External Beam Radiation Treatment Research Articles

Validation of accordance of ArcCHECK diode detector output with Monte Carlo simulation in brachytherapy

There are several accepted methods to verify External Beam Radiation Therapy (EBRT) treatment plans, but there is no standard way to check the quality of a brachytherapy treatment plan. PurposeThis feasibility study assesses whether the ArcCHECK EBRT radiation detector can also be used to verify Treatment Planning System software quality check procedures for brachytherapy. Methods and materialsArcCHECK is a three-dimensional matrix of 1386 semiconductor diodes, arranged spirally around an internal cylindrical space that is 32 cm long and 15 cm in diameter. The detector makes it possible to reproduce the distribution of sources in a planned EBRT procedure (energy range 6–22 MeV) using an appropriate phantom. Detector responses are displayed as a two-dimensional dose distribution map on the diode surface. In this pilot brachytherapy study, we determined values that characterized the output of the detectors to a simulated Ir-192 radiation source with an energy range of approximately 9–1378 keV, and compared this to the actual signal recorded by an ArcCHECK detector. Experimental treatment plan measurement was performed using a standard Elekta micro-Selectron-v2 unit equipped with an iridium-192 source. To avoid unit inconsistencies, the signal from each of the diodes and the simulation results were normalized to the maximum value, with similar statistical parameters. ResultsThe difference between diode indications in the simulation and the actual measurement was analyzed statistically to show the degree of general inconsistency between them. The average difference for diode pairs here is equal 1,07%, with standard deviation 3, 95%. ConclusionThe results obtained represent the first quantitative evidence of potential usefulness of the ArcCHECK detector in brachytherapy Treatment Planning System software QC verification.

The risk of inguinal hernia repair after radical prostatectomy – a population-based cohort study

Objectives A nationwide population-based register study will evaluate the risk of postoperative inguinal hernia repair after primary curative-intent treatment of prostate carcinoma (PCa). Background Several previous studies have suggested an increased risk of inguinal hernia repair after prostatectomy. Only a few studies have compared the risk by PCa treatment modalities. Methods Data were collected between the years 1998 and 2016 from the national hospital discharge database HILMO and between the years 1998 and 2015 from the Finnish cancer registry to identify all men with prostate cancer with data on primary treatment available and information on inguinal hernia diagnoses and procedures among them. The risk of inguinal hernia repair among men managed with prostatectomy was compared to those treated with radiation therapy. Participants treated with prostatectomy were analyzed as a whole and separately stratified into subgroups managed with mini-invasive or open surgery. Multivariate Cox regression with adjustment for age and comorbidities was used for analysis. Results A total of 7207 cases of PCa were included in the study. 4595 men were treated with radical prostatectomy and 2612 with radiation therapy. Overall, the risk of hernia repair was higher among men treated with prostatectomy compared to men who received radiation therapy as the primary PCa treatment (HR 1.42, 95% CI 1.14–1.77). The risk did not differ markedly by the prostatectomy method. Conclusion Prostate cancer treatment with prostatectomy is associated with an increased risk of inguinal hernia surgery than external beam radiation therapy treatment. This risk should be taken into account when planning PCa treatment.

Alpha-Emitter Radiopharmaceuticals and External Beam Radiotherapy: A Radiobiological Model for the Combined Treatment.

