Colin J Hornby

Publications (12) View all

• Article: Reducing posttreatment dysphagia: Support for the relationship between radiation dose to the pharyngeal constrictors and swallowing outcomes

  Jacqui Frowen, Colin Hornby, Marnie Collins, Sashendra Senthi, Robin Cassumbhoy, June Corry
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  ABSTRACT: Purpose This study used prospective swallowing data to establish the following: (1) whether doses to the pharyngeal constrictor muscles (PCMs) were significantly associated with swallowing outcomes; and (2) a mean dose constraint to aim for in intensity modulated radiation therapy planning. Methods and Materials The PCMs were contoured and radiation dose data obtained for 55 patients with head and neck cancer. Associations between radiation dose and percentage of pharyngeal residue, penetration-aspiration and activity limitation measured at 6 months posttreatment were analyzed. Pretreatment swallowing function, tumor site, T classification, and chemotherapy were accounted for in multivariate analyses. Results On multivariate analysis, the percentage of pharyngeal residue was statistically significantly associated with the mean dose to the superior PCM (95% confidence interval [CI], 0.15-1.66; P = .02). Penetration-aspiration was associated with the mean dose to the superior, middle, and inferior PCMs (95% CI, 1.02-1.27; P = .003; 95% CI, 1.02-1.23; P = .003; 95% CI, 1.04-1.21; P = .003, respectively) and the mean dose to the total PCM (95% CI, 1.05-1.31; P = .001). Activity limitation was also associated with the mean dose to the superior, middle, and inferior PCMs (95% CI, 1.01-1.20; P = .02; 95% CI, 1.00-1.15; P = .04; 95% CI, 1.01-1.15; P = .02, respectively) and the mean dose to the total PCM (95% CI, 1.02-1.23; P = .01). On univariate analysis, all 3 swallowing measures were statistically significantly worse for patients who received a biologically equivalent mean dose of > 60 Gy to the PCMs. This remained significant on multivariate analysis for both penetration-aspiration and activity limitation (95% CI, 2.05-58.2, P = .004 and 95% CI, 1.14-27.7, P = .03, respectively). Conclusions The radiation dose to the PCMs is significantly associated with swallowing dysfunction. Limiting the mean PCM dose to less than 60 Gy results in better swallowing outcomes.
  Practical Radiation Oncology. 02/2013;
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  Available from: Colin J Hornby

  Article: Novel 3D conformal technique for treatment of choroidal melanoma with external beam photon radiotherapy

  Claire Phillips, Kathy Pope, Colin Hornby, Brent Chesson, Jim Cramb, Mathias Bressel
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  ABSTRACT: Introduction: To report a 3D conformal radiotherapy (3D-CRT) technique that utilises a specific eye immobilisation and treatment set-up method as an alternative to stereotactic radiotherapy (SRT), for treatment of juxtapapillary choroidal melanoma (CM) and report early treatment outcomes of this technique. Methods: A contact lens and rod system was designed to provide eye immo-bilisation and a treatment reference point for 3D-CRT. The technique is described in detail in the body of the paper. A retrospective chart review was conducted to report freedom from local progression (FFLP) and radiation toxicity in a cohort of patients treated with a dose of 50 Gy in five fractions. Results: Eleven eligible patients with juxtapapillary CM were treated between 2003 and 2009. The median follow-up was 3.2 years (range 1.2–5.3). The FFLP was 100% (95% confidence interval 71.5–100). The reproducibility of the set-up and eye immobilisation for fractionation was excellent. The mean dose to the planning target volume was 51.4 Gy (interquartilic range 51.0– 51.9). Normal tissue dose constraints were achieved; however, the quality of the 3D-CRT plan was variable. The highest acute radiation toxicity score was Common Toxicity Criteria version 3 grade 1. Vision outcomes were poor. Conclusion: In this small series, a novel non-stereotactic technique was found to be an accurate method for the treatment of CM with a high rate of freedom from tumour progression, in keeping with the SRT series. The quality of the conformal plan was variable. Investigation of the optimal dose-fractionation schedule to minimise late radiation toxicity without compromise of tumour control is the focus of ongoing clinical research at our centre.
  Journal of Medical Imaging and Radiation Oncology 01/2013; · 0.87 Impact Factor
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  Available from: Farshad Foroudi

  Article: A dosimetric comparison of 3D conformal vs intensity modulated vs volumetric arc radiation therapy for muscle invasive bladder cancer.

