A retrospective multicenter study of carbon-ion radiotherapy for major salivary gland carcinomas: Subanalysis of J-CROS 1402 HN

Impact of perineural tumor spread in head and neck adenoid cystic carcinoma for carbon-ion radiotherapy

Background and purpose

Despite recognizing the effectiveness of carbon-ion radiotherapy (C-ion RT) in treating head and neck adenoid cystic carcinoma (HN-ACC), the impact of perineural tumor spread (PNTS) on treatment outcomes and the relationship between PNTS and post-treatment marginal recurrences remain unexplored. Therefore, we analyzed the efficacy of C-ion RT in HN-ACC, focusing on PNTS including details of post-treatment marginal recurrence and indicators for future treatment strategies.

Materials and methods

In this retrospective study, we included 74 patients diagnosed with HN-ACC who underwent C-ion RT between June 2010 and July 2022. Treatment dosages were either 57.6 or 64.0 Gy (relative biological effectiveness) delivered in 16 fractions. Patients undergoing C-ion RT were identified retrospectively from medical records. PNTS was evaluated by magnetic resonance imaging for detecting extratumoral extension to peritumoral nerves.

Results

The median duration of follow-up was 46.4 months. Local recurrence developed in 19 patients. Moreover, most marginal recurrences occurred within the irradiated margins. The 5-year rates for local control (LC), progression-free survival (PFS), and overall survival (OS) were 67.6 %, 47.7 %, and 79.0 %, respectively. LC (p = 0.005) and PFS (p = 0.013) demonstrated significant variances on analysis based on PNTS occurrence; however, OS did not exhibit a similar pattern.

Conclusion

Our findings highlight the importance for considering disease-specific characteristics and the need for developing targeted strategies that address the complex nature of HN-ACC, particularly in cases involving PNTS, to enhance treatment outcomes and potentially reduce recurrence rates.

Long-Term Outcomes Following Radiotherapy for Pediatric Salivary Gland Tumors

BACKGROUND

In contrast to adult salivary gland tumors, our institutional guidelines utilize lower radiation doses, smaller target margins, and proton therapy (PT) to minimize radiation to children's developing skull base anatomy. Herein, we report outcomes of our pediatric management approach.

PROCEDURES

We identified 31 pediatric patients with salivary gland tumors treated with PT at our institution between 2006 and 2023. Most common histologies were mucoepidermoid carcinoma (n = 14), acinic cell carcinoma (n = 5), and adenoid cystic carcinoma (n = 5). Eight patients with radiographic lymphadenopathy underwent neck dissection prior to presentation, with selective dissections involving <4 nodal levels in 7/8 cases. The gross tumor volume (GTV) encompassed the residual tumor and tumor bed. Clinical target volume (CTV1), defined as GTV + 1 cm margin, received 50.4 Gy. Prophylactic nodal irradiation was administered to three patients. CTV2 equaled the GTV and was treated to a median total dose of 64.8 Gy (range, 61.2-70.8). Toxicity was assessed with CTCAE Version 5.0.

RESULTS

Median follow-up was 7.5 years (range, 1.2-15). Overall survival (OS) was 96%, and local control was 94%. There were no nodal recurrences. Acute toxicities were limited to mucositis requiring opioids and transient Grade 3 dermatitis. The most serious late toxicity involved the auditory system, including three patients requiring hearing aids, one with chronic otitis media, one with osteonecrosis of the mastoid, and one with external canal stenosis. There was neither Grade 4 toxicity nor second malignancy.

CONCLUSIONS

Conservative neck management and moderate-dose PT delivered to smaller volumes resulted in excellent long-term disease control and limited toxicity in children with common salivary gland tumors.

Clinical outcomes of particle beam radiation therapy for patients with newly-diagnosed major salivary gland tumors

BACKGROUND

Major salivary gland tumors (MSGTs) are rare and pose significant treatment challenges. This study investigates the efficacy and safety of particle beam radiotherapy (PBRT) for patients with newly-diagnosed MSGTs.

METHODS

We conducted a retrospective analysis of 82 patients treated at the Shanghai Proton and Heavy Ion Center (SPHIC) between August 2015 and March 2022. The cohort received various radiotherapy regimens based on surgical history and pathological risk factors. We evaluated survival outcomes, treatment toxicity, and potential prognostic factors.

RESULTS

Our findings revealed promising 3-year survival rates: 94.3% for overall survival (OS), 81.3% for progression-free survival (PFS), 97.2% for locoregional control (LRC), and 82.6% for distant metastasis-free survival (DMFS). Acute and late toxicities were generally mild to moderate, with a favorable safety profile. Distant metastasis was the primary mode of treatment failure, emphasizing the need for early risk assessment.

CONCLUSION

As a potentially safe and efficient treatment option for newly-diagnosed MSGTs, proton and carbon ion radiation offers an excellent alternative for traditional methods. More investigation is required to determine the long-term results and relative efficacy of various treatment modality for major salivary gland cancer when compared to photon therapy.

