To study the feasibility of optimizing the Clinical Target Volume to Planning Target Volume (CTV-PTV) margin in prostate radiotherapy(RT) with a general-purpose linear accelerator using an in-house ...developed position monitoring system, SeedTracker.
A cohort of 30 patients having definitive prostate radiotherapy treated within an ethics-approved prospective trial was considered for this study. The intrafraction prostate motion and the position deviations were measured using SeedTracker system during each treatment fraction. Using this data the CTV-PTV margin required to cover 90% of the patients with a minimum of 95% of the prescription dose to CTV was calculated using van Herk's formula. The margin calculations were performed for treatment scenarios both with and without applying the position corrections for observed position deviations. The feasibility of margin reduction with real-time monitoring was studied by assessing the delivered dose that incorporates the actual target position during treatment delivery and comparing it with the planned dose. This assessment was performed for plans generated with reduced CTV-PTV margin in the range of 7mm-3mm.
With real-time monitoring and position corrections applied the margin of 2.0mm, 2.1mm and 2.1mm in LR, AP and SI directions were required to meet the criteria of 90% population to receive 95% of the dose prescription to CTV. Without position corrections applied for observed position deviations a margin of 3.1mm, 4.0mm and 3.0mm was required in LR, AP and SI directions to meet the same criteria. A mean ± SD reduction of 0.5 ± 1.8% and 3 ± 7% of V60 for the rectum and bladder can be achieved for every 1mm reduction of PTV margin. With position corrections applied, the CTV D99 can be delivered within -0.2 ± 0.3 Gy of the planned dose for plans with a 3mm margin. Without applying corrections for position deviations the CTV D99 was reduced by a maximum of 1.1 ± 1.1 Gy for the 3mm margin plan and there was a statistically significant difference between planned and delivered dose for 3mm and 4mm margin plans.
This study demonstrates the feasibility of reducing the margin in prostate radiotherapy with SeedTracker system without compromising the dose delivery accuracy to CTV while reducing dose to critical structures.
Pain is one of the most burdensome symptoms in people with cancer, and opioid analgesics are considered the mainstay of cancer pain management. For this review, the authors evaluated the efficacy and ...toxicities of opioid analgesics compared with placebo, other opioids, nonopioid analgesics, and nonpharmacologic treatments for background cancer pain (continuous and relatively constant pain present at rest), and breakthrough cancer pain (transient exacerbation of pain despite stable and adequately controlled background pain). They found a paucity of placebo‐controlled trials for background cancer pain, although tapentadol or codeine may be more efficacious than placebo (moderate‐certainty to low‐certainty evidence). Nonsteroidal anti‐inflammatory drugs including aspirin, piroxicam, diclofenac, ketorolac, and the antidepressant medicine imipramine, may be at least as efficacious as opioids for moderate‐to‐severe background cancer pain. For breakthrough cancer pain, oral transmucosal, buccal, sublingual, or intranasal fentanyl preparations were identified as more efficacious than placebo but were more commonly associated with toxicities, including constipation and nausea. Despite being recommended worldwide for the treatment of cancer pain, morphine was generally not superior to other opioids, nor did it have a more favorable toxicity profile. The interpretation of study results, however, was complicated by the heterogeneity in the study populations evaluated. Given the limited quality and quantity of research, there is a need to reappraise the clinical utility of opioids in people with cancer pain, particularly those who are not at the end of life, and to further explore the effects of opioids on immune system function and quality of life in these individuals.
Abstract Background and purpose Three randomised trials have demonstrated the benefit of adjuvant post-prostatectomy radiotherapy (PPRT) for high risk patients. Data also documents the effectiveness ...of salvage radiotherapy following a biochemical relapse post-prostatectomy. The Radiation Oncology Genito-Urinary Group recognised the need to develop consensus guidelines on to whom, when and how to deliver PPRT. Materials and methods Draft guidelines were developed and refined at a consensus conference in June 2006 attended by 63 delegates where urological, radiotherapy and diagnostic imaging experts spoke on aspects of PPRT. Unresolved issues were further developed by working parties and redistributed until consensus was reached. Results Central to the recommendations is that patients with positive surgical margins, seminal vesicle invasion and/or extracapsular extension have a high risk of residual local disease and should be informed of the options of either immediate adjuvant radiotherapy or active surveillance with early salvage in the event of biochemical recurrence. Salvage radiotherapy should be instituted at the earliest confirmation of biochemical recurrence. Detailed contouring guidelines have been developed, defining the regions at risk of residual microscopic disease which should be included in the clinical target volume. The recommended doses are 60–64 Gy for adjuvant, and 60–66 Gy for salvage radiotherapy. The role of hormone therapy in conjunction with PPRT is yet to be defined. Conclusions These consensus guidelines have been developed to give clinical and technical guidance to radiation oncologists and urologists in the management of high risk post-prostatectomy patients.
