Intraoperative Electron Beam Radiotherapy Research Articles

Post-operative complications following dose adaptation of intra-operative electron beam radiation therapy in locally advanced or recurrent rectal cancer

Post-operative complications following dose adaptation of intra-operative electron beam radiation therapy in locally advanced or recurrent rectal cancer

199 Implementation and Early Experience of Breast Intraoperative Electron Beam Radiation Therapy

199 Implementation and Early Experience of Breast Intraoperative Electron Beam Radiation Therapy

Postoperative cosmetic outcome of intraoperative radiotherapy in comparison to whole breast radiotherapy in early stage breast cancer; a retrospective cohort study

BackgroundIn this study, we aim to evaluate the cosmetic outcome differences between Intraoperative electron beam radiation therapy (IOERT) and whole breast radiotherapy (WBR) with further investigation of boosted IOERT.MethodsThis retrospective cohort study was conducted in two referral centers in Tehran, Iran. 116 women aged 30 to 79 with early-stage breast cancer (T0-2N0-1M0) eligible for breast conservation were divided into two groups of 58 based on the intervention they received, and further subgroups were defined based on receiving boosted IOERT. Patients in both groups underwent breast conservation surgery and those in the IOERT group received either a 21 Gy radical dose (radical IOERT) or 12 Gy boosted electron beam radiotherapy and a routine fractionated dose of 50 Gy in 25 sessions of WBR (boosted IOERT). Those in the WBR group were administered 50Gy in 32 sessions. Physician-assessed cosmetic outcome was defined as the primary result and incidence of fat necrosis and fibrosis and post-operative chronic pain were secondary outcomes.ResultsPost-operative cosmetic outcome scores and chronic pain, showed no significant difference between the two groups. The median cosmetic score in both groups was 9. Fat necrosis and fibrosis had significantly higher rates in the IOERT group (P. Value: 0.001). However, the majority (21/34 or 61.8%) of this complication was observed in the boosted IOERT subgroup and no statistical significance was recorded between the radical IOERT subgroup and the WBR group.ConclusionsIn early-stage breast cancer treatment, radical IOERT has noninferiority compared to WBR in terms of cosmesis. Regarding fat necrosis and fibrosis, boosted IOERT was associated with higher rates in comparison to other groups. Therefore, radical IOERT seems to be a better treatment option for selected patients.

Successful Adjuvant Intraoperative Electron Beam Radiotherapy for Keloid: First Case Report and Review of Literature

Treatment of keloids is usually challenging, requiring a multimodal approach with no universally accepted treatment modality among the wide range of alternative keloid treatments. Excision of keloid lesion usually eliminates symptoms and it is the main treatment with considerable recurrence rate. Recurrence rate ranges from 45-100% when surgical excision is performed as monotherapy. Furthermore, Recurrent Keloids have a higher recurrence rate after surgery. In this case we discuss a challenging case of young female presented with third recurrence in lobule of the ear with defect necessitated flap reconstruction with concern for possible damage by the flap if radiation was given as external beam postoperatively. Intraoperative electron beam therapy was utilized with high safety and efficacy. To our knowledge this is the first case in the Middle East to use this technique in treating Keloid. Conclusion Treatment of keloids is usually challenging, requiring a multimodal approach. Excision of keloid lesion usually eliminates symptoms and it is the main treatment with considerable recurrence rate .Recurrence rate ranges from 45-100% when surgical excision is performed as monotherapy. Furthermore, Recurrent Keloids have a higher recurrence rate after surgery. Radiation is a valid option for decreasing risk of recurrence in recurrent keloid with high safety and efficacy profile. In this case we discuss a challenging case of young female presented with third recurrence in lobule of the ear with defect necessitated flap reconstruction with concern for possible damage by the flap if radiation was given as external beam postoperatively. Intraoperative electron beam therapy was utilized with high safety and efficacy. To our knowledge this is the first case in the Middle East to use this technique in treating Keloid. Keywords: Keloid; Radiation; Intraoperative Radiation; IOeRT

Intraoperative electron beam radiotherapy and perioperative high-dose-rate brachytherapy in previously irradiated oligorecurrent gynecological cancer: clinical outcome analysis.

