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Dive into the research topics where Kerwyn Foo is active.

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Featured researches published by Kerwyn Foo.


Lancet Oncology | 2007

Survival benefits from neoadjuvant chemoradiotherapy or chemotherapy in oesophageal carcinoma: a meta-analysis

Val Gebski; Bryan Burmeister; B. Mark Smithers; Kerwyn Foo; John Zalcberg; John Simes

BACKGROUND Resectable oesophageal cancer is often treated with surgery alone or with preoperative (neoadjuvant) chemoradiotherapy or chemotherapy. We aimed to clarify the benefits of neoadjuvant chemoradiotherapy or chemotherapy versus surgery alone by a meta-analysis of randomised trial data. METHODS Eligible trials were identified first from earlier published meta-analyses and systematic reviews. We also used MEDLINE, Cancerlit, and EMBASE databases to identify additional studies and published abstracts from major scientific meetings since 1980. Only randomised studies with an analysis by an intention-to-treat principle were included, and searches were restricted to those databases citing articles in English. We used published hazard ratios if available or estimates from other survival data or survival curves. Treatment effects by type of tumour and treatment sequencing were also investigated. FINDINGS Ten randomised comparisons of neoadjuvant chemoradiotherapy versus surgery alone (n=1209) and eight of neoadjuvant chemotherapy versus surgery alone (n=1724) in patients with local operable oesophageal carcinoma were identified. The hazard ratio for all-cause mortality with neoadjuvant chemoradiotherapy versus surgery alone was 0.81 (95% CI 0.70-0.93; p=0.002), corresponding to a 13% absolute difference in survival at 2 years, with similar results for different histological tumour types: 0.84 (0.71-0.99; p=0.04) for squamous-cell carcinoma (SCC), and 0.75 (0.59-0.95; p=0.02) for adenocarcinoma. The hazard ratio for neoadjuvant chemotherapy was 0.90 (0.81-1.00; p=0.05), which indicates a 2-year absolute survival benefit of 7%. There was no significant effect on all-cause mortality of chemotherapy for patients with SCC (hazard ratio 0.88 [0.75-1.03]; p=0.12), although there was a significant benefit for those with adenocarcinoma (0.78 [0.64-0.95]; p=0.014). INTERPRETATION A significant survival benefit was evident for preoperative chemoradiotherapy and, to a lesser extent, for chemotherapy in patients with adenocarcinoma of the oesophagus. The findings provide an evidence-based framework for the use of neoadjuvant treatment in management decisions.


International Journal of Radiation Oncology Biology Physics | 2010

DOSE-VOLUME CONSTRAINTS TO REDUCE RECTAL SIDE EFFECTS FROM PROSTATE RADIOTHERAPY: EVIDENCE FROM MRC RT01 TRIAL ISRCTN 47772397

S. Gulliford; Kerwyn Foo; Rachel C. Morgan; Edwin Aird; A. Margaret Bidmead; Helen Critchley; Philip M. Evans; Stefano Gianolini; W. Philip M. Mayles; A.Rollo Moore; B. Sánchez-Nieto; Mike Partridge; Matthew R. Sydes; S Webb; David P. Dearnaley

PURPOSE Radical radiotherapy for prostate cancer is effective but dose limited because of the proximity of normal tissues. Comprehensive dose-volume analysis of the incidence of clinically relevant late rectal toxicities could indicate how the dose to the rectum should be constrained. Previous emphasis has been on constraining the mid-to-high dose range (>/=50 Gy). Evidence is emerging that lower doses could also be important. METHODS AND MATERIALS Data from a large multicenter randomized trial were used to investigate the correlation between seven clinically relevant rectal toxicity endpoints (including patient- and clinician-reported outcomes) and an absolute 5% increase in the volume of rectum receiving the specified doses. The results were quantified using odds ratios. Rectal dose-volume constraints were applied retrospectively to investigate the association of constraints with the incidence of late rectal toxicity. RESULTS A statistically significant dose-volume response was observed for six of the seven endpoints for at least one of the dose levels tested in the range of 30-70 Gy. Statistically significant reductions in the incidence of these late rectal toxicities were observed for the group of patients whose treatment plans met specific proposed dose-volume constraints. The incidence of moderate/severe toxicity (any endpoint) decreased incrementally for patients whose treatment plans met increasing numbers of dose-volume constraints from the set of V30<or=80%, V40<or=65%, V50<or=55%, V60<or=40%, V65<or=30%, V70<or=15%, and V75<or=3%. CONCLUSION Considering the entire dose distribution to the rectum by applying dose-volume constraints such as those tested here in the present will reduce the incidence of late rectal toxicity.