Simple SummaryThe linear–quadratic (LQ) model was adapted to 223Ra therapy using brachytherapy formalism for a mixture of radionuclides, considering the contribution of all daughter isotopes in the decay chain. The LQ model allowed us to predict the two-year overall survival and neutropenia rates with a combination of external beam radiotherapy and 223Ra treatment. The fitted model could be used to guide future optimization and personalization of combined treatments.Previously published studies combined external beam radiotherapy (EBRT) treatments with different activities of 223Ra. The data of two-year overall survival (2y-OS) and neutropenia (TOX) incidence when combining EBRT and 223Ra are not homogeneous in literature. We adapted the linear–quadratic model (LQ) to 223Ra therapy using brachytherapy formalism for a mixture of radionuclides, considering the contribution of all daughter isotopes in the decay chain. A virtual cohort of patients undergoing 223Ra therapy was derived using data from the literature. The doses delivered using 223Ra and EBRT were converted into biologically equivalent doses. Fixed-effect logistic regression models were derived for both the 2y-OS and TOX and compared with available literature. Based on the literature search, four studies were identified to have reported the 223Ra injection activity levels varying from the placebo (0) to 80 kBq/kg, associated or not with EBRT. Logistic regression models revealed a dose-dependent increase in both the 2y-OS (intercept = −1.364; slope = 0.006; p-value ≤ 0.05) and TOX (−5.035; 0.018; ≤0.05) using the EBRT schedule of 8 Gy in 1 fr. Similar results were obtained for other schedules. Discrepancies between our TOX model and those derived for EBRT combined with chemotherapy are discussed. Radiobiological models allow us to estimate dose-dependent relationships, to predict the OS and TOX following combined 223Ra + EBRT treatment, which will guide future treatment optimization.

Survival of pediatric Hodgkin lymphoma patients treated with doxorubicin, bleomycin, vincristine, etoposide, prednisone, and cyclophosphamide (ABVE-PC) versus doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) at a single institution.

Adriamycin, bleomycin, vinblastine, dacarbazine (ABVD), the de facto standard of care in adult-onset Hodgkin lymphoma (HL), has not been directly compared to doxorubicin, bleomycin, vincristine, etoposide, prednisone, and cyclophosphamide (ABVE-PC), a pediatric-aimed regimen designed to reduce late effects. We aimed to describe the single-institution experience of using both regimens in patients with pediatric HL. This retrospective cohort study evaluated a total of 224 patients diagnosed with HL between 1999 and 2018 at Children's Hospital Los Angeles (CHLA), of which 93 patients were eligible having received ABVD (n=46) or ABVE-PC (n=47) chemotherapy as their initial treatment. Descriptive analyses were performed using the Student's t-test or Fisher's exact test. Survival analysis used the Kaplan-Meier method. Events included death, relapse, and secondary malignancy. We also describe the use of radiation therapy, pulmonary toxicity, and cardiomyopathy determined by shortening fraction <29%. Analyses followed an intention-to-treat principle. There was no difference in baseline characteristics between the patients receiving ABVE-PC or ABVD in regard for stage, risk group, or prognostic variables, such as the presence or absence of "B" symptoms, bulky disease, and extra-nodal involvement. A greater proportion of patients treated with ABVE-PC received consolidating external beam radiation treatment (XRT) either by randomization or by response compared to ABVD (59.6% vs. 32.6%, respectively, p=.01). While not statistically significant, response to therapy, assessed by positron emission tomography/computerized tomography (PET/CT) where available, mirrored the use for radiation (rapid response 58.3% vs. 90.0%, n=34, p=.11). The median dose of anthracycline (doxorubicin) was the same in patients receiving ABVE-PC versus ABVD (200 vs. 200mg/m2 , interquartile range 200-250 vs. 200-300mg/m2 , p=.002). There was no difference in event-free survival (p=.63) or overall survival (p=.37) with a median follow-up length of 3.9years. ABVD and ABVE-PC achieved similar survival outcomes in our single-institution cohort.

Improving survival prediction of patients treated with external beam radiotherapy for dysphagia in esophageal cancer using prediction models.

