Are oral cancers effectively palliated with radiotherapy? Outcomes of treatment with a modified QUAD SHOT regimen.

BACKGROUND: This study assessed a palliative radiotherapy regimen using daily radiation over 4 days for three courses in inoperable head and neck cancers, emphasizing oral primary cancers. METHODS: Retrospective data of 116 patients treated with a daily dose of 3.6-3.7 Gy in four fractions over 4 days to a total of three courses, with a 2-week gap after every course, were analyzed for survival outcomes. A subgroup analysis was done for oral cancer. RESULTS: Ninety-nine (85%) completed three courses. Overall subjective response rate was 77%. Median overall survival and progression-free survival were 12 months (95% confidence interval [CI]: 8-20) and 8 months (95% CI: 6-10), with numerically higher overall survival in oral cancer. The treatment was well tolerated, with no on-treatment hospitalization or grade 3-4 toxicities. CONCLUSION: The modified QUAD SHOT regimen is practical for palliation in head and neck cancers.

Enhancing quality assurance in radiotherapy for gynaecological cancers: implementation of an on-demand peer review process.

OBJECTIVES: Ensuring high-quality radiotherapy requires peer-reviewing target volumes. The Royal College of Radiologists recommends peer review specifically for individual target volumes in cases of gynaecological cancers. This study presents the outcomes of implementing an on-demand peer review system for gynaecological cancers within our institute. METHODS: The peer review process was planned for gynaecological cancer cases intended for curative radiotherapy. After junior clinical oncologists (COs) completed the segmentation, two senior COs specializing in gynaecological cancers conducted the peer review. All peer review outcomes were recorded prospectively. The audit process compliance, the proportion of patients requiring major and minor modifications in target volumes, the direction of changes, and the factors influencing these changes were reported. RESULTS: A total of 230 patients were eligible, and out of these, 204 (88.3%) patients underwent at least one peer review. Among the patients, 108 required major modifications in their target volumes. P-charts revealed a stabilization in the need for major modifications at the end of three months, indicating that 38.2% and 28% of patients still required major modifications for the nodal and primary CTV, respectively. Multivariable analysis demonstrated that major modifications were associated with the use of extended field radiotherapy and radical radiation in non-cervical primary cases. CONCLUSIONS: An on-demand peer review system was feasible and resulted in clinically meaningful, major modifications in the target volumes for 53% of patients. ADVANCES IN KNOWLEDGE: Gynaecological cancers require ongoing peer review to ensure quality of care in radiotherapy. A flexible on-demand system not only ensures that patient treatment start is not delayed but also has an important educational role for junior trainees.

Comparison of dosimetries of carbon-ion pencil beam scanning, proton pencil beam scanning and volumetric modulated arc therapy for locally recurrent rectal cancer.

We compared the dose distributions of carbon-ion pencil beam scanning (C-PBS), proton pencil beam scanning (P-PBS) and Volumetric Modulated Arc Therapy (VMAT) for locally recurrent rectal cancer. The C-PBS treatment planning computed tomography (CT) data sets of 10 locally recurrent rectal cancer cases were randomly selected. Three treatment plans were created using identical prescribed doses. The beam angles for C-PBS and P-PBS were identical. Dosimetry, including the dose received by 95% of the planning target volume (PTV) (D95%), dose to the 2 cc receiving the maximum dose (D2cc), organ at risk (OAR) volume receiving > 15Gy (V15) and > 30Gy (V30), was evaluated. Statistical significance was assessed using the Wilcoxon signed-rank test. Mean PTV-D95% values were > 95% of the volume for P-PBS and C-PBS, whereas that for VMAT was 94.3%. However, PTV-D95% values in P-PBS and VMAT were < 95% in five and two cases, respectively, due to the OAR dose reduction. V30 and V15 to the rectum/intestine for C-PBS (V30 = 4.2 ± 3.2 cc, V15 = 13.8 ± 10.6 cc) and P-PBS (V30 = 7.3 ± 5.6 cc, V15 = 21.3 ± 13.5 cc) were significantly lower than those for VMAT (V30 = 17.1 ± 10.6 cc, V15 = 55.2 ± 28.6 cc). Bladder-V30 values with P-PBS/C-PBS (3.9 ± 4.8 Gy(RBE)/3.0 ± 4.0 Gy(RBE)) were significantly lower than those with VMAT (7.9 ± 8.1 Gy). C-PBS provided superior dose conformation and lower OAR doses compared with P-PBS and VMAT. C-PBS may be the best choice for cases in which VMAT and P-PBS cannot satisfy dose constraints. C-PBS could be another choice for cases in which VMAT and P-PBS cannot satisfy dose constraints, thereby avoiding surgical resection.