Pelvic recurrences from previously irradiated gynecological cancer lack solid evidence for recommendation on salvage. A total of 58 patients were included in this clinical analysis. Salvage surgery was performed for locoregional relapse within previously irradiated pelvic area after initial surgery and adjuvant radiotherapy or radical external beam radiotherapy.The primary tumor diagnosis included cervical cancer (n = 47, 81%),uterine cancer (n = 4, 7%), and other types (n = 7, 12%). Thirty-threepatients received adjuvant IOERT(1984-2000)at a median dose of 15Gy(range 10-20Gy) and 25 patients received adjuvant PHDRB(2001-2016)at a mediandose of 32Gy (range 24-40Gy) in 6, 8, or 10b.i.d.fractions. The median follow-up was 5.6years (range 0.5-14.2years). Twenty-nine (50.0%) patients had positive surgical margins. Grade ≥ 3 toxic events were recorded in 34 (58.6%) patients. The local control rate at 2years was 51% and remained stable up to 14years. Disease-free survival rates at 2, 5, and 10years were 17.2, 15.5, and 15.5%, respectively. Overall survival rates at 2, 5, and 10years were 58.1, 17.8, and 17.8%, respectively. IOERT and PHDRB account for an effective salvage inoligorecurrent gynecological tumors. Patients with previous pelvic radiation suitable for salvage surgery and at risk of inadequate margins could benefit from adjuvant reirradiation in form of IOERT or PHDRB. However, the rate of severe grade ≥ 3 toxicity associated with the entire treatment program is relevant and needs to be closely counterbalanced against the expected therapeutic gain.

Electron beam intraoperative radiotherapy for metastatic epidural spinal cord compression: a prospective observational study.

To assess the additional effects of intraoperative radiotherapy (IORT) with decompression surgery and adjuvant external beam radiotherapy (EBRT) for metastatic epidural spinal cord compression (MESCC).This single-arm institutional prospective observational study recruited patients between June 2017 and March 2020 and included those with symptoms of spinal cord compression owing to metastases, who were diagnosed using MRI. Patients with radiation-sensitive primary tumors and those who could not tolerate surgery were excluded. The treatment protocol comprised decompression surgery and electron beam IORT of 20 Gy in a single fraction followed by EBRT of 30 Gy in 10 fractions. The primary endpoints included the 1-year local failure rate and ambulatory functions.The study was closed in May 2019 owing to changes in treatment policies at our institution. Twenty patients were registered between June 2017 and May 2019. Although all patients completed surgery and IORT, 2 did not receive postoperative EBRT. Patients most commonly had colorectal cancer (4 patients), followed by thyroid cancer, renal cell carcinoma, lung cancer, breast cancer, sarcomas, and other cancers (3, 3, 2, 2, 2, and 4 patients, respectively). The median follow-up duration was 16 months (range 2-30 months); the 1-year local failure rate was 16%. On comparing ambulatory functions pre-treatment and at 1 year after treatment, improvement, no change, and worsening were observed in 3, 9, and 0 patients, respectively.This study's findings suggest that decompression surgery and IORT followed by EBRT are effective in achieving local control and maintaining ambulation in patients with MESCC.

Ultrasound-guided intraoperative electron beam radiation therapy: A phantom study.