358 Background: The recently published POLDER trial investigated the effects of external beam radiotherapy (EBRT) on dysphagia caused by incurable esophageal cancer. As the effects of EBRT were presumed not to be immediate, an estimated life expectancy of minimally three months was required for inclusion. However, nearly a third of the included patients died within three months. The aim of this study was to investigate if the use of prediction models could have improved the physician’s estimation of the patient’s survival, and thus the eligibility for EBRT treatment. Methods: Data from the POLDER trial (N = 110) were linked to the Netherlands Cancer Registry to retrieve additional patient, tumor and treatment characteristics. Two published prediction models (the SOURCE model and Steyerberg model) were used to predict overall survival for all patients included in the POLDER trial. Predicted survival probabilities were dichotomized (predicted deceased/alive at three months) and the positive predictive value, negative predictive value, sensitivity, specificity and the area under the curve (AUC) were used to evaluate the predictive performance. DeLong’s test was used to test the difference between the AUCs of the SOURCE and Steyerberg models for statistical significance. Results: In the POLDER trial, 35 patients were unjustly presumed to survive three months. Predicting survival at three months, the SOURCE and Steyerberg model had an AUC of 0.76 and 0.60 respectively. The difference between the AUCs of the models was significant (p =.017). Under optimal survival cut-off scores, SOURCE would have incorrectly predicted 16 patients to survive three months. For the Steyerberg model this was 22 patients. Furthermore, using SOURCE under these cut-off scores, seven patients were incorrectly predicted to not survive three months compared to 18 patients using the Steyerberg model. Conclusions: Results showed that the SOURCE and Steyerberg models could have improved survival predictions compared to clinical judgement alone. The SOURCE model was found to be a more useful decision aid than the Steyerberg model as it was more accurate. Accepting that a small proportion of patients are incorrectly predicted not to survive three months and are not considered for EBRT treatment, we recommend using the SOURCE model for patients that are considered for palliative treatment of dysphagia caused by esophageal cancer.

Joint EANM/SNMMI/ESTRO practice recommendations for the use of 2-[18F]FDG PET/CT external beam radiation treatment planning in lung cancer V1.0

Purpose2-[18F]FDGPET/CT is of utmost importance for radiation treatment (RT) planning and response monitoring in lung cancer patients, in both non-small and small cell lung cancer (NSCLC and SCLC). This topic has been addressed in guidelines composed by experts within the field of radiation oncology. However, up to present, there is no procedural guideline on this subject, with involvement of the nuclear medicine societies.MethodsA literature review was performed, followed by a discussion between a multidisciplinary team of experts in the different fields involved in the RT planning of lung cancer, in order to guide clinical management. The project was led by experts of the two nuclear medicine societies (EANM and SNMMI) and radiation oncology (ESTRO).Results and conclusionThis guideline results from a joint and dynamic collaboration between the relevant disciplines for this topic. It provides a worldwide, state of the art, and multidisciplinary guide to 2-[18F]FDG PET/CT RT planning in NSCLC and SCLC. These practical recommendations describe applicable updates for existing clinical practices, highlight potential flaws, and provide solutions to overcome these as well. Finally, the recent developments considered for future application are also reviewed.

Application of Statistical Process Control for Setting Action Thresholds as Quality Assurance of Dose Verifications in External Beam Radiotherapy

Purpose: To test the concept of Statistical Process Control (SPC) as a Quality Assurance (QA) procedure for dose verifications in external beam radiation therapy in conventional and 3D Conformal Radiotherapy (3D-CRT) treatment of cervical cancer. Materials and Methods: A study of QA verification of target doses of 198 cervical cancer patients undergoing External Beam Radiotherapy (EBRT) treatments at two different cancer treatment centers in Kenya was conducted. The target doses were determined from measured entrance doses by the diode in vivo dosimetry. Process Behavior Charts (PBC) developed by SPC were applied for setting Action Thresholds (AT) on the target doses. The AT set was then proposed as QA limits for acceptance or rejection of verified target doses overtime of the EBRT process. Result and Discussion: Target doses for the 198 patients were calculated and SPC applied to test whether the action limits set by the Process Behavior Charts could be applied as QA for verified doses in EBRT. Results for the two sub-groups of n = 3 and n = 4 that were tested produced action thresholds which are within clinical dose specifications for both conventional AP/PA and 3D-CRT EBRT treatment techniques for cervical cancer. Conclusion: Action thresholds set by SPC were within the clinical dose specification of ±5% uncertainty for both conventional AP/PA and 3D-CRT EBRT treatment techniques for cervical cancer. So the concept of SPC could be applied in setting QA action limits for dose verifications in EBRT.

