Sexual function after external-beam radiotherapy for prostate cancer: What do we know?
Introduction
Despite the decrease in overall cancer incidence and mortality rates in developed countries since the early 1990s, cancer remains a major public health problem. Among men, the most common cancer affects the prostate and occurs more often in the older population [1]. In recent years, the number of patients diagnosed with prostate cancer (PC) has increased dramatically because of the widespread use of prostate specific antigen testing and the possibility for cure of early disease. Standard treatments for PC are radical prostatectomy, external-beam radiotherapy (EBRT), brachytherapy, or observation. The choice of treatment is usually determined by tumor staging, patient's age and comorbidity, urologist's and patient's preferences. Sexual dysfunction is one of the more common consequences of cancer treatment [2]. Patient's quality of life, including sexual functioning, should play a more significant role in decision making about treatment type. Men may remain interested in sex and eroticism well into old age [3]. Men are less likely than women to seek professional help for mental and physical health problems. Addis and Mahalik hypothesized that cultural norms of masculinity conflict with help-seeking behavior [4]. Erectile dysfunction (ED) is a medical problem often crucial to men's self-esteem. In the 1980s and 1990s, penile prostheses and penile injections created a market for male sexual dysfunction. With the introduction of sildenafil (Viagra®) in 1998, media attention to ED has made sexual problems more normative and has increased acceptance of help-seeking [4].
The purpose of this paper is to present an overview of the peer-reviewed articles dealing with ED after EBRT. Articles dealing with PC-patients with metastatic disease, or on hormone therapy, are not included in this review. Firstly, the various methods used to evaluate and define ED will be discussed. Then, the etiology of ED after EBRT will be reviewed. The literature on the incidence of erectile and other sexual dysfunctions after EBRT will be summarized. Finally, the therapy of post-radiation ED and prevention possibilities will be discussed.
Section snippets
Methods of evaluating erectile dysfunction
The most practical and quickest way to evaluate ED is by using a questionnaire. Different questionnaires have been used in the published literature. Questions on sexual functioning were quite often limited to two to six items, and were incorporated into a more general questionnaire on toxicity of radiation treatment, or quality of life in general [2], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14]. With a few exceptions [2], [6], [7], [15], [16], the entire questionnaire used was not
Definition of potency
Another significant feature of literature on ED after radiation for PC is the definitions of potency and impotence used. A clear definition is mandatory in order to make meaningful comparisons of the different studies. The National Institutes of Health (NIH) Consensus on ED defined impotence as: the consistent inability to attain and maintain a penile erection sufficient to permit satisfactory sexual intercourse [40]. One could argue that such a definition is strictly relevant in the presence
Etiology of post-radiation erectile dysfunction
See Fig. 1 for a schematic of the male genitalia.
Goldstein et al. [42] performed a detailed study on 23 patients treated with radiotherapy for PC in order to understand the etiology of radiation-induced impotence. Nocturnal penile tumescence testing, bulbo-cavernous reflex latency, perineal electromiography, penile Doppler ultrasonography, and endocrine screening of the hypothalamic-pituitary-gonadal axis were performed. Subjects were considered potent if they could develop an erection
Studies published in the 1970s
Papers from the 1970s dealt with the introduction of EBRT for PC in the pre-PSA era. Until then, surgery was the main stay of treatment as most urologists considered PC to be a relatively radio-resistant tumor, an idea derived from the poor results obtained using conventional orthovoltage therapy. Although studies in the 1970s reported on treatment outcome, and urinary and bowel sequelae, mention of sexual potency or impotence was also frequently made (see Table 1). ED incidence was reported in
Ejaculatory and other sexual dysfunctions
A deterioration of sexual activity has been associated with the severity of ejaculatory dysfunction, particularly a decrease in volume or an absence of semen [48]. After EBRT, a lack of ejaculation was reported in 2–56% of patients [6], [18], [25]. Dissatisfaction with sex life was reported in 25–60% [49], [50], decreased libido in 8–53% [36], [37], [50], and decreased sexual desire in 12–58% [18], [51]. One study reported a decreased intensity of orgasm, decreased frequency and rigidity of
Therapy of post-radiation erectile dysfunction
If there is still uncertainty about the etiology of post-radiation ED, what sort of therapy is to be recommended? Prior to the introduction of sildenafil citrate), there were only three treatment options: intracavernosal injection (ICI), vacuum devices, and penile implants, all three with or without concomitant sexual counseling. To our knowledge, only two papers were published on therapy of post-radiation ED, before sildenafil was introduced.
Pierce et al. reported on eight patients who used an
Prevention of post-radiation ED
Prevention is a difficult matter. If one accepts the hypothesis that radiation induces vascular damage, then decreasing the dose to pelvic vascular structures could decrease ED rate. Both conventional and conformal radiation techniques seem to result in the same rates of ED [11]. But, a relationship between radiation field size and sexual function (i.e. the smaller the field size, the better sexual functioning) has also been reported [8]. However, prospective studies with large series of
Conclusion
There are still no conclusive data on EBRT techniques, field sizes, energy used, and their specific influence on erectile dysfunction. Both conventional EBRT and conformal techniques seem to result in the same rates of ED. However, prospective studies with large series, and the use of standardized validated questionnaires, have to confirm these findings. Conformal techniques using shaped blocks do not appear to spare the neuro-vascular bundles as these are always entirely in the high-dose
Reviewers
Meuleman E.J.H., Consultant Urologist Sexologist, Department of Urology, Free University Medical Centre, P.O. Box 7057, NL-1007 MB Amsterdam, The Netherlands.
Budach W., Professor, Klinik für Strahlentherapie und Radiologische Onkologie, Universitätsklinikum Duesseldorf, Moorenstr. 5, D-40225 Duesseldorf, Germany.
Rowland D.L., Ph.D., Dean, Graduate and Continuing Education, Valparaiso University, 1700 Chapel Drive, Kretzmann Hall 116, Valparaiso, IN 46383, USA.
Luca Incrocci is a radiation oncologist and sexologist in the Department of Radiation Oncology at the Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam, The Netherlands. He received his M.D. in 1992 at the University of Pisa, Italy, and then joined the University Hospital Rotterdam to complete residencies in the departments of urology and radiation oncology. Dr. Incrocci is a member of several scientific societies and he is actively involved in the teaching and research of oncology fellows
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Luca Incrocci is a radiation oncologist and sexologist in the Department of Radiation Oncology at the Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam, The Netherlands. He received his M.D. in 1992 at the University of Pisa, Italy, and then joined the University Hospital Rotterdam to complete residencies in the departments of urology and radiation oncology. Dr. Incrocci is a member of several scientific societies and he is actively involved in the teaching and research of oncology fellows and students. He is an active member in EORTC activities (QLG and GU). Dr. Incrocci is a manuscript reviewer for a number of international journals including European Urology, Cancer Detection & Prevention, International Journal of Impotence Research, and Journal of Sexual Medicine. He is the chief editor of the International Society for Sexual Medicine (ISSM) Newsbulletin, he is the co-founder, secretary/treasurer of the International Society for Sexuality and Cancer (ISSC). Since 2004, he is guest professor lecturing in Cancer and Sexuality, at the University of Pisa, School of Andrology, Pisa, Italy.