To develop the method for ultrasound (US)-guided intra-operative electron beam radiation therapy (IOERT). We first established the simulation, planning, and delivery methods for US-guided IOERT and constructed appropriate hardware (the multi-function applicator, accessories, and US phantom). We tested our US-guided IOERT method using this hardware and the Monte Carlo simulation IOERT treatment planning system (TPS). The IOERT TPS used a compensator to build the conformal dose distribution. Then, we used the TPS to evaluate the effect of setup uncertainty on target coverage by introducing phantom setup error ranging from 0mm to 10mm to the plans with and without the compensator. The simulation, planning, and delivery methods for US-guided IOERT were introduced and validated on a phantom. A complete technique for US-guided IOERT was established. Target coverage decreased by about 12% and 29% as the phantom setup error increased to 5mm and 10mm for the plans with compensator, respectively. Without compensator, the corresponding target coverage decreases were 2% and 13%, respectively. In our study, we developed the multi-function applicator, US Phantom, and TPS for IOERT. The procedures included not only dose distribution planning, but also intraoperative US imaging, which provided the information necessary during surgery to improve IOERT quality assurance. Target coverage was more sensitive to setup errors with compensator compared to no compensator. Further studies are needed to validate the clinical efficacy of this US-guided IOERT method.

Low-kilovolt x-ray intraoperative radiotherapy for pT3 locally advanced colon cancer: a single-institution retrospective analysis

BackgroundPatients with locally advanced colon cancer (LACC) treated with surgery had a high risk of local recurrence. The outcomes can vary significantly among patients with pT3 disease. This study was undertaken to assess whether low-kilovolt (kV) x-ray intraoperative radiotherapy (IORT) can achieve promising results compared with electron beam IORT (IOERT) and whether specific subgroups of patients with pT3 colon cancer may benefit from low-kV x-ray IORT.MethodsWe retrospectively reviewed 44 patients with pT3 LACC treated with low-kV x-ray IORT. Clinicopathologic characteristics were analyzed to identify patients that could potentially benefit from low-kV x-ray IORT. The Kaplan-Meier survival analysis was used to assess overall survival (OS) and progression-free survival (PFS). Correlation analysis was used to discover the association of multiple factors to the results of treatment represented by the values of OS and PFS.ResultsThe median follow-up of patients was 20.5 months (range, 6.1–38.8 months). At the time of analysis, 38 (86%) were alive and 6 (14%) had died of their disease. The 3-year Kaplan-Meier of PFS and OS for the entire cohort was 82.8% and 82.1%, respectively. At median follow-up, no in-field failure within the low-kV x-ray IORT field had occurred. Locoregional and distant failure had occurred in 2 (5%) patients each. The rate of perioperative 30-day mortality was 0%, and the morbidity rate was 11%. Five patients experienced 7 complications, including 4 early complications (30 days) and three late complications (> 30 days) leading early and late morbidity rates of 9% and 7%, respectively.ConclusionPatients with LACC who had undergone an additional low-kV x-ray IORT can achieve encouraging locoregional control, PFS, OS, and distant control without an increase in short-term or long-term complications. Low-kV x-ray IORT can be considered as part of management in pT3 LACC.

Intraoperative electron beam radiotherapy for locoregionally persistent or recurrent head and neck cancer.

To report our institutional experience with intraoperative radiotherapy for persistent or recurrent head and neck cancer. Sixty-one patients were treated with salvage surgery and intraoperative radiation therapy (IORT). Fifty-eight patients (95%) had previously received external beam radiotherapy (EBRT) as a component of their definitive therapy. Forty-four patients (72%) had squamous cell carcinoma (SCC). Surgical margins were positive in 28 patients (46%). IORT was prescribed to a median dose of 12.5 Gy (range, 10-17.5). Twenty-three patients (38%) received a course of postoperative EBRT (median 45 Gy). Clinical outcomes were retrospectively reviewed and univariate analysis was performed using log-rank tests to correlate clinical outcomes with histology, surgical margin, and adjuvant therapy. Median follow-up among surviving patients was 15.9 months. Median progression-free survival (PFS) and overall survival (OS) were 9.8 and 19.1 months, respectively. One- and 2-year rates of locoregional control (LRC) were 59% and 35%, respectively. One- and 2-year rates of PFS were 39% and 19%, respectively. One- and 2-year rates of OS were 62% and 42%, respectively. Overall survival was better for non-SCC histology (P = .03). For SCC patients, negative surgical margin showed a trend toward improved PFS (P = .09) and OS (P = .06). There was one grade-5 toxicity due to carotid rupture. IORT has shown effective LRC and OS with an acceptably low rate of severe toxicity at our institution. OS was significantly better for non-SCC histology. For SCC patients, there is a trend toward improved PFS and OS associated with negative surgical margins.

