Vessel-Sparing Radiation Preserves Sexual Function in Men With Prostate Cancer

Patrick W. McLaughlin, MD

With the use of MRI imaging to restrict doses to erectile tissues, nearly half of men treated with external beam radiation therapy (EBRT) for prostate cancer were able to be sexually active without aids or medications 5 years later, and nearly 80% could be sexually active if such support was an option, according to the results of a study presented at the annual meeting of the American Society of Radiation Oncology (ASTRO). Men were even more likely to have the ability to be sexually active at the 5-year mark if they had been concurrently treated with EBRT and brachytherapy, authors of the study found.

For the study, the researchers evaluated 91 men treated with EBRT at the University of Michigan Providence Cancer Institute whose treatment was guided by MRI-based planning for the restriction of doses to the sub-apex region and specific erectile tissues. About half of the participants were treated simultaneously with brachytherapy, but none received androgen-deprivation therapy.

The authors prospectively gathered information on their sexual function and compared results from the EBRT-alone group (n = 42) with those in the combination group (n = 49). The patients reported their level of sexual function at baseline, 2 years after treatment, and 5 years after treatment using two scales: the International Index of Erectile Function (IIEF), which emphasizes sexual function adequate for intercourse, and a three-question scale (Q3) that did not specify the type or level of sexual activity, but simply asked men if they were able to be sexually active without aids or medication; with aid; or not at all.

Scores from the Q3 showed that 2 years after treatment, 59.2% of men taking the therapy combination and 64.3% of those receiving EBRT alone were able to be sexually active without aid (P = .618), while all of the combination patients and 76.1 of the EBRT-alone cohort could be sexually active if aid was an option (P = .001).

Five years out, 55.1% of the men in the combination arm and 45.2% of those in the EBRT-only arm could be sexually active without aid (P = .348), with those percentages rising to 91.8% in the combination arm and 78.6% in the EBRT-alone arm with medications or aids included as an option ( P = .070).

The 5-year percentages for sexual function, with aid as an option, approached statistical significance, the authors pointed out.

The percentages of men with preserved sexual function were lower according the IIEF scale. At baseline, 36 men in the combination arm and 22 in the EBRT-only arm reported having normal sexual function. At 2 years, 69.4% and 63.6% of those men, respectively, reported that they could be sexually active without aid (P = .648); with aid as an option, those percentages rose to 75% with the combination and 72.7% with EBRT alone (P = .848). At 5 years, 55.6% and 59.1% of patients in the combination and EBRT groups, respectively, reported that they could function sexually without aid (P = .792), versus 66.7% and 63.6% if aid was an option (P = .814).

Those results were still “spectacular,” since the men on both arms were given very high-dose treatments, said the presenter of the data, lead study author Patrick W. McLaughlin, MD, medical director of Radiation Oncology at the University of Michigan Providence Cancer Institute.

“In the past, men with prostate cancer expected to pay a high toll in loss of quality of life to achieve cure and were willing to accept that as necessary,” McLaughlin said in a statement released by ASTRO. “This study makes it clear that even with combination radiation protocols, which are capable of curing the majority of prostate cancers more than 90% of the time, avoidance of critical adjacent tissues, such as vessel-sparing, makes cure and quality of life an achievable goal for many men.”

Liss AL, Evans C, Narayana V, et al. Comparison of External Beam and Combination Therapy for Prostate Cancer: Patient Reported Outcomes of Sexual Function With 5-Year Follow-Up. Presented at: 2014 ASTRO Annual Meeting; September 14-17, 2014; San Francisco, CA. Presentation Number: 111.

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