BACKGROUND:While the ProtecT randomized trial demonstrated comparable oncologic outcomes between radical prostatectomy (RP) and radiation therapy (RT) for localized prostate cancer, several retrospective studies have reported mixed findings. In this study, we investigated whether non-randomized studies tend to favor RP or RT and assessed whether the specialty of leading authors-urologists or radiation oncologists-correlates with study conclusions. METHODS:We identified non-randomized clinical studies published between 1993 and 2024 that compared RP and RT for localized prostate cancer and reported oncologic outcomes including biochemical, metastasis, and/or survival outcomes. Author specialty was determined based on whether the first and senior authors were affiliated with urology or radiation oncology departments. Studies in which a urologist and radiation oncologist were first and senior authors were excluded. Each study's conclusion was categorized as favoring surgery, favoring radiation, or reporting no conclusive difference in oncologic outcomes. Multivariate logistic regression was used to evaluate predictors of study conclusions. RESULTS:A total of 105 studies met inclusion criteria. Nearly half (44%) reported no conclusive difference in outcomes, while 42% favored RP and 14% favored RT. Multivariate analysis showed that use of national databases (P = .01) and urology author specialty (P = .01) predicted conclusions aligning with the author's specialty. In a subgroup excluding studies relying solely on biochemical recurrence-free survival outcomes, author specialty remained associated with conclusions, with urologists more likely to favor RP (P = .006). CONCLUSION:Author specialty was associated with the direction of study conclusions. Further research is needed to understand how these patterns may influence interpretation and decision-making in prostate cancer treatment.

BackgroundLebanon’s radiation therapy (RT) system has been exposed to successive, overlapping crises since 2019, including financial collapse, the Beirut Port explosion, and armed conflict in 2024. This study analyzes the impact of compounded crises on RT access and practice patterns using longitudinal institutional data from Mount Lebanon Hospital (MLH) as a sentinel cohort.MethodsA retrospective observational study was conducted at MLH (2018–2025). Annual treated patient volumes, treatment technique distributions (3D-CRT, IMRT, SBRT, SRS), and hypofractionation adoption patterns were analyzed. Crisis phases were defined as: pre-crisis baseline (2017–2018), acute economic collapse (2019–2020), subacute adaptive phase (2021–2022), and chronic/war-related phase (2023–2025). National RT workforce and infrastructure data were assessed against ESTRO-HERO and IAEA benchmarks.ResultsRT patient volume exhibited non-linear evolution: initial increase from 1,186 (2018) to 1,498 (2022), a modest decline to 1,328 (2023), with recovery to 1,399 (2024) and 1,479 (2025) coinciding with war-related patient centralization. A sustained shift occurred from 3D-CRT (>80% in 2018) to IMRT, SBRT, and SRS (>50% by 2025). Hypofractionated breast radiotherapy increased from 34.1% (2023) to 73.0% (2025), with a marked inflection point in 2024. Lebanon’s RT workforce falls below ESTRO benchmarks for radiation therapists (3.9 vs. 5–7 per LINAC) and medical physicists (0.8 vs. 1.2–1.7 per LINAC).ConclusionRT systems in fragile settings do not fail linearly but fluctuate under sustained strain, and apparent volume stability at a single resilient center can mask systemic national contraction. Crisis conditions accelerated hypofractionation adoption and technique modernization. We further identify the need for a structured Radiation Therapy System Resilience Score (RT-SRS) and define its candidate domains as a conceptual, hypothesis-generating framework to guide proactive vulnerability detection in fragile settings; its operationalization and validation are designated as future work.

