Expression of TLR4-PTGE2 signaling genes in atherosclerotic carotid plaques and peripheral blood.

Toll-like receptor 4 (TLR4)/prostaglandine synthetase 2 (PTGS2) signaling plays a relevant role in atherosclerotic plaque vulnerability. The purpose of this study was to check the gene expression of 6 genes participating to TLR4/PTGS2 signaling (TLR4, PTGS2, ACSL4, PTGER3, PTGER4, and EPRAP) in carotid plaques and blood samples from the same individual and to evaluate these genes as biomarker of plaque progression. We investigated differential gene expression by qRT-PCR in 62 atherosclerotic patients' carotid plaques and corresponding blood sample. A very weak or no correlation was observed in the overall population or analyzing asymptomatic patients. These analyzed genes are most likely not suitable for inclusion in the clinical routine as biomarkers of plaque instability.

What is the prognostic impact of FDG PET in locally advanced head and neck squamous cell carcinoma treated with concomitant chemo-radiotherapy? A systematic review and meta-analysis.

PURPOSE: Evidence is conflicting on the prognostic value of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in head and neck squamous cell carcinoma. The aim of our study was to determine the impact of semiquantitative and qualitative metabolic parameters on the outcome in patients managed with standard treatment for locally advanced disease. METHODS: A systematic review of the literature was conducted. A meta-analysis was performed of studies providing estimates of relative risk (RR) for the association between semiquantitative metabolic parameters and efficacy outcome measures. RESULTS: The analysis included 25 studies, for a total of 2,223 subjects. The most frequent primary tumour site was the oropharynx (1,150/2,223 patients, 51.7%). According to the available data, the majority of patients had stage III/IV disease (1,709/1,799, 94.9%; no information available in four studies) and were treated with standard concurrent chemoradiotherapy (1,562/2,009 patients, 77.7%; only one study without available information). A total of 11, 8 and 4 independent studies provided RR estimates for the association between baseline FDG PET metrics and overall survival (OS), progression-free survival (PFS) and locoregional control (LRC), respectively. High pretreatment metabolic tumour volume (MTV) was significantly associated with a worse OS (summary RR 1.86, 95% CI 1.08-3.21), PFS (summary RR 1.81, 95% CI 1.14-2.89) and LRC (summary RR 3.49, 95% CI 1.65-7.35). Given the large heterogeneity (I2 > 50%) affecting the summary measures, no cumulative threshold for an unfavourable prognosis could be defined. No statistically significant association was found between SUVmax and any of the outcome measures. CONCLUSION: FDG PET has prognostic relevance in the context of locally advanced head and neck squamous cell carcinoma. Pretreatment MTV is the only metabolic variable with a significant impact on patient outcome. Because of the heterogeneity and the lack of standardized methodology, no definitive conclusions on optimal cut-off values can be drawn.

Recovering from chronic myeloid leukemia: the patients' perspective seen through the lens of narrative medicine.

PURPOSE: The main objective of this study is to gain a deeper understanding of how patients suffering from chronic myeloid leukemia (CML) cope with their illness. The study aims to reconstruct the subjective meaning-making process related to CML in order to gain insights into the impact the disease has on patients' emotions and everyday lives, as well as to explore the psychological impact of their being presented with the chance to suspend their therapy and recover from the disease. METHODS: Data were gathered from a qualitative study conducted in Italy on 158 Italian CML patients. Basing the study on the narrative inquiry approach, the patients were required to describe their patient journey in a qualitative narrative diary. These contained prompts to elicit the free expression of their needs, expectations, and priorities. A lexicographic analysis was carried out with T-LAB software and in particular a thematic analysis of elementary contexts (TAECs) and a word association analysis (WAA). RESULTS: The TAEC detected four thematic clusters related to two factors (temporal frame and contextual setting) that explained the variance among the narratives. The WAA evidenced a wide variety of emotions, both positive and negative, as patients reacted to the possibility of interrupting their therapy. CONCLUSIONS: A better understanding of patients' experiences can offer insights into promoting the development of more sustainable healthcare services and into therapeutic innovation aimed at improving patients' quality of life and at engaging them more in their treatment. The findings of this study can also help make medical professionals more aware of the patient's burden and help them identify potential interactions and emotional levers to improve clinical relationships.

Italian version of the M.D. Anderson Symptom Inventory--Head and Neck Module: linguistic validation.

