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Radiotherapy and Oncology : Journal of... Feb 2022This is an evidence-based guideline for prostate brachytherapy. Throughout levels of evidence quoted are those from the Oxford Centre for Evidence based Medicine...
This is an evidence-based guideline for prostate brachytherapy. Throughout levels of evidence quoted are those from the Oxford Centre for Evidence based Medicine (https://www.cebm.ox.ac.uk/resources/levels-of-evidence/oxford-centre-for-evidence-based-medicine-levels-of-evidence-march-2009). Prostate interstitial brachytherapy using either permanent or temporary implantation is an established and evolving treatment technique for non-metastatic prostate cancer. Permanent brachytherapy uses Low Dose Rate (LDR) sources, most commonly I-125, emitting photon radiation over months. Temporary brachytherapy involves first placing catheters within the prostate and, on confirmation of accurate positioning, temporarily introducing the radioactive source, generally High Dose Rate (HDR) radioactive sources of Ir-192 or less commonly Co-60. Pulsed dose rate (PDR) brachytherapy has also been used for prostate cancer [1] but few centres have adopted this approach. Previous GEC ESTRO recommendations have considered LDR and HDR separately [2-4] but as there is considerable overlap, this paper provides updated guidance for both treatment techniques. Prostate brachytherapy allows safe radiation dose escalation beyond that achieved using external beam radiotherapy alone as it has greater conformity around the prostate, sparing surrounding rectum, bladder, and penile bulb. In addition there are fewer issues with changes in prostate position during treatment delivery. Systematic review and randomised trials using both techniques as boost treatments demonstrate improved PSA control when compared to external beam radiotherapy alone [5-7].
Topics: Brachytherapy; Humans; Iodine Radioisotopes; Male; Prostate; Prostatic Neoplasms; Radiotherapy Dosage
PubMed: 34999134
DOI: 10.1016/j.radonc.2021.12.047 -
Fertility and Sterility Feb 2020To provide evidence-based recommendations to practicing physicians and others regarding the effectiveness and safety of therapies for unexplained infertility.
OBJECTIVE
To provide evidence-based recommendations to practicing physicians and others regarding the effectiveness and safety of therapies for unexplained infertility.
METHODS
ASRM conducted a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 1968 through 2019. The ASRM Practice Committee and a task force of experts used available evidence and informal consensus to develop evidence-based guideline recommendations.
MAIN OUTCOME MEASURE(S)
Outcomes of interest included: live-birth rate, clinical pregnancy rate, implantation rate, fertilization rate, multiple pregnancy rate, dose of treatment, rate of ovarian hyperstimulation, abortion rate, and ectopic pregnancy rate.
RESULT(S)
The literature search identified 88 relevant studies to inform the evidence base for this guideline.
RECOMMENDATION(S)
Evidence-based recommendations were developed for the following treatments for couples with unexplained infertility: natural cycle with intrauterine insemination (IUI); clomiphene citrate with intercourse; aromatase inhibitors with intercourse; gonadotropins with intercourse; clomiphene citrate with IUI; aromatase inhibitors with IUI; combination of clomiphene citrate or letrozole and gonadotropins (low dose and conventional dose) with IUI; low-dose gonadotropins with IUI; conventional-dose gonadotropins with IUI; timing of IUI; and in vitro fertilization and treatment paradigms.
CONCLUSION(S)
The treatment of unexplained infertility is by necessity empiric. For most couples, the best initial therapy is a course (typically 3 or 4 cycles) of ovarian stimulation with oral medications and intrauterine insemination (OS-IUI) followed by in vitro fertilization for those unsuccessful with OS-IUI treatments.
Topics: Aromatase Inhibitors; Clomiphene; Evidence-Based Practice; Female; Fertilization in Vitro; Gonadotropins; Humans; Infertility, Female; Insemination, Artificial; Pregnancy; Randomized Controlled Trials as Topic
PubMed: 32106976
DOI: 10.1016/j.fertnstert.2019.10.014 -
Frontiers in Oncology 2022FLASH radiotherapy (FLASH-RT) is a novel radiotherapy technology defined as ultra-high dose rate (≥ 40 Gy/s) radiotherapy. The biological effects of FLASH-RT include... (Review)
Review
FLASH radiotherapy (FLASH-RT) is a novel radiotherapy technology defined as ultra-high dose rate (≥ 40 Gy/s) radiotherapy. The biological effects of FLASH-RT include two aspects: first, compared with conventional dose rate radiotherapy, FLASH-RT can reduce radiation-induced damage in healthy tissue, and second, FLASH-RT can retain antitumor effectiveness. Current research shows that mechanisms of the biological effects of FLASH-RT are related to oxygen. However, due to the short time of FLASH-RT, evidences related to the mechanisms are indirect, and the exact mechanisms of the biological effects of FLASH-RT are not completely clear and some are even contradictory. This review focuses on the mechanisms of the biological effects of FLASH-RT and proposes future research directions.