Radiation-induced morphea (RIM) is a rare, immune-mediated late complication of breast radiotherapy that may clinically mimic radiation fibrosis, malignancy, or other inflammatory dermatoses. Diagnosis is particularly challenging in patients with pre-existing cutaneous T-cell lymphoma (CTCL), in whom new post-radiation skin lesions may raise concern for lymphoma involvement or progression. To the best of our knowledge, based on a non-systematic search of the available literature, this is the first reported case of radiation-induced morphea occurring in a patient with pre-existing mycosis fungoides (MF). A 55-year-old woman with a history of MF and right breast invasive lobular carcinoma underwent bilateral mastectomy followed by adjuvant chest wall radiotherapy. Approximately 6.5 years later, she developed a progressive erythematous, indurated plaque within the irradiated field. Given her history of MF, cutaneous lymphoma involvement and radiation-associated sarcoma were important diagnostic considerations. Punch biopsy demonstrated dermal collagen homogenization with a mixed inflammatory infiltrate, while immunohistochemistry showed preserved pan-T-cell antigen expression without an aberrant phenotype, supporting RIM rather than lymphoma. The patient was treated with topical corticosteroids followed by methotrexate, with mild-to-moderate improvement in erythema without complete resolution; subsequent reconstructive revision was followed by further improvement in erythema, breast softness, and cosmesis. This case highlights the diagnostic overlap between RIM and CTCL and underscores the importance of prompt biopsy and careful clinicopathological correlation in evaluating persistent or atypical post-radiation skin changes.

Total body irradiation (TBI) is a form of radiotherapy that provides a uniform dose of ionizing radiation to the entire body. It has been a mainstay of the conditioning regimen for allogeneic hematopoietic stem cell transplantation (allo-HSCT) for many decades. The clinical usefulness of TBI is based on the balance of its cytotoxic and immunosuppressive effects, which allow for the eradication of remaining malignant cells, including sanctuary sites, as well as the establishment of a successful transplant. Early "supra-lethal" single-dose schedules of TBI were highly effective but also came with a substantial treatment-related toxicity burden. As a result, fractionated doses of TBI were developed to improve the tolerability of the regimen. Currently, TBI is used as a component of the conditioning regimen for all three types of allo-HSCT conditioning: myeloablative conditioning (MAC, typically TBI ≥ 12 Gy or equivalent), nonmyeloablative conditioning (NMA, typically TBI ≤ 2 Gy), and reduced-intensity conditioning (RIC, intermediate doses). The dose of TBI is intended to balance the efficacy of the regimen against non-relapse mortality (NRM). High doses of TBI are more effective in reducing the risk of relapse but also increase the risk of NRM, particularly in the elderly. The lowest doses of NMA, typically 2 Gy, have expanded the scope of allo-HSCT but may be insufficient for durable disease control in high-risk disease because relapse remains a major cause of failure. intermediate TBI doses (4-8 Gy) are used in reduced or intermediate-intensity platforms to enhance antileukemic activity while limiting toxicity relative to fully myeloablative regimens. It is important to note that the outcomes of the regimen are not determined by TBI dose only, but by the interaction among dose/fractionation, the chemotherapy backbone, disease status, and transplant platform. The available data suggests a need for a platform-specific dose-adapted regimen of TBI rather than a standard dose.

Treatment of locally advanced rectal cancer (LARC), clinical stages II–III, typically involves multimodal treatment options. Over the past decade, the role of radiation therapy as a neoadjuvant treatment for LARC has evolved and is currently a part of total neoadjuvant therapy (TNT). Some recently published studies advocate for the omission of radiation therapy entirely, while others report on a non-operative approach that emphasizes the use of higher radiation therapy doses. This review aims to evaluate the latest literature on the current role of radiation therapy in the management of LARC, with a discussion of how to best select the most appropriate treatment protocol based on individual patient and tumor characteristics, comorbidities, and personal needs and preferences.