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.

Long-term outcomes of octogenarian pancreatic cancer patients treated with carbon ion radiotherapy.

BACKGROUND: Pancreatic cancer is a disease of the elderly; patients >65 years are 60% of the cases. Due to multiple comorbidities, treating these patients is challenging. We report the efficacy and safety of carbon ion radiotherapy (C-ion RT) in octogenarians. METHODS: We retrospectively analyzed the cases of 46 pancreatic cancer patients aged ≥80 years (median 83, range 80-97) treated with definitive C-ion RT in 2007-2018 at our institute. RESULTS: Twenty-five patients (54%) had resectable or borderline-resectable disease; none underwent surgery (because of medical reasons, e.g., age, multiple comorbidities). C-ion RT was delivered with a median dose of 55.2 Gy (RBE) in 12 fractions. The survivors' median follow-up period was 43 (range 19-76) months. The entire cohort's median overall survival (OS) was 15 (95%CI: 14-22) months with a 3-year OS of 20% (95%CI: 11%-35%). On both univariate and multivariate analyses, baseline CA19-9 remained the significant independent OS prognostic factor (p = 0.032). The 3-year local control rate for all patients was 34% (95%CI: 19%-53%). Local failure (n = 25, 54%) was as common as distant relapse (n = 26, 57%); 33% of the patients experienced both local and systemic failure. About 15% underwent re-C-ion RT for infield recurrence; they achieved a median 22-month OS. No patients exhibited grade ≥3 severe acute or late toxicities (including those who received re-C-ion RT). CONCLUSIONS: C-ion RT in octogenarians with pancreatic cancer showed promising outcomes with acceptable acute and late toxicities and can be considered a reasonable alternative to radical surgery.

Evaluating Quality Indicators of Glioblastoma Care: Audit Results From an Indian Tertiary Care Cancer Center.

PURPOSE: There are limited reports of quality metrics in glioblastoma. We audited our adherence to quality indicators as proposed in the PRIME Quality Improvement study. METHODS: This is a retrospective audit of patients treated between 2017 and 2020. After postsurgical integrated diagnosis, patients received radiotherapy (RT) with concurrent and adjuvant temozolomide (TMZ). Multiparametric magnetic resonance imaging at predefined times guided management. Numbers with proportions for indices were calculated. Survival was estimated using the Kaplan-Meier method. RESULTS: One hundred six patients were consecutively treated. The median age was 55 years (interquartile range of 47-61 years) with a male preponderance (68%). Ninety-six (90.6%) patients underwent subtotal resection, and 10 (9.4%) biopsy alone. Isocitrate dehydrogenase was wild-type in 96 (91%), and O6-methylguanine-DNA methyltransferase was unmethylated in 70 (66.0%) patients. Telomerase reverse transcriptase promoter was mutated in 64 (60.4%), and TP53 was mutated in 22 (20.8%). Concurrent radiation and TMZ were planned for 104 (98.1%), and radiation alone for 2 (1.9%). The median time to concurrent RT-TMZ was 36 days (interquartile range 30-44 days). All patients planned for RT-TMZ completed treatment, but only 81 (76%) completed adjuvant TMZ. Sixty-three (59%) completed six cycles, 18 (17%) received less than six cycles, and 25 (24%) did not receive adjuvant TMZ. At a median follow-up of 24 months (range 21-31 months), the median (95% CI) progression-free survival and overall survival were 11 (95% CI, 9.4 to 13.0) and 20.0 (95% CI, 15 to 26) months, respectively. CONCLUSION: Our patients met quality indices in most domains; outcomes are comparable with global results. Metrics will be periodically evaluated to include new standards and assess continuous service appropriateness.

