Primary Radiation Research Articles

Systematic study of displacement threshold and the near-threshold primary radiation damage model

Radiation damage is a critical concern for materials employed in radiation environments such as space, radiotherapy centers, and nuclear energy systems. Numerous models have been developed to estimate the primary radiation damage. The slightly modified Athermal Recombination-Corrected (mARC)-Displacement per Atom (DPA) model proposes a simple function to describe the atomic displacement near the Threshold Displacement Energy (TDE). The present work systematically investigates the global minimum TDE and the near-TDE mARC-DPA model against experimental electron irradiation damage data for 26 materials. The determined high-accuracy global minimum TDE values are generally consistent with previous studies. The corresponding theoretical calculations agree well with experimental measurements, implying the applicability of the mARC model. Renormalization of certain experimental data is required due to the potential issues related to experimental measurements, the value of resistivity change per Frenkel pair (ρFP), or average TDE (Ed). Nevertheless, while some experimental data are supposed to be adjusted, the analysis shows that the ratio of ρFP/Ed can be definitively determined if assuming the experimental data for the remainders.

Molecular dynamic simulations of displacement cascades in Molybdenum and Molybdenum-Rhenium alloys

Molybdenum-Rhenium (Mo-Re) alloys are considered core materials for advanced nuclear reactor components due to their excellent mechanical properties, machinability, and resistance to irradiation damage. However, irradiation-induced embrittlement and phase precipitation at high temperatures, along with transmutation nuclides, have hindered their broader application. To address this, we developed a Mo-Re interatomic potential using the Finnis-Sinclair formalism, facilitating molecular dynamics simulations to study primary irradiation damage. Systemically primary irradiation damage simulations for Mo and Mo-Re alloys have been performed. It’s found that there were more Frenkel-pair defects produced during the stage of thermal spike in Mo-Re alloys but fewer defects survived at the end of the cascade compared to Mo. In addition, the number of large-size interstitial clusters and dislocation loops was higher in Mo-Re alloys than in pure Mo with the same PKA energy. This is mainly attributed to the fact that Mo-Re alloys have lower thermal conductivity, while the binding energies of interstitial clusters and dislocation loops with sizes less than 100 in Mo-Re alloys are comparable to those of pure Mo, resulting in higher defect composites and larger defect sizes in Mo-Re alloys. These findings provide valuable insights into the primary damage mechanisms in Mo-Re alloys under irradiation, offering a foundation for developing kinetic models to simulate radiation-induced microstructural evolution.

Outcomes of adjuvant radiation treatment following subtotal resection of world health organization grade II meningiomas.

Existing literature on adjuvant radiation after subtotal resection (STR) of WHO II meningiomas is limited by heterogenous patient cohorts, combining adjuvant and salvage radiation, gross total resection (GTR) and STR, primary radiation treatment vs. re-treatment, or grade II and III meningiomas, all of which have different expected outcomes. Tumor control estimates in a large homogenous patient cohort are needed to accurately counsel patients. A retrospective review of patients that had immediate post-operative imaging-confirmed residual WHO grade II meningioma followed by either adjuvant intensity-modulated radiation therapy (IMRT) or stereotactic radiosurgery (SRS) between 1996 and 2020 was conducted. Kaplan-Meier survival analysis and log-rank test was used to assess progression-free survival (PFS). Thirty-nine patients met inclusion criteria (IMRT = 32; SRS = 7). Overall, the 3-, 5-, and 10-year PFS was 81.1%, 61.2%, and 44.6%, respectively. Median follow-up time was 37 months. When comparing IMRT and SRS cohorts, baseline characteristics did not differ significantly between groups, but significantly larger residual tumor volumes were treated with IMRT (22.2 cm3 vs. 6.3 cm3, p = 0.004). PFS was not significantly different between IMRT and SRS at 3 years (81.1% vs. 80.0%) or 5 years (65.5% vs. 40%) (p = 0.19). There was no significant difference in radiation necrosis between groups (IMRT = 3/32 patients vs. SRS = 0/7 patients, p = 0.32). Our homogenous patient cohort displayed acceptable control rates at 3 years using SRS or IMRT as adjuvant therapy. No significant difference in PFS or radiation necrosis was noted between patients treated with adjuvant IMRT versus SRS.

