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. 2019 Dec 31:21:77-84.
doi: 10.1016/j.ctro.2019.12.006. eCollection 2020 Mar.

Evaluation of erectile potency and radiation dose to the penile bulb using image guided radiotherapy in the CHHiP trial

Julia Murray  1   2 , Sarah Gulliford  1   3 , Clare Griffin  1 , Anna Wilkins  1 , Isabel Syndikus  4 , John Staffurth  5 , Miguel Panades  6 , Christopher Scrase  7 , Chris Parker  1   2 , Vincent Khoo  1   2 , Jamie Dean  1 , Helen Mayles  4 , Philip Mayles  4 , Simon Thomas  8 , Olivia Naismith  2 , Helen Mossop  1 , Clare Cruickshank  1 , Emma Hall  1 , David Dearnaley  1   2 ; CHHiP Investigators
Affiliations

Evaluation of erectile potency and radiation dose to the penile bulb using image guided radiotherapy in the CHHiP trial

Julia Murray et al. Clin Transl Radiat Oncol. .

Abstract

Background and purpose: The penile bulb (PB) dose may be critical in development of post prostate radiotherapy erectile dysfunction (ED). This study aimed to generate PB dose constraints based on dose-volume histograms (DVHs) in patients treated with prostate radiotherapy, and to identify clinical and dosimetric parameters that predict the risk of ED post prostate radiotherapy.

Materials and methods: Penile bulb DVHs were generated for 276 patients treated within the randomised IGRT substudy of the multicentre randomised trial, CHHiP. Incidence of ED in relation to dose and randomised IGRT groups were evaluated using Wilcoxon rank sum, Chi-squared test and atlases of complication incidence. Youden index was used to find dose-volume constraints that discriminated for ED. Multivariate analysis (MVA) of effect of dosimetry, clinical and patient-related variables was performed.

Results: Reduced treatment margins using IGRT (IGRT-R) produced significantly reduced mean PB dose compared with standard margins (IGRT-S) (median: 25 Gy (IGRT-S) versus 11 Gy (IGRT-R); p < 0.0001). Significant difference in both mean (median: 23 Gy (ED) vs. 18 Gy (no ED); p = 0.011) and maximum (median: 59 Gy (ED) vs. 52 Gy (no ED); p = 0.018) PB doses between those with and without clinician reported ED were identified. Mean PB dose cut-point for ED was derived at around 20 Gy. On MVA, PB mean dose and age predicted for impotence.

Conclusion: PB dose appears predictive of post-radiotherapy ED with calculated threshold mean dose of around 20 Gy, substantially lower than published recommendations. IGRT-R enables favourable PB dosimetry and can be recommended provided prostate coverage is not compromised.

Keywords: Erectile dysfunction; Image-guided radiotherapy; Penile bulb; Prostate.

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Figures

Fig. 1
Fig. 1
Trial profile (*endpoints assessable means those patients with DICOM data and complete endpoint data for evaluation). DICOM: Digital imaging and Communications in medicine and is a standard for storing and transmitting medical images; F: fractions.
Fig. 2
Fig. 2
Boxplots illustrating the dose distribution for the calculated dose (Gy) of the penile bulb by IGRT group. IGRT: image guided radiotherapy; IGRT-R: IGRT with reduced margins; IGRT-S: IGRT with standard margins.
Fig. 3
Fig. 3
Boxplots summarising the impact of penile bulb dosimetry on the defined toxicity endpoints using clinician (RMH) reported outcomes. Defined endpoints: RMH Grade 2 EP; 0 = no; 1 = yes. p values determined by Wilcoxon rank sum.
Fig. 4
Fig. 4
Atlases of complication incidence for RMH Grade 2 erectile potency at 2 years in (A) all patients with recorded erectile potency at 2 years and (B) patients treated with IGRT (standard and reduced margins) with recorded erectile potency at 2 years. Dose (Gy) is the equivalent dose in 2 Gy/F using alpha/beta ratio of 3 Gy. The colour of the box is determined by the fractional incidence of the endpoint, with the orange to red representing 70–100%. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Fig. 5
Fig. 5
(A) Chosen model variables, regression coefficient, multiplication values for the variables included in the model and metrics exploring the performance of the model. (B) ROC curve obtained applying model for RMH Grade 2 EP and calibration plot for internal validation. The circles represent the Hosmer-Lemeshow groups, the solid line represents the identity line.
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References

    1. Hamdy F.C., Donovan J.L., Lane J.A., Mason M., Metcalfe C., Holding P. 10-Year outcomes after monitoring, surgery, or radiotherapy for localized prostate cancer. N Engl J Med [Internet] 2016;375(15):1415–1424. http://www.nejm.org/doi/10.1056/NEJMoa1606220 Available from. - DOI - PubMed
    1. Soerjomataram I., Lortet-Tieulent J., Parkin D.M., Ferlay J., Mathers C., Forman D. Global burden of cancer in 2008: a systematic analysis of disability-adjusted life-years in 12 world regions. Lancet. 2012;380(9856):1840–1850. - PubMed
    1. Roach M., III, Nam J., Gagliardi G., El Naqa I., Deasy J.O., Marks L.B. Radiation dose-volume effects and the penile bulb. Int J Radiat Oncol Biol Phys [Internet] 2010;76(3 Suppl):S130–S134. http://www.ncbi.nlm.nih.gov/pubmed/20171507 Available from. - PMC - PubMed
    1. Feldman H.A., Goldstein I., Hatzichristou D.G., Krane R.J., McKinklay J.B. Impotence and its medical and physiological correlates: results of the Massacheusetts male aging study. J Urol. 1994;151:54–61. - PubMed
    1. Fisher W.A., Eardley I., McCabe M., Sand M. Erectile dysfunction (ED) is a shared sexual concern of couples I: couple conceptions of ED. J Sex Med. 2009;6(10):2746–2760. - PubMed

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