Comparison of vaginal gauze packing technique with or without balloon in high-dose-rate brachytherapy of uterine cervical cancer: A crossover randomized controlled trial.

To compare the rectal and bladder doses using two different vaginal packing techniques among uterine cervical cancer patients receiving high-dose-rate (HDR) intracavitary brachytherapy (ICBT). Forty-five patients with cervical cancer were randomized to receive two sessions of ICBT using tandem and ring applicator (Varian©), following completion of pelvic external beam radiotherapy treatment. The procedure was performed with vaginal balloon plus gauze packing or vaginal gauze packing alone, each of which was used in one of two sessions. Sequence of the type of vaginal packing was chosen with computer-generated block randomization. A HDR dose of 8.5 Gy was prescribed to point A in all patients. Volumetric dose parameters, such as D0.1cc, D0.5cc, D1cc, and D2cc of the rectum and bladder were compared between the two techniques of vaginal packing. The mean age of patients was 51 years. Majority (88%) of patients had locally advanced stages of cancer at baseline (stage IIB or more). Rectal doses were significantly less in combined packing technique (D0.1cc: 7.52 Gy vs. 9.02 Gy, p = 0.01; D0.5cc: 6.46 Gy vs. 7.42 Gy, p < 0.01; D1cc: 5.91 Gy vs. 6.7 Gy, p < 0.01; D2cc: 5.29 Gy vs. 5.97 Gy, p < 0.01). Bladder doses were higher in the combined packing technique (D0.1cc: 11.20 Gy vs. 10.76 Gy, p = 0.18; D0.5cc: 9.64 Gy vs. 9.32 Gy, p = 0.56; D1cc: 8.64 Gy vs. 8.36 Gy, p = 0.55; D2cc: 7.56 vs. 7.33 Gy, p = 0.55). Combined vaginal packing resulted in statistically significant reduction in rectal radiation dose compared with standard vaginal gauze packing in high-dose-rate brachytherapy of cervix cancer using tandem and ring applicators.

Is perioperative brachytherapy effective in carcinoma of the tongue?

PurposeTo analyze the results of patients treated with perioperative interstitial brachytherapy (ISBT) in tongue carcinoma (TC).Material and methodsFrom April 2009 to May 2015, 43 squamous cell carcinoma consecutive patients diagnosed with TC were treated with limited partial glossectomy and perioperative ISBT, using high-dose-rate (HDR). Twenty- seven patients were treated by brachytherapy (BT), and sixteen received BT as a complement to subsequent external beam radiotherapy (EBRT) after results of lymph node dissection. Median age was 66 years. Distribution by stage, included 10 patients stage I, 14 stage II, 10 stage III, and 9 stage IV. Eighteen patients had negative margins, nineteen margin involvement, and in six cases, the margin was < 5 mm.ResultsWith a median follow-up of 54 months, LC at 3 and 5 years was 87% and 84%, respectively. LC was 95% at five years in patients with clear margins, and 75% with involved margins. LC in N0 patients treated with BT was 83% at 5 years, and in patients N+ with posterior EBRT treatment, LC was 86%. By tumor size, we found one local relapse in 13 cases T1, in 5 of 27 patients T2 was found, and no local relapse T3 with LC of 87%, 70%, and 100% respectively at five years. Regional control (RC) was 81% at 3 and 5 years. We found a metastasis-free survival of 91% at 3- and 5-year. Twenty-three patients have died, 11 of them due to other causes, with overall survival of 56% at three years and 53% at five years.ConclusionsCombined treatment with conservative surgery and ISBT shows similar results to radical surgery or RT alone, allowing a more patient-tailored approach, with good organ function preservation and cosmetic outcomes.