BACKGROUND: Head and neck cancer (HNC) patients can experience symptoms due to the tumor itself or to the treatment, with an impact on health-related quality of life (HRQoL). Patient-reported outcome (PRO) measures pertaining to HRQoL are used in medical research and to support clinical decisions. PRO instrument applicability and cultural adaptation must be tested for each population. The aim of this study is to linguistically validate the Italian translation of the M.D. Anderson Symptom Inventory--Head and Neck Module (MDASI-HN). METHODS: Following forward and backward translation of the items of the English MDASI-HN into Italian, it was administered along with a cognitive debriefing to HNC patients able to read and understand Italian language. Individual and group responses are presented using descriptive statistics. RESULTS: From May 2013 through September 2013, 56 patients with HNC (18 during curative treatment, 20 in palliative chemotherapy, and 18 in follow-up period) completed the MDASI-HN followed by accompanying cognitive debriefing. Ninety-nine percent of the individual MDASI-HN items were completed. Average time to complete the MDASI-HN was 8.5 min (range 3-15). Results suggested overall ease of completion, relevance, and comprehensibleness of this translated self-report instrument in this Italian patient population. CONCLUSIONS: The Italian version of the MDASI-HN is linguistically valid; future research should explore dimensionality, reliability, and convergent, discriminant, and predictive validity of this patient-reported instrument, in order to use this translated version in outcomes research and clinical settings.

Preoperative chemotherapy in advanced resectable OCSCC: long-term results of a randomized phase III trial.

BACKGROUND: Data on preoperative chemotherapy in resectable oral cavity cancer are conflicting. We present the long-term results of a randomized trial of induction chemotherapy in resectable oral cavity cancer. PATIENTS AND METHODS: A randomized, parallel, multicentre trial evaluated the impact of three cycles of cisplatin 100 mg/m2 and fluorouracil 1000 mg/m2 (120-h infusion administered every 21 days) in stage T2-T4, N0-N2, previously untreated patients with advanced disease. Control group received upfront surgery. Postoperative radiation was offered to both arms when pathologic risk features were identified. The co-primary end points were the occurrence of locoregional or distant tumour relapse, and death. RESULTS: Among the 198 enrolled patients, with a median follow-up of 11.5 years, there was no difference in the incidence of locoregional relapse between chemotherapy and control group (P=0.6337), nor in distant metastasis development (P=0.1527). There was also no difference between groups in overall survival (P=0.3402). Patients with a pathological complete response (pCR) had higher probability of survival than those without (10-year OS: 76.2% versus 41.3%, P=0.0004). Late toxicities in patients with a minimum follow-up of 60 months (42 in each group) were similar between arms, except from fibrosis (cumulative incidence 40% versus 22% in chemotherapy arm) and grade 2 dysphagia (14% versus 5%). CONCLUSIONS: Long-term follow-up of this randomized trial confirmed the absence of survival benefit with preoperative chemotherapy in oral cavity cancer. Late toxicity was similar in the two arms except for fibrosis and dysphagia, which were less in the chemotherapy arm. The survival benefit for patients achieving a pCR was maintained.

Treatment-related outcome of oropharyngeal cancer patients differentiated by HPV dictated risk profile: a tertiary cancer centre series analysis.

BACKGROUND: To date, no treatment modality has been identified as more effective for oropharyngeal cancer (OPC), and no predictive factors are known to guide treatment decision for this disease. This retrospective study evaluates the differential effects of diverse treatment options for OPC according to patient risk profiles. PATIENTS AND METHODS: We considered two series of locally advanced squamous cell OPC patients treated with either surgery followed by radiotherapy (surgical series) or chemoradiation (CRT) with/without induction docetaxel, cisplatin and 5-fluorouracil (TPF) chemotherapy (CRT series). Smoking habits, tumor p16 expression/human papillomavirus (HPV) status and T and N stage were analyzed to stratify the patients according to Ang's risk profile (low, intermediate and high risk). Overall survival (OS) and disease-free survival were calculated with the Kaplan-Meier method. RESULTS: Globally, 171 patients were considered, 56 in surgical and 115 in CRT series. Patients were stratified in low- (20% of surgical and CRT groups), intermediate- (23% and 41%) and high-risk (57% and 39%) groups. In the surgical series, 5-year OS was 54.5%, 46.9% and 40.0% in low, intermediate and high Ang's risk profiles, respectively, whereas in the CRT series those were 100%, 78.9% and 46.7%, respectively. In the multivariable analyses, adjusting for inhomogeneity between the treatment group, the CRT effect was significantly higher in the low- and intermediate-risk groups (P-value for the interaction treatment risk group = 0.034 in the OS analysis). CONCLUSIONS: In this retrospective analysis, low- and intermediate-risk OPC patients had a better survival when treated with CRT compared with open surgery followed by radiation therapy. These data suggest that different treatment approaches might be essential in determining outcome results.

