Intraoperative Radiation Therapy In Treatment Research Articles

Organ absorbed doses in the IORT treatment of breast cancer with the INTRABEAM device: a Monte-Carlo study

Purpose: The current prescription and the assessment of the delivered absorbed dose in intraoperative radiation therapy (IORT) with the INTRABEAM system rely mainly on depth-dose measurements in water. The accuracy of this approach is limited because tissue heterogeneity is ignored. It is also difficult to accurately determine the dose delivered to the patient experimentally as the steep dose gradient is highly sensitive to geometric errors. Our goal is to determine the dose to the target volume and the organs at risk of a clinical breast cancer patient from treatment with the system. Methods: A homogeneous water-equivalent CT dataset was derived from the preoperative CT scan of a patient by setting all materials in the patient volume as water-equivalent. This homogeneous CT data represents the current assumption of a homogenous patient, while the original CT data is considered the ground truth. An in-house Monte Carlo algorithm was used to simulate the delivered dose in both setups for a prescribed treatment dose of 20 Gy to the surface of the 3.5 cm diameter spherical applicator. Results: The doses received by 2% (D2%) of the target volume for the homogeneous and heterogeneous geometries are 16.26 Gy and 9.33 Gy, respectively. The D2% for the heart are 0.035 Gy and 0.119 Gy for the homogeneous and heterogeneous geometries, respectively. This trend is also observed for the other organs at risk. Conclusions: The assumption of a homogeneous patient overestimates the dose to the target volume and underestimates the doses to the organs at risk.

The Use of Intraoperative Radiation Therapy (IORT) in Multimodality Management of Cancer Patients: a Single Institution Experience.

Intraoperative radiation therapy (IORT) is a highly conformal type of radiation therapy given at time of surgery aiming for better tumor local control. It increases the tumor radiation dose without exceeding normal tissues tolerance doses. To assess the feasibility of IORT and short-term toxicities in patients with different cancer sites treated with multidisciplinary protocol including IORT. Medical records of cancer patients who received IORT as a part of their multidisciplinary treatment at King Faisal Specialized Hospital and Research center (KFSH&RC), Riyadh, Saudi Arabia, from January 2013 until December 2017 were retrospectively reviewed. A total of 188 patients with 210 IORT applications were analyzed. Twenty-two patients had two applications at the same time. One hundred sixteen patients were males. Median age at time of diagnosis was 49.5years (19-77). One hundred thirty-four patients had primary, while 54 cases had recurrent disease. Gastroesophageal cancer and soft tissue sarcoma were the most frequent diagnosis in 49 patients followed by colorectal cancer in 35 patients. Major surgeries with curative intent done in 183 patients (97.3%). Hyperthermic intraperitoneal chemotherapy (HIPEC) was performed in 118 (62.8%) patients. The 30-day postoperative mortality rate was 3.2%. Fifty-four (28.7%) patients develop grades III-IV complications according to Clavien-Dindo grading system. The data presented discusses using of IORT treatment for different malignant tumors as a part of multimodality treatment. IORT seems safe and feasible; however, a longer follow-up period is needed for proper evaluation and to define the role of IORT in a tailored multimodality approach.

Abstract P3-19-12: Impact of endocrine therapy (ET) noncompliance following intra-operative radiation therapy (IORT) in treatment of early-stage breast cancer patients (pts) enrolled in the ExBRT trial

