Side effects of treatment are substantial
Treatment for prostate cancer may involve surgery, external beam radiation therapy, brachytherapy, high intensity focused ultrasound (HIFU), watchful waiting, active surveillance, chemotherapy, cryosurgery, hormonal therapy, or combinations. The most frequently applied treatments for organ confined prostate cancer are radical prostatectomy, external beam radiotherapy and brachytherapy.
Although, severe or life-threatening complications with radical prostatectomy are rare, the adverse effects of greatest concern are damage to the urinary sphincter and erectile nerves (nervi erigenti), resulting in urinary incontinence and impotence, respectively. Complete incontinence is uncommon after radical prostatectomy, although a significant number of men experience some degree of stress-urinary incontinence [
31‐
33]. In the Prostate Cancer Outcomes Study, a population-based study of 1,291 men who underwent radical prostatectomy for localized prostate cancer and were followed for 2 years, 1.6% reported no urinary control at 24 months following surgery (compared with 0.7% at baseline prior to surgery), while 7 and 42% reported frequent and occasional leakage, respectively (compared with 2 and 9% at baseline) [
32]. Age had an impact on the degree of incontinence; 14% of men aged between 75 and 79 years experienced the highest level of incontinence compared with 0.7–4% of younger men. In the Prostate Cancer Outcomes Study, 42% of men reported that sexual performance was a moderate to large problem at 24 months (compared with 18% at baseline); 60% were not able to have erections firm enough for sexual intercourse (compared with 16% at baseline) [
32]. At 24 months postoperatively, men over the age of 60 were more likely to be impotent than younger men (78–85 vs. 61%, respectively).
Complications after external beam radiotherapy include bladder irritation (urgency, pain, frequency) in up to 5% of men, and impotence in 40–50% [
34]. In contrast to surgery, these complications tend to increase over time. The reported incidence of radiation proctitis ranges from 2 to 39%, depending upon the definition used, and the dose field, and technique of radiotherapy. Prostate inflammation and swelling can occur acutely following brachytherapy, suggesting that men with significant urinary symptoms or a large prostate are not good candidates. Urinary retention can be severe enough to require self-catheterization; transurethral resection to improve micturition is contraindicated until a substantial portion of the radioactivity (usually five half-lives) has dissipated because of the risk of incontinence and radiation risks to the surgeon and pathologist. Later complications include irritative voiding symptoms, urinary retention, rectal urgency, bowel frequency, rectal bleeding or ulceration, and prostatorectal fistulas [
35‐
37]. The incidence of erectile dysfunction ranges from 14 to 52%, depending on whether it is physician- or patient-reported.
It is obvious that invasive treatment may influence the quality of life of men with prostate cancer and their families substantially. But so does a potential threat of prostate cancer that is not actively treated or not even diagnosed yet. It is unlikely that quality of life studies will be able to indicate the best balance between these points of view for management decisions on an individual patient level.
Risk stratification for indolent disease
Over the last decade, a number of nomograms have been composed to predict the presence of an indolent cancer [
39,
40]. The identification of indolent cancers was strongly based on histologic information of prostate biopsies, and power of Gleason score as a predictive parameter for aggressiveness of prostate cancer was unsurpassed. As a single serum parameter at the time of diagnosis, the level of PSA contributed most to prognosis.
These nomograms were based on extensive clinical series. A new nomogram recently appeared based on information obtained from a screening series of the general population [
41]. Screening series differ from clinical studies, as the incidence of indolent cancer is almost 50% compared to maximal 20% in multicentred clinical series. With the use of the nomogram, at a 70% probability cut-off, at least 69% of all indolent cancers would be diagnosed as such, and be treated with active surveillance.
Conclusions
It is still too early to say whether population-based prostate cancer screening is a useful tool with regard to cancer mortality. We must wait until the results of ongoing prostate cancer screening trials are available. Until then, opportunistic screening should not be encouraged and those men who do want a PSA test should participate in carefully designed, balanced information program. Even if PSA screening is found to reduce prostate-cancer-specific mortality, levels of overdiagnosis may remain unacceptable for population-based screening.
To reduce overdiagnosis in a screening setting, markers are needed that reduce the risk on a positive prostate biopsy, increasing the specificity of this procedure. Men from the age of forty, as well as their advising doctors, need instruments to reduce their doubts and anxiety of the potential presence of a prostate cancer. This, together with balanced information about the benefits and risks of the individual outcome of screening procedures, might induce a more selective and step-wise screening action. Risk assessment, incorporating the main determinants known for the presence of prostate cancer from the age of 50, such as age, family history, and micturition complaints, should form the base of an individual screening approach. Objective values of serum markers might enhance the accuracy of such of risk predictors.
Various efforts are performed to find new markers in the proteome and genome of blood and urine. Based on large and longitudinal serum collections of men diagnosed with prostate cancer in screening settings, the EC-sponsored P-MARK consortium evaluates candidate markers as prognostic tools [
42].
Until alternative screening tools are found, PSA will continue to be used, and overdiagnosis will remain an unavoidable drawback of prostate cancer screening. The current challenge is to ensure that in the still growing numbers of men diagnosed with prostate cancer world-wide, overdiagnosis does not result in overtreatment. To this end, research efforts presently focus on clarifying which cancers can be managed through active surveillance.