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. 2020 May-Jun;25(3):360-366.
doi: 10.1016/j.rpor.2020.03.010. Epub 2020 Mar 19.

A comparison of a moderately hypofractionated IMRT planning technique used in a randomised UK external beam radiotherapy trial with an in-house technique for localised prostate cancer

Ian Gleeson  1
Affiliations

A comparison of a moderately hypofractionated IMRT planning technique used in a randomised UK external beam radiotherapy trial with an in-house technique for localised prostate cancer

Ian Gleeson. Rep Pract Oncol Radiother. 2020 May-Jun.

Abstract

Aim: To compare the radiotherapy technique used in a randomised trial with VMAT and an in-house technique for prostate cancer.

Background: Techniques are evolving with volumetric modulated arc therapy (VMAT) commonly used. The CHHiP trial used a 3 PTV forward planned IMRT technique (FP_CH). Our centre has adopted a simpler two PTV technique with locally calculated margins.

Materials and methods: 25 patients treated with FP_CH to 60 Gy in 20 fractions were re-planned with VMAT (VMAT_CH) and a two PTV protocol (VMAT_60/52 and VMAT_60/48). Target coverage, conformity index (CI), homogeneity index (HI), monitor units (MU) and dose to the rectum, bladder, hips and penile bulb were compared.

Results: PTV coverage was high for all techniques. VMAT_CH plans had better CI than FP_CH (p ≤ 0.05). VMAT_60/52/48 plans had better CI than VMAT_CH. FP_CH had better HI and fewer MU than VMAT (p ≤ 0.05). More favourable rectum doses were found for VMAT _CH than FP_CH (V48.6, V52.8, V57, p ≤ 0.05) with less difference for bladder (p ≥ 0.05). Comparing VMAT_CH to VMAT_60/52/48 showed little differences for the bladder and rectum but VMAT_CH had larger penile bulb doses (V40.8, V48.6, mean, D2, p ≤ 0.05). Femoral head doses (V40.8) were similarly low for all techniques (p = ≥ 0.05).

Conclusion: VMAT produced more conformal plans with smaller rectum doses compared to FP_CH albeit worse HI and more MU. VMAT_60/52 and VMAT_60/48 plans had similar rectal and bladder doses to VMAT_CH but better CI and penile bulb doses which may reduce toxicity.

Keywords: Dosimetric comparison; Hypofractionation; Intensity modulated radiotherapy; Planning technique; Prostate cancer.

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Figures

Fig. 1
Fig. 1
Mean rectum doses for all techniques.
Fig. 2
Fig. 2
Mean bladder doses for all techniques.
Fig. 3
Fig. 3
Mean penile bulb doses for all techniques.
Fig. 4
Fig. 4
Dose distributions for the 4 techniques.
See this image and copyright information in PMC

References

    1. Barrett A., Dobbs J., Morris S., Roques T. 4th ed. Hodder Arnold; London: 2009. Practical radiotherapy planning; p. 332.
    1. Cancer Research UK. Prostate cancer statistics, https://www.cancerresearchuk.org/health-professional/cancer-statistics/s... [Accessed online September 2019].
    1. Dearnaley D., Syndikus I., Mossop H. Conventional versus hypofractionated high-dose intensity modulated radiotherapy for prostate cancer: 5-year outcomes of the randomised, non-inferiority phase 3 CHHiP trial. Lancet Oncol. 2016;17:1047–1060. - PMC - PubMed
    1. Widmark A., Gunnlaugsson A., Beckman L. Ultra-hypofractionated versus conventionally fractionated radiotherapy for prostate cancer: 5-year outcomes of the HYPO-RT-PC randomised, non-inferiority, phase 3 trial. Lancet. 2019;394(10196):385–395. - PubMed
    1. Jackson W.C., Silva J., Hartman H.E. Stereotactic body radiation therapy for localized prostate cancer: a systematic review and meta analysis of over 6,000 patients treated on prospective studies. Int J Radiat Oncol Biol Phys. 2019;104(4):778–789. - PMC - PubMed

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