Relationship between biodosimetric parameters and treatment volumes in three types of prostate radiotherapy

Brachytherapy (BT) and external beam radiotherapy (EBRT) apply different dose rates, overall treatment times, energies and fractionation. However, the overall impact of these variables on the biological dose of blood is neglected. As the size of the irradiated volume influences the biological effect as well, we studied chromosome aberrations (CAs) as biodosimetric parameters, and explored the relationship of isodose surface volumes (ISVs: V1%, V1Gy, V10%, V10Gy, V100%, V150%) and CAs of both irradiation modalities. We performed extended dicentrics assay of lymphocytes from 102 prostate radiotherapy patients three-monthly for a year. Aberration frequency was the highest after EBRT treatment. It increased after the therapy and did not decrease significantly during the first follow-up year. We showed that various types of CAs 9 months after LDR BT, 3 months after HDR BT and in a long time-range (even up to 1 year) after EBRT positively correlated with ISVs. Regression analysis confirmed these relationships in the case of HDR BT and EBRT. The observed differences in the time points and aberration types are discussed. The ISVs irradiated by EBRT showed stronger correlation and regression relationships with CAs than the ISVs of brachytherapy.

Prostate Cancer Aggressiveness Prediction Using CT Images.

Prostate Cancer (PCa) is mostly asymptomatic at an early stage and often painless requiring active surveillance screening. Transrectal Ultrasound Guided Biopsy (TRUS) is the principal method to diagnose PCa following a histological examination by observing cell pattern irregularities and assigning the Gleason Score (GS) according to the recommended guidelines. This procedure presents sampling errors and, being invasive may cause complications to the patients. External Beam Radiotherapy Treatment (EBRT) is presented as curative option for localised and locally advanced disease, as a palliative option for metastatic low-volume disease or after prostatectomy for prostate bed and pelvic nodes salvage. In the EBRT worflow a Computed Tomography (CT) scan is performed as the basis for dose calculations and volume delineations. In this work, we evaluated the use of data-characterization algorithms (radiomics) from CT images for PCa aggressiveness assessment. The fundamental motivation relies on the wide availability of CT images and the need to provide tools to assess EBRT effectiveness. We used Pyradiomics and Local Image Features Extraction (LIFEx) to extract features and search for a radiomic signature within CT images. Finnaly, when applying Principal Component Analysis (PCA) to the features, we were able to show promising results.

Apoptosis and Senescence in Localized Prostate Cancer Tissues Treated With HDR-BT Boost With Radiotherapy (EBRT) and ADT

High dose rate brachytherapy HDR-BT boost with external beam radiotherapy (EBRT) and adjuvant Androgen Deprivation Therapy (ADT) is an effective treatment of localized prostate cancer (PCa). Ionizing radiation (IR) delivered by BT or by EBRT induce DNA damage leading to cell death by activation of apoptosis. On the other hand, ADT can also induce apoptosis or senescence depending on the duration of treatment. The goal of this study is to determine which signaling pathway is activated in PCa cells in response to the DNA damage induced by HDR-BT boost with EBRT and ADT.22 patients with localized PCa signed an informed consent to participate in this clinical pilot study. Ten patients were treated with only HDR-BT / EBRT alone (no ADT group) and twelve patients also received additional ADT (ADT group). The expression of Ki-67 and p53, pro-apoptotic markers Bax and PUMA and p16 as a senescence marker were analyzed by immunohistochemistry in the biopsies taken from all patients before and post-treatment.Our results show an up-regulation of pro-apoptotic markers and reduction of senescence marker expression in the tissues treated by HDR-BT/ EBRT. However, we noticed an increase expression of senescence marker p16 and no change in pro-apoptotic markers receiving additional ADT.HDR-BT/ EBRT treatment alone induces apoptosis in PCa cells while additional ADT appears to promote their senescence. This could explain the mitigated benefit of ADT to improve radiation treatment combined with BT. These results need to be validated in a larger cohort of patients.