Abstract Purpose: To investigate the association between ET noncompliance and ipsilateral breast tumor recurrence (IBTR) in the ExBRT trial (“A Safety and Efficacy Study of Intra-Operative Radiation Therapy [IORT] Using the Xoft® Axxent® Electronic Brachytherapy [eBx®] System at the Time of Breast Conservation Surgery for Early-Stage Breast Cancer”). Methods: The IRB-approved single arm prospective nonrandomized multi-institutional ExBRT trial was designed to determine the efficacy and outcome of a single 20 Gy fraction of IORT delivered at the time of lumpectomy for early-stage breast cancer. The trial included women age ≥ 40 years with invasive ductal carcinoma (IDC) or ductal carcinoma in situ (DCIS) of all molecular subtypes documented by pre-operative biopsy which were ≤ 30 mm by clinical and radiographic evaluation. Tumors with pre-operative lymphovascular invasion and intra-operative positive lymph nodes and/or margins were excluded. ET was defined as treatment with tamoxifen, anastrozole, letrozole, and/or exemestane. Pts were classified as “Compliant with ET” if they completed a 60-month ET course or were compliant with ongoing ET. Pts were defined as “Discontinued ET” if they stopped ET prior to completing a 60-month ET course. Pts were classified as “Declined ET” if they did not initiate recommended ET. Data, collected at enrollment and at 1, 6, 12, 18 and 24 months, then yearly, included demographics, histopathology, estrogen receptor positivity (ER+), progesterone receptor positivity (PR+), adjuvant therapy, IBTR, and survival. The primary endpoint was IBTR. Preliminary results evaluating the impact of ET noncompliance on pts who successfully completed treatment with a single 20 Gy fraction of IORT per protocol are presented. Results: Between May 2012 - July 2018, 1105 pts (mean age 64 years) with pre-operative biopsy-proven IDC or DCIS successfully completed a single fraction of IORT treatment per protocol. Mean follow-up was 4.0 years (range 2-8 years). One-hundred fifteen (10%) pts, who were either ER negative or had an unknown ER status, are not included in this analysis. Pt cohorts and tumor characteristics are presented in Table 1. There were 39 (3.93%) IBTR in the ER+ subset at mean follow-up of 4 years. IBTR in the “Compliant with ET” group was 2.53%. Although the percentages were greater in the “Discontinued ET” (5.68%) and “Declined ET” (7.10%) cohorts, this did not reach statistical significance (Chi square test, p-value = 0.147). Conclusion: IORT allows pts to conveniently receive both their surgery and electronic brachytherapy radiation treatment in one setting. Early-stage ER+ breast cancer pts compliant with a subsequent course of ET in this study experienced a lower IBTR rate, improving the collective outcome of their multidisciplinary treatment. These preliminary ExBRT trial results demonstrate that IBTR rates are improved with ET compliance. Although this has not reached statistical significance in this trial, it may partially explain the slight differences in IBTR rates noted in comparison with similar electronic brachytherapy early-stage breast cancer studies. Table 1.IORT pt cohorts and tumor characteristicsCompliant with ETDiscontinued ETDeclined ETNNNER +631176183PR +597170162Mean age (years)65.766.366.7Postmenopausal580162161Mean tumor size (mm)11.110.712.7Tumor HistologyIDC524136120grade I2116055grade II2535955grade III54159Unknown grade621DCIS933756Low grade2099Intermediate grade421925High grade30922Unknown grade100Infiltrating lobular ca505Other932Chemotherapy given4286Ethnicity/RaceCaucasian498143151African American351013Hispanic46188Asian/Pacific Islander2812Native American211Other2238Recurrences16 (2.53%)10 (5.68%)13 (7.10%) Citation Format: Barbara Schwartzberg, AMNisar Syed, Robert Cohen, William Dooley, Maen Farha, Veronica Jones, Wesley Hodge. Impact of endocrine therapy (ET) noncompliance following intra-operative radiation therapy (IORT) in treatment of early-stage breast cancer patients (pts) enrolled in the ExBRT trial [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-19-12.

Intraoperative radiation therapy induces immune response activity after pancreatic surgery

BackgroundPancreatic cancer has highly aggressive features, such as local recurrence that leads to significantly high morbidity and mortality and recurrence after successful tumour resection. Intraoperative radiation therapy (IORT), which delivers targeted radiation to a tumour bed, is known to reduce local recurrence by directly killing tumour cells and modifying the tumour microenvironment.MethodsAmong 30 patients diagnosed with pancreatic cancer, 17 patients received IORT immediately after surgical resection. We investigated changes in the immune response induced by IORT by analysing the peritoneal fluid (PF) and blood of patients with and without IORT treatment after pancreatic cancer surgery. Further, we treated three pancreatic cell lines with PF to observe proliferation and activity changes.ResultsLevels of cytokines involved in the PI3K/SMAD pathway were increased in the PF of IORT-treated patients. Moreover, IORT-treated PF inhibited the growth, migration, and invasiveness of pancreatic cancer cells. Changes in lymphocyte populations in the blood of IORT-treated patients indicated an increased immune response.ConclusionsBased on the characterisation and quantification of immune cells in the blood and cytokine levels in the PF, we conclude that IORT induced an anti-tumour effect by activating the immune response, which may prevent pancreatic cancer recurrence.Clinical trial registrationNCT03273374.