Abstract OT2-04-04: Multi-institution phase II trial of intraoperative electron beam radiotherapy boost at the time of breast conserving surgery with oncoplastic reconstruction in women with early-stage breast cancer

Abstract Background: In women amenable to breast conserving therapy, lumpectomy followed by adjuvant whole breast irradiation (WBI) remains the standard of care. Randomized trials demonstrate that addition of a lumpectomy cavity boost significantly reduces the risk of ipsilateral breast tumor recurrences but also increases the risk of breast fibrosis. Contemporary randomized trials define the lumpectomy cavity boost volume as a 1.7 cm isometric expansion on the lumpectomy cavity as delineated on CT. However, identifying the lumpectomy cavity can be challenging, especially in women that receive adjuvant chemotherapy and in cases in which surgical clips are not present. Recently, the use of oncoplastic techniques in breast conserving surgery has increased. These techniques are used to prevent the poor cosmetic results that can occur when a large volume of breast tissue is resected. Women that undergo oncoplastic reconstruction represent especially difficult cases for lumpectomy cavity delineation. Retrospective series have evaluated the use of intraoperative electron radiotherapy (IOERT) as a boost prior to WBI in women receiving lumpectomy without oncoplastic reconstruction. In the largest series of IOERT boost prior to WBI the local control rate of this approach was >99%. Prospective data regarding IOERT boost in women undergoing oncoplastic reconstruction are limited. The advantages of this approach include direct visualization/irradiation of the tumor bed, sparing the skin of irradiation, and reducing the treatment time by ˜1 week. We hypothesize that IOERT boost followed by WBI will result in acceptably low rates of grade 3 fibrosis in women undergoing lumpectomy with oncoplastic reconstruction. Trial Design: This is a single-arm, prospective study to evaluate the safety, toxicity and efficacy of IOERT boost at the time of breast conserving surgery in women with early-stage breast cancer undergoing oncoplastic reconstruction. Eligible women will receive 1 dose of 8 Gy to the surgical bed after lumpectomy but prior to oncoplastic reconstruction. Women will then receive adjuvant WBI of 40 Gy in 15 fractions or 50 Gy in 25 fractions. Eligibility: Key criteria include age≥18 yo, clinically node-negative stage I/II, any breast cancer subtype. Specific Aims: To determine the rate of grade 3 breast fibrosis at 1 year. Additional aims include surgical complication rates, cosmesis, and local regional cancer control. Statistical Methods: Safety will be evaluated by the rate of surgical complications necessitating hospital readmission or return to the operating room within 30 days of surgery+IOERT. If ≥4 events in the first 10 patients, ≥7 events in the first 20 patients, or ≥9 events in the first 30 patients are seen, the study will be halted. We hypothesize that the grade 3 fibrosis rate in our study will be ≤5%. Assuming an actual rate of 4%, an unacceptable rate of 9%, and a drop-out rate of 10%, the expected sample size is 176. Sites: Ohio State University, Avera Medical Group, University of North Carolina-Chapel Hill Patient Accrual: Current accrual is 5/176. Contact Information: Jose Bazan (jose.bazan2@osumc.edu) Funding Source: Intraop Medical Citation Format: Bazan JG, Stephens J, Agnese D, Skoracki R, Arneson K, Reiland J, Gupta G, Gallagher K, McElroy S, Gupta N, White JR. Multi-institution phase II trial of intraoperative electron beam radiotherapy boost at the time of breast conserving surgery with oncoplastic reconstruction in women with early-stage breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-04-04.