Automated Plan Checking Software Demonstrates Continuous and Sustained Improvements in Safety and Quality: A 3-year Longitudinal Analysis

PurposeThis study aimed to perform a longitudinal analysis of the performance of our automated plan checking software by retrospectively evaluating the number of errors identified in plans delivered to patients in 3, month-long, data collection periods between 2017 and 2020. Methods and MaterialsEleven automated checks were retrospectively run on 1169 external beam radiation therapy treatment plans identified as meeting the following criteria: planning target volume–based multifield photon plans receiving a status of treatment approved in March 2017, March 2018, or March 2020. The number of passes (true positives) and flags were recorded. Flags were subcategorized into false negatives, false negatives due to naming conventions, and true negatives. In addition, 2 × 2 contingency tables using a 2-tailed Fisher's exact test were used to determine whether there were nonrandom associations between the output of the automated plan checking software and whether the check was manual or automated at the original time of treatment approval. ResultsA statistically significant decrease in flags between the pre- and postautomation data sets was observed for 4 contour-based checks, namely adjacent structures overlap, empty structures and missing slices, overlap between body and couch, and laterality, as well as a check that determined whether the plan's global maximum dose was within the planning target volume. A review of the origins of false negatives was fed back into the design of the checks to improve the reliability of the system and help avoid warning fatigue. ConclusionsPeriodic and longitudinal review of the performance of automated software was essential for monitoring and understanding its impact on error rates, as well as for optimization of the tool to adapt to regular changes of clinical practice. The automated plan checking software has demonstrated continuous contributions to the safe and effective delivery of external beam radiation therapy to our patient population, an impact that extends beyond its initial implementation and deployment.

Radiation Induced Cavernomas in the Treatment of Pediatric Medulloblastoma: Comparative Study Between Proton and Photon Radiation Therapy

Radiation induced cavernomas among children with medulloblastoma are common following external beam radiation (XRT) treatment with either photon or proton beams. However, with the increased utilization of proton beam therapy over the last decade we sought to determine if there was any difference in the development or natural history of these cavernous malformations (CM) or CM-like lesions. We performed a retrospective analysis of 79 patients from 2003 to 2019 who had undergone resection of medulloblastoma and subsequent XRT (30 photon or 49 proton beam therapy). The average age of patients at radiation treatment was 8.7 years old. Average follow up for patients who received photon beam therapy was 105 months compared to 56.8 months for proton beam therapy. A total of 68 patients (86.1%) developed post-radiation CMs, including 26 photon and 42 proton patients (86.7% and 85.7% respectively). The time to cavernoma development was significantly different, with a mean of 40.2 months for photon patients and 18.2 months for proton patients (p = 1.98 x 10-4). Three patients, one who received photon and two who received proton beam radiation, required surgical resection of a cavernoma. Although CM or CM-like lesions are detected significantly earlier in patients after receiving proton beam therapy, there appears to be no significant difference between the two radiation therapy modalities in the development of significant CM requiring surgical resection or intervention other than continued follow up and surveillance.

…and this is my voice: autopathophonography and the politics of variable voice

This essay describes the production and theoretical context of an audio work entitled “…and this is my voice.” In May and June 2010, I took recordings of my voice while on the way into external beam radiation treatments for an aggressive case of papillary thyroid cancer in my neck. I then used these recordings as the raw material for the work. This essay provides full documentation of the production process for those who may want or need something beyond the original audio work to engage with it fully, as well as a theoretical discussion of the ideology of vocal ability: the belief that voices are expressions of subjects’ inner states and abilities.&#x0D; &#x0D; Work available at: https://jonathansterne.bandcamp.com/track/and-this-is-my-voice

Impact of different treatment plans on EQD2 for intracavitary brachytherapy of cervical cancer