Accurate Delineation of Mucosal Lesions in Treatment-Planning Computed Tomography Using Iodine Paste Markers for Oral Mucosal Melanoma.

This technical report introduces the utility of iodine paste markers using endodontic materials for the accurate contouring of mucosal lesions of oral mucosal melanoma, which are difficult to delineate on imaging during the planning of carbon-ion radiation therapy (CIRT). The patient had a primary oral mucosal melanoma located in the palatal mucosa without palatal or maxillary bone invasion. A dental root canal filling material, which is a calcium hydroxide/iodoform nonhardenable paste, was used as a marker. We first performed treatment-planning computed tomography (CT) without an iodine paste marker for mucosal lesions. Subsequently, we placed an iodine paste marker on the palatal mucosal lesion to accurately delineate the mucosal lesions of the palate. Finally, we obtained a reference CT image with an iodine paste marker. Computed tomography without the marker was fused to the reference CT with markers during treatment planning, and the gross tumor volume was contoured. Thereafter, CIRT was delivered without markers. During CIRT, expected acute mucositis was observed in the area of the planning target volume, including melanosis, in accordance with the dose distribution. The use of iodine paste markers for localized mucosal lesions, which are difficult to delineate on CT and magnetic resonance imaging, may be useful for accurately contouring gross tumor volumes on treatment-planning CT.

Stopping-power ratio of mouthpiece materials for charged-particle therapy in head and neck cancer.

In this study, the stopping-power ratios (SPRs) of mouthpiece materials were measured and the errors in the predicted SPRs based on conversion table values were further investigated. The SPRs of the five mouthpiece materials were predicted from their computed tomography (CT) numbers using a calibrated conversion table. Independently, the SPRs of the materials were measured from the Bragg peak shift of a carbon-ion beam passing through the materials. The errors in the SPRs of the materials were determined as the difference between the predicted and measured values. The measured SPRs (errors) of the Nipoflex 710™ and Bioplast™ ethylene-vinyl acetate copolymers (EVAs) were 0.997 (0.023) and 0.982 (0.007), respectively. The SPRs of the vinyl silicon impression material, light-curable resin, and bis-acrylic resin were 1.517 (0.134), 1.161 (0.068), and 1.26 (0.101), respectively. Among the five tested materials, the EVAs had the lowest SPR errors, indicating the highest human-tissue equivalency.

Can the CROSS protocol be safely implemented in real world scenario with broader eligibility criteria? Experience from a tertiary care centre in India.

BACKGROUND: The Chemoradiotherapy for Oesophageal Cancer Followed by Surgery Study (CROSS) trial established a new benchmark in the management of oesophageal cancer with neoadjuvant chemoradiation followed by surgery with a marked benefit for squamous cell carcinomas (SCCs). We evaluate if the CROSS protocol can be safely implemented with a broader eligibility criteria in a real-world setting. METHODS: A retrospective analysis of 80 patients of SCC oesophagus was performed, who were treated with neoadjuvant chemoradiation with radiation therapy (RT) to 41.4 Gy/23 Fr/4.5 weeks and weekly paclitaxel and carboplatin, followed by surgery at our institute between 2012 and 2019. Eligibility for the use of this regimen was expanded beyond the limits of size and stage allowed in the CROSS trial. RESULTS: The median age of this cohort was 57 years (range: 39-78 years). Most of the patients (77/80; 96.3%) had T3 disease and 25% patients (20/80) had N2/N3 disease. Thirty-three patients (41.3%) had the disease beyond CROSS eligibility criteria. All patients completed planned course of RT and five cycles of weekly chemotherapy were received by 61 patients (76.2%). Overall pathological complete response (pCR) could be achieved in 33 patients (41.3%). Among 33 CROSS ineligible patients, 14 (42.4%) had pCR. Acute grade 3 dysphagia and grade ≥ 3 neutropenia were seen in seven cases (8.3%) and nine cases (10.7%), respectively. At a median follow-up of 16 months, 1-year and 2-year overall survival (OS) were 84.4% (95% confidence interval (CI): 73.5%-91.1%) and 76.3% (95% CI: 63.2%-85.2%), respectively, for the entire cohort. For CROSS ineligible patients, 1-year and 2-year OS were 82% (95% CI: 61.8%-92.2%) and 72.7% (95% CI: 50.4%-86.2%), respectively. On univariate analysis, patients who had pathologically N0 disease had significantly better 2-year OS (85.7% versus 48.4%; p = 0.03) as compared to pathologically N+ patients. On univariate and multivariate analysis, there was no significant difference in OS and progression free survival between CROSS eligible and CROSS ineligible patients. CONCLUSION: CROSS protocol can be safely implemented for carefully selected patients of SCC oesophagus outside clinical trial settings with expanded eligibility criteria.