Medical Dosimetry | 2011

Comparison of prostate IMRT and VMAT biologically optimised treatment plans.

Nicholas Hardcastle; Wolfgang A. Tomé; Kerwyn Foo; Andrew Alexis Miller; Martin G Carolan; Peter E Metcalfe

Recently, a new radiotherapy delivery technique has become clinically available--volumetric modulated arc therapy (VMAT). VMAT is the delivery of IMRT while the gantry is in motion using dynamic leaf motion. The perceived benefit of VMAT over IMRT is a reduction in delivery time. In this study, VMAT was compared directly with IMRT for a series of prostate cases. For 10 patients, a biologically optimized seven-field IMRT plan was compared with a biologically optimized VMAT plan using the same planning objectives. The Pinnacle RTPS was used. The resultant target and organ-at-risk dose-volume histograms (DVHs) were compared. The normal tissue complication probability (NTCP) for the IMRT and VMAT plans was calculated for 3 model parameter sets. The delivery efficiency and time for the IMRT and VMAT plans was compared. The VMAT plans resulted in a statistically significant reduction in the rectal V25Gy parameter of 8.2% on average over the IMRT plans. For one of the NTCP parameter sets, the VMAT plans had a statistically significant lower rectal NTCP. These reductions in rectal dose were achieved using 18.6% fewer monitor units and a delivery time reduction of up to 69%. VMAT plans resulted in reductions in rectal doses for all 10 patients in the study. This was achieved with significant reductions in delivery time and monitor units. Given the target coverage was equivalent, the VMAT plans were superior.


Physics in Medicine and Biology | 2011

Surface dosimetry for breast radiotherapy in the presence of immobilization cast material

Andrew H Kelly; Nicholas Hardcastle; Peter E Metcalfe; Dean L Cutajar; Alexandra Quinn; Kerwyn Foo; Michael Cardoso; Sheree Barlin; Anatoly B. Rosenfeld

Curative breast radiotherapy typically leaves patients with varying degrees of cosmetic damage. One problem interfering with cosmetically acceptable breast radiotherapy is the external contour for large pendulous breasts which often results in high doses to skin folds. Thermoplastic casts are often employed to secure the breasts to maintain setup reproducibility and limit the presence of skin folds. This paper aims to determine changes in surface dose that can be attributed to the use of thermoplastic immobilization casts. Skin dose for a clinical hybrid conformal/IMRT breast plan was measured using radiochromic film and MOSFET detectors at a range of water equivalent depths representative of the different skin layers. The radiochromic film was used as an integrating dosimeter, while the MOSFETs were used for real-time dosimetry to isolate the contribution of skin dose from individual IMRT segments. Strips of film were placed at various locations on the breast and the MOSFETs were used to measure skin dose at 16 positions spaced along the film strips for comparison of data. The results showed an increase in skin dose in the presence of the immobilization cast of up to 45.7% and 62.3% of the skin dose without the immobilization cast present as measured with Gafchromic EBT film and MOSFETs, respectively. The increase in skin dose due to the immobilization cast varied with the angle of beam incidence and was greatest when the beam was normally incident on the phantom. The increase in surface dose with the immobilization cast was greater under entrance dose conditions compared to exit dose conditions.


Clinical Lymphoma, Myeloma & Leukemia | 2008

Efficacy of palliative low-dose involved-field radiation therapy in advanced lymphoma: a phase II study.