PubMed: 36212435
DOI: 10.3389/fonc.2022.995612 -
BMJ (Clinical Research Ed.) Aug 2023To evaluate the effect of protracted low dose, low dose rate exposure to ionising radiation on the risk of cancer.
OBJECTIVE
To evaluate the effect of protracted low dose, low dose rate exposure to ionising radiation on the risk of cancer.
DESIGN
Multinational cohort study.
SETTING
Cohorts of workers in the nuclear industry in France, the UK, and the US included in a major update to the International Nuclear Workers Study (INWORKS).
PARTICIPANTS
309 932 workers with individual monitoring data for external exposure to ionising radiation and a total follow-up of 10.7 million person years.
MAIN OUTCOME MEASURES
Estimates of excess relative rate per gray (Gy) of radiation dose for mortality from cancer.
RESULTS
The study included 103 553 deaths, of which 28 089 were due to solid cancers. The estimated rate of mortality due to solid cancer increased with cumulative dose by 52% (90% confidence interval 27% to 77%) per Gy, lagged by 10 years. Restricting the analysis to the low cumulative dose range (0-100 mGy) approximately doubled the estimate of association (and increased the width of its confidence interval), as did restricting the analysis to workers hired in the more recent years of operations when estimates of occupational external penetrating radiation dose were recorded more accurately. Exclusion of deaths from lung cancer and pleural cancer had a modest effect on the estimated magnitude of association, providing indirect evidence that the association was not substantially confounded by smoking or occupational exposure to asbestos.
CONCLUSIONS
This major update to INWORKS provides a direct estimate of the association between protracted low dose exposure to ionising radiation and solid cancer mortality based on some of the world's most informative cohorts of radiation workers. The summary estimate of excess relative rate solid cancer mortality per Gy is larger than estimates currently informing radiation protection, and some evidence suggests a steeper slope for the dose-response association in the low dose range than over the full dose range. These results can help to strengthen radiation protection, especially for low dose exposures that are of primary interest in contemporary medical, occupational, and environmental settings.
Topics: Humans; United States; Cohort Studies; Neoplasms, Radiation-Induced; Radiation Dosage; Radiation, Ionizing; Industry; United Kingdom; Occupational Exposure; Occupational Diseases; Radiation Exposure
PubMed: 37586731
DOI: 10.1136/bmj-2022-074520 -
Frontiers in Oncology 2021The biological effects of radiation dose to organs at risk surrounding tumor target volumes are a major dose-limiting constraint in radiotherapy. This can mean that the... (Review)
Review
The biological effects of radiation dose to organs at risk surrounding tumor target volumes are a major dose-limiting constraint in radiotherapy. This can mean that the tumor cannot be completely destroyed, and the efficacy of radiotherapy will be decreased. Thus, ways to reduce damage to healthy tissue has always been a topic of particular interest in radiotherapy research. Modern radiotherapy technologies such as helical tomotherapy (HT), intensity-modulated radiation therapy (IMRT), and proton radiotherapy can reduce radiation damage to healthy tissues. Recent outcomes of animal experiments show that FLASH radiotherapy (FLASH-RT) can reduce radiation-induced damage in healthy tissue without decreasing antitumor effectiveness. The very short radiotherapy time compared to that of conventional dose-rate radiotherapy is another advantage of FLASH-RT. The first human patient received FLASH-RT in Switzerland in 2018. FLASH-RT may become one of the main radiotherapy technologies in clinical applications in the future. We summarize the history of the development of FLASH-RT, its mechanisms, its influence on radiotherapy, and its future.
PubMed: 34113566
DOI: 10.3389/fonc.2021.644400 -
Radiation and Environmental Biophysics Nov 2022Despite decades of research to understand the biological effects of ionising radiation, there is still much uncertainty over the role of dose rate. Motivated by a... (Review)
Review
Despite decades of research to understand the biological effects of ionising radiation, there is still much uncertainty over the role of dose rate. Motivated by a virtual workshop on the "Effects of spatial and temporal variation in dose delivery" organised in November 2020 by the Multidisciplinary Low Dose Initiative (MELODI), here, we review studies to date exploring dose rate effects, highlighting significant findings, recent advances and to provide perspective and recommendations for requirements and direction of future work. A comprehensive range of studies is considered, including molecular, cellular, animal, and human studies, with a focus on low linear-energy-transfer radiation exposure. Limits and advantages of each type of study are discussed, and a focus is made on future research needs.
