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Management of Outlet Obstruction Before and After Radiation Therapy for Prostate Cancer

By: Joshua A. Cohn, MD, Fox Chase-Temple Urologic Institute, Philadelphia, Pennsylvania; Eric M. Ghiraldi, DO, Fox Chase-Temple Urologic Institute, Philadelphia, Pennsylvania; Justin I. Friedlander, MD, Fox Chase-Temple Urologic Institute, Philadelphia, Pennsylvania | Posted on: 01 Mar 2024

The incidence of prostate cancer in the United States in 2023 was estimated to be 288,300.1 Most patients will choose to undergo radiation therapy (RT).2 Given the frequency with which symptomatic prostatic obstruction impacts men in the same age demographic, overlap is inevitably common.3 However, data informing optimal treatment and modality for men with symptomatic prostatic obstruction before or after RT are lacking.

The AUA guidelines on management of benign prostatic hyperplasia (BPH) outline optional use index cases for minimally invasive, endoscopic, and enucleative therapies primarily based upon prostate size and the presence or absence of a significant median lobe component.4,5 RT, however, presents unique challenges, including a greater incidence of coexistent bladder pathology such as detrusor overactivity (DO) or altered compliance, prostatic urethral stenosis, or compromised external sphincter function as well as radiation cystitis and radiation necrosis.6,7 Each of these potential factors can render traditional BPH therapies suboptimal at best and potentially devastating at worst.

One aspect of care that must be determined is whether the best defense is a good offense. That is to say, should we identify men with bothersome lower urinary tract symptoms secondary to prostatic obstruction for treatment prior to RT so that outlet reduction surgery—and healing—take place in a nonradiated field. In our institution, we have developed a protocol for preradiation referral and when indicated pressure-flow testing and cystoscopy. Men who are symptomatic and obstructed are treated prior to RT based upon prostate size, anatomy, and surgeon and patient preference balancing side effects/risks of treatment and durability. However, some men may undergo unnecessary surgery as outlet obstruction may have been adequately relieved or not meaningfully worsened by prostate-directed cancer therapy. We are also inevitably missing men who are minimally symptomatic but nevertheless obstructed and may ultimately present with rather complex lower urinary tract symptoms subsequent to RT.

The motivation, however, for attempting to treat symptomatic obstruction prior to radiation are the challenges patients experience when obstruction presents after RT. Limited available data suggest we should expect high rates of incontinence (8%-70%) regardless of BPH treatment modality.8-11 However, these studies tend to (1) be outdated, not considering modern treatment options for RT or bladder outlet surgery, (2) not include potentially valuable inputs such as urodynamic and cystoscopic findings, or both. In nonradiated patients, terminal DO, earlier and high-amplitude DO, and peak flow rate have all been associated with persistent storage symptoms after relief of outlet obstruction12,13; however, it is not known if these same factors are predictive in the postradiation patient population.

While acknowledging the absence of robust data, we incorporate cystometric and cystoscopic data in our patient counseling and clinical decision-making in the postradiation patient with suspected outlet obstruction from prostatic enlargement.

Cystometric Findings

Bladder contractility

Our understanding of the impact of extensive prostatic resection (eg, enucleation) vs more limited therapy (eg, channel transurethral resection of the prostate, prostatic urethral lift) is limited. However, flow is linked to bladder contractility and diameter of the urethra.14 It follows, then, that patients with preserved bladder contractility may better “afford” to consider balancing side effects from more extensive prostatic resection, whereas those with poor contractility cannot. The cutoff for meaningfully poor contractility is not established, and studies defining it by bladder contractility index < 100 fail to capture the difference between patients with marked detrusor underactivity with urinary retention and those with weakened but adequate contractility.15 Nonradiated data suggest that when detrusor contractility is markedly diminished or absent, enucleation performs better than standard resection—and in some cases quite well.16-18 Our preference, therefore, is typically for enucleation in prostates of suitable size when contractility is markedly diminished, frequently in patients with urinary retention.