BackgroundCancer is one of the leading causes of death worldwide. According to GLOBOCAN estimates, there were 341,831 deaths from cervical cancer in 185 countries in 2020. The aim of this study was to compare equieffective dose (EQD2) at 2 Gy per fraction by using dose volume histograms (DVHs) derived from external beam radiotherapy (EBRT) and high-dose rate brachytherapy (HDR-BRT) treatment plans used in cervical cancer radiotherapy.MethodsFifteen patients with stage IIB-IIIB cervical cancer were included in this retrospective study. Treatment with three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) was planned for all patients in 28 fractions, with a total of 50.4 Gy to be delivered to the whole pelvic region. After EBRT, manual optimization (MO) or inverse optimization (IO) HDR-BRT plans were created in 4 fractions with a total of 28 Gy. The plans obtained were grouped as IMRT + IO, IMRT + MO, 3DCRT + IO, and 3DCRT + MO by calculating EQD2s among these plans. D90, D95, and D98 values were compared in all plans for CTVHR total EQD2. In addition, EQD2 values ​for critical organs at risk (OARs) such as rectum, bladder, small intestine, and sigmoid were compared in all plans for volumes of 2 cm3, 1 cm3, and 0.1 cm3, respectively.ResultsThere was no significant difference between the treatment groups in terms of CTVHR D90 and CTVIR D90 values; However, CTVHR D95 (p = 0.000) and CTVHR D98 (p = 0.000) values ​were found to be better in IMRT + IO technique. The IMRT + IO technique provided better protection for 2 cm3, 1 cm3, and 0.1 cm3 volumes of OARs compared to other techniques.ConclusionsConsidering all parameters such as CTVHR, CTVIR, rectum, bladder, small intestine, and sigmoid, combination of IMRT + IO treatment option was found to be significantly superior in total EQD2 calculations compared to other plans.

793P Comparison of two high-dose rate (HDR) brachytherapy regimens in treatment of cervical cancer

Chemoradiation with external beam radiation therapy (EBRT) followed by high dose-rate (HDR) intracavitary brachytherapy (ICBT) is the standard treatment for locally advanced cervical cancer. HDR ICBT for cervical cancer is now well established because of its numerous advantages. Although there are decades of published literature and research on the efficacy of HDR brachytherapy, optimum treatment time, dose, and fractionation still need to be defined. The aim of this study was to assess and compare the local control and toxicities between HDR ICBT with 7.5 Gy per fraction in three fractions (Control Arm) and 9 Gy per fraction in two fractions (Study Arm) after EBRT in treatment of carcinoma cervix.

Therapeutic applications of radioactive sources: from image-guided brachytherapy to radio-guided surgical resection.

It is well known nowadays that radioactivity can destroy the living cells it interacts with. It is therefore unsurprising that radioactive sources, such as iodine-125, were historically developed for treatment purposes within radiation oncology with the goal of damaging malignant cells. However, since then, new techniques have been invented that make creative use of the same radioactivity properties of these sources for medical applications. Here, we review two distinct kinds of therapeutic uses of radioactive sources with applications to prostate, cervical, and breast cancer: brachytherapy and radioactive seed localization. In brachytherapy (BT), the radioactive sources are used for internal radiation treatment. Current approaches make use of real-time image guidance, for instance by means of magnetic resonance imaging, ultrasound, computed tomography, and sometimes positron emission tomography, depending on clinical availability and cancer type. Such image-guided BT for prostate and cervical cancer presents a promising alternative and/or addition to external beam radiation treatments or surgical resections. Radioactive sources can also be used for radio-guided tumor localization during surgery, for which the example of iodine-125 seed use in breast cancer is given. Radioactive seed localization (RSL) is increasingly popular as an alternative tumor localization technique during breast cancer surgery. Advantages of applying RSL include added flexibility in the clinical scheduling logistics, an increase in tumor localization accuracy, and higher patient satisfaction; safety measures do however have to be employed. We exemply the implementation of RSL in a clinic through our experiences at the Netherlands Cancer Institute.

Risk of secondary neoplasms after external-beam radiation therapy treatment of pediatric low-grade gliomas: a SEER analysis, 1973-2015.