Atomistic Simulation of Primary Radiation Damage Profiles in Fluorine-Doped Tin Oxide Thin Film Target Using SRIM Code

In this study, we investigated the discrepancy between the numbers of atomic displacements obtained from the Vac.txt method and those obtained from the Vac.dam method using SRIM-2013 operated in full cascade mode. The SRIM simulations also calculated energy partitioning, damage dose and distribution profiles of the implanted He, C and O ions at three different ion energies of 10 keV, 100 keV and 1 MeV. In all the simulations and at each ion energy value, the target thickness was increased until the entire ion beam was absorbed within the target. The simulated fluorine-doped tin oxide (FTO) thin film target stoichiometrically comprised 78.6% Sn, 16.4% O and 5.0% F, and a 6.013 g/cm3 bulk density. To achieve relatively good statistics with compromised computational time, each run followed 10 000 ion histories. The results indicated that, with increasing ion energies, the peaks of vacancy concentrations moved deeper into the material. For He ions, the vacancy profiles have peaks at ∼0.04, ~0.45 and ~2.9 µm at 10 keV, 100 keV and 1 MeV, respectively. Meanwhile, for C and O ions, the peaks were at ∼0.012, ~0.15 and ~1.23 µm for C ions and ∼0.01, 0.12 and 1.2 µm for O ions at 10 keV, 100 keV and 1 MeV, respectively. We also observed that for all the ions and at all ion energies considered, the Vac.txt method predicted more vacancies than the Vac.dam method, and the discrepancies generally increased with increasing Z by an average value of ∼1.21, ∼1.45 and 1.48 for He, C and O ions respectively. In addition, the electronic and nuclear partitioning profiles revealed that most of the energies of the ions were lost in collision with atomic electrons due to ionisation and excitations, and little to nuclear events. The simulations also revealed that nuclear stopping powers increase at low ion energies. This study also indicated that damage dose profiles strongly depend on the type of incident particle and its energy. A comparison of SRIM and iradina calculated vacancies and incident ion distribution profiles generally indicated perfect agreements between the two codes. FTO thin film remains a promising material for thermal control applications in future spacecraft. However, further analyses are still necessary to comprehensively understand its evolution under intense radiation environments comprising various ions and at different energies.

Irradiation damage evolution dependence on misorientaton angle for ∑ 5 grain boundary of Nb: An atomistic simulation-based study

Abstract Niobium as refractory element holds ability to arrest the primary radiation damage in reactor's fissionable conditions and can withstand high temperature applications. We have inclined the investigation of irradiated Nb ∑ 5 symmetric tilt angled-grain boundary (STGB) models at two high-angled grain boundary misorientation: 53.13 ° (∑ 5(2-10)/ (120)) and 36.87 ° (∑ 5(3-10)/ (130)) respectively. A hybrid of Ziegler-Biersack-Littmark (ZBL) and embedded atom method (EAM) potentials were superimposed to simulate radiation damage. Statistical averaging of the displacement cascades were conducted to study dynamic evolution of the point defects and interstitial clusters at varying magnitudes of primary knock-on atom (PKA) energies, irradiation temperatures and PKA directions respectively. The irradiated GB models were compared with a irradiated bulk Nb specimen and the results of the study indicate that the irradiated Nb system with greater misorientation angle i.e., Nb ∑ 5 (θ = 53.13 ° ) survived with lower number Frenkel pair defects as well as the population small-sized interstitial clusters. The cluster analysis indicated the highest population of interstitial clusters survived in Nb STGB models were irradiated along <1 3 5> PKA direction and 100 keV recoil energies respectively.

Post-Metastasis Survival of Patients with High-Risk Localized and Locally Advanced Prostate Cancer Undergoing Primary Treatment in the United States: A Retrospective Study.