Real-world results of definitive chemoradiation in carcinoma oesophagus: can SCOPE1 results be replicated outside trial setting?

BACKGROUND: Definite concurrent chemoradiation is the standard of care for locally advanced unresectable oesophageal cancers. However, heterogeneity exists in the practice of concurrent chemoradiation approaches. Here we describe the efficacy and toxicities of the standard arm of SCOPE1 protocol implemented at our institute. METHODS: Treatment records of 36 patients with unresectable oesophageal cancers treated with concurrent chemoradiation between January 2015 and June 2019 were audited. Treatment was based on the standard arm of SCOPE1 protocol (neoadjuvant and concurrent platinum and capecitabine with external beam radiation to a dose of 50 Gy/25 fractions/5 weeks). The electronic hospital information system and oncology information system were queried to obtain information on patient characteristics and treatment delivery patterns. RESULTS: Out of 36 patients, 35 had squamous cell carcinomas. 25% of the patients (9/36) were 70 years or older. 66.7% of patients (24/36) had T4 disease, and 16 (44.4%) had N2-N3 nodal disease at presentation. A total of 30 patients (83.3%) could not undergo surgery because of the location and locoregional extent of the disease. The median follow-up of the entire cohort and the surviving patients was 10 months (range 3-51 months) and 13 months (range 4-51 months), respectively. The median overall survival (OS) of the entire cohort was 28 months. The 2-year local progression-free survival and OS were 71.2% (95% CI: 48.5%-85.3%) and 57.4% (95%CI: 29.6%-77.6%), respectively. Commonly observed acute Grade 3 toxicities were dysphagia (22.2%) and thrombocytopenia (19.4%). CONCLUSION: The outcomes of the SCOPE1 protocol have been validated for the first time in a different geographical, racial and ethnic population. Implementation of the standard arm of SCOPE1 protocol is feasible in our setting with acceptable adverse effects and good treatment compliance. Results are comparable to the results of the published trial.

Intensity modulated radiotherapy in anal canal squamous cell carcinoma: Implementation and outcomes.

