Radiation therapy is known to achieve treatment outcomes comparable to surgery for localized and locally advanced prostate cancer. However, because the prostate is located directly below the bladder, the bladder may inevitably be exposed to a certain amount of radiation when the pelvic region is irradiated. As a result, some patients may develop radiation cystitis months or even years after treatment, particularly hemorrhagic cystitis accompanied by bleeding.
According to a study published in the *Journal of Urology* in 2009 by Dr. Pavlidakey and colleagues, approximately 5–10 percent of patients who undergo radiation therapy for prostate cancer develop cystitis as a late complication one to two years after treatment. In these cases, radiation cystitis involves more than simple inflammation. Structural damage occurs in the bladder mucosa and blood vessels, and the bladder wall may become fragile with dilated microvessels that bleed easily, resembling findings seen in interstitial cystitis.
Radiation works by damaging the DNA of cancer cells to inhibit cell division, but this process can also affect nearby healthy tissues. The bladder is particularly sensitive to radiation exposure. Radiation can damage the bladder mucosal cells and muscle layers, weaken blood vessel walls, and lead to reduced local blood flow and tissue hypoxia. Over time, these changes may accumulate and result in bladder mucosal necrosis, rupture of microvessels, and chronic inflammation. Patients may experience persistent symptoms such as frequent urination, pain during urination, a sensation of incomplete emptying, and blood in the urine. In severe cases, blood clots can obstruct urine flow, leading to emergency department visits or even the need for blood transfusions.
Treatment for hemorrhagic cystitis varies depending on symptom severity and may include bladder irrigation, endoscopic cauterization, and medication therapy. However, tissues damaged by radiation tend to recover slowly and are prone to recurrence. In this context, intravesical drug instillation therapy has recently gained attention as a treatment option. Studies such as those reported by Dr. Giannitsas and colleagues in *Current Urology* have shown that injecting medication directly into the bladder in patients with radiation-induced bladder wall damage can lead to meaningful improvements, including reduced urinary pain, decreased urinary frequency, and increased bladder capacity.
The procedure is performed by inserting a catheter into the bladder and instilling medication, which is then retained for at least 30 minutes. Treatment is typically administered once a week initially and then repeated every two weeks. This therapy is considered relatively safe and less burdensome, particularly for patients whose symptoms persist despite conventional treatments or who suffer from chronic radiation cystitis.
Radiation cystitis following prostate cancer treatment is therefore a complication that requires appropriate medical attention. Because symptoms can develop several years after radiation therapy, many patients do not immediately recognize the connection between their current symptoms and their previous cancer treatment. Specialists emphasize that during long-term follow-up after prostate cancer surgery or radiation therapy, early detection and systematic management of urologic side effects—such as radiation cystitis or hemorrhagic cystitis—play a crucial role in maintaining patients’ quality of life.
Dr. Ryu Kyung-ho of Goldman Urology Clinic Gangnam Branch explained that with the introduction of evidence-based treatments, including intravesical drug instillation therapy, long-term management of radiation-induced cystitis is becoming increasingly possible. He advised that even mild symptoms should not be ignored, as early evaluation and treatment can help reduce recurrence and improve long-term outcomes.