PURPOSEOne crucial use of telemedicine that is underreported is its role in providing health services in conflict-affected zones. The aim of this report is to describe the process and challenges of implementing a telemedicine-based radiation oncology (RO) clinic in a war zone in southern Lebanon, and to assess its effectiveness in providing care to patients with cancer residing in this unsafe, resource-limited area.METHODSAfter the outbreak of the Lebanese-Israeli war in October 2023, we had to shift our RO clinic in Nabatieh Governmental Hospital to an exclusively remote clinic without on-site physicians. Consultations, treatment planning, and follow-ups were conducted virtually by physicians at the American University of Beirut Medical Center. Patient data and imaging were shared electronically between both hospitals, and treatment was administered locally by trained staff. RESULTSFrom October 2023 to September 2024, 669 new patient consultations were completed remotely. Despite infrastructure limitations, including lack of electronic health records and occasional connectivity issues, we developed a model to ensure care continuity was largely maintained for the local patients with cancer.CONCLUSIONTelemedicine can serve as a tool for delivering cancer care in times of war, improving access and equity for underprivileged groups in the face of severe logistical and infrastructural challenges.

ABSTRACT Background The Euronet‐PHL‐C1 protocol has yielded excellent results for pediatric Hodgkin Lymphoma (HL), by omitting radiotherapy (RT) in early responders, thereby decreasing long‐term toxicities. However, its application in resource‐limited countries remains challenging. This study aims to evaluate patient outcomes using this protocol and the feasibility of omitting RT for early responders. Methods We conducted a retrospective analysis of 87 previously untreated pediatric HL patients at our Center from 2012 to 2022, following the Euronet‐PHL‐C1 protocol. RT was omitted for patients with an early rapid response at interim evaluation. Collected data were analyzed to determine survival outcomes and predictors of relapse. Results The mean age of the patients was 13 years, with 51.7% female. B‐symptoms were present in 59.8% of the patients, while 37.9% had bulky disease, 57.1% had elevated erythrocyte sedimentation rate, and 42.5% had stage IV disease. RT was omitted for early rapid responders in 22.9% of the patients. The therapy was generally well tolerated, with only 36 episodes of febrile neutropenia and no treatment‐related mortality. The 5‐year progression‐free survival and overall survival of the entire cohort were 89.3% and 97.6%, respectively. Nine patients relapsed, and two patients died. No independent predictors of event‐free survival were identified. Conclusion The implementation of Euronet‐HL protocol in our center provided excellent outcomes and a safety profile despite a few challenges. While RT can be removed in low‐stage, rapid‐responder patients, caution persists in resource‐limited settings for those with advanced stage or bulky disease, highlighting the need for prospective trials to guide safe RT omission.

While radical cystectomy remains the primary treatment of choice for bladder cancer, increased evidence supports the use of bladder-preservation strategies based on adjuvant radiotherapy. This highlights the need for a better understanding of bladder cancer radiosensitivity to different types of treatment deliveries. The purpose of this study is to analyze the effect of treatment time, dose and fractionation on the number and sizes of grown three-dimensional (3D) bladder cancer spheres, and to assess the capacity of the linear-quadratic model in describing the response of cells cultured in 3D. 3D MatrigelTM-based cultures were employed to enrich for cancer stem cells (CSCs) from three human bladder cancer cell lines, RT4, T24 and UM-UC-3. Three single dose radiation treatments were performed at different time points after plating, and sphere number and sizes were assessed. Anti-CD44 immunofluorescence, clonogenic assay and anti-γH2AX staining were also performed to analyze the cell lines’ radiosensitivity. The radiosensitivity of spheres was dependent on the treatment timing after plating. Current linear quadratic dose fractionation models were shown to over-estimate radiosensitivity in 3D models. Our results showed the importance of treatment timing on the radio-response of bladder cancer spheres. We also demonstrated that bladder cancer spheres are more resistant to dose-fractionation than the estimation from the theoretical linear-quadratic model.