Evaluating the performance characteristics of some ion chamber dosimeters in high dose per pulse intraoperative electron beam radiation therapy

IntroductionEmploying routine dosimetry protocols for intraoperative electron beam needs further refinements to obtain reliable results. In this regard, the performance of some cylindrical and parallel plate ion chambers for both relative and absolute dosimetry of intraoperative electron beam has been evaluated. Materials and methodsFour different ion chambers including Semiflex and PinPoint cylindrical chambers as well as Advanced Markus and Roos parallel plate ones were employed for PDD measurement and dose rate determination in reference condition of the electron beam produced by LIAC intraoperative accelerator. The results of PDD measurements were compared with those of Gafchromic EBT2 film. Specific recommendations were followed to determine the chamber correction factors including ks and kQ,Q0 for absolute dosimetry in intraoperative reference condition. ResultsThere was good agreement between PDDs measured by employed chambers and EBT2 film at all nominal energies. Nevertheless, Advanced Markus chamber had the best performance based on the gamma analysis results. Obtained kQ,Q0 and ks for studied ion chambers largely differed from expected values by TRS-398 protocol. The difference of measured dose rates at 12 MeV energy by investigated chambers was less than 1.1% and Advanced Markus had the best accordance with pre-set dose rate by manufacture. ConclusionResults showed that ignoring the specific recommended procedures in determining the chamber correction factors causes the overestimation of the measured dose. Therefore, dedicated dosimetry protocol should be developed for high dose per pulse intraoperative electron dosimetry including all of the updated correction factors and deviations from routine ionometric electron dosimetry formalisms.

Evaluation of organs at risk dose in the left breast IOERT procedures whit and without shielding disc using monte carlo simulation

Introduction: One of the treatment choices in breast cancer is Intra operative electron beam radiation therapy (IOERT). Due to high dose delivery in this procedure, shielding disk is used to protect organs at risk (OARs). In this study, we evaluate the OARs dose in the breast IOERT using Monte Carlo simulation with and without shielding disk in RANDO phantom. Material and Methods: Simulation of dedicated IOERT linear accelerator (LIAC) head with 5cm diameter applicator was performed using BEAMnrc Monte Carlo simulation cod. Three phase-space files for each nominal electron beam energies (6,8,10,12 MeV) produced in the end of the applicator, after 2 cm tissue in the end of applicator. The last phase-space was created after disk. These phase- space were used in DOSXYZnrc for irradiation of RANDO phantom. Both lungs and heart were considered as OARs in the IOERT of the left breast irradiation. For each energy, the 3ddose files, as an output of DOSXYZnrc and contoured organs in the RANDO phantom imported to CERR software. 12Gy was considered as a normalized value in the target. Then dose-volume- histogram (DVH) data were extracted for analysis. Results: The mean and maximum dose for each OAR in all energies with and without disk and with consideration of 2 cm tissue as a target were extracted from DVH data. For all nominal energies, the right lung dose was zero. The maximum and mean dose range in the left lung without disk were 11.5-13.9 and 0.15-0.5 Gy, respectively. These values for heart were 0-2.9 and 0-0.16Gy. The mean dose of heart and the left lung were un-remarkable with applying 2cm tissue and disk. Conclusion: With the increase of the electron beam energy in the IOERT, an increase of OARs dose was seen with and without shielding disk application. On the other hand, application of shielding disk in breast IOERT reduces OARs dose significantly

Research progress in intraoperative radiotherapy for tumor

Intraoperative radiotherapy (IORT) is a radiotherapy method that uses a radiotherapy device to provide a brachytherapy with single high-dose radiation to a target tissue (primary tumor beds, residual tumors, and lymphatic drainage areas) during surgery, which includes intraoperative electron beam radiotherapy and high-dose-rate intraluminal brachytherapy. Nowadays, the implementation of precise radiation dose is an important part of multidisciplinary, individualized treatment of tumors. IORT achieves precise treatment by maximizing the radiation dose to the target volume and protecting surrounding normal tissues as much as possible. This article describes the recent research on IORT. Key words: Neoplasms/intraoperative radiotherapy; Theoretical basis; Clinical practice

Abstract OT2-03-01: Multi-institution phase II trial of intraoperative electron beam radiotherapy boost at the time of breast conserving surgery with oncoplastic reconstruction in women with early-Stage breast cancer