Patients with high-risk localized and locally advanced prostate cancer (HR-LPC/LAPC) have increased risk of metastasis, leading to reduced survival rates. Segmenting the disease course [time to recurrence, recurrence to metastasis, and post-metastasis survival (PMS)] may identify disease states for which the greatest impacts can be made to ultimately improve survival. Evaluate real-world PMS of patients with HR-LPC/LAPC who received primary radical prostatectomy (RP) or radiotherapy (RT) with or without androgen deprivation therapy (ADT). Electronic health records from an oncology database were used to assess PMS. Risk of death was estimated using theKaplan-Meier method. Hazard ratios (HRs) were used to analyze the impact of treatment and time to metastasis (TTM) on PMS. Standardized mortality ratios (SMRs) were calculated for patients with HR-LPC/LAPC versus the US general male population. Overall, 5008 patients with HR-LPC/LAPC were identified, and 1231 developed metastases after primary treatment (RP, n = 885; RT only, n = 262; RT+ADT, n = 84). Age-adjusted PMS HR between the RP and RT only cohorts was 1.19 (p = 0.077) and between RP and RT+ADT cohorts was 1.32 (p = 0.078). TTM was unrelated to PMS in unadjusted (HR 1.01, p = 0.2) and age-adjusted models (HR 0.99, p = 0.3). Relative to pre-metastasis SMRs, post-metastasis SMRs increased eightfold and fivefold in patients treated with RP and RT±ADT, respectively. PMS was unrelated to TTM in patients with HR-LPC/LAPC, suggesting PMS may be independent of the trajectory to development of metastases. Given PMS may be a fixed length of time, delaying the development of metastasis may improve survival in patients with HR-LPC/LAPC.

The Demographic and Clinical Characteristics, Prognostic Factors, and Survival Outcomes of Head and Neck Carcinosarcoma: A SEER Database Analysis

Background: Head and neck carcinosarcoma (HNCS) is a rare and highly aggressive malignancy with limited research, resulting in an incomplete understanding of disease progression and a lack of reliable prognostic tools. This study aimed to retrospectively analyze the clinical characteristics and outcomes of HNCS patients using data from the Surveillance, Epidemiology, and End Results (SEER) database and to develop a nomogram to predict overall survival (OS) and cancer-specific survival (CSS). Methods: Patients diagnosed with HNCS from 1975 to 2020 were identified in the SEER database. Univariate and multivariate Cox regression analyses were conducted to identify independent prognostic indicators, with the optimal model selected using the minimal Akaike Information Criterion (AIC). The identified prognostic factors were incorporated into nomograms to predict OS and CSS. Model performance was assessed using the concordance index (C-index), area under the curve (AUC), calibration curves, and decision curve analysis (DCA). Survival curves were generated using Kaplan–Meier analysis and compared via the log-rank test. Results: A total of 152 HNCS patients were included, with 108 assigned to the training cohort and 44 to the validation cohort in a 7:3 ratio. Prognostic factors including age, primary tumor site, marital status, radiotherapy, chemotherapy, tumor size, pathological grade, and tumor stage were incorporated into the nomogram models. The models demonstrated strong predictive performance, with C-index values for OS and CSS of 0.757 and 0.779 in the training group, and 0.777 and 0.776 in the validation group, respectively. AUC values for predicting 3-, 5-, and 10-year OS were 0.662, 0.713, and 0.761, and for CSS the values were 0.726, 0.703, and 0.693. Kaplan–Meier analysis indicated significantly improved survival for patients with lower risk scores. The 3-, 5-, and 10-year OS rates for the entire cohort were 54.1%, 45.6%, and 35.1%, respectively, and the CSS rates were 62.9%, 57.5%, and 52.2%, respectively. Conclusions: This study provides validated nomograms for predicting OS and CSS in HNCS patients, offering a reliable tool to support clinical decision-making for this challenging malignancy. These nomograms enhance the ability to predict patient prognosis and personalize treatment strategies.

Criteria for Re-Irradiation.