Background: Bladder cancer is the fourth most commonly diagnosed cancer among males worldwide. Current treatment strategies established for bladder cancer mainly consist of cystectomy yet advances in radiation therapy have pointed to the value of organ-preserving strategies in preserving patients' quality of life. Aim: To study and compare the radiosensitivity in two-dimension (2D) and physiologically-relevant three-dimension (3D) in vitro culture of three human bladder cancer cell lines, RT4, T24, and UM-UC-3. Materials and Methods: Clonogenic assay was performed to assess cells' radiosensitivity in 2D. Employing the 3D Matrigel™-based cultures to enrich for cancer stem cells (CSCs) allowed us to assess the survival of this subpopulation of cells via evaluating the number, i.e., sphere forming unit (SFU), and the sizes of cultured spheres, formed from cells exposed to different radiation doses compared to non-irradiated cells. Results: Irradiating cells with increasing radiation doses revealed highest survival rates with RT4 cells in 2D, followed by T24 and UM-UC-3. In 3D, however, UM-UC-3 cells were shown to be the most radio-resistant as evidenced by the number of spheres formed, yet they displayed the least efficient volume reduction/regression (VR), whilst the volume decreased significantly for both RT4 and T24 cells. Sphere VR and sphere ratio (SR) values were then plotted against each other demonstrating a linear correlation between volume and number with RT4 and UM-UC-3 cell lines, but not T24. Lastly, multiple regression model was employed to evaluate the possibility of obtaining a function combining both 3D parameters, SR and VR, with the surviving fraction (SF) in 2D, and showed a linear regression for T24 cells only, with a correlation coefficient of 0.97 for the combined parameters. Conclusion: We were able to radiobiologically characterize 3 human bladder cancer cell lines showing differential effects of radiation between 2D and 3D culture systems, paving the way for achieving better assessment of radiosensitivity of bladder cancer in vitro.

Retinoblastoma is an ocular tumor that occurs in young children, in either heritable or sporadic manner. The relative rarity of retinoblastoma, and the need for expensive equipment, anesthesia, and pediatric ophthalmologic expertise, are barriers for effective treatment in developing countries. Also, with an average age-adjusted incidence of two to five cases per million children, patient number limits development of local expertise in countries with small populations. Lebanon is a small country with a population of approximately 4.5 million. In 2012, a comprehensive retinoblastoma program was formalized at the Children's Cancer Institute (CCI) at the American University of Beirut Medical Center, and resources were allocated for efficient interdisciplinary coordination to attract patients from neighboring countries such as Syria and Iraq, where such specialized therapy is also lacking. Through this program, care was coordinated across hospitals and borders such that patients would receive scheduled chemotherapy at their institution, and monthly retinal examinations and focal laser therapy at the CCI in Lebanon. Our results show the feasibility of successful collaboration across borders, with excellent patient and physician adherence to treatment plans. This was accompanied by an increase in patient referrals, which enables continued expertise development. However, the majority of patients presented with advanced intraocular disease, necessitating enucleation in 90% of eyes in unilateral cases, and more than 50% of eyes in bilateral cases. Future efforts need to focus on expanding the program that reaches to additional hospitals in both countries, and promoting early diagnosis, for further improvement of globe salvage rates.