Abstract Background: In women amenable to breast conserving therapy, lumpectomy followed by adjuvant whole breast irradiation (WBI) remains the standard of care. Randomized trials have demonstrated that the addition of a lumpectomy cavity boost significantly reduces the risk of ipsilateral breast tumor recurrences but also increases the risk of breast fibrosis. Contemporary randomized trials define the lumpectomy cavity boost volume as a 1.7 cm isometric expansion on the lumpectomy cavity as delineated on CT. However, identifying the lumpectomy cavity can be challenging, especially in women that receive adjuvant chemotherapy and in cases in which surgical clips are not present. Recently, the use of oncoplastic techniques in breast conserving surgery has increased. These techniques are used to prevent the poor cosmetic results that can occur when a large volume of breast tissue is resected. Women that undergo oncoplastic reconstruction represent especially difficult cases for lumpectomy cavity delineation. Retrospective series have evaluated the use of intraoperative electron radiotherapy (IOERT) as a boost prior to WBI in women receiving lumpectomy without oncoplastic reconstruction. In the largest series of IOERT boost prior to WBI the local control rate of this approach was >99%. Prospective data regarding IOERT boost in women undergoing oncoplastic reconstruction are limited. Advantages of this approach include direct visualization/irradiation of the tumor bed, sparing the skin of irradiation, and reducing the treatment time by ˜1 week. We hypothesize that IOERT boost followed by WBI will result in acceptably low rates of grade 3 fibrosis in women undergoing lumpectomy with oncoplastic reconstruction. Trial Design: This is a single-arm, prospective study to evaluate the safety, toxicity and efficacy of IOERT boost at the time of breast conserving surgery in women with early-stage breast cancer undergoing oncoplastic reconstruction. Eligible women will receive 1 dose of 8 Gy to the surgical bed after lumpectomy but prior to oncoplastic reconstruction. Women will then receive adjuvant WBI of 40 Gy in 15 fractions or 50 Gy in 25 fractions. Eligibility: Key inclusion criteria include age≥18 yo, clinically node-negative stage I/II, any breast cancer subtype. Specific Aims: Our primary aim is to determine the rate of grade 3 breast fibrosis at 1 year. Additional aims include surgical complication rates, cosmesis, and local regional cancer control. Statistical Methods: Safety will be evaluated by the rate of surgical complications necessitating hospital readmission or return to the operating room within 30 days of surgery+IOERT. If ≥4 events in the first 10 patients, ≥7 events in the first 20 patients, or ≥9 events in the first 30 patients are seen, the study will be halted. We hypothesize that the grade 3 fibrosis rate in our study will be ≤5%. Assuming an actual rate of 4%, an unacceptable rate of 9%, and a drop-out rate of 10%, the expected sample size is 176. Patient Accrual: Current accrual is 0 of 176. Contact Information: Soyhum McElroy (soyhun.mcelroy@osumc.edu) or Jose Bazan (jose.bazan2@osumc.edu) Funding Source: Intraop Medical Citation Format: Bazan JG, Stephens J, Terando A, Skoracki R, McElroy S, Sexton J, Gupta N, White J. Multi-institution phase II trial of intraoperative electron beam radiotherapy boost at the time of breast conserving surgery with oncoplastic reconstruction in women with early-Stage breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-03-01.

Electron Beam Intraoperative Radiotherapy (ELIOT) in Pregnant Women with Breast Cancer: From in Vivo Dosimetry to Clinical Practice

