Secondary radiation therapy does not negatively impact continence

Milan, Italy-The clinical advantages of adjuvant or salvage radiation therapy in patients treated for prostate cancer by radical prostatectomy is currently a much-debated issue and is frequently decided for the individual patient. New evidence, however, seems to indicate that secondary radiation therapy (RT) does not negatively affect urinary continence.

“Secondary radiation therapy does not negatively affect urinary continence results after radical prostatectomy, nor is it a statistically significant factor for the risk of incontinence after prostatectomy. Secondary RT is independent of intent, whether adjuvant or salvage,” said first author Meike Adam, MD, of the Martini Klinik, Hamburg, Germany, who presented the outcomes of the investigation on behalf of her colleagues at the European Association of Urology annual congress in Milan, Italy.

In an investigation carried out at the Martini Klinik, Dr. Adam assessed the impact of adjuvant RT and salvage RT on patients with long-term urinary incontinence. She analyzed 7,884 men who underwent radical prostatectomy at the Martini Klinik between 1992 and 2012 whose complete long-term urinary continence data were available. Urinary data such as continence rates were assessed annually for the first 3 years after prostatectomy using a self-administered questionnaire.

Continence was defined as the use of no pads and no leakage of urine. Incontinence was categorized by the number of pads the patients used. The impact of additional radiation therapy on continence results was analyzed by logistic regression analyses and the chi-squared likelihood test.

Adjuvant RT was performed in 225 patients (2.9%) within the first 6 months after surgery (median time, 3.6 months) and salvage RT was performed in 417 patients (5.3%) with proven biochemical relapse for prostate cancer, within a median time frame of 15.9 months.

Incontinence risk not raised by RT

The multivariate logistic regression analysis, including factors such as age, prostate volume, extent of nerve sparing (bilateral, unilateral, both, none), year of surgery, and additive RT, showed that the risk of incontinence was not significantly increased in patients who received additive RT compared to patients who did not receive RT (OR=1.2, p=.20).

In a second multivariate logistic regression model, Dr. Adam used histopathologic parameters adjusted for tumor features, including preoperative PSA, prostate volume, pT stage/Gleason score, nerve sparing, RT, margin status, and additive RT to analyze the impact on continence. She observed no correlation between RT and continence in this model (OR=1.2, p=.10), and noted that radiation therapy implemented with adjuvant or salvage intent had no negative impact on the continence status.

In a subset of 97 patients for whom the complete pre- and post-radiation continence data were available, Dr. Adam observed an increasing rate of continence from 88.7% before RT (median time to RT, 15.9 months) to 94.8% after RT (median time after RT, 20.3 months). Incontinence decreased from 11.4% prior to RT to 5.2% after RT. She noted no negative impact after additive RT before and at least 6 months after RT was performed (p<.0001).

Dr. Adam was not able to obtain the radiation protocols for the patients she included in her investigation, and it was therefore not possible to further analyze the effects of different radiation dosages or techniques, which would possibly be relevant to the outcomes. She recommended further studies with long-term urinary continence data after prostatectomy.UT