiotherapy (C‐ion RT) for non‐squamous cell malignant tumors of the nasopharynx.

Methods

The Japan Carbon‐ion Radiation Oncology Study Group collected and analyzed data for 43 patients with non‐squamous cell malignant tumors of the nasopharynx treated with C‐ion RT at four institutions in Japan.

Results

Twenty‐nine patients had adenoid cystic carcinomas, seven had malignant melanomas, three had adenocarcinomas, two had mucoepidermoid carcinomas, and two had other pathologies. Twenty‐six of the 43 patients (61%) had T4 tumors. The most common dose‐fractionation schedule was 64 Gy (relative biological effectiveness) in 16 fractions. The median follow‐up period was 30 months. The 2‐year local control (LC) and overall survival (OS) rates were 88% and 84%, respectively. For late toxicity, one patient developed grade 4 optic nerve disorder and two developed grade 5 pharyngeal hemorrhage. Actual incidence of grade 3 or higher late adverse events was 19%, and included cranial nerve dysfunction, jaw bone necrosis, central nervous system necrosis, and ear inflammation.

Conclusions

C‐ion RT provided good LC and OS rates with acceptable toxicity for treatment of non‐squamous cell malignant tumors of the nasopharynx.

Revisiting the dose constraints for head and neck OARs in the current era of IMRT

Head and neck cancer poses a particular challenge in radiation therapy, whilst being an effective treatment modality it requires very high doses of radiation to provide effective therapy. This is further complicated by the fact that the head and neck region contains a large number of radiosensitive tissues, often resulting in patients experiencing debilitating normal tissue complications. In the era of intensity-modulated radiation therapy (IMRT) treatments can be delivered using non-uniform dose distributions selectively aimed at reducing the dose to critical organs-at-risk while still adequately covering the tumor target. Dose-volume constraints for the different risk organs play a vital role in one's ability to devise the best IMRT treatment plan for a head and neck cancer patient. To this end, it is pivotal to have access to the latest and most relevant dose constraints available and as such the goal of this review is to provide a summary of suggested dose-volume constraints for head and neck cancer RT that have been published after the QUANTEC reports were made available in early 2010.

Assessing Novel Drugs and Radiation Technology in the Chemoradiation of Oropharyngeal Cancer

Integrating immunotherapy, proton therapy and biological dose escalation into the definitive chemoradiation of oropharyngeal cancer poses several challenges. Reliable and reproducible data must be obtained in a timely fashion. However, despite recent international radiotherapy contouring guidelines, controversy persists as to the applicability of such guidelines to all cases. Similarly, a lack of consensus exists concerning both the definition of the organ at risk for oral mucositis and the most appropriate endpoint to measure for this critical toxicity. Finally, the correlation between early markers of efficacy such as complete response on PET CT following treatment and subsequent survival needs elucidation for biological subsets of oropharyngeal cancer.

Association between XRCC1 single-nucleotide polymorphism and acute radiation reaction in patients with nasopharyngeal carcinoma: A cohort study

To explore the association of the X-ray repair cross-complementing gene 1 (XRCC1) codon 399 single-nucleotide polymorphism (SNP) with acute radiation dermatitis and oral mucositis in nasopharyngeal carcinoma (NPC) patients treated by intensity-modulated radiation therapy (IMRT).Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to detect the SNP of the XRCC1 codon 399 in 114 NPC patients before radiotherapy.The risk of patients with the Arg/Arg genotype suffering from acute radiation dermatitis Grade ≥2 was higher than the other 2 genotypes (P = .014, 95% CI: 1.182-4.582). No significant difference was observed in the degree of acute radiation oral mucositis injury among the patients with different genotypes (P = .449, 95% CI: 0.691-2.304). Multivariate analysis showed that N stage and genotype were significantly associated with acute radiation dermatitis of Grade ≥2 (OR = 3.221, P < .001, 95% CI: 1.669-6.216, OR = 2.860, P = .006, 95% CI: 1.354-6.043). T stage and smoking status were significantly associated with acute radiation oral mucositis with Grade ≥2 (OR = 2.508, P = .001, 95% CI: 1.427-4.408, OR = 6.355, P < .001, 95% CI: 2.533-15.841).The XRCC1 codon 399 genotype in NPC could be an important predicting factor in the risk of acute radiation dermatitis during IMRT.

