October 10, 2011
2 min read

Models helped predict erectile dysfunction after prostate cancer

Alemozaffar M. JAMA. 2011;doi:10.1001/jama.2011.1333.

Barry MJ. JAMA. 2011;doi:10.1001/jama.2011.1363.

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Newly developed prediction models using variables in patient characteristics and treatments were able to predict the likelihood of erectile dysfunction 2 years after treatment for prostate cancer.

In the study, researchers sought to determine whether a patient's likelihood for erectile dysfunction could be predicted based on baseline characteristics, such as baseline sexual function, and treatment plans.

To develop predictive models, the researchers took data on pretreatment patient characteristics, sexual health-related quality of life and treatment details from a longitudinal multicenter cohort study that enrolled men with prostate cancer from 2003 to 2006. The models were then externally validated in a community-based cohort of men who also had data on health-related quality of life.

After 2 years of treatment, 63% of men who underwent prostatectomy reported erectile dysfunction, 63% of men in the external radiotherapy group and 57% of men who underwent brachytherapy.

In men who underwent prostatectomy, younger age, lower PSA level, better pretreatment sexual functioning score and nerve-sparing surgery were all associated with decreased odds for erectile dysfunction. In men who underwent external radiotherapy, low PSA level, better pretreatment sexual functioning score and no use of neoadjuvant hormone therapy decreased the odds. In the brachytherapy group, better pretreatment sexual health-related quality of life, younger age, black race/ethnicity and lower BMI decreased risk.

The predictive models performed well in the validation cohort. The areas under the receiver operating characteristic curve were 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.

In an accompanying editorial, Michael J. Barry, MD, of Massachusetts General Hospital, wrote that routinely collecting objective measures of subjective phenomena from patients will need to become part of usual care rather than just research to optimize outcome prediction.

"More importantly, better ways of ensuring that patients are informed about their choices and invited to participate in making decisions need to be identified and disseminated. Outcomes data for all important options and outcomes need to be integrated in a useful synthesis for the broad spectrum of men facing this decision. A meta-analysis of randomized trials of patient decision aids to support a shared decision-making process for preference-sensitive conditions demonstrated better decision quality when these tools are used. For the most fateful decisions, coaches or navigators may be helpful and efficient as well," Barry wrote.

"The promise of patient-centered outcomes research will be realized not only when high-quality outcomes data are available for all common medical problems but also when patients are routinely informed and invited to participate in their health care decisions. To achieve this promise, patients must increasingly be encouraged to adopt the position of 'no decision about me, without me,'" he wrote.


Donald L. Trump, MD
Donald L. Trump, MD

The study by Alemozaffar and colleagues presents an extensive, well-reasoned and thoughtful analysis of factors associated with erectile dysfunction 2 years following the treatment of localized prostate cancer. The report is based on analysis of patient characteristics, a well-validated questionnaire to assess sexual function (the HRQOL), and analysis of treatment details in longitudinal academic multicenter and community-based cohorts. This analysis provides a statistically robust analysis of those factors associated with maintenance of erectile function insufficient for intercourse (eg, PSA .4 ng/mL, use of neoadjuvant hormonal therapy, pretreatment sexual function). These data provide physicians with important data to use in advising patients regarding treatment outcome. The authors appropriately point out that this analysis does not provide information with which to compare treatment modalities because of the non-randomized and self-reported nature of the data obtained. This report provides very important information with which to inform patients about expected outcomes. It is an important step in analyzing patient factors and treatment modalities to continue to be sure patients are informed and to improve our treatments.

– Donald L. Trump, MD
HemOnc Today Editorial Board member

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