Introduction Bladder cancer is the fourth most commonly diagnosed cancer among males worldwide. Recent advances in radiation delivery have increased the importance of bladder preserving strategies using radiotherapy, while also improving patient’s quality of life. However, the outcome of radiotherapy depends on the radiosensitivity of both the patient and his/her tumour. Recent developments in radiobiology have highlighted the importance of the assessment of radiation-induced DNA double-strand breaks (DSB) repair kinetics in predicting radiosensitivity of both normal and cancerous tissues. Indeed, after irradiation, several proteins (ATM, γH2AX, etc.) involved in the signalling and repair of DNA DSB relocalize as nuclear foci. The purpose of this study is to characterise the radiosensitivity of bladder cell lines, based on their capacity to repair radio-induced DNA damage. Material and methods Four human bladder cell lines were used in this study: T24, UM-UC3, RT4 and SVHUC. Clonogenic assay was performed to study cell survival after irradiation: cells were irradiated with doses ranging from 0 to 10 Gy and their capacity to form colonies was assessed. Immunofluorescent analysis using anti-pATM and anti-γH2AX antibodies was then performed to assess DNA DSB signalling and repair kinetics after a 2Gy irradiation. Finally, we performed the three-dimensional (3D) sphere formation assay to assess the effect of irradiation on cancer/stem progenitor cells. Irradiated cells with doses ranging from 0 to 10 Gy were embedded in Matrigel and their capacity to form spheres was assessed. Results and discussions RT4 was found to have the highest survival rate after irradiation, followed by T24, UM-UC3 and SVHUC according to the clonogenic assay results. Immunofluorescence results were consistent with cell survival as RT4 showed the fastest DSB recognition and repair kinetics while SVHUC had a much slower rate. Furthermore, the capacity of cells to recognise radio-induced DNA damage was found to have the best correlation with their survival. Lastly, the sphere formation ability of the different cell lines showed a differential response to increasing irradiation doses. Conclusion We were able to radiobiologically characterise 4 human bladder cell lines by assessing their survival and capacity to repair radio-induced DNA damage. Moreover, we showed the differential effects of radiation on cancer stem/progenitor cells. The results highlighted the importance of DNA DSB signalling through the ATM protein and its role in cell survival after irradiation.

Purpose: The purpose of this study was to evaluate patient-related non-dosimetric predictors of cardiac sparing with the use of deep inspiration breath-hold (DIBH) in patients with left-sided breast cancer undergoing irradiation (RT). Materials and Methods: We retrospectively reviewed charts and treatment plans of one-hundred and three patients with left-sided breast cancer. All patients had both free-breathing (FB) and DIBH (with body surface tracking) plans available. (MHD) and V4 (heart volume receiving at least 4 Gy) were extracted from dose volume histograms. Fisher's exact and Chi-square tests were used to identify predictors of reductions in MHD and V4 after DIBH. Results: One-hundred and three patients were identified and most underwent mastectomy. MHD and V4 decreased significantly in DIBH plans (0.74 ± 0.25 Gy vs. 1.72 ± 0.98 Gy, p < 0.0001 for MHD; 4 ± 4.98 cc vs. 20.79 ± 18.2 cc, p < 0.0001 for V4). Body mass index (BMI), smoking and timing of CT simulation (spring/winter vs. summer/fall) were significant predictors of reduction in MHD whereas BMI, field size, chemotherapy, axillary dissection, and timing of CT simulation predicted reduction in V4. On multivariate analysis, BMI, and timing of CT simulation remained significant predictors of the heart-sparing effect of DIBH. Conclusions: In the setting of limited resources, identifying patients who will benefit the most from DIBH is extremely important. Prior studies have identified multiple dosimetric predictors of cardiac sparing and hereby we identified new non-dosimetric factors such as BMI and timing of treatments.

PURPOSE:Acute radiation dermatitis is a common side-effect of radiotherapy in breast cancer and has a profound impact on patients' quality of life, due to pain and discomfort. The aim of this study is to compare the effect of β-sitosterol (Mebo) ointment to trolamine (Biafine) cream for the prevention and treatment of radiation dermatitis in breast cancer patients receiving adjuvant radiation therapy.MATERIALS AND METHODS:This is a prospective open-label randomized phase III study developed to assess the efficacy of 2 topical agents used for management of acute radiation dermatitis. Female breast cancer patients who needed a course of radiation therapy in our institution were enrolled and randomized into 2 groups 1 with Mebo ointment and 1 with Biafine cream. Both medications were applied twice per day during the whole period of treatment and skin reactions and related symptoms were assessed weekly during the entire course. Grading of skin reactions was done according to the Radiation Therapy Oncology Group grading system.RESULTS:Between September 2015 and May 2017, a total of 161 patients were recruited for this trial. Mean age was similar for both groups (50.19±12.57 vs. 51.73±11.23, respectively, P=0.41). All other patients and treatment characteristics were similar in both groups, except for the use of boost (82.7% in the Biafine group vs. 36.7% in Mebo group, P=0.012). Analysis was done for reactions recorded before the beginning of the boost and for the entire course including the boost. Using univariate and multivariate analysis, there was no significant difference in grades 2 and 3 dermatitis between the 2 groups. However, the incidence of severe pruritus and severe local skin pain were both significantly reduced in the Mebo group (14.1% in Biafine vs. 2.9% in Mebo, P=0.016 for pruritus and 11.5% vs. 1.4%, respectively, P=0.02 for severe pain).CONCLUSIONS:This study showed no difference between Mebo and Biafine in the incidence and severity of breast skin dermatitis during radiation therapy. However, the use of Mebo ointment was associated with decreased severe pruritus and pain which could positively affect patient comfort and quality of life.