Neutron brachytherapy in the modern era: Indications and evidence.

Hadrontherapy is a form of radiation therapy (RT) that relies on heavy particles, such as proton, heavy ions, or neutrons, to enhance anti-tumoral efficacy based on their specific dosimetric and radio-biological properties. Neutrons are characterized by specific radiobiological properties that might deserve greater consideration, including the high linear energy transfer and the low oxygen enhancement ratio. Neutron brachytherapy, relying on interstitial or intracavitary neutron sources, has been developed since the 1950s using Californium-252 (252Cf) as a mixed emitter of fission fast neutrons and γ-photos. However, the place of NBT in the era of modern radiation therapy is yet to be precisely defined. In this systematic review, we aim to provide an up-to-date analysis of current experience and clinical evidence of NBT in the XXI th century, by answering the following clinical questions: How is NBT currently delivered? What are the current efficacy data and tolerance profiles of NBT?

Virtual 4DCT generated from 4DMRI in gated particle therapy: phantom validation and application to lung cancer patients.

Objective. Respiration negatively affects the outcome of a radiation therapy treatment, with potentially severe effects especially in particle therapy (PT). If compensation strategies are not applied, accuracy cannot be achieved. To support the clinical practice based on 4D computed tomography (CT), 4D magnetic resonance imaging (MRI) acquisitions can be exploited. The purpose of this study was to validate a method for virtual 4DCT generation from 4DMRI data for lung cancers on a porcine lung phantom, and to apply it to lung cancer patients in PT.Approach. Deformable image registration was used to register each respiratory phase of the 4DMRI to a reference phase. Then, a static 3DCT was registered to this reference MR image set, and the virtual 4DCT was generated by warping the registered CT according to previously obtained deformation fields. The method was validated on a physical phantom for which a ground truth 4DCT was available and tested on lung tumor patients, treated with gated PT at end-exhale, by comparing the virtual 4DCT with a re-evaluation 4DCT. The geometric and dosimetric evaluation was performed for both proton and carbon ion treatment plans.Main results. The phantom validation exhibited a geometrical accuracy within the maximum resolution of the MRI and mean dose deviations, with respect to the prescription dose, up to 3.2% for targetD95%, with a mean gamma pass rate of 98%. For patients, the virtual and re-evaluation 4DCTs showed good correspondence, with errors on targetD95%up to 2% within the gating window. For one patient, dose variations up to 10% at end-exhale were observed due to relevant inter-fraction anatomo-pathological changes that occurred between the planning and re-evaluation CTs.Significance. Results obtained on phantom data showed that the virtual 4DCT method was accurate, allowing its application on patient data for testing within a clinical scenario.

Patients' needs in proton therapy: A survey among ten European facilities.

Aims: The number of Proton Therapy (PT) facilities is still limited worldwide, and the access to treatment could be characterized by patients' logistic and economic challenges. Aim of the present survey is to assess the support provided to patients undergoing PT across Europe. Methods: Through a personnel contact, an online questionnaire (62 multiple-choice and open-ended questions) via Microsoft Forms was administered to 10 European PT centers. The questionnaire consisted of 62 questions divided into 6 sections: i) personal data; ii) general information on clinical activity; iii) fractionation, concurrent systemic treatments and technical aspects of PT facility; iv) indication to PT and reimbursement policies; v) economic and/ or logistic support to patients vi) participants agreement on statements related to the possible limitation of access to PT. A qualitative analysis was performed and reported. Results: From March to May 2022 all ten involved centers filled the survey. Nine centers treat from 100 to 500 patients per year. Paediatric patients accounted for 10-30%, 30-50% and 50-70% of the entire cohort for 7, 2 and 1 center, respectively. The most frequent tumours treated in adult population were brain tumours, sarcomas and head and neck carcinomas; in all centers, the mean duration of PT is longer than 3 weeks. In 80% of cases, the treatment reimbursement for PT is supplied by the respective country's Health National System (HNS). HNS also provides economic support to patients in 70% of centers, while logistic and meal support is provided in 20% and 40% of centers, respectively. PT facilities offer economic and/or logistic support in 90% of the cases. Logistic support for parents of pediatric patients is provided by HNS only in one-third of centers. Overall, 70% of respondents agree that geographic challenges could limit a patient's access to proton facilities and 60% believe that additional support should be given to patients referred for PT care. Conclusions: Relevant differences exist among European countries in supporting patients referred to PT in their logistic and economic challenges. Further efforts should be made by HNSs and PT facilities to reduce the risk of inequities in access to cancer care with protons.