Fast optimized Monte Carlo phase-space generation and dose prediction for low energy x-ray intra-operative radiation therapy

Low energy x-ray intra-operative radiation therapy (IORT) is used mostly for breast cancer treatment with spherical applicators. X-ray IORT treatment delivered during surgery (ex: INTRABEAM®, Carl Zeiss) can benefit from accurate and fast dose prediction in a patient 3D volume. However, full Monte Carlo (MC) simulations are time-consuming and no commercial treatment planning system (TPS) was available for this treatment delivery technique. Therefore, the aim of this work is to develop a dose computation tool based on MC phase space information, which computes fast and accurate dose distributions for spherical and needle INTRABEAM® applicators. First, a database of monoenergetic phase-space (PHSP) files and depth dose profiles (DDPs) in water for each applicator is generated at factory and stored for on-site use. During commissioning of a given INTRABEAM® unit, the proposed fast and optimized phase-space (FOPS) generation process creates a phase-space at the exit of the applicator considered, by fitting the energy spectrum of the source to a combination of the monoenergetic precomputed phase-spaces, by means of a genetic algorithm, with simple experimental data of DDPs in water provided by the user. An in-house hybrid MC (HMC) algorithm which takes into account condensed history simulations of photoelectric, Rayleigh and Compton interactions for x-rays up to 1 MeV computes the dose from the optimized phase-space file. The whole process has been validated against radiochromic films in water as well as reference MC simulations performed with penEasy in heterogeneous phantoms. From the pre-computed monoenergetic PHSP files and DDPs, building the PHSP file optimized to a particular depth-dose curve in water only takes a few minutes in a single core (i7@2.5 GHz), for all the applicators considered in this work, and this needs to be done only when the x-ray source (XRS) is replaced. Once the phase-space file is ready, the HMC code is able to compute dose distributions within 10 min. For all the applicators, more than 95% of voxels from dose distributions computed with the FOPS+hybrid code agreed within 7%–0.5 mm with both reference MC simulations and measurements. The method proposed has been fully validated and it is now implemented into radiance (GMV SA, Spain), the first commercial IORT TPS.

Risk analysis of electronic intraoperative radiation therapy for breast cancer

PurposeTo evaluate the process and improve safety of intraoperative radiation therapy (IORT) for early-stage breast cancers treated with electronic brachytherapy. Methods and MaterialsA multidisciplinary team conducted a failure mode and effects analysis (FMEA) for IORT breast cancer treatments by first developing a process map. This map was then used to identify failure modes for all steps in the treatment workflow. Risk priority numbers (RPNs) were assigned to each failure mode and were calculated as the product of the failure mode's probability of occurrence (O), severity (S), and lack of detectability (D). Corrective steps were implemented to address failure modes with the highest risk, and a revised process was generated. ResultsThe steps with the highest risk failure modes were related to source calibration, use of correct plan and dwell times, and the correct site and intent. The introduction of a physician calibration check and an extended time-out checklist reduced the risk of these failure modes. The highest risk steps in the Xoft breast IORT treatment process are associated with source calibration and manual entry of dwell positions for each balloon size and volume combination. High-risk failure modes that could be mitigated with improved hardware and software interlocks were identified. ConclusionHigh-risk failure modes are identified with FMEA and addressed with corrective steps. This application of FMEA can be used in principle for clinical processes throughout breast cancer care. This analysis demonstrates the importance of well-designed QC policies, procedures, and oversight in a Xoft electronic brachytherapy program for breast cancer IORT.

P172] Establishment and transfer of a primary dosimetry standard for breast cancer IORT using the INTRABEAM(R) system