Feasibility and safety of Taipei Veterans General Hospital Heavy Ion Therapy Center: The first carbon-ion irradiation facility in Taiwan

BACKGROUND

Unlike conventional photon radiotherapy, particle therapy has the advantage of dose distribution. Carbon-ion radiotherapy is also advantageous in terms of biological effectiveness and other radiobiological aspects. These benefits lead to a higher response probability for previously known radioresistant tumor types. Therefore, Taipei Veterans General Hospital, which is located in the northern district of Taipei, built the first carbon-ion irradiation facility in Taiwan.

METHODS

Taipei Veterans General Hospital completed a phase 1 trial to evaluate the safety of carbon-ion radiotherapy. Six patients (4 males and 2 females with prostate adenocarcinoma, sacral chordoma, hepatocellular carcinoma, lung adenocarcinoma, or parotid high-grade carcinoma) were enrolled in this study. The mean age of the patients was 62.7 years. The mean dose was 57.3 Gy(RBE) (fraction range, 4-16 Gy[RBE]).

RESULTS

During this phase 1 trial, all patients were monitored for 3 months to evaluate acute toxicity and short-term outcomes after treatment with carbon irradiation. Only 2 patients experienced grade 2 toxicity, which resolved without medication 1 month after completing treatment. The tumor response demonstrated 1 complete response, 1 partial response, and 4 cases of stable disease.

CONCLUSION

Carbon-ion radiotherapy was determined to be an effective and safe treatment.

A Practical Primer on Particle Therapy

PURPOSE

Particle therapy is a promising treatment technique that is becoming more commonly used. Although proton beam therapy remains the most commonly used particle therapy, multiple other heavier ions have been used in the preclinical and clinical settings, each with its own unique properties. This practical review aims to summarize the differences between the studied particles, discussing their radiobiological and physical properties with additional review of the available clinical data.

METHODS AND MATERIALS

A search was carried out on the PubMed databases with search terms related to each particle. Relevant radiobiology, physics, and clinical studies were included. The articles were summarized to provide a practical resource for practicing clinicians.

RESULTS

A total of 113 articles and texts were included in our narrative review. Currently, proton beam therapy has the most data and is the most widely used, followed by carbon, helium, and neutrons. Although oxygen, neon, silicon, and argon have been used clinically, their future use will likely remain limited as monotherapy.

CONCLUSIONS

This review summarizes the properties of each of the clinically relevant particles. Protons, helium, and carbon will likely remain the most commonly used, although multi-ion therapy is an emerging technique.

Particle Beam Therapy and Surgery as Radical Treatments for Parotid Malignancies-A Single-Center Preliminary Case Study

Background/Objectives: Particle beam therapy (PBT) was approved in April 2018 for head and neck malignancies and has since been introduced as a radical therapy for parotid malignancies. However, its prevalence and effectiveness in relation to surgical treatment have not been investigated. Methods: In this study, we evaluated 36 patients with parotid malignancy who underwent surgery (n = 26) or PBT (n = 10) and then analyzed the annual changes in the number of patients, survival rates, and clinical factors affecting prognosis. Results: Of the ten patients who opted for PBT, two and eight patients underwent PBT before and after 2018, respectively. There was a significant difference between these two groups of patients (p = 0.04). Of the ten patients who underwent PBT, five patients were recurrent cases; meanwhile, all twenty-six patients who underwent surgery were receiving initial treatment. Only one patient in each group had local recurrence after the treatment. Conclusions: The use of PBT as a radical therapy for parotid malignancies has been increasing since 2018, and patients with recurrent tumors tended to choose PBT. The outcome of the patients who underwent PBT did not seem to be inferior compared with those of the patients who underwent surgery. The histopathological type was a crucial issue in the outcomes of patients who underwent radical therapy for parotid malignancies.

Clinical indications for carbon-ion radiotherapy in the UK: A critical review

INTRODUCTION

Carbon-ion radiotherapy (CIRT) has unique radiobiological properties that cause increased radiobiological effect and tumour control, especially with hypoxic tissues. This critical review aimed to evaluate clinical response to CIRT across all published tumour sites to establish if there is a clinical need for a CIRT centre in the UK.

METHODS

A critical review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Literature searching was undertaken in November 2022 within the PubMed, Science Direct, SCOPUS and Web of Science databases using the term 'carbon ion radiotherapy' in the title, abstract or author keywords.

RESULTS

After critical appraisal, data was extracted from 78 primary study papers. Strong evidence supported use of CIRT for chondrosarcoma, chordoma, nasopharyngeal, non-small cell lung cancer (NSCLC), oral cavity, prostate, rectal and salivary gland tumours. Further research is needed to strengthen the evidence base for some other tumour types.

CONCLUSION

The UK's incidence and mortality rates suggest a clinical need for CIRT for chondrosarcoma, chordoma, NSCLC, oral cavity, prostate, and rectal tumours. There is a need to improve survivorship amongst pancreatic, liver, and oesophageal cancer patients. Data published relating to CIRT for these tumours is promising but of lower quality and more research is needed in these areas.