Risk of second cancers in Waldenström macroglobulinemia.

BACKGROUND: An increased incidence of second cancers has been reported in lymphoproliferative disorders. PATIENTS AND METHODS: We assessed the frequency, characteristics and predictive factors of second cancers in 230 patients with Waldenström macroglobulinemia (WM) and compared the incidence of second cancers in WM with that of an age- and sex-matched control population. RESULTS: Twenty-two patients (10%) developed solid cancers and 10 (4%) second hematologic malignancies. In a competing risk model, the cumulative incidence of solid cancers was 12% at 10 years and 17% at 15 years while the incidence of hematologic malignancies was 6% and 8%, respectively. The overall risk of second cancer in WM was 1.69 times higher than expected (P = 0.002). WM patients were at increased risk for diffuse large B-cell lymphoma [standardized incidence ratio (SIR) 9.24, P < 0.0001], myelodisplastic syndrome/acute myeloid leukemia (SIR 8.4, P < 0.0001), brain cancer (SIR 8.05, P = 0.0004). The risk of a second hematologic malignancy was fourfold higher in patients previously treated, though not reaching statistical significance (P = 0.19). CONCLUSIONS: WM patients are at higher risk of second cancers as compared with the general population. The sample size does not allow firm conclusions about the effect of therapy on the development of second cancers.

Tumor stage, human papillomavirus and smoking status affect the survival of patients with oropharyngeal cancer: an Italian validation study.

BACKGROUND: Tumor human papillomavirus (HPV) status strongly affects overall survival (OS) of oropharyngeal cancer (OPC) patients. Recently, three groups with different outcomes were identified based on HPV status, smoking history and tumor stage. Our objective was to validate this model using a single-institutional retrospective database. PATIENTS AND METHODS: Patients (n=120) diagnosed with OPC at our institution, treated with concomitant cisplatin plus radiotherapy (RT) (n=64), induction chemotherapy followed by concomitant chemoradiation (n=39) or RT alone (n=17), were stratified in three groups with respect to the risk of death (low 26, intermediate 46 and high 49 patients) according to tumor p16 expression as surrogate of HPV status, pack-years of tobacco smoking and nodal/tumor stage. Group-stratified Kaplan-Meier OS curves were estimated and compared using the log-rank test. RESULTS: The 2-year OS estimates were 100%, 86% and 70%, respectively. The difference between the survival curves was statistically significant (P=0.009). The Harrell's concordance index was 0.70. The calibration plot showed a good concordance between our results and those observed in the original study. CONCLUSIONS: This study validates the risk grouping previously identified. Risk-driven clinical decision making and trial designs will help in better defining the most appropriate treatment in OPC patients.

Omentum flap as a spacer before carbon ion radiotherapy for gynecological recurrences. A technical note.

Re-irradiation of pelvic recurrent gynecological cancer is a challenge due to the proximity of high-radiation-sensitive organs, such as the bowel and the urinary tract. Hadrontherapy for re-irradiation emerges as a safe and effective treatment with a mild rate of morbidity of surrounding normal tissue. To improve the dose to the tumor, a prophylactic displacement of organs at risk is needed, and a multidisciplinary approach is recommended. In this technical note, we report a surgical technique of omentum spacer placement for patients enrolled for carbon ion radiotherapy as re-irradiation for recurrent gynecological tumors.

Docetaxel, cisplatin and 5-fluorouracil-based induction chemotherapy followed by intensity-modulated radiotherapy concurrent with cisplatin in locally advanced EBV-related nasopharyngeal cancer.