Whole brain radiation therapy (WBRT) remains standard for patients with brain metastasis not amenable to stereotactic radiation. Incidental irradiation of the parotid glands can result in xerostomia that could persist for several months after treatment and each additional Gray of mean parotid dose decreases salivary flow at 6 months by around 4%. A novel technique using 3D conformal radiotherapy (3DCRT) was used to decrease the radiation dose to the parotid glands and hence the risk of xerostomia. CT simulations of 20 de-identified patients were randomly selected. For each patient, 3 different WBRT plans were generated. The first using the standard opposed laterals fields with the inferior border at C2, the second using opposed laterals with the inferior border at C1 and the third using a novel proposed technique. In the new technique, we placed the isocenter 0.5-1 cm above the contoured parotid glands. Above the isocenter, 2 upper lateral fields were designed similar to the standard opposed laterals. Below the isocenter, 2 lower fields were used,conformal to the contoured brain, with a 1cm collimation to the edge of the MLC. The lower beams used were a left posterior oblique (angle: 115 degrees) and a right posterior oblique (angle: 245 degrees) such that each beam completely spares one ipsilateral parotid gland. Prescription dose was 30Gy in 10 fractions for all plans. Dose volume histogram data were generated for each of the three plans for every patient. Brain coverage and the means of the right parotid, left parotid and bilateral parotids were compared in each of the 3 plans using dependent samples t-test in IBM SPSS version 23. In all three techniques of WBRT, brain coverage was adequate with 95% of the dose covering more than 95% of the brain. The average of the mean right parotid dose using C2, C1, and the new technique were 17 Gy ± 4, 12 Gy ± 3, and 6 Gy ± 2. The average of the mean left parotid dose using C2, C1, and the new technique were 18 Gy ± 4, 13 Gy ± 3, and 6 Gy ± 1. The average of the mean bilateral parotids dose using C2, C1, and the new technique were 18 Gy ± 4, 12 Gy ± 3, and 6 Gy ± 1. There was a statistically significant decrease in the mean dose to the parotids, by at least one-half, using our new technique versus the standard WBRT with the inferior border at C2 (P-value<0.0001) and by at least a third using the inferior border at C1 (p-value<0.0001). Our new 3DCRT technique for WBRT significantly reduces mean parotid gland dose compared to the standard WBRT fields and can significantly decrease the risk of xerostomia and thus improve patients’ quality of life.

AbstractWe are reporting an unusual case of lymphoepithelial-like carcinoma (LELC) in an 8-year-old female patient where the tumor cells showed unusual CD4 expression. The lesion was found in the left submandibular neck region, in the vicinity of the submandibular gland. The salivary gland was not infiltrated by the tumor, and the tumor exhibited a classic LELC with single and clusters of tumor cells surrounded by many hematolymphoid cells. The tumor cells revealed strong positivity for Epstein–Bar virus as confirmed by the EBER: Epstein-Barr Virus in situ hybridization (EBER-ISH) method of staining. Interestingly, the tumor cells expressed membranous immunostaining for the T-helper lymphocyte antibody (CD4) in addition to pan-cytokeratin. A brief discussion about this unusual finding is offered. The patient was treated as a case of Epstein–Bar virus-associated nasopharyngeal carcinoma with excellent response.