IMPLICATIONS FOR PRACTICE

The clinical response to CIRT for certain tumours suggests the need for a carbon-ion centre in the UK. Demand for further research [phase III trials] has been identified, giving the UK opportunity to establish a research centre, with opportunity to treat, contributing to world-renowned research whilst improving patient outcomes.

Sole brachytherapy for inoperable, recurrent, and irradiated salivary gland cancer

BACKGROUND AND PURPOSE

Salivary gland cancers (SGCs) are hard to treat when inoperable, and sole brachytherapy appears to be a promising therapeutic strategy. This study aimed to evaluate the effectiveness, safety, and capability of pain palliation using sole brachytherapy for inoperable, recurrent, and irradiated SGCs.

MATERIALS AND METHODS

Patients with inoperable SGCs treated using sole brachytherapy at Peking University School and Hospital of Stomatology were retrospectively included. Patients were divided into primary and recurrent groups and irradiated and non-irradiated groups. Local control (LC), overall survival (OS), radiation-relevant toxicities, and Visual Analogue Scale (VAS) score for pain, were recorded and evaluated.

RESULTS

A total of 176 patients from 2006 to 2020 were included. The 5-year LC rate was 48.6 %; for the primary, recurrent, non-irradiated and irradiated groups, the rates were 72.6 %, 39.5 %, 56.8 %, and 34.5 %, respectively. The 5-year OS rates was 52.6 %; for the primary, recurrent, non-irradiated, and irradiated groups, the rates were 62.9 %, 48.6 %, 58.9 %, and 42.3 %, respectively. The mean ± standard deviation of posttreatment VAS score of pain was 2.154 ± 2.989, which was significantly decreased from the score of 6.923 ± 2.280 prior to brachytherapy. Skin hyperpigmentation, mucositis, and dysphagia were the most frequently reported adverse events.

CONCLUSIONS

Brachytherapy as a sole modality, was retrospectively proven effective and safe in the management of inoperable SGCs and was beneficial in multiple irradiation and pain control.

Current management and future challenges in salivary glands cancer

Salivary gland cancers (SGCs) are rare, accounting for less than 5% of all malignancies of the head and neck region, and are morphologically heterogeneous. The diagnosis is mainly based on histology, with the complementary aid of molecular profiling, which is helpful in recognizing some poorly differentiated, borderline, or atypical lesions. Instrumental imaging defines the diagnosis, representing a remarkable tool in the treatment plan. Ultrasound and magnetic resonance are the most common procedures used to describe the primary tumour. The treatment of SGCs is multimodal and consists of surgery, radiotherapy, and systemic therapy; each treatment plan is, however, featured on the patient and disease's characteristics. On 24 June 2022, in the meeting "Current management and future challenges in salivary gland cancers" many experts in this field discussed the state of the art of SGCs research, the future challenges and developments. After the meeting, the same pool of experts maintained close contact to keep these data further updated in the conference proceedings presented here. This review collects the insights and suggestions that emerged from the discussion during and after the meeting per se.

Dental Infections and Risk for Brain Abscess: A Literature Review

Dental work is commonly accepted as a low-risk procedure but has been associated with serious brain abscesses. Bacteria from the oral cavity can spread to the brain and cause life-threatening infections. In this literature review, the focus was placed on the relevant causative bacteria, surgical procedures, and correlated medical conditions revolving around brain abscesses following dental work. This paper is written from a neurological surgery perspective, using information collected from several case studies, case reviews, and other related published manuscripts. Several risk factors have been identified to predispose oral cavity bacterial infection to cause brain abscess: dental work done in the upper molars; right-to-left shunts in the heart; and poor dental hygiene. If the bacterium of the abscess is correctly identified, there is a greater effectiveness of treatment, but prolonging antibiotic and/or surgical treatment increases morbidity.

Salivary gland cancers in elderly patients: challenges and therapeutic strategies

Salivary gland carcinomas (SGCs) are the most heterogeneous subgroup of head and neck malignant tumors, accounting for more than 20 subtypes. The median age of SGC diagnosis is expected to rise in the following decades, leading to crucial clinical challenges in geriatric oncology. Elderly patients, in comparison with patients aged below 65 years, are generally considered less amenable to receiving state-of-the-art curative treatments for localized disease, such as surgery and radiation/particle therapy. In the advanced setting, chemotherapy regimens are often dampened by the consideration of cardiovascular and renal comorbidities. Nevertheless, the elderly population encompasses a broad spectrum of functionalities. In the last decades, some screening tools (e.g. the G8 questionnaire) have been developed to identify those subjects who should receive a multidimensional geriatric assessment, to answer the question about the feasibility of complex treatments. In the present article, we discuss the most frequent SGC histologies diagnosed in the elderly population and the relative 5-years survival outcomes based on the most recent data from the Surveillance, Epidemiology, and End Results (SEER) Program. Moreover, we review the therapeutic strategies currently available for locoregionally advanced and metastatic disease, taking into account the recent advances in precision oncology. The synergy between the Multidisciplinary Tumor Board and the Geriatrician aims to shape the most appropriate treatment pathway for each elderly patient, focusing on global functionality instead of the sole chronological age.