The treatment options for patients with progressive malignant tumors despite primary radiotherapy are often limited. In selected cases, re-irradiation can be offered. This article concerns the selection criteria and results of re-irradiation for certain types of cancer. This review is based on pertinent publications retrieved by a selective search in PubMed, with particular attention to glioblastoma, head and neck tumors, and prostatic carcinoma. The published studies of re-irradiation are few in number and often of limited methodological quality. For glioblastoma, a randomized controlled trial (RCT) found that adding re-irradiation to treatment with bevacizumab yielded no significant improvement in either median progression-free survival or median overall survival (hazard ratio [HR] 0.73; p = 0.05 and HR 0.98; p = 0.46, respectively). Re-irradiation is a treatment option for locoregional recurrences of head and neck tumors after primary radiotherapy, but it carries a risk of serious side effects. For unresectable recurrences of nasopharyngeal carcinoma, an RCT has shown that hyperfractionated re-irradiation is more effective than normofractionated re-irradiation (overall survival: HR 0.54, p = 0.014). For locally recurrent prostatic carcinoma after radiotherapy, re-irradiation can yield good oncologic outcomes with an acceptable level of urogenital and gastrointestinal side effects (5-year recurrence-free survival: stereotactic body radiation therapy (SBRT), 58%; high dose rate (HDR) brachytherapy, 77%; versus salvage prostatectomy, 72%). RCTs on this topic are lacking. Re-irradiation is a treatment option for selected cancer patients. As the available scientific evidence is limited, multidisciplinary collaboration and participatory decision-making are particularly important.

Predictive factors for biochemical relapse in non-metastatic prostate cancer following primary radiotherapy

<p><strong>Aim</strong> To investigate the predictors of biochemical relapse (BCR) among patients with non-metastatic prostate cancer treated with radiotherapy as the first-line therapy. <br /><strong>Methods</strong> The study included 91 patients diagnosed with prostate cancer at the University Clinical Centre in Tuzla, Bosnia and Herzegovina. After the radiation treatment as the first line of treatment, the patients were monitored for the next 36 months. If patients were classified in medium and high-risk groups, hormone therapy was administered. The occurrence of BCR was determined based on prostate-specific antigen (PSA) values. Potential prognostic parameters, including Gleason score (GS), PSA, tumour size (TNM), and standardised risk classification (RC), were monitored.<br /><strong>Results</strong> A total of 46 (50.5%) patients were aged 66-75, with a median PSA of 14.50 ng/mL. A Gleason score <6 was found in 72 (79.1%) of patients, and 31 (34.1%) had T2c tumours. The BCR occurred in 32 (35.2%) patients, with a median relapse time of 18 months. Significant predictors of BCR were Gleason score ≥6 (OR:4.46; p=0.006) and tumour stage >T2b (OR:3.59; p=0.021). The RC showed an Area Under Curve (AUC) of 0.634 (p=0.050), indicating its potential diagnostic accuracy.<br /><strong>Conclusion</strong> Gleason score ≥6 and TNM>T2b are significant predictors of biochemical relapse in prostate cancer patients treated with radiotherapy. These results emphasize the need for additional monitoring and timely treatment of clinical disease progression in patients with Gleason score ≥6 and tumour stage >T2b.</p>

P090 Ten year results of a phase i trial of oncolytic adenovirus-mediated sodium Iodide Symporter (nis) gene delivery in locally recurrent prostate cancer following primary radiotherapy

P090 Ten year results of a phase i trial of oncolytic adenovirus-mediated sodium Iodide Symporter (nis) gene delivery in locally recurrent prostate cancer following primary radiotherapy

A natural protopanaxatriol from Panax notoginseng enhances osteosarcoma sensitivity to ferroptosis via ASCL4 upregulation

Current treatments for osteosarcoma, the most common primary bone cancer, including surgery, radiotherapy, and chemotherapy, are largely ineffective against metastatic and chemo-resistant cases, emphasizing the need for novel therapies. In this study, we investigated (20S)-Protopanaxatriol [(20S)-PPT], a natural product from Panax notoginseng, an herb used both as food and medicine, for its ability to enhance osteosarcoma sensitivity to ferroptosis induced by inducers such as RSL3, ML210, and IKE. Specifically, (20S)-PPT increased lipid peroxidation in osteosarcoma cells exposed to RSL3. This effect was mediated by ACSL4 upregulation, as ACSL4 knockdown reversed (20S)-PPT-sensitized ferroptosis. Importantly, (20S)-PPT significantly reduced tumor growth in xenograft models when combined with IKE. Collectively, our study confirms that combining (20S)-PPT with ferroptosis inducers offers a promising novel strategy for treating osteosarcoma.