BACKGROUND: This monocentric study evaluates the activity and tolerability of docetaxel (Taxotere), cisplatin and 5-fluorouracil (5-FU) (TPF) induction chemotherapy followed by intensity-modulated radiotherapy (IMRT) concurrent with high-dose cisplatin in Epstein-Barr virus -related locally advanced undifferentiated nasopharyngeal cancer. PATIENTS AND METHODS: We retrospectively reviewed the records of patients who received induction docetaxel 75 mg/m(2) and cisplatin 75 mg/m(2) on day 1, and 5-FU 750 mg/m(2)/day (96-h continuous infusion). Following induction, patients received full doses of IMRT concurrently with cisplatin 100 mg/m(2) every 21 days for three cycles. RESULTS: Thirty patients received three TPF cycles (median). Induction was well tolerated; the main toxicity was neutropenia (33%, grade 3-4). During chemoradiotherapy, neutropenia (40%) and mucositis (43%) were the most frequent grade 3-4 adverse events. Mean dose of IMRT was 68.8 Gy. Worst late toxicity was xerostomia. Complete response rate was 93%. At 35 months, two patients had locoregional recurrence, three had distant metastases, and one had both. Three-year progression-free survival and overall survival were 79% [95% confidence interval (CI) 64% to 94%] and 87% (95% CI 74%- to 100%), respectively. CONCLUSIONS: In this high-stage nonendemic cancer population, TPF followed by high-dose cisplatin IMRT was promising; this treatment approach deserves evaluation in randomized trials.

Analysis of tumour microstructure estimation from conventional diffusion MRI and application to skull-base chordoma.

Skull-base chordoma (SBC) is a rare tumour whose molecular and radiological characteristics are still being investigated. In neuro-oncology microstructural imaging techniques, like diffusion-weighted MRI (DW-MRI), have been widely investigated, with the apparent diffusion coefficient (ADC) being one of the most used DW-MRI parameters due to its ease of acquisition and computation. ADC is a potential biomarker without a clear link to microstructure. The aim of this work was to derive microstructural information from conventional ADC, showing its potential for the characterisation of skull-base chordomas. Sixteen patients affected by SBC, who underwent conventional DW-MRI were retrospectively selected. From mono-exponential fits of DW-MRI, ADC maps were estimated using different sets of b-values. DW-MRI signals were simulated from synthetic substrates , which mimic the cellular packing of a tumour tissue with well-defined microstructural features. Starting from a published method, an error-driven procedure was evaluated to improve the estimates of microstructural parameters obtained through the simulated signals. A quantitative description of the tumour microstructure was then obtained from the DW-MRI images. This allowed successfully differentiating patients according to histologically-verified cell proliferation information.Clinical Relevance - The impact on cancer management derives from the expected improvement of radiation treatment quality tailored to a patient-specific non-invasive description of tumour microstructure.

Identification of suitable mRNAs and microRNAs as reference genes for expression analyses in skin cells under sex hormone exposure.

Quantitative RT-PCR is the most accurate technique for the study of gene expression profiles, however, to ensure the accuracy of qPCR results, suitable reference genes are necessary for data normalization. Hormones influence the development and function of skin cells, regulating the expression of genes and miRNAs. Nevertheless, the stability of reference genes after sex hormone treatment has not been thoroughly investigated. In this study, we evaluated the expression of a set of candidate mRNAs and microRNsA (miRNA) as reference genes in keratinocytes (HaCaT cells), primary human fibroblasts and a melanoma cell line (LM-36 cells) under testosterone or 17ß-estradiol treatment. Two algorithms, namely geNorm, Best-Keeper, and the comparative ΔCt method were used to evaluate the expression stability of the candidate reference genes. The comprehensive ranking showed that TBP and miR-191-5p are the most stable expressed genes across all cultured cells under hormone treatment. Furthermore, we observed that GAPDH, HPRT1 and U6 snRNA expression may be altered by hormone exposure, thus, these genes are not recommended as reference genes. In conclusion, the present study provides, to the best of our knowledge, the first evaluation of expressed mRNA(s) and miRNA(s) as reference genes in three different types of skin cells under the stimulation of sex hormones.

Dosimetric effect of variable rectum and sigmoid colon filling during carbon ion radiotherapy to sacral chordoma.