OBJECTIVE: Concurrent chemoradiotherapy (CCRT) is the standard curative treatment option for nonmetastatic anal squamous cell carcinoma (SCC). Intensity modulated radiotherapy (IMRT) can reduce doses delivered to bowel and skin and reduce toxicities associated with conventional fields. Here, we present our institutional data on dosimetry, toxicity, and clinical outcomes with IMRT for anal cancer. MATERIALS AND METHODS: We analyzed 23 patients of anal SCC treated with curative-intent CCRT/radiation therapy alone, utilizing IMRT, between August 2011 and December 2016. The standard prescription dose was 54 Gy/27Fr/5.5 weeks, delivered in two phases, and concurrent chemotherapy with 5-fluorouracil and mitomycin-C. Acute and late toxicities and dosimetric data were compiled and analyzed. RESULTS: The median age was 65 years. Fourteen (60.7%) patients had Stage IIIC disease. Eighteen patients received concurrent chemotherapy. No patient had any treatment breaks. Grade 3 acute perianal dermatitis was recorded in 11 (47.8%) patients. Proctitis, diarrhea, and cystitis were limited to Grade 1 in 73.9%, 47.8%, and 8.6% patients, respectively. The only late Grade 2+ toxicities were gastrointestinal toxicities in 4 (17.4%) patients. Twenty (87%) patients had complete response at 6 months. The 3-year local control, nodal control, and distant metastases-free survival were 85.9%, 86.6%, 84.7%, respectively, with 3-year disease-free survival and overall survival of 63.4% and 81%, respectively. CONCLUSION: In this report on IMRT in anal cancer from India, treatment was well tolerated with lower acute toxicity than reported in other prospective studies. Long-term results are at par with other published studies.

Research Goal-Driven Data Model and Harmonization for De-Identifying Patient Data in Radiomics.

There are various efforts in de-identifying patient's radiation oncology data for their uses in the advancement of research in medicine. Though the task of de-identification needs to be defined in the context of research goals and objectives, existing systems lack the flexibility of modeling data and normalization of names of attributes for accomplishing them. In this work, we describe a de-identification process of radiation and clinical oncology data, which is guided by a data model and a schema of dynamically capturing domain ontology and normalization of terminologies, defined in tune with the research goals in this area. The radiological images are obtained in DICOM format. It consists of diagnostic, radiation therapy (RT) treatment planning, RT verification, and RT response images. During the DICOM de-identification, a few crucial pieces of information are taken about the dataset. The proposed model is generic in organizing information modeling in sync with the de-identification of a patient's clinical information. The treatment and clinical data are provided in the comma-separated values (CSV) format, which follows a predefined data structure. The de-identified data is harmonized throughout the entire process. We have presented four specific case studies on four different types of cancers, namely glioblastoma multiforme, head-neck, breast, and lung. We also present experimental validation on a few patients' data in these four areas. A few aspects are taken care of during de-identification, such as preservation of longitudinal date changes (LDC), incremental de-identification, referential data integrity between the clinical and image data, de-identified data harmonization, and transformation of the data to an underlined database schema.

Aberrant origin of right vertebral artery from the arch of aorta.

We present a rare case of an aberrant right vertebral artery originating from the arch of aorta distal to the origin of the left subclavian artery. The incidence of this particular variant of aberrant origin of the right vertebral artery is extremely uncommon with only seventeen cases reported in literature to date. This case was incidentally detected on a staging positron emission tomography-computerized tomography (PET-CT) scan for lung cancer. We review the incidence, embryological mechanism, and clinical importance of this aberrant course of the right vertebral artery.

Geographic disparities in access to cancer clinical trials in India.

INTRODUCTION: The current study was aimed at quantifying the disparity in geographic access to cancer clinical trials in India. METHODS: We collated data of cancer clinical trials from the Clinical Trial Registry of India and data on state-wise cancer incidence from the Global Burden of Disease Study. The total sample size for each clinical trial was divided by the trial duration to get the sample size per year. This was then divided by the number of states in which accrual was planned to get the sample size per year per state (SSY).For interventional trials investigating a therapy, the SSY was divided by the number of incident cancers in the state to get the SSY per 1,000 incident cancer cases. The SSY data was then mapped to visualise the geographical disparity. RESULTS: We identified 181 ongoing studies, of which 132 were interventional studies. There was a substantial inter-state disparity-with a median SSY of 1.55 per 1,000 incident cancer cases (range 0.00-296.81 per 1,000 incident cases) for therapeutic interventional studies. Disparities were starker when cancer site-wise SSY was considered. Even in the state with the highest SSY, only 29.7% of the newly diagnosed cancer cases have an available slot in a therapeutic cancer clinical trial. Disparities in access were also apparent between academic (range: 0.21-226.60) and industry-sponsored trials (range: 0.17-70.21). CONCLUSION: There are significant geographic disparities in access to cancer clinical trials in India. Future investigations should evaluate the reasons and mitigation approaches for such disparities.