Stereotactic radiosurgery (SRS) delivered to arrhythmogenic foci within the heart is a promising treatment modality. We dosimetrically evaluated the radiation dose to the organs at risk of 4 swine that were successfully treated with Linac based SRS for AV node ablation. Single-chamber pacemakers were implanted in four large white breed swine (weight 40–75 kg). The pigs were placed under general anesthesia, and coronary/cardiac computed tomography simulation scans were performed to localize the AV node that was contoured in addition to organs at risk. SRS doses ranging from 35 to 40 Gy were delivered by a Linac to the AV node, and the pigs were followed up with pacemaker interrogations to detect potential electrocardiographic changes. Planning was done using Panther software (Prowess Inc., Concorde, CA) version 5.10. One sample t-tests were used to evaluate Dmax of great vessels, esophagus and chest wall as compared to known normal tissue constraints as per RTOG 0631(Dmax great vessels<37Gy; esophagus<16Gy) and AAPM Task Group 101 (Dmax chest wall<22Gy). All pigs had disturbances of AV conduction with progressive transition into complete heart block. After euthanasia, macroscopic and microscopic evaluation showed fibrosis in the AV node but did not reveal any changes in non-nodal cardiac tissue or vessels. The mean Dmax ± SD (p-value) of the chest wall (14.7 ± 3.3 (0.02)), esophagus (10.7 ± 1.1 (<0.01)) superior vena cava (3.3 ± 4.1 (<0.01)), right pulmonary artery(16.1 ± 6.4 (<0.01)), and vein(15.7 ± 5 (<0.01)), left pulmonary artery(11.1 ± 1.7 (<0.01)) and vein(14.1 ± 2.6 (<0.01)) were significantly below the normal tissue constraint cutoffs . Mean ± SD (p-value) of ascending aorta (25.4 ± 16.2 (0.25)) and inferior vena cava (35.7 ± 3.7 (0.54)) were not significantly different than normal tissue constraint cut offs. Two swine models treated at 40Gy had small areas of hotspots in the ascending aorta (37.9 (0.1cc) and 40.8(1.4cc)) and inferior vena cava (37.4 (0.1 cc) and 39.9 (1.0cc)). Stereotactic radiosurgery is technically feasible and effective for swine AV node ablation using doses 35-40Gy. We have demonstrated, in our swine models that this can be done without exceeding known human normal tissue constraints to the chest wall, esophagus, and great vessels. Phase 1 clinical trials on human patients with cardiac arrhythmias who are unfit for catheter ablation are warranted to study this promising treatment modality.

OBJECTIVE/BACKGROUND:Management of Wilms tumor (WT) in children depends on a multidisciplinary approach to treatment, and outcomes have significantly improved as reported by cooperative group clinical trials. Here, we review the clinical outcomes of patients with WT and identify challenges and barriers encountered in multidisciplinary management outside of cooperative clinical trials. METHODS:We retrospectively reviewed the clinical records of 35 children with WT treated between April 2002 and June 2013 at the Children's Cancer Institute in Lebanon. RESULTS:Upfront resection was performed in 23 cases. Biopsies were performed for Stage V tumors (n=4), those with unresectable tumors or inferior vena caval thrombus (n=5), and patients who had partial surgery performed elsewhere prior to presentation (n=2). One patient died due to toxicity prior to surgery. The tumor was Stage I in eight patients, Stage II in five patients, Stages III and IV in nine patients each, and bilateral (Stage V) in four patients. Adherence to The National Wilms Tumor Study-5 recommendations was adequate. At the time of analysis, 30 patients were free of disease and four patients had relapse-all having metastatic disease initially. CONCLUSION:The National Wilms Tumor Study-5 therapy resulted in favorable outcomes in children with nonmetastatic Wilms tumor in the setting of a multidisciplinary approach to therapy and resolution of financial barriers to medical care. Upstaging due to prior intervention and lung radiation therapy to all those with computed tomography-detected lung nodules may both have resulted in overtreatment of a subset of patients. Finally, the relatively high incidence of bilateral tumors suggests the need for further genetic and molecular studies in this patient population.

