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Prediction of Erectile Function After Treatment for Prostate Cancer

Tuesday, September 27, 2011 // Uncategorized

When men are diagnosed with prostate cancer, they face the prospect of treatments that have substantial side effects.  the biggest concerns are urinary incontinence and erectile dyfunction.  Here is a summary of an article that appears in the current issue of JAMA (Journal of the American Medical Association). The study compares the risk of erectile dysfunction with surgery, external radiation and radioactive seeds which are a form of internal radiation. Following that I have the abstract of the article.

Model predicts erectile function after prostate cancer

Researchers have developed a new model to predict the risk of erectile dysfunction for men undergoing prostate cancer treatment.

The model was developed using pre- and post-treatment data for more than 1,000 men who had prostatectomy, external radiotherapy or brachytherapy for prostate cancer at one of several academic medical centers between 2003 and 2006. The model’s ability to predict erectile dysfunction two years after treatment was then validated in a community-based cohort of almost 2,000 men. The results were published in the Sept. 21 Journal of the American Medical Association.

Two years after treatment, post-treatment erections were reported by 37% of the overall patient group (95% CI, 34% to 40%) and 48% of the men who had functional erections before treatment (95% CI, 45% to 52%). Of those men who were potent before treatment, erectile dysfunction was reported posttreatment in 60% of the prostatectomy group (95% CI, 55% to 65%), 42% of the external radiotherapy group (95% CI, 33% to 51%) and 37% of the brachytherapy group (95% CI, 30% to 45%).

The researchers identified several factors in addition to the method of treatment that appeared to affect the rate of posttreatment dysfunction, including pretreatment function (measured by a sexual health-related quality-of-life score), age, serum prostate-specific antigen (PSA) level, race/ethnicity, and body mass index. The model’s predictions of erectile function ranged from 10% to 70% depending on individual patient characteristics. The validation cohort indicated that the model performed well at predicting dysfunction.

The study also looked at the treatments men used to assist with erectile function. Phosphodiesterase-5 inhibitors were the most commonly used, and intracorporal penile injections were the least used but the most effective. Due to limitations of the observational design of the study, the results should be used not to determine treatment superiority, but rather to help set physicians’ and patients’ expectations after prostate cancer treatment, the authors said.

An accompanying editorial noted that the study was also limited by its failure to include men who chose watchful waiting over active surveillance and by the development of the model at academic medical centers, which may have better results.

After cautioning that the findings should be used cautiously, the editorialist offered a informal synopsis: “[F]or most scenarios, the take-away message is that if the patient has chosen surgery, he will more than likely lose erectile function, whereas if he has chosen radiotherapy, he has a better than even chance of preserving it, at least for 2 years.”

Original Contribution
JAMA. 2011;306(11):1205-1214. doi: 10.1001/jama.2011.1333

Prediction of Erectile Function Following Treatment for Prostate Cancer

  1. Mehrdad Alemozaffar, MD;
  2. Meredith M. Regan, ScD;
  3. Matthew R. Cooperberg, MD, MPH;
  4. John T. Wei, MD;
  5. Jeff M. Michalski, MD;
  6. Howard M. Sandler, MD;
  7. Larry Hembroff, PhD;
  8. Natalia Sadetsky, PhD;
  9. Christopher S. Saigal, MD, MPH;
  10. Mark S. Litwin, MD, MPH;
  11. Eric Klein, MD;
  12. Adam S. Kibel, MD;
  13. Daniel A. Hamstra, MD;
  14. Louis L. Pisters, MD;
  15. Deborah A. Kuban, MD;
  16. Irving D. Kaplan, MD;
  17. David P. Wood, MD;
  18. Jay Ciezki, MD;
  19. Rodney L. Dunn, MS;
  20. Peter R. Carroll, MD, MPH;
  21. Martin G. Sanda, MD

[+] Author Affiliations


  1. Author Affiliations: Urology Division (Drs Alemozaffar and Sanda) and Radiation Oncology Department (Dr Kaplan), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts; Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute and Harvard Medical School (Dr Regan); Department of Urology, University of California, San Francisco (Drs Cooperberg, Sadetsky, and Carroll); Departments of Urology (Drs Wei and Wood) and Radiation Oncology (Dr Hamstra) and Biostatistics Core (Mr Dunn), School of Medicine, University of Michigan, Ann Arbor; Departments of Radiation Oncology (Dr Michalski) and Surgery (Dr Kibel), Washington University, St Louis, Missouri; Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, California (Dr Sandler); Office for Survey Research, Institute for Public Policy and Social Research, Michigan State University, East Lansing (Dr Hembroff); Departments of Urology (Drs Saigal and Litwin) and Health Services (Dr Litwin), UCLA Center for Health Sciences, Los Angeles; Glickman Urological and Kidney Institute (Dr Klein) and Department of Radiation Oncology (Dr Ciezki), Cleveland Clinic Hospitals, Cleveland, Ohio; and Departments of Urology (Dr Pisters) and Radiation Oncology (Dr Kuban), M.D. Anderson Cancer Center, Houston, Texas.

Abstract

Context Sexual function is the health-related quality of life (HRQOL) domain most commonly impaired after prostate cancer treatment; however, validated tools to enable personalized prediction of erectile dysfunction after prostate cancer treatment are lacking.

Objective To predict long-term erectile function following prostate cancer treatment based on individual patient and treatment characteristics.

Design Pretreatment patient characteristics, sexual HRQOL, and treatment details measured in a longitudinal academic multicenter cohort (Prostate Cancer Outcomes and Satisfaction With Treatment Quality Assessment; enrolled from 2003 through 2006), were used to develop models predicting erectile function 2 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 pretreatment (N = 1201) underwent follow-up after prostatectomy, external radiotherapy, or brachytherapy for prostate cancer. Sexual outcomes among men completing 2 years’ follow-up (n = 1027) were used to develop models predicting erectile function that were externally validated among 1913 patients in a community-based cohort.

Main Outcome Measures Patient-reported functional erections suitable for intercourse 2 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. Pretreatment sexual HRQOL score, age, serum prostate-specific antigen level, race/ethnicity, body mass index, and intended treatment details were associated with functional erections 2 years after treatment. Multivariable logistic regression models predicting erectile function estimated 2-year function probabilities from as low as 10% or less to as high as 70% or greater depending on the individual’s pretreatment 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 pretreatment patient characteristics and treatment details enables prediction of erectile function 2 years after prostatectomy, external radiotherapy, or brachytherapy for prostate cancer.

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