Purpose Intraoperative radiation therapy (IORT) using low-energy X-rays (⩽50 keV) delivers a concentrated dose by placing, during surgery, a miniaturized X-ray tube in contact with the treated tumor bed. In France, the most used IORT treatment system is the INTRABEAM one, manufactured by the Zeiss Company, which is delivered with a database used to assess the absolute dose distribution. This work aims at establishing traceability to a dosimetry reference independent from the manufacturer, as recommended in the report published in 2016 by the French National Authority for Health on the evaluation of such treatment. Methods Several types of IORT low-energy photon sources are commercially available and any metrology laboratory cannot afford to be equipped with all of them. So a multi-step methodology, applicable to any of these sources, was developed both to establish and transfer a dosimetry reference. This methodology removes the requirement to bring together, within the same laboratory, the source and the dedicated, but non-transportable, primary standard Free-Air-Chamber (FAC). Firstly, the photon energy spectrum of the commercial source is characterized at the hospital, then the spectrum is reproduced at the primary laboratory using a conventional X-ray generator. The reproduced beam is then characterized, in terms of air kerma rate, using a primary FAC and also used to calibrate a transfer cavity ionization chamber, which is in turn used to calibrate the INTRABEAM® system. Finally, a Monte Carlo model of the source is developed to calculate a conversion factor, from air kerma to absorbed dose to water under reference conditions. Results This methodology was applied to the INTRABEAM® system of a hospital associated with a 4 cm spherical applicator. The absorbed dose to water was established at a depth of 1 cm in water. The Zeiss Company recently changed its dosimetry procedure, going from the TARGIT method to the non-TARGIT one. Our value is higher by 33% and 16% respectively than those given by the TARGIT and non-TARGIT methods. Conclusions The present study shows, for IORT X-ray sources, the importance of making available to end-users independent dosimetry measurements traceable to national standards.

Wound fluids affect miR-21, miR-155 and miR-221 expression in breast cancer cell lines, and this effect is partially abrogated by intraoperative radiation therapy treatment.

Breast cancer is the most common malignant disease occurring in women. Conservative breast cancer surgery followed by radiation therapy is currently the standard treatment for this type of cancer. The majority of metastases occur within the scar, which initiated a series of studies. As a result, clinical trials aimed to assess whether localized radiotherapy, as intraoperative radiotherapy (IORT), may more effective in inhibiting the formation of local recurrence compared with the standard postoperative whole breast radiotherapy. The present study determined the role of postoperative wound fluids (WFs) from patients diagnosed with breast cancer subsequent to breast conserving surgery or breast conserving surgery followed by IORT on the expression of three microRNAs (miRNAs), consisting of miR-21, miR-155 and miR-221, in distinct breast cancer cell lines that represent the general subtypes of breast cancer. It was determined that the miRNAs responsible for breast cancer progression, induction of tumorigenesis and enrichment of the cancer stem cell phenotype, which is responsible for resistance to tumor therapy, were highly upregulated in the human epidermal growth factor receptor 2-positive breast cancer SK-BR-3 cell line following stimulation with WFs. It is worth emphasizing, that those changes were more significant in WFs collected from patients after surgery alone. The BT-549 cell line showed altered expression only of miR-155 following incubation with WFs. Notably, this change was not associated with IORT. Additionally, it was indicated that both WFs and RT-WF strongly downregulated the expression of miR-21, miR-155 and miR-221 in basal/epithelial and luminal subtypes of breast cancer. It was concluded that the present study contributes to an increased understanding of the role of surgical WFs and IORT treatment in the regulation of miRNA expression. This may enable the development of the current knowledge of breast cancer biology subsequent to IORT treatment and substantially to improve the therapy in the future.

Effects of shielding on pelvic and abdominal IORT dose distributions

PurposeTo study the impact of shielding elements in the proximity of Intra-Operative Radiation Therapy (IORT) irradiation fields, and to generate graphical and quantitative information to assist radiation oncologists in the design of optimal shielding during pelvic and abdominal IORT. MethodAn IORT system was modeled with BEAMnrc and EGS++ Monte Carlo codes. The model was validated in reference conditions by gamma index analysis against an experimental data set of different beam energies, applicator diameters, and bevel angles. The reliability of the IORT model was further tested considering shielding layers inserted in the radiation beam. Further simulations were performed introducing a bone-like layer embedded in the water phantom. The dose distributions were calculated as 3D dose maps. ResultsThe analysis of the resulting 2D dose maps parallel to the clinical axis shows that the bevel angle of the applicator and its position relative to the shielding have a major influence on the dose distribution. When insufficient shielding is used, a hotspot nearby the shield appears near the surface. At greater depths, lateral scatter limits the dose reduction attainable with shielding, although the presence of bone-like structures in the phantom reduces the impact of this effect. ConclusionsDose distributions in shielded IORT procedures are affected by distinct contributions when considering the regions near the shielding and deeper in tissue: insufficient shielding may lead to residual dose and hotspots, and the scattering effects may enlarge the beam in depth. These effects must be carefully considered when planning an IORT treatment with shielding.