Intensity-modulated proton and carbon-ion radiation therapy in the management of major salivary gland carcinomas

Background

Primary major salivary gland carcinomas (SGCs) present with diverse histological types that are known to be largely radioresistant with a high tendency to develop distant metastasis (DM). Photon-based radiotherapy (RT) is limited in terms of its therapeutic effect and toxicities. In view of the physical and biological advantages of intensity-modulated proton and/or carbon-ion radiation therapy, we aimed to evaluate the short-term therapeutic effect and toxicities in patients with major SGCs treated with this form of radiation therapy.

Methods

Between August 2015 and November 2019, a total of 55 consecutive and non-selected major SGC patients who received particle RT at the Shanghai Proton and Heavy Ion Center (SPHIC) were retrospectively analyzed. The 2-year overall survival (OS), progression-free survival (PFS), local-regional recurrence-free survival (LRRFS), and distant metastasis-free survival (DMFS) rates, as well as prognostic factors were analyzed. Additionally, acute and late toxicities were also analyzed.

Results

With a median follow-up time of 24 (range, 6-57) months, the 2-year OS, PFS, LRRFS, and DMFS rates were 91.6%, 78.6%, 94.2%, and 83.9%, respectively. At the time of this analysis, four patients had developed local or regional recurrence, and seven additional patients had developed DM. Three patients had died due to disease progression, and another patient with recurrence experienced a late Grade 5 event (hemorrhage) at 9 months after re-irradiation with carbon ion and subsequently died. Otherwise, none of the patients had grade 3 or higher treatment-induced acute or late adverse effects except one who developed grade 3 acute mucositis.

Conclusions

Overall, intensity-modulated proton and/or carbon-ion radiation therapy provided satisfactory therapeutic effectiveness in our major SGCs patients with a low incidence of acute and late toxicities.

Normal Tissue Complication Probability Model for Acute Radiation Dermatitis in Patients with Head and Neck Cancer Treated with Carbon Ion Radiotherapy

PURPOSE

This study aimed to explore the prognostic factors associated with acute radiation dermatitis (ARD). A normal tissue complication probability (NTCP) model for ARD in patients with head and neck cancer (HNC) treated with carbon ion radiotherapy (CIRT) was developed.

MATERIALS AND METHODS

A total of 187 patients were included in the analysis, and the endpoint was ≥grade 2 ARD. The biological and physical dose-surface parameters associated with ARD were used in the logistic regression model. The mean areas under the receiver operating characteristic curve (AUC) in the internal cross-validation and Akaike's corrected Information Criterion (AICc) were examined for model evaluation and selection. The multivariate logistic regression NTCP models were established based on factors with weak correlation.

RESULTS

Tumour volume, planning target volume to the skin, radiation technique and all dose-surface parameters were significantly associated with ARD (P < 0.05). Models with high performance for grade 2-3 ARD were constructed. The most significant prognostic predictors were S_{40 Gy (relative biological effectiveness, RBE)} and S_{20 Gy} [absolute surface area receiving RBE-weighted dose of 40 Gy (RBE) or physical dose of 20 Gy]. The internal cross-validation-based AUCs for models with S_{40 Gy (RBE)} and S_{20 Gy} were 0.78 and 0.77, respectively. The biological and physical dose-surface parameters had similar performance at various dose levels. However, the performance of the multivariate NTCP models based on two factors was not better than that of the univariate models.

CONCLUSIONS

NTCP models for ARD may provide a basis for the development of individualised treatment strategies and reduce the incidence of severe ARD in patients with HNC receiving CIRT. Furthermore, biological and physical dose-surface parameter-based models are comparable. However, further validation with more evaluation parameters is warranted.

Particle Radiotherapy for Skull Base Chondrosarcoma: A Clinical Series from Italian National Center for Oncological Hadrontherapy

Simple Summary

Skull-base chondrosarcoma is a rare locally aggressive or malignant group of cartilaginous neoplasm. The standard of care consists of surgery and high-dose radiation therapy, better if with particle, due to their radioresistance and proximity to organs at risk such as brainstem and optic pathways. Due to the rarity of the tumor and its site, outcomes in terms of local control and toxicity of patients with this malignancy after receiving particle therapy has been documented only in a limited number of series with a restricted number of patients, in particular with regard to carbon ions. The aim of our retrospective study is to assess the role of particle therapy (protons and carbon ions) after surgery in our Institute in skull-base chondrosarcomas.