Meningioma En Plaque associated with Cerebrospinal Fluid Rhinorrhea: A Systematic Review of Literature with Case Presentation

BackgroundMeningiomas are the most frequently diagnosed benign intracranial tumors. However, meningioma en plaque (MEP) is a rare subset accounting for 2.5% of all meningiomas and is characterized by flat, carpet-like proliferation along the dura, typically arising in the spheno-orbital region; therefore, causes proptosis, decreased visual acuity, and orbital pain. We present a unique case of MEP presenting with cerebrospinal fluid (CSF) rhinorrhea and conduct a systematic review of literature. MethodsFollowing PRISMA guidelines, a systematic search was conducted in PubMed and Embase databases. Keywords and standardized index terms related to MEP were used. The search was performed without restriction on the publication date. Screening, data extraction, and quality assessment were carried out. Data on demographics, clinical presentations, management modalities, and treatment outcomes were analyzed. ResultsThe search yielded 487 titles, with 36 studies eligible for inclusion. A total of 530 patients with MEP were reported, with a mean age of 50.1±11.62 years. Proptosis was the most common symptom (95%), followed by visual impairment (57.3%), orbital pain (38.3%), ophthalmoplegia (28.6%), and headache (23%). Our patient represented the only case with a spontaneous CSF leak. Surgical resection was performed in 85%, adjuvant radiotherapy in 15.7%, and one patient received primary radiotherapy, while 8 patients were closely followed up with no intervention. ConclusionMEP associated with spontaneous CSF rhinorrhea is extremely rare and poses diagnostic and therapeutic challenges. Conservative management for select cases of MEP can be a good choice, refraining the patient from surgical complications, especially for difficult-access skull base areas.

Clinical trial comparing the use of Orcellex® Brush versus Cervex-Brush® on vaginal vault smear cytology adequacy rate in patients treated with radiotherapy for cervical cancer.

This study aims to evaluate and compare the Cervex-Brush® and Orcellex® Brush as sampling devices for vaginal vault smear cytology in cervical cancer patients treated primarily with radiotherapy. A randomized crossover trial was conducted at a gynecological oncology center in Hong Kong to compare the Cervex-Brush® and Orcellex® Brush in terms of their vault smear adequacy rate in cervical cancer patients who underwent radiotherapy. One hundred sixty cervical cancer patients treated with primary radiotherapy and undergoing follow-up surveillance by vaginal vault cytology were recruited. The smear adequacy rate was 90.6% for Cervex-Brush® and 91.9% for Orcellex® Brush. The rates of low cellularity for both brushes were similar (76.8% for Cervex-Brush® vs. 76.1% for Orcellex® Brush). The detection rates of abnormal smears were also not significantly different (2.8% for Cervex-Brush® vs. 4.2% for Orcellex® Brush). The 2 brushes were also not significantly different in terms of pain score and degree of bleeding. It was further observed that the second smear collection was more painful and patients who were on hormonal replacement therapy demonstrated less bleeding. There was no difference between the Orcellex® brush and the Cervex-Brush® in terms of smear adequacy rate, rate of high cellularity and the detection of abnormal smears. There was also no significant difference between the 2 brushes in terms of pain and the degree of bleeding. Therefore, the Orcellex® Brush can be considered a suitable alternative sampling device for vault smear collection in patients who have undergone radiotherapy for cervical cancer. ClinicalTrials.gov Identifier: NCT04461574.