A Novel Form of Breast Intraoperative Radiation Therapy With CT-Guided High-Dose-Rate Brachytherapy: Results of a Prospective Phase 1 Clinical Trial

Existing intraoperative radiation therapy (IORT) techniques are criticized for the lack of image guided treatment planning and energy deposition with, at times, poor resultant dosimetry and low radiation dose. We pioneered a novel method of IORT that incorporates customized, computed tomography (CT)-based treatment planning and high-dose-rate (HDR) brachytherapy to overcome these drawbacks: CT-HDR-IORT. A phase 1 study was conducted to demonstrate the feasibility and safety of CT-HDR-IORT. Eligibility criteria included age ≥50years, invasive or in situ breast cancer, tumor size <3cm, and N0 disease. Patients were eligible before or within 30days of breast-conserving surgery (BCS). BCS was performed, and a multilumen balloon catheter was placed. CT images were obtained, a customized HDR brachytherapy plan was created, and a dose of 12.5Gy was delivered to 1-cm depth from the balloon surface. The catheter was removed, and the skin was closed. The primary endpoints were feasibility and acute toxicity. Feasibility was defined as IORT treatment interval (time from CT acquisition until IORT completion) ≤90minutes. The secondary endpoints included dosimetry, cosmetic outcome, quality of life, and late toxicity. Twenty-eight patients were enrolled. The 6-month follow-up assessments were completed by 93% of enrollees. The median IORT treatment interval was 67.2minutes (range, 50-108minutes). The treatment met feasibility criteria in 26 women (93%). The dosimetric goals were met in 22 patients (79%). There were no Radiation Therapy Oncology Group grade 3+toxicities; 6 patients (21%) experienced grade 2 events. Most patients (93%) had good/excellent cosmetic outcomes at the last follow-up visit. CT-HDR-IORT is feasible and safe. This promising approach for a conformal, image-based, higher-dose breast IORT is being evaluated in a phase 2 trial.

Intraoperative breast radiation therapy with image guidance: Findings from CT images obtained in a prospective trial of intraoperative high-dose-rate brachytherapy with CT on rails.

Intraoperative radiation therapy (IORT) is an increasingly popular approach to breast conserving therapy in the treatment of early-stage breast cancer. A drawback to IORT compared with postoperative adjuvant radiation therapy is that it is not performed using image guidance. Our aim was to report on how our institution's unique IORT workflow integrates CT image guidance and how these CT images were used intraoperatively to change applicator positioning. We retrospectively reviewed the first 29 patients who participated in a prospective clinical trial of breast IORT at our institution. All patients underwent lumpectomy, multicatheter balloon placement, intraoperative CT scan, and high-dose-rate brachytherapy treatment delivery to 12.5 Gy to 1 cm from the balloon surface. This report focuses on the intraoperative CT findings that led to clinical changes, followed by repeat CT for IORT treatment planning. After initial intraoperative CT, 7 patients underwent an additional intraoperative CT scan (24.1%). In 6 patients, the initial intraoperative CT scan identified large air cavities and/or poor tissue conformity. This defect could be improved in all patients with adjustment of the balloon applicator before planning and delivering IORT. Intraoperative CT scan was used in one patient to localize a biopsy clip and aided in excision to negative margin. In our study, intraoperative CT identifies actionable findings in breast IORT, including residual tumor or errors in applicator positioning, in almost 25% of patients. Clinical results of the described trial will serve to further validate this image-guided approach to IORT.

Techniques for intraoperative radiation therapy for early-stage breast carcinoma.

Intraoperative radiation therapy (IORT) is a method of accelerated partial breast irradiation developed to replace other longer courses of radiotherapy with a single radiation session administered at the time of breast-conserving surgery. The purpose of this review is to summarize the advantages and disadvantages of breast IORT techniques that are currently available, as well to consider potential alternative techniques for breast IORT or ultra-short course breast radiotherapy. Furthermore, we highlight the published outcomes for the IORT treatment approaches including: electron therapy, superficial photon therapy and other techniques. Potential future directions of IORT are explored including novel IORT techniques utilizing intraoperative brachytherapy with in-room imaging and rapid treatment planning.