Abstract

Background: The standard treatment for skull base chondrosarcoma (SB-CHS) consists of surgery and high-dose radiation therapy. Our aim was to evaluate outcome in terms of local control (LC) and toxicity of proton therapy (PT) and carbon ion (CIRT) after surgery. Materials and methods: From September 2011 to July 2020, 48 patients underwent particle therapy (67% PT, 33% CIRT) for SB-CHS. PT and CIRT total dose was 70 GyRBE (relative biological effectiveness) in 35 fractions and 70.4 GyRBE in 16 fractions, respectively. Toxicity was assessed using the Common Terminology Criteria for Adverse Events (CTCAE v5). Results: After a median follow-up time of 38 months, one local failure (2%) was documented and the patient died for progressive disease. Overall, 3-year LC was 98%. One (2%) and 4 (8%) patients experienced G3 acute and late toxicity, respectively. White-matter brain changes were documented in 22 (46%) patients, but only 7 needed steroids (G2). No patients had G3 brain toxicity. No G4–5 complications were reported. We did not find any correlation between high-grade toxicity or white-matter changes and characteristics of patients, disease and surgery. Conclusions: PT and CIRT appeared to be effective and safe treatments for patients with SB-CHS, resulting in high LC rates and an acceptable toxicity profile.

The Role of Particle Therapy in Adenoid Cystic Carcinoma and Mucosal Melanoma of the Head and Neck

Particle irradiation is suitable for resistant histologies owing to a combination of improved dose delivery with potential radiobiologic advantages in high linear energy transfer radiation. Within the head and neck, adenoid cystic carcinoma and mucosal melanoma are two such histologies, being radioresistant and lying closely proximal to critical structures. Here, we review the use of particle irradiation for adenoid cystic carcinoma and mucosal melanoma of the head and neck.

Carbon Ion Dose Constraints in the Head and Neck and Skull Base: Review of MedAustron Institutional Protocols

BACKGROUND

Dose constraints are of paramount importance for the outcome of any radiotherapy treatment. In this article, we report dose-volume constraints as well as currently used fractionation schedules for carbon ion radiotherapy as applied in MedAustron (Wiener Neustadt, Austria).

MATERIALS AND METHODS

For fractionation schedules, both German and Japanese regimes were used. From the clinical experience of National Institute of Radiological Sciences (Chiba, Japan) and Heidelberg Ion Therapy (Heidelberg, Germany; formerly GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany) and the work by colleagues in Centro Nazionale Adroterapia Oncologica (Pavia, Italy) recalculating the dose from the microdosimetric kinetic model to the local effect model, we have set the dose constraints for critical organs of the head and neck area. Where no clinical data was available, an educated guess was made, based on data available from photon and proton series.

RESULTS

We report the constraints for the optic nerve and chiasm, brainstem, spinal cord, cochlea, brain parenchyma, salivary gland, eye and adnexa, and mandibular/maxillary bone; constraints are grouped based on a fractionation scheme (German versus Japanese) and the risk of toxicity (safe, low to middle, and middle to high).

CONCLUSION

We think validation of dose constraints should present a relevant part of the activity of any carbon ion radiotherapy facility, and we anticipate future multicentric, joint evaluations.

Management of Salivary Gland Malignancy: ASCO Guideline

PURPOSE

To provide evidence-based recommendations for practicing physicians and other healthcare providers on the management of salivary gland malignancy.

METHODS

ASCO convened an Expert Panel of medical oncology, surgical oncology, radiation oncology, neuroradiology, pathology, and patient advocacy experts to conduct a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 2000 through 2020. Outcomes of interest included survival, diagnostic accuracy, disease recurrence, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 293 relevant studies to inform the evidence base for this guideline. Six main clinical questions were addressed, which included subquestions on preoperative evaluations, surgical diagnostic and therapeutic procedures, appropriate radiotherapy techniques, the role of systemic therapy, and follow-up evaluations.

RECOMMENDATIONS

When possible, evidence-based recommendations were developed to address the diagnosis and appropriate preoperative evaluations for patients with a salivary gland malignancy, therapeutic procedures, and appropriate treatment options in various salivary gland histologies.Additional information is available at www.asco.org/head-neck-cancer-guidelines.

Therapeutic challenges in radiation-induced salivary gland cancers

PURPOSE OF REVIEW

To give an overview of recent advances in therapeutic approaches of radiation-induced salivary gland cancers (ri-SGCs).

RECENT FINDINGS

Reirradiation with protons and carbon ions demonstrated to be feasible, safe and to offer good local control rates, with the possibility of overcoming radioresistance and dosimetric issues in previously irradiated cancer patients. Chromosomal rearrangements, gene fusions and expression profiles are important to identify specific cancer subtypes and can guide tailored systemic therapy.

SUMMARY

Ri-SGCs are rare and heterogeneous. Patients are often heavily pretreated and at risk of toxicities, and their management remain challenging. A multidisciplinary approach in referral centers is mandatory. Knowledge about SGCs cellular and molecular mechanisms is constantly evolving. In the last years, novel advances in therapeutic approaches, such as carbon ion radiotherapy, are emerging as safe and effective options in active treatment, but further efforts are needed to offer tailored personalized treatments and to improve survival.