  Farshad Foroudi, Lesley Wilson, Mathias Bressel, Annette Haworth, Colin Hornby, Daniel Pham, Jim Cramb, Suki Gill, Keen Hun Tai, Tomas Kron
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  ABSTRACT: To compare 3 Dimensional Conformal radiotherapy (3D-CRT) with Intensity Modulated Radiotherapy (IMRT) with Volumetric-Modulated Arc Therapy (VMAT) for bladder cancer. Radiotherapy plans for 15 patients with T2-T4N0M0 bladder cancer were prospectively developed for 3-DCRT, IMRT and VMAT using Varian Eclipse planning system. The same radiation therapist carried out all planning and the same clinical dosimetric constraints were used. 10 of the patients with well localised tumours had a simultaneous infield boost (SIB) of the primary tumour planned for both IMRT and VMAT. Tumour control probabilities and normal tissue complication probabilities were calculated. Mean planning time for 3D-CRT, IMRT and VMAT was 30.0, 49.3, and 141.0 minutes respectively. The mean PTV conformity (CI) index for 3D-CRT was 1.32, for IMRT 1.05, and for VMAT 1.05. The PTV Homogeneity (HI) index was 0.080 for 3D-CRT, 0.073 for IMRT and 0.086 for VMAT. Tumour control and normal tissue complication probabilities were similar for 3D-CRT, IMRT and VMAT. The mean monitor units were 267 (range 250-293) for 3D-CRT; 824 (range 641-1083) for IMRT; and 403 (range 333-489) for VMAT (P < 0.05). Average treatment delivery time were 2:25min (range 2:01-3:09) for 3D-CRT; 4:39 (range 3:41-6:40) for IMRT; and 1:14 (range 1:13-1:14) for VMAT. In selected patients, the SIB did not result in a higher dose to small bowel or rectum. VMAT is associated with similar dosimetric advantages as IMRT over 3D-CRT for muscle invasive bladder cancer. VMAT is associated with faster delivery times and less number of mean monitor units than IMRT. SIB is feasible in selected patients with localized tumours.
  Radiation Oncology 07/2012; 7:111. · 2.32 Impact Factor
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  Available from: Colin J Hornby

  Article: Optimising the dosimetric quality and efficiency of post-prostatectomy radiotherapy: a planning study comparing the performance of volumetric-modulated arc therapy (VMAT) with an optimised seven-field intensity-modulated radiotherapy (IMRT) technique.

  Brandon T Nguyen, Colin Hornby, Tomas Kron, Jim Cramb, Aldo Rolfo, Daniel Pham, Annette Haworth, Keen-Hun Tai, Farshad Foroudi
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  ABSTRACT: The purpose of this study was to compare and evaluate radiotherapy treatment plans using volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT) for post-prostatectomy radiotherapy. The quality of radiotherapy plans for 10 patients planned and treated with a seven-field IMRT technique for biochemical failure post-prostatectomy were subsequently compared with 10 prospectively planned single-arc VMAT plans using the same computed tomography data set and treatment planning software. Plans were analysed using parameters to assess for target volume coverage, dose to organs at risk (OAR), biological outcomes, dose conformity and homogeneity, as well as the total monitor units (MU), planning and treatment efficiency. The mean results for the study population are reported for the purpose of comparison. For IMRT, the median dose to the planning target volume, V(95%) and D(95%) was 71.1 Gy, 98.9% and 68.3 Gy compared with 71.2 Gy, 99.2% and 68.6 Gy for VMAT. There was no significant difference in the conformity index or homogeneity index. The VMAT plans achieved better sparing of the rectum and the left and right femora with a reduction in the median dose by 7.9, 6.3 and 3.6 Gy, respectively. The total number of monitor units (MU) was reduced by 24% and treatment delivery time by an estimated 3 min per fraction without a significant increase in planning requirements. VMAT can achieve post-prostatectomy radiotherapy plans of comparable quality to IMRT with the potential to reduce dose to OAR and improve the efficiency of treatment delivery.
  Journal of Medical Imaging and Radiation Oncology 04/2012; 56(2):211-9. · 0.87 Impact Factor
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  Available from: Colin J Hornby

  Article: Minimising critical organ irradiation in limited stage Hodgkin lymphoma: a dosimetric study of the benefit of involved node radiotherapy.

  B A Campbell, C Hornby, J Cunninghame, M Burns, M MacManus, G Ryan, E Lau, J F Seymour, A Wirth
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  ABSTRACT: Chemotherapy plus radiotherapy is the standard of care for patients with limited stage Hodgkin lymphoma (HL). Radiotherapy is evolving from involved field radiotherapy (IFRT) to involved node radiotherapy (INRT) to decrease radiotherapy-related morbidity. In the absence of long-term toxicity data, dose-volume metrics of organs at risk (OAR) provide a surrogate measure of toxicity risk. Ten female patients with stage I-IIA supradiaphragmatic HL were randomly selected. All patients had pre-chemotherapy computerised tomography (CT) and CT-positron emission tomography staging. Using CT planning, three radiotherapy plans were produced per patient: (i) IFRT, (ii) INRT using parallel-opposed beams and (iii) INRT using volumetric modulated arc therapy (VMAT). Radiotherapy dose was 30.6 Gy in 1.8 Gy fractions. OAR evaluated were lungs, breasts, thyroid, heart and coronary arteries. Compared with IFRT, INRT significantly reduced mean doses to lungs (P < 0.01), breasts (P < 0.01), thyroid (P < 0.01) and heart (P < 0.01), on Wilcoxon testing. Compared with conventional INRT, VMAT improved dose conformality but increased low-dose radiation exposure to lungs and breasts. VMAT reduced the heart volume receiving 30 Gy (V30) by 85%. Reduction from IFRT to INRT decreased the volumes of lungs, breasts and thyroid receiving high-dose radiation, suggesting the potential to reduce long-term second malignancy risks. VMAT may be useful for patients with pre-existing heart disease by minimising further cardiac toxicity risks.
  Annals of Oncology 11/2011; 23(5):1259-66. · 6.43 Impact Factor