Impact of distant metastasis on overall survival and cancer specific survival of elderly patients with differentiated thyroid cancer

Distant metastases are common in most elderly patients, because elderly patients are diagnosed with advanced thyroid cancer due to delayed diagnosis. There is still few specific real-world data regarding prognosis in the elderly with differentiated thyroid cancer (DTC). The purpose of this study is to evaluate the prognostic factors and survival rate of elderly DTC patients with metastasis. This retrospective study included 14,603 elderly patients diagnosed with DTC from 2010 to 2015, including 447 patients with distant metastasis via the Surveillance, Epidemiology and End Results (SEER) database. The prognostic factors of overall survival (OS) and cancer-specific survival (CSS) in elderly DTC patients with metastasis or non-metastasis were determined by univariate and multivariate analysis. Age, primary site operation, radiotherapy, chemotherapy and tumor size are associated with OS and CSS in elderly DTC patients with distant metastasis. Compared with the patients without surgery, patients with total thyroidectomy showed significantly better OS. For the elderly DTC patients, radiotherapy was associated with improving OS and CSS. Chemotherapy increased the risk of death. For elderly DTC patients, early identification of distant metastasis, total thyroidectomy and radiotherapy are associated with better prognosis.

Treatment Strategies' Impact on Progression-Free Survival According to RMST Function in Metastatic Colorectal Cancer Patients: A Retrospective Study from Romania.

Background: This retrospective study investigates the impact of various treatment strategies on progression-free survival (PFS) in patients with metastatic colorectal cancer (mCRC), a significant global health issue. Methods: We employed the restricted mean survival time (RMST) to evaluate how different treatments affect PFS over a defined period. The study included 225 patients with mCRC who were treated between 2015 and 2023 at the Oncology Department of Colțea Clinical Hospital in Bucharest. To assign KRAS status, mutation data from exons 2, 3, and 4 of the KRAS gene were required. Eligibility criteria included a confirmed histopathological diagnosis of colorectal adenocarcinoma, a valid RAS mutation test from a solid biopsy, radiological confirmation of stage IV disease by computed tomography, and at least one line of systemic treatment in the metastatic setting. Results: Our analysis revealed a small difference in PFS based on KRAS status, but this difference was not statistically significant. Neither sex nor the urban versus rural environment impacted PFS; however, the data indicated that educational level affected survival outcomes. Conclusions: Consistent with existing literature, our findings showed no survival benefit from locoregional treatments such as surgery of the primary tumor or curative radiotherapy at diagnosis. In contrast, resection of hepatic metastases was associated with improved survival outcomes.

AUDIT TO EVALUATE CURRENT RADIOTHERAPY (RT) PLANNING PATHWAY: COULD CURRENT PRACTICE BE IMPROVED BY THE TIMING OF MAGNETIC RESONANCE IMAGING (MRI)?

Abstract AIMS To evaluate the current guidance for glioblastoma (GBM) and primary brain radiotherapy (RT) planning. Current practice in this centre utilises pre and post-surgical MRI for RT target delineation. This study aims to explore the practicality and impact of scheduling an RT planning-specific MRI no more than 2 weeks before RT treatment start date (TSD). Time from surgery to RT TSD will also be explored. METHOD Fifty GBM patients, treated between August 2022 and October 2023, were audited retrospectively. Included patients were treated with radical intent and must have had surgery or biopsy. Age, gender or performance status (PS) were excluded from audit criteria. Age of MRI used for RT planning and surgery to TSD was noted. RESULTS Early results showed that the average age of MRI used for RT planning was 7 weeks old and Surgery to TSD was 7 weeks. A new pathway was introduced after 37 patients as these results were considered unacceptable. The new pathway included 1 reserved MRI appointment and one reserved RT Mask/CT appointment per week. 13 patients’ pathways were audited after introduction of the new pathway. The results showed that the average age of MRI used for RT planning was 2 weeks old and surgery to TSD was 6 weeks. CONCLUSION Limitations of the audit included disparity between number of patients before and after introduction of the new pathway. This was because of the time limitation for completion of the study. Improvement was seen in timing of MRI to TSD. However, the small improvement in timing of surgery to TSD was impacted by human factors rather than organisational influence, for example, surgical deconditioning, delays for wound healing and patient choice. This study has shown that the ideal timing of MRI can be achieved.