PURPOSE: Carbon ion radiotherapy (CIRT) is sensitive to anatomical density variations. We examined the dosimetric effect of variable intestinal filling condition during CIRT to ten sacral chordoma patients. METHODS: For each patient, eight virtual computed tomography scans (vCTs) were generated by varying the density distribution within the rectum and the sigmoid in the planning computed tomography (pCT) with a density override approach mimicking a heterogeneous combination of gas and feces. Totally full and empty intestinal preparations were modelled. In addition, five different intestinal filling conditions were modelled by a mixed density pattern derived from two combined and weighted Gaussian distributions simulating gas and feces respectively. Finally, a patient-specific mixing proportion was estimated by evaluating the daily amount of gas detected in the cone beam computed tomography (CBCT). Dose distribution was recalculated on each vCT and dose volume histograms (DVHs) were examined. RESULTS: No target coverage degradation was observed at different vCTs. Rectum and sigma dose degradation ranged respectively between: [-6.7; 21.6]GyE and [-0.7; 15.4]GyE for D50%; [-377.4; 1197.9] and [-95.2; 1027.5] for AUC; [-1.2; 10.7]GyE and [-2.6; 21.5]GyE for D1%. CONCLUSIONS: Variation of intestinal density can greatly influence the penetration depth of charged particle and might compromise dose distribution. In particular cases, with large clinical target volume in very close proximity to rectum and sigmoid colon, it is appropriate to evaluate the amount of gas present in the daily CBCT images even if it is totally included in the reference planning structures.

Development and validation of a new set-up simulator dedicated to ocular proton therapy at CNAO.

An Eye Tracking System (ETS) is used at CNAO for providing a stable and reproducible ocular proton therapy (OPT) set-up, featuring a fixation light (FL) and monitoring stereo-cameras embedded in a rigid case. The aim of this work is to propose an ETS set-up simulation algorithm, that automatically provides the FL positioning in space, according to patient-specific gaze direction and avoiding interferences with patient, beam and collimator. Two configurations are provided: one in the CT room for acquiring images required for treatment planning with the patient lying on a couch, and one related to the treatment room with the patient sitting in front of the beam. Algorithm validation was performed reproducing ETS simulation (CT) and treatment (room) set-up for 30 patients previously treated at CNAO. The positioning accuracy of the device was quantified through a set of 14 control points applied to the ETS case and localizable both in the CT volume and in room X-ray images. Differences between the position of ETS reference points estimated by the algorithm and those measured by imaging systems are reported. The corresponding gaze direction deviation is on average 0.2° polar and 0.3° azimuth for positioning in CT room and 0.1° polar and 0.4° azimuth in the treatment room. The simulation algorithm was embedded in a clinically usable software application, which we assessed as capable of ensuring ETS positioning with an average accuracy of 2 mm in CT room and 1.5 mm in treatment room, corresponding to gaze direction deviations consistently lower than 1°.

Organs at risk's tolerance and dose limits for head and neck cancer re-irradiation: A literature review.

Re-irradiation is becoming an established treatment option for recurrent or second primary head and neck cancer(HNC). However, acute and long-term RT-related toxicities could dramatically impact patients' quality of life. Due to the sparse literature regarding HNC re-irradiation, data on tolerance doses for various organs at risk (OARs) are scarce. Our aim was to systematically review the clinical literature regarding HNC re-irradiation, focusing on treatment toxicity, OARs tolerance, and dose limit recommendations. Thirty-nine studies (three randomized, five prospective, 31 retrospective) including 3766 patients were selected. The median interval time between the first course and re-irradiation was 28  months (range, 6-90). In 1043 (27.6%) patients, postoperative re-irradiation was performed. Re-irradiation doses ranged from 30 Gy in 3 fractions using stereotactic technique to 72 Gy in conventional fractionation using intensity-modulated radiotherapy. Pooled acute and late toxicityrates ≥G3 were 32% and 29.3%, respectively. The most common grade 3-4 toxic effects were radionecrosis, dysphagia requiring feeding tube placement and trismus. In 156 (4.1%) patients, carotid blowout was reported. Recommendations for limiting toxicity included the time interval between radiation treatments, the fractionation schedules, and the re-irradiation treatment volumes. Cumulative dose limit suggestions were found and discussed for the carotid arteries, temporal lobes, and mandible.