Baseline-Status und Dosis auf den Bulbus penis als Prädiktoren für Impotenz ein Jahr nach Radiotherapie bei Prostatakrebs

Cesare Cozzarini, Tiziana Rancati, Fabio Badenchini, Federica Palorini, Barbara Avuzzi, Claudio Degli Esposti, Giuseppe Girelli, Ilaria Improta, Vittorio Vavassori, Riccardo Valdagni, Claudio Fiorino

Research output: Contribution to journalArticle

Abstract

Aim: To assess the predictors of the onset of impotence 1 year after radiotherapy for prostate cancer. Patients and methods: In a multi-centric prospective study, the International Index of Erectile Function (IIEF) questionnaire-based potency of 91 hormone-naïve and potent patients (IIEF1-5 > 11 before radiotherapy) was assessed. At the time of this analysis, information on potency 1 year after treatment was available for 62 of 91 patients (42 treated with hypofractionation: 2.35–2.65 Gy/fr, 70–74.2 Gy; 20 with conventional fractionation: 74–78 Gy). Prospectively collected individual information and Dmax/Dmeanto the penile bulb were available; the corresponding 2 Gy-equivalent values (EQD2_max/EQD2_mean) were also considered. Predictors of 1‑year impotency were assessed through uni- and multi-variable backward logistic regression: The best cut-off values discriminating between potent and impotent patients were assessed by ROC analyses. The discriminative power of the models and goodness-of-fit were measured by AUC analysis and the Hosmer–Lemeshow (H&L) test. Results: At 1‑year follow-up, 26 of 62 patients (42 %) became impotent. The only predictive variables were baseline IIEF1-5 values (best cut-off baseline IIEF1-5 ≥ 19), Dmax≥ 68.5 Gy and EQD2_max≥ 74.2 Gy. The risk of 1‑year impotence may be predicted by a two-variable model including baseline IIEF1-5 (OR: 0.80, p = 0.003) and EQD2_max≥ 74.2 Gy (OR: 4.1, p = 0.022). The AUC of the model was 0.77 (95% CI: 0.64–0.87, p = 0.0007, H&L: p = 0.62). The 1‑year risk of impotency after high-dose radiotherapy in potent men depends on the EQD2_maxto the penile bulb and on baseline IIEF1-5 values. Conclusion: A significant reduction in the risk may be expected mainly when sparing the bulb in patients with no/mild baseline impotency (IIEF1-5 > 17).

Original languageGerman
Pages (from-to)297-304
Number of pages8
JournalStrahlentherapie und Onkologie
Volume192
Issue number5
DOIs
Publication statusPublished - May 1 2016

Keywords

  • Dose-response
  • Erectile dysfunction
  • Predictive models
  • Prostate cancer
  • Radiotherapy

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Oncology

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