Correlation of the treatment sensitivity of patient-derived organoids with treatment outcomes in patients with head and neck cancer (SOTO): protocol for a prospective observational study

IntroductionOrganoids have been successfully used in several areas of cancer research and large living biobanks of patient-derived organoids (PDOs) have been developed from various malignancies. The characteristics of the original...

Evaluation of Two Different Approaches for Selecting Patients for Postoperative Radiotherapy in Deep-Seated High-Grade Soft Tissue Sarcomas in the Extremities and Trunk Wall.

Two national sarcoma centers have had different approaches for selecting patients with grade 2-3 deep-seated soft tissue sarcomas (STS) for postoperative radiotherapy (RT). We evaluated potential differences in local recurrence in patients treated at the two centers. At Sarcoma Center 1 (SC1), RT was the standard treatment for all tumors except certain small tumors excised with a margin wider than 1 cm. Sarcoma Center 2 (SC2) avoided RT for tumors regardless of tumor size if removed with a margin wider than 1 cm and/or a solid barrier. We included 386 patients (SC1/SC2 = 196/190) over 18 years of age diagnosed with a non-metastatic grade 2-3, deep-seated STS of the extremities or trunk wall, who underwent primary surgical treatment (only tumors excised with a negative margin) from 1 January 2000, to 31 December 2016. Kaplan-Meier survival analysis, competing risk analysis, and cause-specific Cox regression were applied. A total of 284 patients received primary RT, 163 (83%) at SC1 and 121 (64%) at SC2 (p < 0.001). The cumulative incidence of local recurrence at five years was 15% (95% CI: 10-19%) at SC1 and 14% (95% CI: 9-19%) at SC2. Multivariate analysis showed no significant differences in local recurrence between the centers. We concluded that when entering all available patients into the analysis using an intention-to-treat principle, a more selective approach to postoperative RT in patients with grade 2-3 deep-seated STS did not lead to a higher local recurrence rate. However, with this study design, we cannot rule out if the local recurrence rate could have been lower if RT was administered to all tumors removed with a margin wider than 1 cm and/or a solid barrier.

Surgical Treatment of Hypopharyngeal Carcinoma, Neck Dissection and Adjuvant Postoperative Therapy of Oropharyngeal and Hypopharyngeal Cancer: Recommendations of the current S3 Guideline - Part II

Part II of the S3 guideline report deals with the surgical treatment of hypopharyngeal carcinoma, neck dissection for oropharyngeal and hypopharyngeal carcinomas and adjuvant therapy options. Primary surgical therapy ± adjuvant radio- or radiochemotherapy and primary radio- or radiochemotherapy are established as primary therapies for local-regional hypopharyngeal carcinomas. Direct randomized comparisons of both basic therapeutic procedures were never conducted. Available registry data show a worse prognosis of hypopharyngeal carcinoma compared to oropharyngeal carcinomas in all locoregional tumor stages, regardless of the treatment method. For T1N0-T2N0 squamous cell carcinoma of the hypopharynx, there are no relevant differences in overall survival and locoregional relapse rate between primary surgical and primary non-surgical treatment. Primary surgical therapy ± adjuvant radiotherapy or radiochemotherapy and primary radiotherapy or radiochemotherapy are established as primary therapies for advanced but locoregionally limited hypopharyngeal carcinomas. Neck dissection is an integral part of the primary surgical treatment of oropharyngeal and hypopharyngeal cancer. There are only a few randomized studies on non-surgical organ preservation for advanced hypopharyngeal cancer as an alternative to pharyngolaryngectomy, but these have led to the recommendation of alternative concepts in the new guideline. The indication and implementation of postoperative adjuvant radiotherapy and radiochemotherapy for hypopharyngeal carcinoma do not differ from those for HPV/p16-negative and -positive oropharyngeal carcinoma.

TCT-746 Reduction of Primary Operator Radiation Dose With Portable Radiation Shielding and Real-Time Dosimetry Monitoring

TCT-746 Reduction of Primary Operator Radiation Dose With Portable Radiation Shielding and Real-Time Dosimetry Monitoring