Vedang Murthy; Karen Thomas; Kerwyn Foo; David Cunningham; Bernadette Johnson; Andrew R. Norman; A. Horwich

PURPOSE To confirm the efficacy of low-dose involved-field radiation therapy (LD-IFRT) as palliative treatment in patients symptomatic from advanced lymphoma. PATIENTS AND METHODS A total of 36 patients (47 sites), received 4 Gy in 2 fractions to the lymphoma with a 1.5-2-cm margin. Pathology subtypes included 29 (62%) sites with indolent lymphoma and 18 (36%) sites with aggressive lymphoma histology. Bulky disease was seen in 22 (48%) sites and, of these, 6 sites had disease > 10 cm. A median of 3 previous chemotherapy regimens (range, 0 to 9 regimens) preceded LD-IFRT. The primary endpoint of the study was in-field lymphoma control. Patients completed the European Organization for the Research and Treatment of Cancer QLQ-C30 quality of life (QOL) questionnaire before RT and at 3-4 weeks after treatment. RESULTS The overall response rate (RR) at 1-3 months after the RT was 75%. A complete remission (CR) was observed in 13 patients (36%) lasting up to a maximum of 31.3 months and ongoing at analysis. A partial remission (PR) was achieved in 14 patients (39%) lasting up to 10 months. The response rate for non-diffuse large B-cell lymphoma (DLBCL) sites was 86%, while it was 50% for sites with DLBCL histology. Median time to local progression for the entire group was 15 months. There was no statistical difference between the QOL before and after LD-IFRT. CONCLUSION LD-IFRT is an effective and easy treatment for patients with advanced lymphoma that can be repeated at previously irradiated sites, a particularly useful attribute because of the relapsing nature, especially of advanced follicular subtypes.


International Journal of Radiation Oncology Biology Physics | 2015

Gastrointestinal Dose-Histogram Effects in the Context of Dose-Volume-Constrained Prostate Radiation Therapy: Analysis of Data From the RADAR Prostate Radiation Therapy Trial

Martin A. Ebert; Kerwyn Foo; Annette Haworth; S. Gulliford; Angel Kennedy; David Joseph; James W. Denham

PURPOSE To use a high-quality multicenter trial dataset to determine dose-volume effects for gastrointestinal (GI) toxicity following radiation therapy for prostate carcinoma. Influential dose-volume histogram regions were to be determined as functions of dose, anatomical location, toxicity, and clinical endpoint. METHODS AND MATERIALS Planning datasets for 754 participants in the TROG 03.04 RADAR trial were available, with Late Effects of Normal Tissues (LENT) Subjective, Objective, Management, and Analytic (SOMA) toxicity assessment to a median of 72 months. A rank sum method was used to define dose-volume cut-points as near-continuous functions of dose to 3 GI anatomical regions, together with a comprehensive assessment of significance. Univariate and multivariate ordinal regression was used to assess the importance of cut-points at each dose. RESULTS Dose ranges providing significant cut-points tended to be consistent with those showing significant univariate regression odds-ratios (representing the probability of a unitary increase in toxicity grade per percent relative volume). Ranges of significant cut-points for rectal bleeding validated previously published results. Separation of the lower GI anatomy into complete anorectum, rectum, and anal canal showed the impact of mid-low doses to the anal canal on urgency and tenesmus, completeness of evacuation and stool frequency, and mid-high doses to the anorectum on bleeding and stool frequency. Derived multivariate models emphasized the importance of the high-dose region of the anorectum and rectum for rectal bleeding and mid- to low-dose regions for diarrhea and urgency and tenesmus, and low-to-mid doses to the anal canal for stool frequency, diarrhea, evacuation, and bleeding. CONCLUSIONS Results confirm anatomical dependence of specific GI toxicities. They provide an atlas summarizing dose-histogram effects and derived constraints as functions of anatomical region, dose, toxicity, and endpoint for informing future radiation therapy planning.


Journal of Medical Imaging and Radiation Oncology | 2010

Rectal dose reduction with IMRT for prostate radiotherapy

Nicholas Hardcastle; A Davies; Kerwyn Foo; Andrew Alexis Miller; Peter E Metcalfe