A systematic review of molecular responses to cancer therapy in normal human mucosa

OBJECTIVE

Cancer therapy-induced inflammation of oral and gastrointestinal mucosae affects patients nonuniformly. Preventive strategies are limited; no biomarker exists for pretreatment identification of patients likely to be severely affected. Animal models are preferred for studying molecular responses in mucosae during chemotherapy, but translation into clinical practice is difficult. We performed a systematic review to retrieve articles that described molecular changes in human mucosae during cancer therapy.

STUDY DESIGN

We searched MEDLINE and Ovid Embase searches for studies reported in the English language literature from January 1990 to November 2016 and studies referenced in selected articles, which analyzed mucosae from patients at risk of developing mucositis during cancer therapy. Two authors extracted data according to predefined data fields, including study quality indicators.

RESULTS

We identified 17 human studies on chemotherapy (n = 9) and radiotherapy (n = 8), but no studies on targeted therapy. Studies were heterogeneous with regard to patient cohorts, analysis methods, cancer treatments, biopsy timings, and correlations to clinical mucositis. Consequently, a meta-analysis was not feasible.

CONCLUSIONS

Few human studies described the molecular responses of the normal mucosa to cancer therapy. Studies were heterogeneous and had sparse correlations to clinical mucositis. We proposed a model for acquiring data on treatment- and disease-specific phenotypes and transcriptomes for predictive or preventive initiatives.

Systematic Review of Normal Tissue Complication Models Relevant to Standard Fractionation Radiation Therapy of the Head and Neck Region Published After the QUANTEC Reports

There has recently been an increasing interest in model-based evaluation and comparison of different treatment options in radiation oncology studies. This is partly driven by the considerable technical advancements in radiation therapy of the last decade, leaving radiation oncologists with a multitude of options to consider. In lieu of randomized trials comparing all of these different treatment options for varying indications, which is unfeasible, treatment evaluations based on normal tissue complication probability (NTCP) models offer a practical alternative. The Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) effort, culminating in a number of reports published in 2010, provided a basis for many of the since-implemented dose-response models and dose-volume constraints and was a key component for model-based treatment evaluations. Given that 7 years have passed since the QUANTEC publications and that patient-reported outcomes have emerged as an important consideration in recent years, an updated summary of the published radiation dose-response literature, which includes a focus on patient-reported quality of life outcomes, is warranted. Here we provide a systematic review of quantitative dose-response models published after January 1, 2010 for endpoints relevant to radiation therapy for head and neck cancer, because these patients are typically at risk for a variety of treatment-induced normal tissue complications.

Dose-volume histogram analysis of brainstem necrosis in head and neck tumors treated using carbon-ion radiotherapy

BACKGROUND AND PURPOSE

We aimed to evaluate the relationship between brainstem necrosis and dose-volume histograms in patients with head and neck tumors after carbon-ion radiotherapy.

MATERIAL AND METHODS

We evaluated 85 patients with head and neck tumors who underwent carbon-ion radiotherapy and were followed-up for ≥12months. Brainstem necrosis was evaluated using the Common Terminology Criteria for Adverse Events (version 4.0).

RESULTS

The median follow-up was 24months, and four patients developed grade 1 brainstem necrosis, with 2-year and 3-year cumulative rates of 2.8% and 6.5%, respectively. Receiver operating characteristic curve analysis revealed the following significant cut-off values: a maximum brainstem dose of 48Gy (relative biological effectiveness [RBE]), D1cm³ of 27Gy (RBE), V40Gy (RBE) of 0.1cm³, V30Gy (RBE) of 0.7cm³, and V20Gy (RBE) of 1.4cm³. Multivariate analysis revealed that V30Gy (RBE) was most significantly associated with brainstem necrosis. The 2-year cumulative rates were 33% and 0% for V30Gy (RBE) of ≥0.7cm³ and <0.7cm³, respectively (p<0.001).

CONCLUSIONS

The present study indicated that the dose constraints might help minimize brainstem necrosis after carbon-ion radiotherapy.

