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Peter Hoskin

Publications and source records attributed to Peter Hoskin.

6 recordsLinked to original sources
PubMed2026

Technical note: reconstructing dose distributions from manually planned electron boosts in breast radiotherapy.

PURPOSE: In breast radiotherapy, delivery of manually-calculated electron boosts limits retrospective dose-response analyses as dose distribution is unavailable. This work evaluates the feasibility of reconstructing dose distributions from manually planned electron boosts in breast-conserving radiotherapy. METHODS: Only 72 out of 198 breast cancer patients had complete stored dose distributions from sequential electron boosts in the REQUITE study. Arbitrary data from 70/72 patients were used to develop and validate dose reconstruction method. Twenty patients were used to determine optimal parameters for Monte-Carlo-based (MC) electron dose reconstruction on RayStation (v.11B-R), considering CT-calibration curve, MC-history number, andcalculation grid resolution. Remaining 50 patients were used to quantify dose reconstruction accuracy. The similarity between reconstructed and stored dose was evaluated using 3D-gamma index and dosimetric parameters extracted from breast and tumour bed contours. Dose difference location was evaluated using dose-location histogram. RESULTS: Calculation grid resolution significantly impacted electron dose distribution (p&#xa0;<&#xa0;0.01), where the finest grid (0.15&#xa0;cm) showed highest similarity to stored doses. CT-calibration curve and MC-history number had a negligible influence on dose reconstruction. Dosimetric difference between reconstructed and stored doses was&#xa0;<&#xa0;1&#xa0;Gy for breast and tumour bed. Reconstructed dose was achieved&#xa0;>&#xa0;90% gamma passing rate in the validation set. However, around 2.5&#xa0;Gy dose differences were observed at the skin and tissue interface regions. CONCLUSIONS: Retrospective electron boost dose reconstruction is feasible with acceptable accuracy, and could increase data completeness in large cohort studies. Caution is advised when assessing dose near tissue interface and further validation is needed outside the REQUITE dataset.

Electrons↗
PubMed2006

Overview of brachytherapy resources in Europe: a survey of patterns of care study for brachytherapy in Europe.

BACKGROUND AND PURPOSE: The Patterns of Care for Brachytherapy in Europe (PCBE) study is aimed at establishing a detailed information system on brachytherapy throughout Europe. MATERIALS AND METHODS: The questionnaire was web-based and the analysis used data from each radiotherapy department with brachytherapy. There were three groups: Group I with 19 countries (15 initial European Community (EC) countries plus Iceland, Monaco, Norway and Switzerland -EC+4-), Group II with 10 countries (New European Community countries -NEC-) and Group III with 14 countries (Other European Countries -OEC-). RESULTS: In the European area there are 36 of 43 countries (85%) which achieved data collection from at least 50% of centres, and were included in the analysis. The tumour site that had the largest number of treated patients was gynaecological tumours. Several variations have been found in the mean number of patients treated per consultant radiation oncologist and physicist; and in the proportion of brachytherapy patients with gynaecology, prostate and breast tumours, by country and by European area. The provided data showed that the average number of brachytherapy patients per centre increased by 10% between 1997 and 2002. CONCLUSIONS: A European wide evaluation of brachytherapy practice using a web-based questionnaire is feasible and that there is considerable variation in both patterns of practice and available resources.

Brachytherapy↗
PubMed2003

Open-label, randomized study of pegfilgrastim vs. daily filgrastim as an adjunct to chemotherapy in elderly patients with non-Hodgkin's lymphoma.

Pegfilgrastim is composed of the protein filgrastim to which a 20-kDa polyethylene glycol (PEG) is covalently bound at the N-terminal residue resulting in decreased renal clearance and increased plasma half-life compared with filgrastim. This open-label, randomized, phase 2 study compared two doses of single administration pegfilgrastim (60 and 100 microg/kg) with daily doses of filgrastim (5 microg/kg/day) or no cytokine treatment after standard CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone) chemotherapy for non-Hodgkin's lymphoma in 50 elderly patients. The primary endpoint was the duration of grade 4 (severe) neutropenia (absolute neutrophil count < 0.5 x 10(9)/l) in cycle 1. Duration of grade 4 neutropenia in cycle 1 was 2.2 (SD 1.2), 1.5 (SD 1.1), 0.8 (1.2) and 5.0 (2.0) days for patients who received pegfilgrastim 60 microg/kg, pegfilgrastim 100 microg/kg, filgrastim 5 microg/kg and no cytokine, respectively. The baseline characteristics of the pegfilgrastim and filgrastim groups were imbalanced with increased bone-marrow involvement and prior therapy in the former. When the treatment groups were balanced for these risk factors, duration of grade 4 neutropenia was comparable with 2.0 and 3.0 vs. 0.6 and 0.5 days for pegfilgrastim 100 microg/kg and filgrastim patients with and without these risk factors, respectively. The incidence of febrile neutropenia (defined as ANC < 0.5 x 10(9)/l and temperature > 38.2degrees C) was low (10% of patients). Pegfilgrastim was well tolerated with a safety profile similar to daily filgrastim. Once per chemotherapy cycle administration of pegfilgrastim was comparable to filgrastim in this clinical setting.

Aged↗
PubMed2002

International consensus on palliative radiotherapy endpoints for future clinical trials in bone metastases.

PURPOSE: To reach a consensus on a set of optimal endpoint measurements for future external beam radiotherapy trials in bone metastases. METHODS: An International Bone Metastases Consensus Working Party invited principal investigators and individuals with a recognized interest in bone metastases to participate in the two surveys and a panel meeting on their preference of choice of optimal endpoints. RESULTS: Consensus has been reached on the following: (a) eligibility criteria for future trials; (b) pain and analgesic assessments; (c) radiation techniques; (d) follow-up and timing of assessments; (e) parameters at follow-up; (f) endpoints; (g) re-irradiation; and (h) statistical analysis. CONCLUSIONS: Based on the available literature and the clinical experience of the working party members, an acceptable set of endpoints has been agreed upon for future clinical trials to promote consistency in reporting. It is intended that the consensus will be re-examined every 5 years. Areas of further research were identified.

Bone Neoplasms↗