Background
A new area of research focusing on ‘patient-centred outcomes’ asks questions about what outcomes patients can expect from various medical interventions given their personal characteristics, conditions and preferences.
Prostate cancer treatments have varying risks associated with them and choices about treatments may be influenced by possible adverse outcomes such as erectile dysfunction.
Sexual function is the health-related quality of life (HRQOL) domain most commonly impaired after prostate cancer treatment. However, validated tools to enable personalised prediction of erectile dysfunction after prostate cancer treatment are lacking
Aim
To predict long-term erectile function following prostate cancer treatment based on individual patient and treatment characteristics.
Methods
Pre-treatment patient characteristics, sexual HRQOL, and treatment details measured in a longitudinal academic multi-centre cohort (Prostate Cancer Outcomes and Satisfaction With Treatment Quality Assessment; enrolled from 2003 through 2006), were used to develop models predicting erectile function two years after treatment.
A community-based cohort (community-based Cancer of the Prostate Strategic Urologic Research Endeavor [CaPSURE]; enrolled 1995 through 2007) externally validated model performance.
Patients in US academic and community-based practices whose HRQOL was measured pre-treatment (N = 1201) underwent follow-up after prostatectomy, external radiotherapy, or brachytherapy for prostate cancer.
Sexual outcomes among men completing two years follow-up (n = 1027; 86%) were used to develop models predicting erectile function that were externally validated among 1913 patients in a community-based cohort.
The main outcome measure was patient-reported functional erections suitable for intercourse two years following prostate cancer treatment.
Results
Two years after prostate cancer treatment, 368 (37% [95% CI, 34%-40%]) of all patients and 335 (48% [95% CI, 45%-52%]) of those with functional erections prior to treatment reported functional erections; 531 (53% [95% CI, 50%-56%]) of patients without penile prostheses reported use of medications or other devices for erectile dysfunction.
Pre-treatment sexual HRQOL score, age, serum prostate-specific antigen level, race/ethnicity, body mass index, and intended treatment details were associated with functional erections two years after treatment.
Multivariable logistic regression models predicting erectile function estimated two-year function probabilities from as low as 10% or less to as high as 70% or greater depending on the individual’s pre-treatment patient characteristics and treatment details.
The models performed well in predicting erections in external validation among CaPSURE cohort patients (areas under the receiver operating characteristic curve, 0.77 [95% CI, 0.74-0.80] for prostatectomy; 0.87 [95% CI, 0.80-0.94] for external radiotherapy; and 0.90 [95% CI, 0.85-0.95] for brachytherapy).
Conclusion
Stratification by pre-treatment patient characteristics and treatment details enables prediction of erectile function two years after prostatectomy, external radiotherapy, or brachytherapy for prostate cancer.