Intensity Modulated Radiotherapy with Carbon Ion Radiotherapy Boost for Acinic Cell Carcinoma of the Salivary Glands

Simple Summary

Acinic cell carcinoma is a rare disease treated usually by surgery. The role of radiotherapy is controversially discussed. In this retrospective analysis based on 15 patients undergoing postoperative or definitive radiotherapy (intensity-modulated radiotherapy, IMRT) with carbon ion radiotherapy boost leads to excellent results after R1-resection, and is a promising treatment modality in inoperable patients. G1-2 xerostomia, dysgeusia, and trismus were the main reported morbidity symptoms after radiotherapy. Confirmation of the results with larger patient cohorts is needed.

Abstract

Aim: to report clinical outcome in patients with acinic cell carcinoma of the salivary glands treated with intensity-modulated radiotherapy (IMRT) and carbon ion radiotherapy (CIRT) boost. Materials and Methods: all patients with acinic cell carcinoma of the salivary glands treated at the Heidelberg Ion-Beam Therapy Center were considered for this retrospective analysis. All patients received a CIRT boost with 18–24 Gy radiobiologic effectiveness (RBE)-weighted dose in 3 Gy RBE-weighted dose per fraction followed by IMRT, with 50–54 Gy in 2 Gy per fraction. Disease outcome was evaluated for local (LR), nodal (NR), distant recurrence (DR), and disease-free (DFS) and overall survival (OS). Morbidity was scored based on Common Terminology Criteria for Adverse Events (CTCAE) version 5. Descriptive statistics and the Kaplan-Meier method were used for analysis. Results: fifteen patients were available for analysis. Median follow-up after radiotherapy was 43 months. Six patients were treated for primary disease and nine for recurrent disease. Eight patients were treated with radiotherapy for macroscopic disease. Disease recurrence was observed in four patients: 1 LR, 2 NR, and 2 DR; 5-year local control, DFS, and OS were 80%, 52%, and 80%, respectively. No radiotherapy-related G3-5 morbidity was observed. Conclusion: In acinic cell carcinoma, IMRT with carbon ion radiotherapy boost leads to excellent results after R1-resection and is a promising treatment modality for definitive treatment in inoperable patients.

Treatment outcomes of elderly salivary gland cancer patients undergoing radiotherapy - Results from a large multicenter analysis

BACKGROUND AND PURPOSE

To evaluate oncological outcomes and treatment-related toxicities of elderly salivary gland cancer patients undergoing (chemo)radiotherapy.

MATERIAL AND METHODS

Local/locoregional control (LRC), progression-free survival (PFS) and overall survival (OS) of elderly patients ≥ 65 years with primary salivary gland cancers undergoing (chemo)radiotherapy between 2005 and 2020 at three tertiary cancer centers were calculated. The impact of clinicopathological and treatment parameters on outcomes were analyzed, and acute and chronic toxicities were quantified.

RESULTS

288 elderly salivary gland cancer patients were included in this multicenter analysis, and their median LRC, PFS and OS amounted to 113, 39 and 75 months, respectively. Age, performance status, comorbidities, definitive vs. adjuvant (chemo)radiotherapy as well as locally/locoregionally advanced cancers and distant metastases correlated with reduced outcomes in elderly salivary gland patients. Patients receiving dose-escalated radiotherapy (total doses > 70 Gy_EQD2) with carbon ion boost radiation resulted in improved LRC, but no improvements in PFS or OS. Concomitant chemoradiotherapy did not improve treatment outcomes in elderly salivary gland carcinoma patients. Radiotherapy of elderly salivary gland cancer patients resulted in moderate higher-grade toxicities despite dose escalation with 70 (24.3%) and 48 patients (16.7%) experiencing acute and chronic grade 3 toxicities, respectively. No grade 4/5 toxicities were observed in this patient cohort.

CONCLUSION

Data from the largest multicenter analysis of elderly salivary gland cancer patients undergoing (chemo)radiotherapy demonstrate favorable LRC and tolerable toxicity rates. Decision-making for these vulnerable patients should be based on patient performance rather than chronological patient age.

Particle therapy in the future of precision therapy

The first hospital-based treatment facilities for particle therapy started operation about thirty years ago. Since then, the clinical experience with protons and carbon ions has grown continuously and more than 200,000 patients have been treated to date. The promising clinical results led to a rapidly increasing number of treatment facilities and many new facilities are planned or under construction all over the world. An inverted depth-dose profile combined with potential radiobiological advantages make charged particles a precious tool for the treatment of tumours that are particularly radioresistant or located nearby sensitive structures. A rising number of trials have already confirmed the benefits of particle therapy in selected clinical situations and further improvements in beam delivery, image guidance and treatment planning are expected. This review summarises some physical and biological characteristics of accelerated charged particles and gives some examples of their clinical application. Furthermore, challenges and future perspectives of particle therapy will be discussed.