Topics: Animals; Humans; Radiation Protection; Radiation Dosage; Radiation Injuries; Radiation Exposure; Radiation, Ionizing; Radiobiology
PubMed: 36241855
DOI: 10.1007/s00411-022-00996-0 -
Frontiers in Oncology 2021The three-dimensional iridium-192 (Ir) high-dose-rate (HDR) brachytherapy manifests itself as a high-precision, hypofractionated, dose-escalating, minimally invasive... (Review)
Review
The three-dimensional iridium-192 (Ir) high-dose-rate (HDR) brachytherapy manifests itself as a high-precision, hypofractionated, dose-escalating, minimally invasive method in the armamentarium of contemporary radiation oncology clinical applications. In this study, the physical aspects of the Ir radionuclide are presented. Its dosimetric application in HDR brachytherapy for different anatomical sites (prostate, gynecological malignancies, liver, and intrathoracic tumors) as well as the corresponding dosimetric comparison with the stereotactic body radiation therapy (SBRT) techniques based on a representative selection of dosimetric publications is reviewed and illustrated.
PubMed: 34858815
DOI: 10.3389/fonc.2021.728452 -
Frontiers in Oncology 2022
PubMed: 35356219
DOI: 10.3389/fonc.2022.877165 -
Frontiers in Oncology 2021High-dose-rate brachytherapy by remote afterloading is now performed under three-dimensional image guidance by CT or MRI. Three-dimensional image-guided brachytherapy in... (Review)
Review
High-dose-rate brachytherapy by remote afterloading is now performed under three-dimensional image guidance by CT or MRI. Three-dimensional image-guided brachytherapy in cervical cancer disclosed that the traditional intracavitary brachytherapy by Manchester method cannot deliver an adequate dose to the large tumor with resulting local recurrence. To improve the local control rate, combined interstitial and intracavitary (hybrid) brachytherapy can increase the dose to the large parametrial involvement without increasing the dose to the rectum and bladder. Whether hybrid brachytherapy can be performed safely on a multi-institutional basis remains to be studied. From 2015, phase I/II study of hybrid brachytherapy was launched in Japan, and it was revealed that hybrid brachytherapy can be performed safely and with a high quality of radiation dose distribution in a multi-institutional study. In Japan, the number of patients undergoing hybrid brachytherapy in cervical cancer is rapidly rising. Education and clinical trial are very important to establish hybrid brachytherapy in the management of cervical cancer.
PubMed: 35096614
DOI: 10.3389/fonc.2021.809825 -
Therapeutic Advances in... 2023In patients attempting to discontinue their antidepressant medication, there have been no prospective studies on patterns of withdrawal as a function of the rate of...
BACKGROUND
In patients attempting to discontinue their antidepressant medication, there have been no prospective studies on patterns of withdrawal as a function of the rate of antidepressant reduction during the tapering trajectory, and moderators thereof.
OBJECTIVE
To investigate withdrawal as a function of gradual dose reduction.
DESIGN
Prospective cohort study.
METHODS
The sampling frame consisted of 3956 individuals in the Netherlands who received an antidepressant tapering strip between 19 May 2019 and 22 March 2022 in routine clinical practice. Of these, 608 patients, majorly with previous unsuccessful attempts to stop, provided daily ratings of withdrawal in the context of reducing their antidepressant medications (mostly venlafaxine or paroxetine), using hyperbolic tapering strips offering daily tiny reductions in dose.
RESULTS
Withdrawal in daily-step hyperbolic tapering trajectories was limited, and inverse to the rate of taper. Female sex, younger age, presence of one or more risk factors and faster rate of reduction over shorter tapering trajectories were associated with more withdrawal and differential course over time. Thus, sex and age differences were less marked early in the course of the trajectory, whereas differences associated with risk factors and shorter trajectories tended to peak early in the trajectory. There was evidence that tapering in weekly larger steps (mean per-week dose reduction: 33.4% of previous dose), in comparison with daily tiny steps (mean per-day dose reduction: 4.5% of previous dose or 25.3% per week), was associated with more withdrawal in trajectories of 1, 2 or 3 months, particularly for paroxetine and the group of other (non-paroxetine, non-venlafaxine) antidepressants.
CONCLUSION
Antidepressant hyperbolic tapering is associated with limited, rate-dependent withdrawal that is inverse to the rate of taper. The demonstration of multiple demographic, risk and complex temporal moderators in time series of withdrawal data indicates that antidepressant tapering in clinical practice requires a personalised process of shared decision making over the entire course of the tapering period.
PubMed: 37200818
DOI: 10.1177/20451253231171518