Evidence behind use of orthovolt intraoperative radiotherapy and other techniques of IORT in recurrent colorectal cancer treatment

There are only scarce literature data on the use of with orthovolt intraoperative radiation therapy in treatment of colorectal cancer recurrence. Previous experience with intraoperative radiotherapy using low-energy photons highlights the need for better strategies of combined therapy in referral centres where multidisciplinary treatment options are widely available. There is an absolute need for large randomized studies that will clearly assess the value of different treatment options in colorectal cancer (CRC) recurrences, and thus create uniform rules to be observed in this disease.

Twenty years of evolution in breast cancer intraoperative radiation therapy

Introduction Since the first breast cancer Intraoperative Radiation Therapy treatment in October 1992 performed in our institution, this technique never stopped to evolve. Until 2011 a linear accelerator delivering high energy electron beam was used to treat approximately 130 patients. The first treatments with INTRABEAM® system (Carl Zeiss SAS) using low energy X-rays were performed in October 2011. Materials and methods Nighty-four patients have now been treated with INTRABEAM®. For each, the radiation dose required was 20 Gy to the surface of the surgical margin in a single fraction. The Intrabeam® system produces low energy photons from a 50 kV and 40 μA source while preceding irradiation technique used electrons energy of 6 or 9 MeV. The isotropy of the low energy photon beam and the dose rate were measured before each treatment. Sterile applicators with variable diameters from 3 to 5 cm are selected to exactly fit the surgical cavity, thus allowing a homogeneous spherical irradiation. Results With INTRABEAM®, the dose attenuation is rapid (5 Gy at 1 cm from the applicator surface), thereby reducing damage to surrounding healthy tissue. The mobile X-ray source is installed in one of two operating ambulatory surgery and does not require as before the immobilization of a radiotherapy bunker. The time needed to deliver the dose was between 20 and 53 min and depends on the size of the applicator. The total time needed for the room and the staff for the dose delivery step is not more important with Intrabeam® system as before. Conclusion The shift from breast intraoperative radiotherapy using a linear accelerator to Intrabeam® was realized with no major problems in our institution. Using this new system has improved the workflow of radiotherapy and surgery, and thus increases the number of patients that can benefit from this technique.

High-dose-rate (HDR) Intraoperative Brachytherapy and Radical Surgical Resection in the Management of Recurrent Head-and-Neck Cancer

High-dose-rate (HDR) Intraoperative Brachytherapy and Radical Surgical Resection in the Management of Recurrent Head-and-Neck Cancer

Cost-effectiveness of intraoperative radiation therapy for breast conservation.

6081 Background: Results from the TARGIT trial at 4 years median follow-up for women >50 yrs with node negative tumors show equivalent outcomes in local recurrence, however, it has been argued that long-term follow-up is required before adoption. Modeling can inform this decision by evaluating the tradeoffs between costs, adverse outcomes, and quality of life. Methods: Using a Markov model, a cost-utility analysis compared lumpectomy with Intraoperative Radiation Therapy (IORT) versus standard External Beam Radiation Therapy (EBRT). Local recurrence rates (LRR) were based on results from the TARGIT trial. For the base case, LRR for EBRT was assumed to progress linearly to an expected 2.4% at 10 years. LRR for IORT was set to 5.5%, resulting in a more than 3-fold increase from the observed, published 4-year rate. Utilities were derived from the literature. Baseline utility for no disease after RT was set to .92 for IORT and EBRT. Medicare CPT codes were used for direct costs and non-medical costs were ascertained. Quality adjusted life years (QALY), costs, and the incremental cost-effectiveness ratio (ICER) were calculated over 10 years. Results: In the baseline analysis, IORT is less costly than EBRT, but less effective in terms of QALYs. The use of EBRT led to an increase in .011 QALYS (<5 days) but an incremental increase in $2840, resulting in an ICER of more than $250,000 per QALY. For the ICER to decrease to $81,000/QALY the observed LRR for IORT must increase 8.8 fold from the 4-year rate. Sensitivity analyses demonstrated the ICER to be affected most by the costs of radiation treatment, LRR, and utility measures for post-lumpectomy IORT and EBRT. If the utility for IORT were increased by .002 (out of 1.000), IORT becomes cost-saving, offering greater QALY’s for less cost. Conclusions: The ICER for EBRT is much higher than the accepted willingness-to-pay threshold of $75,000 on the conservative assumption that the utility for no disease after RT is equal for both IORT and EBRT, and that LRR for IORT would more than triple at 10 years. Only a minute improvement in utility for IORT—which is likely since it is a single dose given at time of surgery and avoids multiple visits for EBRT—makes the IORT treatment less expensive and more effective.