Skin Dose Reduction by Layer-Stacking Irradiation in Carbon Ion Radiotherapy for Parotid Tumors

Background: Layer-stacking irradiation (LSI) results in the accumulation of multiple small spread-out Bragg peaks along the beam direction. Although the superiority of LSI to conventional passive irradiation (CPI) regarding normal tissue sparing is theoretically evident, the clinical benefit of LSI has not been demonstrated. Here, we compared LSI with CPI using the same treatment planning-computed tomography images used for carbon ion radiotherapy (CIRT). Methods: Twenty-one parotid tumors were analyzed. The clinical target volume (CTV) 1 and CTV2 encompassed the parotid grand and the tumor, respectively. CTV1 and CTV2 received 36 Gy (RBE: relative biological effectiveness) in nine fractions and 64 Gy (RBE) in 16 fractions, respectively, using either LSI or CPI. CTV coverage was assessed by DX%, which is the dose covering at least X% of the target volume. Skin dose was assessed by SX, which is the skin surface area receiving at least X Gy (RBE). Results: For CTV1 and CTV2, there were no significant differences in D2% between LSI and CPI. D50% and D98% were slightly higher for CPI; however, the absolute difference between the two methods was <3%. S10-S60 (in increments of 10) were significantly lower for LSI than for CPI (P < 0.001 for all parameters). LSI was associated with a significant trend toward dose reduction at the skin area irradiated with a higher dose by CPI (P < 0.001). Conclusions: LSI achieved better skin sparing than CPI without sacrificing target volume coverage in parotid tumor patients.

Carbon Ion Therapy: A Modern Review of an Emerging Technology

Radiation therapy is one of the most widely used therapies for malignancies. The therapeutic use of heavy ions, such as carbon, has gained significant interest due to advantageous physical and radiobiologic properties compared to photon based therapy. By taking advantage of these unique properties, carbon ion radiotherapy may allow dose escalation to tumors while reducing radiation dose to adjacent normal tissues. There are currently 13 centers treating with carbon ion radiotherapy, with many of these centers publishing promising safety and efficacy data from the first cohorts of patients treated. To date, carbon ion radiotherapy has been studied for almost every type of malignancy, including intracranial malignancies, head and neck malignancies, primary and metastatic lung cancers, tumors of the gastrointestinal tract, prostate and genitourinary cancers, sarcomas, cutaneous malignancies, breast cancer, gynecologic malignancies, and pediatric cancers. Additionally, carbon ion radiotherapy has been studied extensively in the setting of recurrent disease. We aim to provide a comprehensive review of the studies of each of these disease sites, with a focus on the current trials using carbon ion radiotherapy.

The impact of age on the outcome of patients treated with radiotherapy for mucoepidermoid carcinoma (MEC) of the salivary glands in the head and neck: A 15-year single-center experience

INTRODUCTION

Data regarding treatment and survival outcome of patients with mucoepidermoid carcinoma of the head and neck are limited to case reports and case series. As a consequence of lacking evidence, treatment guidelines do not exist. We aimed to analyze the effect of modern radiotherapy in form of intensity modulated radiotherapy (IMRT) either with simultaneously integrated boost or carbon ion boost on local control and survival for a relatively large patient collective.

MATERIALS AND METHODS

Patient records of 62 consecutive patients treated with postoperative (n = 53, 85%) or definitive (n = 9, 15%) radiotherapy between 2004 and 2019 were analyzed retrospectively. Kaplan-Meier estimates for overall survival (OS), distant progression-free survival (PFS), local control (LC) and locoregional control (LRC) were statistically calculated and prognostic factors were identified using the log-rank test. Toxicity was assessed according to the Common Terminology Criteria for Adverse Events (CTCAE).

RESULTS

The median follow-up was 47 months (range, 4-188 months). The 3-year OS, DPFS, LC and LRC, estimated by Kaplan-Meier curves, were 82%, 87%, 89% and 92%, the estimated 5-year OS, DPFS, LC and LRC were 78%, 87%, 84% and 88%, respectively. In univariate analysis, age >56 years (vs. age ≤56 years) was identified as the only independent negative prognostic factor for decreased OS (HR = 1.078; 95%-CI = 1.029-1.130; p = 0.001), DPFS (HR = 1.055; 95%-CI = 1.000-1.114; p = 0.051) and LC (HR = 1.087; 95%-CI = 1.022-1.157; p = 0.008). Treatment was well tolerated without any grade ≥4 toxicity. Acute and late grade 3 toxicities were rare with 16% acute (n = 10) and 13% late toxicities (n = 8).

CONCLUSION

Radiotherapy with intensity modulated radiotherapy including either simultaneously integrated photon boost or active raster-scanning carbon ion boost for mucoepidermoid carcinomas of the head and neck resulted in excellent survival outcome and locoregional control with moderate toxicity. However, patients older than 56 years seem to have a disadvantage in all calculated endpoints (OS, DPFS, LRC) due to frequent local and distant relapses.

