Waiting for radiotherapy: new initiatives may transform service.
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Humans↗
Biomedical subjects
Robin D Hunter
Publications and source records attributed to Robin D Hunter.
Compensation for changes in dose-rate in radical low-dose-rate brachytherapy: a radiobiological analysis of a randomised clinical trial.
BACKGROUND AND PURPOSE: This study reanalysed the results of the Cs-137 low-dose-rate brachytherapy trials for stage I and II cervix carcinoma at the Christie Hospital, Manchester, UK, in order to quantify the clinical outcome as a function of dose, and to extract radiobiological parameter values by modelling the data for local control and morbidity. PATIENTS AND METHODS: Kaplan-Meier survival curves and Cox regression analyses were used to analyse the time to event data. Linear-quadratic (LQ) analysis was also used in a mixture model, incorporating a half-time for repair, a time factor, and a heterogeneity function between patients. Full 5-year follow-up data were available for 339 patients receiving Cs-137 doses between 60 and 75 Gy delivered at 1.4-1.8 Gy/h, and 178 patients receiving a Ra-226 dose of 75 Gy at 0.5 Gy/h, using two insertions 7-10 days apart. RESULTS: With the increased dose-rate, a dose reduction between 20 and 25% was required to achieve a similar morbidity rate. This reduction had a detrimental effect on tumour control, by about 15% points. Unexpectedly, this loss in local control did not lead to a decrease in cancer-specific survival. For both tumour control and complications a high alpha/beta and short half-time for repair best fitted the data, suggesting that consequential late reactions may be responsible for much of the bowel and urinary morbidity after these short treatments. The variability in response between patients was greater (CV 40%) for morbidity than for tumour control (CV 17%), probably reflecting the greater variation in dose at the target tissue. There was no significant dependence on overall treatment time detected over the 7-10-day range of these treatments. CONCLUSIONS: The therapeutic ratio was somewhat less for the higher dose-rate, in agreement with radiobiological expectations, although cancer-specific survival was inexplicably unchanged. The LQ-parameter analysis suggests that high alpha/beta ratios and/or short repair half-times are applicable for both tumour and normal tissue responses in these treatments.
Brachytherapy↗
Training logbook for radiotherapy.
AIM: To develop a structured logbook for trainees in the medical specialty of radiotherapy with Europe that records the increasing experience throughout their training period. MATERIAL AND METHODS: A working party appointed by the European Board of Radiotherapy developed a draft version of a European logbook for trainees in radiotherapy. For development, the update European Core Curriculum for Radiotherapists (Radiation Oncologists) was taken into consideration. The logbook is composed of six sections: (1) biodata of the trainee, (2) scientific training documentation, (3) clinical training documentation, (4) record of formal presentations by the trainee, (5) publications, (6) training courses. Decisions were made to suggest that the clinical section of the logbook should: (a) only collect data that was essential for the purposes of appraisal, assessment and regulation, (b) be as user friendly as possible, (c) concentrate on quality of the data and not volume. The logbook was tested by trainees in several European training departments and adapted according to their suggestions. A final draft of the logbook was circulated among the national and professional societies for radiotherapy in Europe for review before a European consensus conference took place in Brussels in December 2002. RESULTS: The European training logbook for radiotherapy was endorsed by representatives of 35 European nations during the Brussels consensus conference on December 14, 2002. CONCLUSION: Keeping a training logbook is an essential feature of the record of training for all EU trainees who wish to retain an opportunity to spend part of their training time in another country of the Union, important for someone who seeks an appointment as a specialist in another country within a few years of achieving specialist accreditation, and good professional practice for all other trainees. The European training logbook for radiotherapy is a robust instrument that allows the systematic collection of the information that needs to be recorded to monitor the professional development of European trainees in Radiation Oncology.
Clinical Competence↗
Prediction of radiotherapy outcome using dynamic contrast enhanced MRI of carcinoma of the cervix.
PURPOSE: To investigate whether analysis of MRI enhancement data using a pharmacokinetic model improved a previously found correlation between contrast enhancement and tumor oxygenation measured using PO2 histograph. To evaluate the prognostic value of gadolinium enhancement data for radiotherapy outcome, and to study the efficacy of combined enhancement and MRI volume data. METHODS AND MATERIALS: Fifty patients underwent dynamic gadolinium-enhanced MRI as part of their initial staging investigations before treatment. Gadolinium enhancement was analyzed using the Brix pharmacokinetic model to obtain the parameters amplitude and rate of contrast enhancement. Pretreatment tumor oxygen measurements (Eppendorf PO2 histograph) were available for 35 patients. RESULTS: Both standard and pharmacokinetic-derived enhancement data correlated with tumor oxygenation measurements, and poorly enhancing tumors had low tumor oxygen levels. However, only the pharmacokinetic-analyzed data correlated with patient outcome and patients with poorly (amplitude less than median) vs. well-enhancing tumors had significantly worse disease-specific survival (p = 0.024). For the 50 patients studied, no relationship was found between enhancement and volume data. Combining MRI volume and enhancement information highlighted large differences in outcome (p = 0.0054). At the time of analysis, only 55% of patients with large, poorly enhanced tumors were alive compared with 92% of patients with small, well-enhanced tumors. CONCLUSION: These preliminary results suggest that pharmacokinetic modeling of dynamic contrast-enhanced MRI provides data that reflect tumor oxygenation and yields useful prognostic information in patients with locally advanced carcinoma of the cervix. Combining MRI-derived enhancement and volume data delineates large differences in radiotherapy outcome.
Adenocarcinoma↗