Multimodality approach in extra cervical locally advanced cervical cancer: Chemoradiation, surgery and intra-operative radiation therapy. A phase II trial

Background The goal of this study was to determine the rational of radical surgery with intra-operative high-dose radiotherapy after chemoradiation (RT-CT) in extra cervical locally advanced cervical cancer (LACC) patients. Methods Between 2000 and 2007, 42 LACC (stage IIA bulky-IVA) patients were treated at the Gynecologic Oncology Unit of the C.R.O. of Aviano in a Phase II Clinical Trial. Radiotherapy was administered to the whole pelvic region (50.4 Gy in 28 fractions) in combination with cisplatin (60 mg/mq) plus 5FU (750 mg/mq for 4 days) on first and fifth week of RT. Radical surgery with Intra-Operative Radiation Therapy (IORT) was performed 6–8 weeks after the end of RT-CT treatment. Results After RT-CT, 35/42 patients (83%) underwent radical surgery and IORT treatment. At pathologic examination 8/35 (23%) patients showed complete response, while the rest (27/35) had residual disease either microscopic (17/27) or gross (10/27). The 5-year disease free survival (DFS) and the 5-year overall survival (OS) were 46% and 49% respectively. There were significant better DFS and OS when residual tumor was absent or limited to the cervix, respectively 78% versus 16% and 81% versus 20% ( p < 0.001). All recurrences occurred within 24 months from treatment. Conclusions RT-CT followed by surgery and IORT in LACC patients seems to be active in a subgroup of patients with pathological complete response to treatment or partial response with residual tumor limited to the cervix.

Design and dosimetry characteristics of a commercial applicator system for intra‐operative electron beam therapy utilizing ELEKTA Precise accelerator

The design concept and dosimetric characteristics of a new applicator system for intraoperative radiation therapy (IORT) are presented in this work. A new hard‐docking commercial system includes polymethylmethacrylate (PMMA) applicators with different diameters and applicator end angles and a set of secondary lead collimators. A telescopic device allows changing of source‐to‐surface distance (SSD). All measurements were performed for 6, 9, 12 and 18 MeV electron energies. Output factors and percentage depth doses (PDD) were measured in a water phantom using a plane‐parallel ion chamber. Isodose contours and radiation leakage were measured using a solid water phantom and radiographic films. The dependence of PDD on SSD was checked for the applicators with the smallest and the biggest diameters. SSD dependence of the output factors was measured. Hardcopies of PDD and isodose contours were prepared to help the team during the procedure on deciding applicator size and energy to be chosen. Applicator output factors are a function of energy, applicator size and applicator type. Dependence of SSD correction factors on applicator size and applicator type was found to be weak. The same SSD correction will be applied for all applicators in use for each energy. The radiation leakage through the applicators is clinically acceptable. The applicator system enables effective collimation of electron beams for IORT. The data presented are sufficient for applicator, energy and monitor unit selection for IORT treatment of a patient.PACS number: 87.00.00, 29.20.‐c

Spinal Cord Stimulation as a Treatment Option for Intractable Neuropathic Cancer Pain

Nearly 6,750,000 people suffer moderate to severe cancer-related pain each year. Unfortunately, 10% to 15% of these patients fail to achieve acceptable pain relief with conventional management. Spinal cord stimulation (SCS) has been used with increased frequency for successful treatment of intractable cancer pain. We present two cases of intractable, refractory-to-conventional treatment cancer pain that were successfully treated with SCS. Case 1 reports a 51-year-old male with burning pain at the left groin site of inguinal metastases, post-surgical and intraoperative radiation therapy for treatment of squamous cell carcinoma of the anus. Case 2 reports a 43-year-old woman with intractable, burning, throbbing, and shooting pain, post-debulking followed by radiation of a metastatic colon carcinoma. In both cases SCS implantation provided 90% to 100% pain relief, improved functioning and sleep, and discontinuation of pain medications, sustained through 12 months.

Surgery and Intraoperative Radiation Therapy in Treatment of Advanced Cancer of the External and Middle Ear

Surgery and Intraoperative Radiation Therapy in Treatment of Advanced Cancer of the External and Middle Ear