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Erectile Dysfunction and Absorbed Dose to Penile Base Structures in a Randomized Trial Comparing Ultrahypofractionated and Conventionally Fractionated Radiation Therapy for Prostate Cancer

Rasmusson, Elisabeth LU ; Gunnlaugsson, Adalsteinn LU ; Wieslander, Elinore LU ; Höglund, Peter LU ; Widmark, Anders ; Fransson, Per ; Kjellén, Elisabeth LU and Nilsson, Per LU (2020) In International Journal of Radiation Oncology Biology Physics 107(1). p.143-151
Abstract

Purpose: To study the relationships between absorbed dose to penile base structures and erectile dysfunction (ED) in patients treated with ultrahypofractionated (UHF) radiation therapy (RT) or conventionally fractionated (CF) RT for prostate cancer. Methods and Materials: This dose-response study comprises 673 patients (57%) of the 1180 per-protocol patients included in the HYPO-RT-PC trial (median follow-up 5, years), where patients were randomized to CF (39 × 2.0 Gy, 8 weeks) or UHF (7 × 6.1 Gy, 2.5 weeks). No androgen deprivation therapy was allowed. Only patients with erectile function sufficient for intercourse at baseline and complete RT data were included in this study. Erectile function was assessed by physician at regular... (More)

Purpose: To study the relationships between absorbed dose to penile base structures and erectile dysfunction (ED) in patients treated with ultrahypofractionated (UHF) radiation therapy (RT) or conventionally fractionated (CF) RT for prostate cancer. Methods and Materials: This dose-response study comprises 673 patients (57%) of the 1180 per-protocol patients included in the HYPO-RT-PC trial (median follow-up 5, years), where patients were randomized to CF (39 × 2.0 Gy, 8 weeks) or UHF (7 × 6.1 Gy, 2.5 weeks). No androgen deprivation therapy was allowed. Only patients with erectile function sufficient for intercourse at baseline and complete RT data were included in this study. Erectile function was assessed by physician at regular follow-ups. The main endpoint was severe ED (EDs). The penile bulb (PB) and crus were retrospectively delineated on the treatment planning computed tomography scans. Dose-volume descriptors were derived from EQD2 converted dose matrices (α/β = 3 Gy). Univariable and multivariable Cox proportional hazard regression and logistic regression were used to find predictors for EDS. Results: No significant difference in EDs was found between CF and UHF. During the follow-up period, EDs occurred in 27% of the patients in both treatment groups. Average (median) PB mean dose, Dmean, was 24.5 (20.2) in CF and 18.7 (13.1) Gy3 in UHF. Age was the only significant predictor for EDs in Cox analyses. All dose-volume variables contributed significantly in univariable logistic regression at 2-year follow-up. Age and near maximum dose (D2%) were significant predictors for EDs in multivariable logistic regression analyses at both 1 and 2 years. Conclusions: The frequency of EDS was similar in the CF and UHF treatment groups. Age at radiation therapy was the strongest predictor for EDs, followed by dose to PB, and was most evident for younger patients. We propose D2 % <50 Gy3 and Dmean <20 Gy3 to the PB as the primary objectives to be applied in the treatment planning process.

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published
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in
International Journal of Radiation Oncology Biology Physics
volume
107
issue
1
pages
9 pages
publisher
Elsevier
external identifiers
  • pmid:32004582
  • scopus:85080138653
ISSN
0360-3016
DOI
10.1016/j.ijrobp.2020.01.022
language
English
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yes
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798e11ac-e077-46c6-bbe5-2c31e25614aa
date added to LUP
2020-06-26 14:07:08
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2021-02-23 02:27:00
@article{798e11ac-e077-46c6-bbe5-2c31e25614aa,
  abstract     = {<p>Purpose: To study the relationships between absorbed dose to penile base structures and erectile dysfunction (ED) in patients treated with ultrahypofractionated (UHF) radiation therapy (RT) or conventionally fractionated (CF) RT for prostate cancer. Methods and Materials: This dose-response study comprises 673 patients (57%) of the 1180 per-protocol patients included in the HYPO-RT-PC trial (median follow-up 5, years), where patients were randomized to CF (39 × 2.0 Gy, 8 weeks) or UHF (7 × 6.1 Gy, 2.5 weeks). No androgen deprivation therapy was allowed. Only patients with erectile function sufficient for intercourse at baseline and complete RT data were included in this study. Erectile function was assessed by physician at regular follow-ups. The main endpoint was severe ED (ED<sub>s</sub>). The penile bulb (PB) and crus were retrospectively delineated on the treatment planning computed tomography scans. Dose-volume descriptors were derived from EQD2 converted dose matrices (α/β = 3 Gy). Univariable and multivariable Cox proportional hazard regression and logistic regression were used to find predictors for ED<sub>S</sub>. Results: No significant difference in ED<sub>s</sub> was found between CF and UHF. During the follow-up period, ED<sub>s</sub> occurred in 27% of the patients in both treatment groups. Average (median) PB mean dose, D<sub>mean</sub>, was 24.5 (20.2) in CF and 18.7 (13.1) Gy<sub>3</sub> in UHF. Age was the only significant predictor for ED<sub>s</sub> in Cox analyses. All dose-volume variables contributed significantly in univariable logistic regression at 2-year follow-up. Age and near maximum dose (D<sub>2%</sub>) were significant predictors for ED<sub>s</sub> in multivariable logistic regression analyses at both 1 and 2 years. Conclusions: The frequency of ED<sub>S</sub> was similar in the CF and UHF treatment groups. Age at radiation therapy was the strongest predictor for ED<sub>s</sub>, followed by dose to PB, and was most evident for younger patients. We propose D<sub>2 %</sub> &lt;50 Gy<sub>3</sub> and D<sub>mean</sub> &lt;20 Gy<sub>3</sub> to the PB as the primary objectives to be applied in the treatment planning process.</p>},
  author       = {Rasmusson, Elisabeth and Gunnlaugsson, Adalsteinn and Wieslander, Elinore and Höglund, Peter and Widmark, Anders and Fransson, Per and Kjellén, Elisabeth and Nilsson, Per},
  issn         = {0360-3016},
  language     = {eng},
  month        = {05},
  number       = {1},
  pages        = {143--151},
  publisher    = {Elsevier},
  series       = {International Journal of Radiation Oncology Biology Physics},
  title        = {Erectile Dysfunction and Absorbed Dose to Penile Base Structures in a Randomized Trial Comparing Ultrahypofractionated and Conventionally Fractionated Radiation Therapy for Prostate Cancer},
  url          = {http://dx.doi.org/10.1016/j.ijrobp.2020.01.022},
  doi          = {10.1016/j.ijrobp.2020.01.022},
  volume       = {107},
  year         = {2020},
}