Although past studies have associated external-beam radiation therapy (EBRT) with higher incidences of secondary neoplasms (SNs), its effect on SN development from pediatric low-grade gliomas (LGGs), defined as WHO grade I and II gliomas of astrocytic or oligodendrocytic origin, is not well understood. Utilizing a national cancer registry, the authors sought to characterize the risk of SN development after EBRT treatment of pediatric LGG. A total of 1245 pediatric patient (aged 0-17 years) records from 1973 to 2015 were assembled from the Surveillance, Epidemiology, and End Results (SEER) database. Univariable and multivariable subdistribution hazard regression models were used to evaluate the prognostic impact of demographic, tumor, and treatment-related covariates. Propensity score matching was used to balance baseline characteristics. Cumulative incidence analyses measured the time to, and rate of, SN development, stratified by receipt of EBRT and controlled for competing mortality risk. The Fine and Gray semiparametric model was used to estimate future SN risk in EBRT- and non-EBRT-treated pediatric patients. In this study, 366 patients received EBRT and 879 did not. Forty-six patients developed SNs after an LGG diagnosis, and 27 of these patients received EBRT (OR 3.61, 95% CI 1.90-6.95; p < 0.001). For patients alive 30 years from the initial LGG diagnosis, the absolute risk of SN development in the EBRT-treated cohort was 12.61% (95% CI 8.31-13.00) compared with 4.99% (95% CI 4.38-12.23) in the non-EBRT-treated cohort (p = 0.013). Cumulative incidence curves that were adjusted for competing events still demonstrated higher rates of SN development in the EBRT-treated patients with LGGs. After matching across available covariates and again adjusting for the competing risk of mortality, a clear association between EBRT and SN development remained (subhazard ratio 2.26, 95% CI 1.21-4.20; p = 0.010). Radiation therapy was associated with an increased risk of future SNs for pediatric patients surviving LGGs. These data suggest that the long-term implications of EBRT should be considered when making treatment decisions for this patient population.

Utilization of brachytherapy in Quebec, Canada

Despite the excellent clinical outcomes from brachytherapy treatments compared with other modalities and the low associated costs, there have been reports of a decline in utilization of brachytherapy. The aim of this study was to investigate in detail the trend in utilization of brachytherapy in the province of Québec, Canada, from 2011 to 2019. All radiotherapy clinics in the province of Quebec, and among these the clinics that provide brachytherapy treatments, were identified. This observational retrospective cohort study involved analysis of data compiled by the Ministère de la Santé et des Services Sociaux du Québec for the period of 2011 to end of 2019 on all brachytherapy procedures performed in the province of Quebec. Time series graphs were used to describe the number of high dose rate (HDR) and low dose rate (LDR) brachytherapy treatments during the studied time period. Statistical analysis was conducted using R statistical software. Between 2011 and 2019, 12 hospitals in the province of Québec provided radiotherapy treatments, and all of them offered brachytherapy services. The median annual number of brachytherapy sessions was 4413 (range 3930-4829). HDR brachytherapy represented over 90% of all brachytherapy treatments throughout the study period. Significant changes over time were observed in the number of treatments: at least 5% change was seen only for the two most common subtypes of brachytherapy, HDR interstitial and HDR intracavitary, with an increase of 9.6% and a decrease of 9.2%, respectively. The use of other subtypes of brachytherapy (HDR-plesiotherapy, LDR-interstitial, LDR-intracavitary, LDR-eye plaque) was stable between 2011 and 2019, with ≤ 2.5% variation. This study demonstrates an overall steady use of brachytherapy between 2011 and 2019 in Quebec. Brachytherapy offers numerous advantages for the treatment of diverse cancer sites. Although more sophisticated external beam radiotherapy treatments have emerged in the last decades, the precision and cost-effectiveness of brachytherapy remain unbeaten. To ensure the continued use and availability of brachytherapy, governments must put in place policies and regulations to that effect. Training and exposure of future health care professionals to brachytherapy within Quebec and Canada is essential to provide all patients the same access to this life saving modality.