Prioritizing Delivery of Cancer Treatment During a COVID-19 Lockdown: The Experience of a Clinical Oncology Service in India.

PURPOSE: A COVID-19 lockdown in India posed significant challenges to the continuation of radiotherapy (RT) and systemic therapy services. Although several COVID-19 service guidelines have been promulgated, implementation data are yet unavailable. We performed a comprehensive audit of the implementation of services in a clinical oncology department. METHODS: A departmental protocol of priority-based treatment guidance was developed, and a departmental staff rotation policy was implemented. Data were collected for the period of lockdown on outpatient visits, starting, and delivery of RT and systemic therapy. Adherence to protocol was audited, and factors affecting change from pre-COVID standards analyzed by multivariate logistic regression. RESULTS: Outpatient consults dropped by 58%. Planned RT starts were implemented in 90%, 100%, 92%, 90%, and 75% of priority level 1-5 patients. Although 17% had a deferred start, the median time to start of adjuvant RT and overall treatment times were maintained. Concurrent chemotherapy was administered in 89% of those eligible. Systemic therapy was administered to 84.5% of planned patients. However, 33% and 57% of curative and palliative patients had modifications in cycle duration or deferrals. The patient's inability to come was the most common reason for RT or ST deviation. Factors independently associated with a change from pre-COVID practice was priority-level allocation for RT and age and palliative intent for systemic therapy. CONCLUSION: Despite significant access limitations, a planned priority-based system of delivery of treatment could be implemented.

Efficacy and feasibility of re-irradiation using carbon ions for pancreatic cancer that recurs after carbon-ion radiotherapy.

BACKGROUND AND PURPOSE: Patients who receive carbon-ion radiotherapy (C-ion RT) for primary pancreatic cancer may experience locoregional recurrence; however, the treatment options for such patients are limited. We aimed to investigate the feasibility and efficacy of carbon-ion re-irradiation for patients with pancreatic cancer who experienced recurrence after initial C-ion RT. MATERIALS AND METHODS: Twenty-one patients with recurrent pancreatic cancer who underwent repeat C-ion RT between December 2010 and November 2016 at our institute were retrospectively evaluated. The sites of post-initial C-ion RT failure were in-field central in 16 patients (76.2%) and marginal in 5 (23.8%). The median doses of initial and repeat C-ion RT were both 52.8 Gy (relative biological effectiveness [RBE]). Thirteen patients (61.9%) received concurrent chemotherapy with re-irradiation, while 11 (52.4%) received adjuvant chemotherapy. RESULTS: The median follow-up period after re-irradiation was 11 months. The 1-year local control, progression-free survival, and overall survival rates were 53.5%, 24.5%, and 48.7%, respectively. Toxicity data was obtained from the patients' charts. Only 1 patient (4.8%) developed grade 3 acute toxicities and none developed grade ≥3 late toxicities. Univariate analysis indicated that patients who received adjuvant chemotherapy had significantly improved local control rates compared with those who did not; the 1-year local control rates were 80.0% and 0.0%, respectively (P = 0.0469). CONCLUSION: Repeating C-ion RT may be a reasonable option with tolerable toxicity for patients with recurrent pancreatic cancers. Adjuvant chemotherapy appears to improve the local control rate. This is the first study to examine re-irradiation using C-ion for recurrent pancreatic cancer after initial C-ion RT.

Heavy charged particles for gastrointestinal cancers.

Carbon ion beams constitute the primary delivery method of heavy ion radiotherapy. It offers improved dose distribution, and enables concentration of dose within target volumes with minimal extraneous exposure of normal tissue, while delivering superior biological effect in comparison with photon and proton technologies. Here, we review the application of this technology to various gastrointestinal cancers.

Long-term outcomes and toxicities of carbon-ion radiotherapy in malignant tumors of the sphenoid sinus.

