Can radiation therapy cause blood in urine, and how can you cope?

Yes blood in the urine (hematuria) can occur as a side effect of radiation therapy to the pelvis (for example, prostate, bladder, gynecologic, or rectal cancers). ^[1] Hematuria may appear during treatment (acute radiation cystitis) or months to years later (late radiation cystitis), and the severity and timing vary by dose, technique, and individual factors. ^{[2] [3]}

Why it happens

• Acute phase: Radiation can irritate and inflame the bladder lining, causing urinary frequency, burning, urgency, and sometimes visible blood in the urine during or shortly after treatment. ^{[4] [5]}
• Late phase: Over time, radiation may reduce small blood vessels in the bladder lining (obliterative endarteritis), making tissue fragile and more likely to bleed, even 6 months to 20 years after therapy. ^{[3] [2]}

In people treated for prostate cancer, urinary symptoms are common and a small amount of blood can occur, usually improving over time, though flare‑ups can happen. ^[1]

How common is it?

Acute bladder irritation during pelvic radiation is common, with reported rates across pelvic cancers ranging roughly from 23% to 80%, though not all cases include bleeding. ^[6] Late radiation cystitis (which may include hematuria) occurs in about 5–10% of people after pelvic radiation. ^[6]

When to seek urgent care

• Passing blood clots, inability to pass urine, severe pain, or signs of infection (fever, chills) warrant prompt evaluation. ^{[7] [1]}
• New hematuria in anyone with prior radiation exposure should be assessed, because other causes (stones, infection, tumor) must be ruled out. ^[7]

At‑home coping strategies during treatment

These steps can ease bladder irritation and may reduce mild bleeding risk, especially in the acute phase:

• Hydration: Aim for about 2–3 liters (8–12 cups) of fluid spread through the day unless your care team advises otherwise. ^[8]
• Avoid irritants: Limit caffeine, alcohol, carbonated drinks, very spicy or peppery foods, and acidic items (tomato, citrus) that can aggravate the bladder. ^{[8] [9]}
• Timed voiding: Urinate regularly; don’t hold urine for long, which can worsen urgency and irritation. ^[5]
• Report changes: Let your radiation team know promptly about new urinary symptoms so they can suggest medications or adjustments. ^[8]

Medical evaluation and tests

Your team may use these to determine the cause and severity:

• Urinalysis and culture to check for infection and confirm blood. ^[7]
• Cystoscopy (camera exam of the bladder) if bleeding persists or recurs, especially in late presentations, to look for fragile vessels (telangiectasias) or other causes. ^[7]
• Imaging if stones, blockage, or upper tract bleeding are suspected. ^[7]

Treatment options

Treatment depends on whether symptoms are acute (during/soon after radiation) or late (months–years later), and on severity.

• Symptom relief during acute irritation:

  • Bladder‑calming medicines for urgency and frequency may be used under clinician guidance. ^[8]
  • Pain/burning management and short courses of medications as advised by your team. ^[8]

• If infection is present:

  • Antibiotics are used when urine tests confirm a bacterial infection. ^[7]

• For persistent or late hematuria (radiation cystitis):

  • Bladder instillations (medications placed directly into the bladder) can help protect the lining and reduce bleeding. ^[10]
  • Cauterization or endoscopic treatments may target fragile bleeding vessels seen on cystoscopy. ^[10]
  • In more severe cases, hyperbaric oxygen therapy may be considered by specialists to promote healing of damaged bladder tissue. ^[10]

Many acute symptoms are self‑limited and improve within weeks to a few months after therapy, while late radiation cystitis can appear long after treatment and may need urology input. ^{[2] [4]}

Practical tips day to day

• Keep a symptom diary: Track frequency, burning, visible blood, clots, and fluid intake to share with your team. ^[8]
• Plan hydration earlier in the day to lessen nighttime urination. ^[9]
• Protect skin: If frequency and urgency lead to leakage, gentle skin care and barrier creams can prevent irritation. ^[11]
• Avoid smoking, which can worsen bladder symptoms and is a risk factor your clinician will ask about when evaluating hematuria. ^[7]

Summary

• Blood in urine can be a side effect of pelvic radiation due to bladder lining inflammation acutely or fragile vessels in the bladder wall later on. ^{[4] [3]}
• Mild cases often settle with time and supportive care, but any visible blood especially with clots or pain should be reported for evaluation to rule out infection or other causes and to guide treatment. ^{[1] [7]}
• Hydration, avoiding bladder irritants, timely reporting of symptoms, and tailored treatments ranging from medications to bladder procedures can make a meaningful difference. ^{[8] [10] [2]}

Would you like help creating a simple checklist you can use to track urinary symptoms during or after radiation therapy?