DO and altered compliance

The combination of long-standing prostatic obstruction and radiation may result in marked storage abnormalities, including DO and altered compliance. Routine changes in cystometric capacity may be experienced as early as 3 months after RT,19 but the development of DO and altered compliance is not universal even at 18 months.20 However, logic dictates that storage changes are likely to be more frequent among those with refractory symptoms. In nonradiated patients, altered bladder compliance has been associated with worse outcomes after outlet reduction surgery21 and poorer response to overactive bladder therapy,22 and the presence of high-amplitude DO predicts its persistence.12,13 Therefore, we counsel patients with altered compliance that a satisfactory outcome may not be possible, and those with DO that the likelihood of need for subsequent overactive bladder therapy is high and its efficacy uncertain.

Cystoscopic Findings

Enlarged and/or “ball valving” median lobe

Some patients may be found to have marked enlargement and intravesical protrusion of the median lobe (Figure 1). In the nonradiated patient, selective treatment of the median lobe has been associated with durable relief of voiding symptoms.23,24 We have found this experience to extend to our radiated patients, with the important caveat that formal study is ongoing. Selective enucleation is our treatment of choice in patients with classically enlarged median lobes with preserved bladder contractility and relatively limited lateral lobe coaptation. The rationale is a theoretically reduced surface area for potential radionecrosis-associated calcification, reduced risk of incontinence, and potentially preserved ejaculatory function if present. However, we do also counsel patients that a failure to improve and pressure-flow studies indicative of persistent obstruction may warrant repeat surgery. Most are interested in this “staged” approach when their evaluation suggests it should be considered.


Figure 1. Classically enlarged median lobe. This patient underwent selective enucleation.

Radiation cystitis and radionecrosis

In historical cohorts, as many as 20% of patients who had received RT required hospital admission for genitourinary toxicity, of which approximately 60% was hematuria.6 Two percent required major operative interventions, including urinary diversion in 0.2%. One of the challenges in managing prostatic obstruction after RT is trying to avoid pushing a patient who is otherwise managing reasonably well onto a path of repeated hospitalizations, life-threatening complications, and/or severely debilitating symptoms necessitating cystectomy. One such sign of potential for a disastrous outcome intervention may be radiation cystitis and radionecrosis. If marked radiation changes are encountered in the prostatic urethra within the acute phase of toxicity after RT (within the first 2-3 months),7 we favor delayed intervention with repeat cystoscopy at the 4- to 6-month time frame to evaluate for continued healing (Figure 2). When significant calcifications or tissue loss is encountered, particularly remote from RT, we discourage significant endoscopic intervention if symptoms are manageable and encourage patients to consider urinary diversion if symptoms are severe and debilitating (Figure 3). When heroic endoscopic interventions are to be attempted, patients ideally understand the potential for their disease to progress to needing urinary diversion even in the absence of intervention and for our interventions to result in complications that mandate it.


Figure 2. Apical (A) and intravesical (B) radionecrosis at 3 months. C and D, When radionecrosis is visualized in the first 3 months following completion of radiation, repeat cystoscopy to evaluate for healing is performed at 6 months. The patient underwent selective enucleation of the median lobe.



Figure 3. Severe radionecrosis in a patient who underwent transurethral resection of the prostate prior to subsequent radiation therapy. Further endoscopic interventions are performed with extreme caution.

Management of prostatic obstruction after prostate RT is one of the most challenging and unchartered clinical dilemmas in urology. Given improvements in RT, with reduced associated toxicity, some patients may have fairly normal physiology and potential for healing and be treated similarly to their nonradiated counterparts. However, the heterogeneous group of post-RT patients will inevitably include those with marked detrusor dysfunction, severe radiation changes, and every gradation in between. Finding the right balance between undertreatment and disaster requires incorporating symptoms, patient priorities, cystometric and cystoscopic findings, and humility into clinical decision-making.

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