A variety of oral and injectable therapies have been utilized in the management of Peyronie's Disease (PD). While all medical options for PD are based on sound scientific rationale, very few of these therapies are supported by well-designed, double blind, placebo controlled, randomized trials.1
Obstacles within the literature that make deciphering PD clinical trials difficult have been well documented.2,3 Few trials actually enroll enough patients to attain sufficient power. Meta-analysis is difficult because of the heterogeneity of treatments and duration of follow-up, as well as the variety of study endpoints that are documented. Because the goal of intervention largely revolves around the stabilization or correction of penile deformity, it is critical that studies perform, at a minimum, objective curvature measurements before and after intervention. Yet, this is not routinely done. Ideally, studies would utilize an objective, uniform means of deformity assessment, and consistently assess pain and sexual function including ability to achieve penetration. Clinically meaningful endpoints are critical, and it needs to be emphasized that vague endpoints such as "decrease in curvature" are undermined if the patient is still unable to engage in satisfying penetrative sexual relations, or if the patient still requires surgical intervention because of inadequate improvement. Evaluating the resolution of pain in men with PD is a laudable goal, but any trial assessing pain must also contain a control group with comparable pain assessment, as resolution of pain is thought to be common in PD even without intervention. Furthermore, changes in plaque dimension and morphology are poor study end-points, not only because of the difficulty in reproducing plaque measurements, but also because the nature of the plaque itself has poor correlation to the actual clinical deformity that men experience. Many studies include both men who present during the acute phase, as well as men with chronic, stable disease; these two groups of men are at very different points in their disease course and are likely to have different responses to any intervention. Mulhall et al have demonstrated that 33% of men screened with PD were not aware they had PD, suggesting that there is an unknown lag time in many men between the onset of disease and their awareness of it.4 Therefore, the inclusion of men in clinical studies who have only recently noticed penile curvature, and assuming that they either have "new disease" or are in the acute phase of the disease, is suspect and fraught with methodological error.
See AUA Core Curriculum: Hypogonadism Physiology, Epidemiology, Pathophysiology, Evaluation.
1.1 Key words
Peyronie’s, bent penis, curved penis, penile plaque, penile pain, penile scar tissue, collagenase, clostridium, xiaflex (trademark), intralesional injection
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