Stereotactic ablative body radiotherapy is used in prostate cancer to deliver a high dose of radiation to the tumour over a small number of treatments. This involves the simulation of the patient ...using both CT and MRI. Current practice is to insert an indwelling catheter (IDC) during CT to assist with visualisation of the urethra and subsequently minimise dose to this highly critical structure. However, this procedure is invasive and has an associated risk of infection. This is a case study, which demonstrates our initial experience of using a real-time non-invasive MRI technique to replace the use of IDC for prostate cancer patients. The patient was scanned on a dedicated 3T MRI and was instructed to micturate in their own time whereupon a sagittal T2 weighted HASTE sequence was acquired every 5 s. This was subsequently followed by T2 weighted axial imaging at the level of mid prostate to provide improved urethral definition. Acquired images showed bladder voidance in real-time and an increase in signal intensity in the proximal urethra post voiding allowing for delineation of the urethra. The dimension and shape of the proximal urethra was well visualised and accumulation time of urine in the urethra was sufficient to enable optimum timing of the scanning technique. We have presented for the first time a micturating urethography technique using MRI, which has allowed us to visualise the urethra without contrast and with minimal invasiveness to the patient.
To implement an in-house developed position monitoring software, SeedTracker, for conventional fractionation prostate radiotherapy, and study the effect on dosimetric impact and intrafraction motion.
...Thirty definitive prostate radiotherapy patients with implanted fiducial markers were included in the study. All patients were treated with VMAT technique and plans were generated using the Pinnacle planning system using the 6MV beam model for Elekta linear accelerator. The target dose of 60 Gy in 20 fractions was prescribed for 29 of 30 patients, and one patient was treated with the target dose of 78 Gy in 39 fractions. The SeedTracker position monitoring system, which uses the x-ray images acquired during treatment delivery in the Elekta linear accelerator and associated XVI system, was used for online prostate position monitoring. The position tolerance for online verification was progressively reduced from 5 mm, 4 mm, and to 3 mm in 10 patient cohorts to effectively manage the treatment interruptions resulting from intrafraction motion in routine clinical practice. The delivered dose to target volumes and organs at risk in each of the treatment fractions was assessed by incorporating the observed target positions into the original treatment plan.
In 27 of 30 patients, at least one gating event was observed, with a total of 177 occurrences of position deviation detected in 146 of 619 treatment fractions. In 5 mm, 4 mm, and 3 mm position tolerance cohorts, the position deviations were observed in 13%, 24%, and 33% of treatment fractions, respectively. Overall, the mean (range) deviation of -0.4 (-7.2 to 5.3) mm, -0.9 (-6.1 to 15.6) mm, and -1.7 (-7.0 to 6.1) mm was observed in Left-Right, Anterior-Posterior, and Superior-Inferior directions, respectively. The prostate CTV D99 would have been reduced by a maximum value of 1.3 Gy compared to the planned dose if position deviations were uncorrected, but with corrections, it was 0.3 Gy. Similarly, PTV D98 would have been reduced by a maximum value of 7.6 Gy uncorrected, with this difference reduced to 2.2 Gy with correction. The V60 to the rectum increased by a maximum of 1.0% uncorrected, which was reduced to 0.5%.
Online target position monitoring for conventional fractionation prostate radiotherapy was successfully implemented on a standard Linear accelerator using an in-house developed position monitoring software, with an improvement in resultant dose to prostate target volume.
The management of patients with biochemical, local, nodal, or oligometastatic relapsed prostate cancer has become more challenging and controversial. Novel imaging modalities designed to detect ...recurrence are increasingly used, particularly PSMA-PET scans in Australia, New Zealand and some European countries. Imaging techniques such as MRI and PET scans using other prostate cancer-specific tracers are also being utilised across the world. The optimal timing for commencing salvage treatment, and the role of local and/or systemic therapies remains controversial. Through surveys of the membership, the Australian and New Zealand Faculty of Radiation Oncology Genito-Urinary Group (FROGG) identified wide variation in the management of recurrent prostate cancer. Following a workshop conducted in April 2017, the FROGG management committee reviewed the literature and developed a set of recommendations based on available evidence and expert opinion, for the appropriate investigation and management of recurrent prostate cancer. These recommendations cover the role and timing of post-prostatectomy radiotherapy, the management of regional nodal metastases and oligometastases, as well as the management of local prostate recurrence after definitive radiotherapy.