CONDENSED ABSTRACT

Modern radiotherapy with intensity modulated radiotherapy including either a simultaneously integrated photon boost or carbon ion boost for mucoepidermoid carcinoma results in excellent survival outcome and locoregional control with moderate toxicity. The 5-year OS, DPFS, LC and LRC, estimated by Kaplan-Meier curves, were 89%, 75%, 84% and 80%, respectively. Patients older than 56 years seem to have a disadvantage in all calculated endpoints (OS, DPFS, LRC).

Modern radiotherapy for head and neck cancer

Radiation therapy (RT) plays a key role in curative-intent treatments for head and neck cancers. Its use is indicated as a sole therapy in early stage tumors or in combination with surgery or concurrent chemotherapy in advanced stages. Recent technologic advances have resulted in both improved oncologic results and expansion of the indications for RT in clinical practice. Despite this, RT administered to the head and neck region is still burdened by a high rate of acute and late side effects. Moreover, about 50% of patients with high-risk disease experience loco-regional recurrence within 3 years of follow-up. Therefore, in recent decades, efforts have been dedicated to optimize the cost/benefit ratio of RT in this subset of patients. The aim of the present review was to highlight modern concepts of RT for head and neck cancers considering both the technological advances that have been achieved and recent knowledge that has informed the biological interaction between radiation and both tumor and healthy tissues.

An update on head and neck cancer: new entities and their histopathology, molecular background, treatment, and outcome

The head and neck region harbor numerous specialized tissues of all lineages giving rise to a plethora of different malignancies. In recent years, new types and subtypes of cancer has been described here due to the recognition of their histological and molecular characteristics. Some have been formally accepted in the most recent classifications from the World Health Organization (WHO) and American Joint Committee on Cancer (AJCC) as distinct diseases due to characteristics in clinical presentation, outcome, and treatment. In particular, this applies to malignancies of the salivary gland, sinonasal tract, and oropharynx. In this overview, we present the most recent developments in the classification, histopathological characteristics, and molecular features of head and neck cancer. The clinical and radiological characteristics, outcome, and treatment options including perspectives for targeted therapies, are discussed.

A retrospective multicenter study of carbon-ion radiotherapy for external auditory canal and middle ear carcinomas

Background

We conducted a retrospective multicenter study to assess the clinical outcomes of carbon‐ion radiotherapy (CIRT) for head and neck malignancies (Japan Carbon‐Ion Radiation Oncology Study Group [J‐CROS] study: 1402 HN). We aimed to evaluate the safety and efficacy of CIRT in patients with external auditory canal (EAC) and middle ear (ME) carcinomas.

Methods

Thirty‐one patients treated with CIRT at four Japanese institutions were analyzed. Fourteen patients (45.2%) had squamous cell carcinomas, 13 (41.9%) had adenoid cystic carcinomas, and four (12.9%) had other types. Nineteen (61.3%), six (19.4%), three (9.7%), and three (9.7%) patients had T4, T3, T2, and T1 disease, respectively. All patients had N0M0 status. The median radiation dose was 64 Gy (relative biological effectiveness) in 16 fractions. The median gross tumor volume was 33.3 mL.

Results

The median follow‐up period was 18.4 months (range, 5.1‐85.6). The 1‐ and 3‐year local control and overall survival rates were 75.0% and 55.0% and 79.3% and 58.7%, respectively. Regarding grade 3 or higher toxicities, three patients (9.7%) had grade 3 dermatitis, one (3.2%) had grade 3 mucositis, and two (6.5%) had grade 3 central nervous necrosis (ie, radiation‐induced brain necrosis). No grade 4 or worse reactions were observed.

Conclusion

CIRT was effective for EAC and ME carcinomas.

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.

A retrospective multicenter study of carbon-ion radiotherapy for major salivary gland carcinomas: Subanalysis of J-CROS 1402 HN

A retrospective multicenter study was carried out to assess the clinical outcomes of carbon-ion radiotherapy for head and neck malignancies (Japan Carbon-Ion Radiation Oncology Study Group [J-CROS] study: 1402 HN). We evaluated the safety and efficacy of carbon-ion radiotherapy in patients with major salivary gland carcinoma. Sixty-nine patients treated with carbon-ion radiotherapy at four Japanese institutions were analyzed. Thirty-three patients (48%) had adenoid cystic carcinomas, 10 (14%) had mucoepidermoid carcinomas, and 26 (38%) had other disease types. Three patients (4%) had T1 disease, 8 (12%) had T2, 25 (36%) had T3, and 33 (48%) had T4. The median radiation dose was 64 Gy (relative biological effectiveness) in 16 fractions. The median gross tumor volume was 27 mL. The median follow-up period was 32.7 months. The 3-year local control rate and overall survival rate were 81% and 94%, respectively. Regarding acute toxicities, seven patients had grade 3 mucositis and seven had grade 3 dermatitis. Regarding late toxicities, one patient had grade 3 dysphagia and one had a grade 3 brain abscess. No grade 4 or worse late reactions were observed. In conclusion, definitive carbon-ion radiotherapy was effective with acceptable toxicity for major salivary gland carcinomas.