Prospective observational study of carbon-ion radiotherapy for non-squamous cell carcinoma of the head and neck

To evaluate the efficacy and safety of carbon-ion radiotherapy for non-squamous cell carcinoma of the head and neck, 35 patients were enrolled in this prospective study. The primary end-point was the 3-year local control rate, and the secondary end-points included the 3-year overall survival rate and adverse events. Acute and late adverse events were evaluated according to the Common Terminology Criteria for Adverse Events, version 4.0. The median follow-up time for all patients was 39 months. Thirty-two and three patients received 64.0 Gy (relative biological effectiveness) and 57.6 Gy (relative biological effectiveness) in 16 fractions, respectively. Adenoid cystic carcinoma was dominant (60%). Four patients had local recurrence and five patients died. The 3-year local control and overall survival rates were 93% and 88%, respectively. Acute grade 2-3 radiation mucositis (65%) and dermatitis (31%) was common, which improved immediately with conservative therapy. Late mucositis of grade 2, grade 3, and grade 4 were observed in 11, one, and no patients, respectively. There were no adverse events of grade 5. Carbon-ion radiotherapy achieved excellent local control and overall survival rates for non-squamous cell carcinoma. However, the late mucosal adverse events were not rare, and meticulous treatment planning is required. Trial registration no. UMIN000007886.

Oral Mucosa Dose Parameters Predicting Grade ≥3 Acute Toxicity in Locally Advanced Nasopharyngeal Carcinoma Patients Treated With Concurrent Intensity-Modulated Radiation Therapy and Chemotherapy: An Independent Validation Study Comparing Oral Cavity versus Mucosal Surface Contouring Techniques

PURPOSE: To determine whether volumes based on the contours of the mucosal surface instead of the oral cavity can be used to predict grade ≥3 acute oral mucosa toxicity in patients with locally advanced nasopharyngeal carcinoma (LANPC) treated with concurrent intensity-modulated radiation therapy (IMRT) and chemotherapy. METHODS AND MATERIALS: A standardized method for the oral cavity (oral cavity contours, OCC) and a novel method for the mucosal surface (mucosal surface contours, MSC) were developed for the oral mucosa and prospectively applied to the radiation treatment plans of 92 patients treated with concurrent IMRT and chemotherapy for LANPC. Dose–volume histogram (DVH) data were extracted and then toxicity was analyzed. Receiver operating characteristic analysis and logistic regression were carried out for both contouring methods. RESULTS: Grade ≥3 acute oral mucosa toxicity occurred to 20.7% (19/92) of patients in the study. A highly significant dose–volume relationship between oral mucosa irradiation and acute oral mucosa toxicity was supported by using both oral cavity and mucosal surface contouring techniques. In logistic regression, body weight loss was an independent factor related to grade ≥3 acute toxicity for OCC and MSC (P = .017 and 0.005, respectively), and the independent factor of dosimetric parameters for OCC and MSC were V30Gy (P = .003) and V50Gy (P = .003) respectively. In the receiver operating characteristics curve, the areas under V30Gy of the OCC curves was 0.753 (P = .001), while the areas under V50Gy of MSC curves was 0.714 (P = .004); the cut-off value was 73.155% (sensitivity, 0.842; specificity, 0.671) and 14.32% (sensitivity, 0.842; specificity, 0.575), respectively. CONCLUSION: DVH analysis of mucosal surface volumes accurately predicts grade ≥3 acute oral mucosa toxicity in patients with LANPC receiving concurrent IMRT and chemotherapy, but in clinical practice the MSC method appears no better than the OCC one.

Multi-institutional retrospective study of mucoepidermoid carcinoma treated with carbon-ion radiotherapy

This study aimed to evaluate the clinical outcomes of patients with mucoepidermoid carcinomas in the head and neck treated with carbon‐ion radiotherapy. Data from 26 patients who underwent carbon‐ion radiotherapy in four facilities were analyzed in this multi‐institutional retrospective study: the Japan Carbon‐ion Radiation Oncology Study Group. The median follow‐up time was 34 months. One patient experienced local recurrence, and the 3‐year local control rate was 95%. One patient developed lymph node recurrence and five developed distant metastases. The 3‐year progression‐free survival rate was 73%. Five patients died, two of mucoepidermoid carcinoma and three of intercurrent disease. The 3‐year overall survival rate was 89%. Acute mucositis and dermatitis of grade 3 or higher were experienced by 19% and 8% of patients, respectively; these improved with conservative therapy. Late mucositis and osteonecrosis of jaw were observed in 12% and 23% of patients, respectively. The 3‐year cumulative rate of any late adverse event of grade 3 or higher was 14%. None of the patients died of the acute or late adverse events. Carbon‐ion radiotherapy was efficacious and safe for treating mucoepidermoid carcinoma in this multi‐institutional retrospective study (registration no. UMIN000024473). We are currently undertaking a prospective multicenter study.