Background: The aim of this study was to confirm our preliminary results with in vivo dosimetry in non-pregnant breast cancer patients receiving electron beam intraoperative radiotherapy (ELIOT) and to report on the first treatment in a pregnant woman. Patients and Methods: Following our previous experience, 5 non-pregnant patients receiving ELIOT to the tumor bed after breast-conserving surgery (BCS) were studied with thermoluminescent dosimeters positioned in the subdiaphragmatic region, within the uterus, and in the ovarian region. In December 2011, the first pregnant breast cancer patient underwent BCS and ELIOT (21 Gy at 90% isodose) during the 15th week of gestation. Results: The mean dose to the subdiaphragmatic external region in the 5 non-pregnant patients was 5.57 mGy, while pelvic measurements were below 1 mGy. The actual dosimetry of the pregnant patient showed a mean subdiaphragmatic dose of 4.34 mGy, a mean suprapubic dose of 1.64 mGy, and mean ovarian doses of 1.48 mGy (right-sided) and 1.44 mGy (left-sided). The expected dose to the fetus was estimated as 0.84 mGy (0.004% of the prescribed dose). Conclusion: ELIOT as an anticipated boost to the breast could be considered in pregnant women in the early second trimester, postponing whole-breast irradiation after delivery.

FMECA Application to Intraoperative Electron Beam Radiotherapy Procedure As a Quality Method to Prevent and Reduce Patient's Risk in Conservative Surgery for Breast Cancer.

Failure Mode Effects and Criticalities Analysis (FMECA) represents a prospective method for risk assessment in complex medical practices. Our objective was to describe the application of FMECA approach to intraoperative electron beam radiotherapy (IOERT), delivered using a mobile linear accelerator, for the treatment of early breast cancer as an anticipated boost. A multidisciplinary Working Group, including several different professional profiles, was created before the beginning of clinical practice in 2012, with the purpose of writing the Flow Chart and applying the FMECA methodology to IOERT procedure. Several criticalities were identified a priori in the different steps of the procedure and a list of all potential failure modes (FMs) was drafted and ranked using the risk priority number (RPN) scoring system, based on the product of three parameters: severity, occurrence, and detectability (score between 1 and 5). The actions aimed at reducing the risk were then defined by the Working Group and the risk analysis was repeated in 2014 and in 2016, in order to assess the improvement achieved. Fifty-one FMs were identified, which represented the issues prospectively investigated according to the FMECA methodology. Considering a set threshold of 30, the evaluated RPNs show that 33 out of 51 FMs are critical; 6 are included in the moderate risk class (RPN: 31-40); 16 in the intermediate risk class (RPN: 41-50), and 11 in the high risk class (RPN: >50). The most critical steps concerned the surgical procedure and IOERT set-up. The introduction of the corrective actions into the clinical practice achieved the reduction of the RPNs in the re-analysis of the FMECA worksheet after 2 and 4 years, respectively. FMECA proved to be a useful tool for prospective evaluation of potential failures in IOERT and contributed to optimize patient safety and to improve risk management culture among all the professionals of the Working Group.

Intraoperative radiotherapy for extremity soft-tissue sarcomas: can long-term local control be achieved?

Intraoperative electron-beam radiation therapy (IOERT) during limb-sparing surgery has the advantage of delivering a single high boost dose to sarcoma residues and surgical bed area near to radiosensitive structures with limited toxicity. Retrospective studies have suggested that IOERT may improve local control compared to standard radiotherapy and we aimed to demonstrate this theory. Therefore, we performed an observational prospective study to determine (1) if it is possible to achieve high local control by adding IOERT to external-beam radiation therapy (EBRT) in extremity soft-tissue sarcomas (STS), (2) if it is possible to improve long-term survival rates, and (3) if toxicity could be reduced with IOERT MATERIALS AND METHODS: From 1995-2003, 39 patients with extremity STS were treated with IOERT and postoperative radiotherapy. The median follow-up time was 13.2years (0.7-19). Complications, locoregional control and survival rates were collected. Actuarial local control was attained in 32 of 39 patients (82%). Control was achieved in 88% of patients with primary disease and in 50% of those with recurrent tumors (p=0.01). Local control was shown in 93% of patients with negative margins and in 50% of those with positive margins (p=0.002). Limb-sparing was achieved in 32 patients (82%). The overall survival rate was 64%. 13% of patients had grade ≥3 acute toxicity, and 12% developed grade ≥3 chronic toxicity. IOERT used as a boost to EBRT provides high local control and limb-sparing rates in patients with STS of the extremities, with less toxicity than EBRT alone.