Background Children with malignant bone tumors have average 5-year survival rates of 60% to 70% with current multimodality therapy. Local control modalities aimed at preserving function greatly influence the quality of life of long-term survivors. In developing countries, the limited availability of multidisciplinary care and limited expertise in specialized surgery and pediatric radiation therapy, as well as financial cost, all form barriers to achieving optimal outcomes in this population. Methods We describe the establishment of a collaborative pediatric bone tumor program among a group of pediatric oncologists in Lebanon and Syria. This program provides access to specialized local control at a tertiary children’s cancer center to pediatric patients with newly diagnosed bone tumors at participating sites. Central review of pathology, staging, and treatment planning is performed in a multidisciplinary tumor board setting. Patients receive chemotherapy at their respective centers on a unified treatment plan. Surgery and/or radiation therapy are performed centrally by specialized staff at the children’s cancer center. Cost barriers were resolved through a program development initiative led by St Jude Children’s Research Hospital. Once program feasibility was achieved, the Children’s Cancer Center of Lebanon Foundation, via fundraising efforts, provided continuation of program-directed funding. Results Findings over a 3-year period showed the feasibility of this project, with timely local control and protocol adherence at eight collaborating centers. We report success in providing standard-of-care multidisciplinary therapy to this patient population with complex needs and financially challenging surgical procedures. Conclusion This initiative can serve as a model, noting that facilitating access to specialized multidisciplinary care, resolution of financial barriers, and close administrative coordination all greatly contributed to the success of the program.

e21020 Background: Osteosarcoma and Ewing sarcoma are the most common malignant bone tumors in pediatrics. Average 5-year survival rates of 60-70% are achieved with current multimodality therapy. Local control modalities aiming at preserving function greatly influence quality of life of long term survivors. In developing countries, the limited availability of multidisciplinary care, expertise in specialized surgeries, and in pediatric radiation therapy, forms barriers to achieving optimal outcomes. Methods: We established a multi-institutional Collaborative Pediatric Bone Tumor Program, where children newly diagnosed with bone tumors have access to specialized local control at a tertiary Children’s Cancer Center. Central review of pathology, staging and treatment planning was performed in a multidisciplinary tumor board setting. Patients received chemotherapy locally on a unified treatment plan; local control was done at the Children’s Cancer Center at no cost to families through a program development initiative led by St Jude Children’s Research Hospital (SJCRH). Challenging cases were discussed with SJCRH team via teleconference. Results: Over 2.5 years, 30 patients were enrolled. Nationalities were Lebanese (15), Iraqi (8), and Syrian (7). Seventeen patients (57%) had Ewing sarcoma, 13 (43%) had osteosarcoma. Nineteen (63%) had localized disease. Protocol adherence was > 90%. Local control included 3 expandable and 6 standard prostheses, 3 fibular allografts, 7 simple resections and 3 amputations. Eleven patients received radiation therapy, and in 5 it was the sole mode of local control. At a median follow up of 16 months (range 5-29), 20 patients (67%) are in CR, 7 (23%) had disease progression or relapse, 2 (7%) were lost to follow-up in CR, and 1 (3%) died of toxicity. Conclusions: A collaborative bone tumor program in Lebanon resulted in timely local control and protocol adherence at 8 collaborating centers. Overall survival and functional outcome were comparable to those of international published series. Facilitating access to specialized multidisciplinary care, resolution of financial barriers, and close coordination, all contributed to the success of the program.