AbstractThe management of node-positive prostate cancer is highly variable, with both locoregional and systemic treatment options available. With the increasing use of novel imaging techniques such ...as PSMA-PET and MRI, combined with the increasing use of surgery for high-risk prostate cancer, clinical and pathological regional nodal disease is being detected at a higher rate and at an earlier stage than previously. This creates a window for a potentially curative management approach. The role of radiotherapy including optimal radiation target volumes and dose, as well as the timing and duration of accompanying systemic therapy remains uncertain. At a workshop in 2017, the Australian and New Zealand Faculty of Radiation Oncology Genito-Urinary Group (FROGG) identified variations in the management of node-positive prostate cancer identified on primary staging or on histopathology at radical prostatectomy. FROGG reviewed the literature and developed a set of evidence-based recommendations on the appropriate investigation and management of clinically and pathologically node-positive prostate cancer. These recommendations encompass imaging techniques, radiation treatment target volumes and doses, as well as the use of androgen deprivation therapy.
Consensus is growing that multidisciplinary meetings (MDMs) provide the best means of formulating comprehensive treatment plans for patients with cancer. Although many doctors attend MDMs and ...contribute to the decision-making process, only a few will become involved in a patient's care after the team meeting. Despite this, if a patient was grieved by a decision made in a MDM and wished to recover damages, all doctors present at the meeting would be personally accountable for decisions related to their area of expertise. Doctors should be made aware of the legal implications of their participation in such meetings. A greater awareness of these responsibilities and improved team dynamics should optimise outcomes for patients while limiting exposure of the participants to legal liability. Special attention should be given to providing patients with adequate information in this combined speciality setting.
Prostate cancer (PC) is the most common malignancy in men. Internal radiotherapy (brachytherapy) has been used to treat PC successfully for over a century. In particular, there is level-one evidence ...of the benefits of using brachytherapy to escalate the dose of radiotherapy compared with standard external beam radiotherapy approaches. However, the use of PC brachytherapy is declining, despite strong evidence for its improved cancer outcomes. A method using external beam radiotherapy known as virtual high-dose-rate brachytherapy boost (vHDRB) aims to noninvasively mimic a brachytherapy boost radiation dose plan. In this review, we consider the evidence supporting brachytherapy boosts for PC and the continuing evolution of vHDRB approaches, culminating in the current generation of clinical trials, which will help define the role of this emerging modality.
To report feasibility, early toxicity, and PSA kinetics following gantry-based, stereotactic radiotherapy (SBRT) boost within a prospective, phase 2, multicenter study (PROMETHEUS: ...ACTRN12615000223538).
Patients were treated with gantry-based SBRT, 19-20 Gy in two fractions delivered 1 week apart, followed by conventionally fractionated IMRT (46 Gy in 23 fractions). The study mandated MRI fusion for RT planning, rectal displacement, and intrafraction image guidance. Toxicity was prospectively graded using the Common Terminology Criteria for Adverse Events version 4.0 (CTCAE v4).
Between March 2014 and July 2018, 135 patients (76% intermediate, 24% high-risk) with a median age of 70 years (range 53-81) were treated across five centers. Short course (≤6 months) androgen deprivation therapy (ADT) was used in 36% and long course in 18%. Rectal displacement method was SpaceOAR in 59% and Rectafix in 41%. Forty-two and ninety-three patients were treated at the 19 Gy and 20 Gy dose levels, respectively. Median follow-up was 24 months. Acute grade 2 gastrointestinal (GI) and urinary toxicity occurred in 4.4 and 26.6% with no acute grade 3 toxicity. At 6, 12, 18, 24, and 36 months post-treatment the prevalence of late grade ≥2 gastrointestinal toxicity was 1.6, 3.7, 2.2, 0, and 0%, respectively, and the prevalence of late grade ≥2 urinary toxicity was 0.8, 11, 12, 7.1, and 6.3%, respectively. Three patients experienced grade 3 late toxicity at 12 to 18 months which subsequently resolved to grade 2 or less. For patients not receiving ADT the median PSA value pre-treatment was 7.6 ug/L (1.1-20) and at 12, 24, and 36 months post-treatment was 0.86, 0.36, and 0.20 ug/L.
Delivery of a gantry-based SBRT boost is feasible in a multicenter setting, is well-tolerated with low rates of early toxicity and is associated with promising PSA responses. A second transient peak in urinary toxicity was observed at 18 months which subsequently resolved. Follow-up is ongoing to document late toxicity, long-term patient reported outcomes, and tumor control with this approach.
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