Radiation cystitis is the inflammation and irritation of the bladder lining that develops as a complication following therapeutic radiation for pelvic cancers (e.g., prostate, cervical, or rectal cancer). This adverse effect occurs when healthy bladder tissue is unintentionally exposed to ionizing radiation. The damage manifests in two distinct timelines: an acute phase, occurring during or shortly after treatment, and a chronic (late) phase, which can emerge months or even many years after therapy completion.
The Mechanism of Bladder Injury
Radiation initially damages the bladder wall at the cellular level, targeting fast-dividing cells and the delicate network of blood vessels. Ionizing radiation directly injures the urothelial lining, the protective layer inside the bladder. This leads to inflammation and cellular swelling, characterizing the acute phase. The injury disrupts the protective glycosaminoglycan layer, allowing urine to contact the underlying tissue and sustain the inflammatory response.
In the chronic phase, the injury shifts from surface inflammation to deep structural changes, primarily targeting vascular endothelial cells. Radiation causes a progressive thickening and narrowing of the small arteries and arterioles in the bladder wall, known as obliterative endarteritis. This reduction in blood flow starves the tissue of oxygen, leading to chronic ischemia and hypoxia. The body attempts to repair this damage by depositing excessive collagen, resulting in fibrosis (scar tissue) throughout the muscular layers. This fibrosis makes the bladder wall rigid and less elastic, reducing its capacity to store urine and contributing to persistent chronic symptoms.
Common Symptoms and Clinical Presentation
Symptoms depend on whether the condition is in the acute or chronic phase, reflecting the underlying biological injury. Acute symptoms usually begin during the radiation course or within three months, often resembling a urinary tract infection. These irritative symptoms include urinary frequency, urgency (a sudden, strong urge to urinate), and dysuria (painful urination). These acute manifestations are due to initial inflammation and swelling of the bladder mucosa, and they often resolve once radiation therapy is complete.
Chronic symptoms result from deep, irreversible tissue changes, such as fibrosis and ischemia, developing six months to two decades after treatment. The most recognizable and severe symptom is hematuria (blood in the urine), which can be microscopic or visible. This bleeding is caused by the rupture of fragile, dilated blood vessels called telangiectasias that form on the damaged bladder surface. Other chronic symptoms related to the loss of bladder elasticity include severe urinary frequency, nocturia (waking up multiple times at night to urinate), and in advanced cases, urinary incontinence or the formation of fistulas due to tissue necrosis.
Confirming the Diagnosis
Confirming radiation cystitis begins with reviewing the patient’s history, focusing on prior pelvic radiation and the timeline of symptom onset. Diagnostic testing is performed primarily to rule out other causes, such as infection, kidney stones, or cancer recurrence, since many symptoms overlap with other urinary conditions. An initial urinalysis checks for blood cells, white blood cells (pyuria), and bacteria, which may indicate a coexisting infection requiring separate treatment.
Urine culture and cytology are performed to exclude bacterial infection and screen for malignant cells, which is important given the patient’s cancer history. The most definitive diagnostic tool is cystoscopy, where a thin, lighted tube is inserted into the bladder for visual inspection of the lining. During cystoscopy, a physician observes characteristic signs of radiation injury, including patches of erythema (redness), mucosal edema, and telangiectasias (small, delicate blood vessels prone to bleeding). Imaging studies like CT or MRI assess the bladder wall thickness and rule out upper urinary tract issues or other masses.
Treatment Approaches
Treatment strategies are tailored to the severity and chronicity of symptoms, ranging from supportive care to advanced interventional procedures. For mild, acute symptoms, management is conservative, focusing on symptomatic relief. This includes using medications like anticholinergic or antispasmodic agents to reduce urgency and frequency. Painful urination can be temporarily alleviated with urinary analgesics, and patients are advised to maintain high fluid intake to dilute the urine.
Chronic or severe symptoms, especially persistent hematuria, require more aggressive intervention. A common approach involves intravesical instillations, where liquid medications are delivered directly into the bladder via a catheter.
Intravesical Instillations
Agents used include:
- Alum or formalin solutions, which act as astringents to help stop bleeding.
- Pentosan polysulfate and hyaluronic acid, which help restore the damaged protective layer of the bladder lining.
Oral medications, such as pentosan polysulfate sodium, are also used to target chronic inflammation and help repair the damaged urothelium.
Hyperbaric Oxygen Therapy (HBOT) is an effective non-invasive option for chronic radiation cystitis, particularly for severe, refractory bleeding. This treatment involves breathing 100% oxygen in a pressurized chamber, dramatically increasing oxygen concentration in the blood and damaged tissues. The high oxygen levels stimulate angiogenesis (the growth of new, healthy blood vessels), bypassing the radiation-damaged, narrowed vessels. HBOT reverses underlying tissue hypoxia and ischemia, promoting healing and tissue regeneration, with success rates for symptom improvement often exceeding 85%.
For the most severe complications, such as intractable gross hematuria that does not respond to other treatments or a severely contracted bladder causing debilitating frequency, surgical intervention may be necessary. Initial surgical efforts include cystoscopy with fulguration, where bleeding vessels are cauterized to stop hemorrhage. If bleeding remains uncontrollable or bladder capacity is severely compromised, the last resort is often a urinary diversion procedure. This reroutes urine flow away from the bladder, sometimes requiring a cystectomy (removal of the bladder).