BACKGROUND: Most of the primary sphenoid sinus tumors present with locally advanced stages with involvement of adjacent critical structures and are not amenable to radical resection. We sought to evaluate the safety and efficacy of carbon-ion radiotherapy (C-ion RT) for sphenoid sinus malignancies. METHODS: This is a retrospective analysis of 22 patients of primary sphenoid carcinomas treated with definitive C-ion RT. RESULTS: Adenoid cystic carcinoma was the most common histology (15 patients, 68.2%). The median follow-up of this cohort was 48.5 months. The actuarial local control and overall survival at 5 years were 51.0% and 62.7%, respectively. Grade 4 visual impairment and grade 4 brain necrosis were seen in six and one patient, respectively. CONCLUSION: C-ion RT can provide a reasonably good clinical outcome in locally advanced sphenoid sinus malignancies with a marginally higher late toxicity profile because of extremely close proximity of the target volume to critical structures.

Influence of dose-averaged linear energy transfer on tumour control after carbon-ion radiation therapy for pancreatic cancer.

BACKGROUND AND PURPOSE: High linear energy transfer (LET) radiation carbon-ion radiotherapy (C-ion RT) is one of the most promising modalities for treating unresectable primary pancreatic cancers. However, how LET contributes to a therapeutic effect is not clear. To assess whether there is an enhanced effect of high LET radiation on tumour control, we aimed to determine the impact of dose-averaged LET on local control (LC) of primary pancreatic tumours. MATERIALS AND METHODS: A retrospective analysis of 18 patients with primary pancreatic carcinomas treated with definitive C-ion RT with concurrent chemotherapy in 2013 was conducted. The dose of irradiation was 55.2 Gy (RBE). The relationship between dose-averaged LET and LC of primary tumours was evaluated. RESULTS: All patients had histologically confirmed adenocarcinoma. The median follow-up duration was 22 months. The actuarial LC and overall survival (OS) at 18 months were 62.5% and 70.1%, respectively. There were no cases of grade ≥3 late toxicities observed. Local recurrences developed in four patients (22%), all of which were infield central recurrences. Although there were no significant differences in gross tumour volume (GTV) dose coverage, patients with higher minimum dose-averaged LET (LETmin) values within the GTV had better LC (dose-averaged LETmin ≥44 keV/microm; 18-months LC 100.0% vs 34.3%; p = 0.0366). CONCLUSION: Dose-averaged LETmin within the GTV was significantly associated with LC of primary pancreatic cancers. Our data suggest that outcomes for patients with unresectable primary pancreatic cancers receiving C-ion RT can be improved by modulating the dose-averaged LET within the GTV.

Assessment of risk factors associated with development of oronasal fistula as a late complication after carbon-ion radiotherapy for head and neck cancer.

BACKGROUND: Oronasal fistulae (ONF) are one of the rare but serious complications of conventional photon radiotherapy. This study aimed to identify the risk factors for the development of ONF after carbon-ion radiotherapy (C-ion RT). MATERIALS AND METHODS: The data of 62 cases of sinonasal and oral cavity cancers treated with C-ion RT and followed-up in excess of 5 years were retrospectively reviewed. The correlation between the clinical and dosimetric parameters and the development of ONF was analysed. RESULTS: A total of 80.6% cases had sinonasal malignancies, and most tumours had advanced T stages (96.8%). Maxillary invasion was observed in 16 cases (25.8%), and malignant melanoma was the most common histology (46.8 %). All the cases received a dose of between 57.6 Gy (RBE) and 64 Gy (RBE) in 16 fractions over 4 weeks. At a median follow up of 88.8 months, 23 cases (37.1%) developed small localised ONF; however, none were of grade III severity. On separate multivariate analyses of clinical parameters in the entire cohort and in cases without maxillary invasion, the number of teeth irradiated with more than 50 Gy (RBE) was found to be the common significant independent risk factor for development of ONF. CONCLUSION: The number of teeth irradiated with more than 50 Gy (RBE) is a significant independent risk factor for the development of ONF, which is a late complication of C-ion RT delivered in 16 fractions.