Dose escalation in radiation therapy has led to increased control rates with some clinical trial evidence that rectal toxicity may be reduced when using intensity‐modulated radiotherapy (IMRT) over 3D conformal radiotherapy (3DCRT) for dose‐escalated prostate radiotherapy. However, IMRT for prostate patients is not yet standard in many Australian radiation oncology centres. This study investigates dosimetric changes that can be observed between IMRT and 3DCRT in prostate radiotherapy. Fifteen patients were selected for analysis. Two target definitions were investigated – prostate‐only and prostate plus seminal vesicles (p + SVs). A five‐field 3DCRT and seven‐field IMRT plan were created for each patient and target definition. The planning target volume coverage was matched for both plans. Doses to the rectum, bladder and femoral heads were compared using dose volume histograms. The rectal normal tissue complication probabilities (NTCPs) were calculated and compared for the 3DCRT and IMRT plans. The delivery efficiency was investigated. The IMRT plans resulted in reductions in the V25, V50, V60, V70 and V75 Gy values for both the prostate‐only and p + SVs targets. Rectal NTCP was reduced with IMRT for three different sets of model parameters. The reductions in rectal dose and NTCP were much larger for the p + SVs target. Delivery of IMRT plans was less efficient than for 3DCRT plans. IMRT resulted in superior plans based on dosimetric and biological endpoints. The dosimetric gains with IMRT were greater for the more complex p + SVs target. The gains made came at the cost of decreased delivery efficiency.


Journal of Medical Imaging and Radiation Oncology | 2012

Constrained-beam inverse planning for intensity-modulated radiation therapy of prostate cancer patients with bilateral hip prostheses

Darren Martin; George Hruby; May Whitaker; Kerwyn Foo

Hip prostheses present a technical challenge in the planning of curative external beam radiation treatment for patients with prostate cancer. Bilateral prostheses compel planners to compromise between target coverage and avoidance of beam entry through the prostheses. Inverse planning systems given objectives to avoid dose to prostheses are overly restricted from allowing exit dose to them. We report a novel inverse planning technique for intensity‐modulated radiation therapy of patients with prostate cancer and bilateral hip prostheses, by constraining beam characteristics rather than dose in the inverse planning process.


Physics in Medicine and Biology | 2014

Two non-parametric methods for derivation of constraints from radiotherapy dose-histogram data

Martin A. Ebert; S. Gulliford; F. Buettner; Kerwyn Foo; Annette Haworth; Angel Kennedy; David Joseph; James W. Denham

Dose constraints based on histograms provide a convenient and widely-used method for informing and guiding radiotherapy treatment planning. Methods of derivation of such constraints are often poorly described. Two non-parametric methods for derivation of constraints are described and investigated in the context of determination of dose-specific cut-points-values of the free parameter (e.g., percentage volume of the irradiated organ) which best reflect resulting changes in complication incidence. A method based on receiver operating characteristic (ROC) analysis and one based on a maximally-selected standardized rank sum are described and compared using rectal toxicity data from a prostate radiotherapy trial. Multiple test corrections are applied using a free step-down resampling algorithm, which accounts for the large number of tests undertaken to search for optimal cut-points and the inherent correlation between dose-histogram points. Both methods provide consistent significant cut-point values, with the rank sum method displaying some sensitivity to the underlying data. The ROC method is simple to implement and can utilize a complication atlas, though an advantage of the rank sum method is the ability to incorporate all complication grades without the need for grade dichotomization.


Journal of Medical Imaging and Radiation Oncology | 2016

Results of the Australasian (Trans-Tasman Oncology Group) radiotherapy benchmarking exercise in preparation for participation in the PORTEC-3 trial

M. Jameson; Joanne McNamara; Michael Bailey; Peter E Metcalfe; Lois C Holloway; Kerwyn Foo; Viet Do; Linda Mileshkin; Carien L. Creutzberg; Pearly Khaw

Protocol deviations in Randomised Controlled Trials have been found to result in a significant decrease in survival and local control. In some cases, the magnitude of the detrimental effect can be larger than the anticipated benefits of the interventions involved. The implementation of appropriate quality assurance of radiotherapy measures for clinical trials has been found to result in fewer deviations from protocol. This paper reports on a benchmarking study conducted in preparation for the PORTEC‐3 trial in Australasia.

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S. Gulliford

The Royal Marsden NHS Foundation Trust

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Martin A. Ebert

University of Western Australia

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Nicholas Hardcastle

Peter MacCallum Cancer Centre

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Angel Kennedy

Sir Charles Gairdner Hospital

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David Joseph

Sir Charles Gairdner Hospital

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David P. Dearnaley

Institute of Cancer Research

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