Baseline status and dose to the penile bulb predict impotence 1 year after radiotherapy for prostate cancer.
Strahlenther Onkol
; 192(5): 297-304, 2016 May.
Article
in En
| MEDLINE
| ID: mdl-27079673
ABSTRACT
AIM:
To assess the predictors of the onset of impotence 1 year after radiotherapy for prostate cancer. PATIENTS ANDMETHODS:
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/Dmean to the penile bulb were available; the corresponding 2 Gy-equivalent values (EQD2_max/EQD2_mean) were also considered. Predictors of 1year 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 1year 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 1year 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 1year risk of impotency after high-dose radiotherapy in potent men depends on the EQD2_max to 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).Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Prostatic Neoplasms
/
Radiation Injuries
/
Outcome Assessment, Health Care
/
Radiation Exposure
/
Erectile Dysfunction
Type of study:
Clinical_trials
/
Diagnostic_studies
/
Etiology_studies
/
Observational_studies
/
Prevalence_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Aged
/
Aged80
/
Humans
/
Male
/
Middle aged
Country/Region as subject:
Europa
Language:
En
Journal:
Strahlenther Onkol
Journal subject:
NEOPLASIAS
/
RADIOTERAPIA
Year:
2016
Document type:
Article
Affiliation country:
Italy