Intraoperative High Dose Rate Brachytherapy Can Be Used to Salvage Patients with Previously lrradiated Head and Neck Recurrences

Purpose: To develop a novel technique, intraoperative high-dose rate brachytherapy (IOHDR), in the treatment of previously irradiated head and neck cancers located at anatomical sites inaccessible to intraoperative electron beam radiotherapy (IOERT). 
 
 Methods: Between October 1992 and June 1997, seven patients (median age=65 years; range=52 to 71 years) with previously irradiated head and neck recurrences at anatomical sites inaccessible to IOERT in the base of skull were treated with IOHDR after maximal resection for microscopic residual disease. Treatment volume ranged from 6 cc to 24 cc. Six patients received 15 By of IOHDR at 0.5 cm; one received 10 By using custom-made surface foam applicators. 
 
 Results: The median follow-up was 59 months (range 33 to 67 months). It was technically feasible to deliver IOHDR in all seven patients at sites that were inaccessible to IOERT. The morbidity (observed in two patients) was acceptable and generally surgically related. Four of seven patients (57%) were locally controlled at IOHDR site. Two failed regionally, outside the IOHDR treated sites. The disease-free survival ranged from 3 to 30 months (median 9 months) with two patients still alive, disease-free at 28 and 30 months. 
 
 Conclusions: IOHDR can be used, with limited toxicity, to treat previously irradiated head and neck cancers at sites inaccessible to IOERT. We are currently evaluating the addition of limited EBRT dose to improve the local control of these poor prognosis recurrent tumors.

EP-1038: Intraoperative electron beam radiotherapy for locoregionally recurrent head and neck cancer

EP-1038: Intraoperative electron beam radiotherapy for locoregionally recurrent head and neck cancer

Clinical effect of intraoperative electron beam radiotherapy in treatment of unresectable locally advanced pancreatic cancer

Objective To assess the prognostic benefits of intraoperative radiotherapy (IORT) with electron beam among patients with unresectable locally advanced pancreatic cancer. Methods Between January 2009 and December 2014, 167 patients with unresectable locally advanced pancreatic cancer received IORT with electron beam (10-20 Gy) in our hospital. After surgery, 12 patients were treated with external beam radiotherapy, 56 patients with chemoradiotherapy (CRT), and 17 patients with chemotherapy. Overall survival (OS), local recurrence, and toxicities were retrospectively analyzed. The Kaplan-Meier method was used to calculate survival rates, the log-rank test was used for survival difference analysis and univariate prognostic analysis, and the Cox model was used for multivariate prognostic analysis. Results The follow-up rate was 100%. The median OS time was 10.3 months, and the 2-year OS rate was 22%. The median progression-free survival (PFS) time was 6.3 months, and the 2-year PFS rate was 9.9%. The cancer-specific survival (CSS) time was 11.2 months, and the 2-year CSS rate was 23.6%. In the patients treated with IORT alone at doses of 15 Gy, the median OS times were 6.2 months vs. 9.1 months vs. 22.2 months, and the 1-year OS rates were 10.0% vs. 39.6% vs. 74.4%(P=0.000). Among the patients receiving postoperative adjuvant therapy, those treated with IORT+ CRT had the best survival, with a median OS time of 11.6 months (P=0.033). The univariate analysis showed that IORT dose (P=0.000), tumor size (P=0.006), and IORT applicator diameter (P=0.007) were prognostic factors. The multivariate analysis showed that IORT dose (P=0.000) and IORT combined with CRT (P=0.006) were independent prognostic factors. Conclusions IORT with electron beam is an effective and safe treatment strategy for unresectable locally advanced pancreatic cancer. After protecting surrounding organs, increasing the IORT dose can improve the survival. IORT combined with CRT should be recommended because it improves survival for unresectable locally advanced pancreatic cancer without increasing toxicities. Key words: Pancreatic neoplasms/intraoperative radiotherapy; Intraoperative radiotherapy, electron beam; Pancreatic neoplasms/postoperative radiochemotherapy; Prognosis