The short answer
Bladder cancer happens when cells in the bladder start to grow without control. The bladder is a hollow, balloon-shaped organ in the lower abdomen that stores urine. Almost all bladder cancers start in the cells that line the inside of the bladder. Using tobacco, especially smoking, is a major risk factor.
Bladder cancer occurs when cells in the bladder grow without control.
The bladder is a hollow, balloon-shaped organ in the lower abdomen that stores urine made by the kidneys.
Almost all bladder cancers are urothelial carcinoma, which begins in the cells that line the bladder.
Using tobacco, especially smoking cigarettes, is a major risk factor for bladder cancer.
Subjective: What you might experience
This section describes the symptoms and history a patient might report to their doctor.
Blood in the urine (hematuria)
often painless and the most common presenting symptom; may be visible or found only on testing.
Urinary changes
needing to urinate more often, urgency, pain or burning with urination.
Feeling the need to urinate without being able to pass urine.
In advanced disease
low back or pelvic pain, bone pain, unexplained weight loss, fatigue.
Risk history noted
cigarette smoking, occupational chemical exposure (dyes, rubber, paint), prior pelvic radiation, chronic bladder irritation.
Objective: Tests and findings
Urinalysis and urine cytology to look for blood and cancer cells in the urine.
Cystoscopy
a thin lighted scope is passed into the bladder to view the lining directly; the key diagnostic test.
Biopsy or transurethral resection (TURBT) of any suspicious areas for tissue diagnosis.
Imaging
CT urogram, MRI, ultrasound, or chest imaging to assess the upper urinary tract and look for spread.
Blood chemistry and kidney function tests.
Interactive anatomy guide
Explore where cancers start and how they are found, on an interactive body map.
Open the anatomy guideAssessment: Staging and prognosis
Diagnosis confirmed by biopsy; most are urothelial (transitional cell) carcinoma.
Classified as non-muscle-invasive (confined to the inner lining) versus muscle-invasive, which guides treatment.
Staging uses the TNM system (tumor depth, lymph nodes, metastasis), grade, and whether disease is superficial or invasive.
Assessment of risk of recurrence and progression based on stage, grade, and number/size of tumors.
Plan: The treatment approach
Non-muscle-invasive
TURBT to remove tumors, often with intravesical (in-the-bladder) chemotherapy or BCG immunotherapy.
Muscle-invasive
surgery (partial or radical cystectomy), often with chemotherapy before surgery; radiation as an option.
Advanced/metastatic
chemotherapy, immunotherapy, targeted therapy, or clinical trials.
Ongoing surveillance cystoscopy and urine testing because recurrence is common.
Smoking cessation support and management of symptoms.
These are simplified, educational SOAP-style summaries showing the kinds of findings clinicians document when evaluating each cancer, based on National Cancer Institute resources. They describe typical diagnostic criteria and workups — not a real patient, and not medical advice. Real clinical notes are individualized. Always rely on your own care team. Based on National Cancer Institute educational content. Educational only — not medical advice.
Words to know
Tap any term to see what it means.

Common questions
Where does bladder cancer start?
Bladder cancer starts in the bladder, a hollow, balloon-shaped organ in the lower part of the abdomen that stores urine. Almost all bladder cancers begin in the urothelial cells that line the inside of the bladder.
What is the most common type of bladder cancer?
Urothelial carcinoma, also called transitional cell carcinoma, is by far the most common type. It begins in the urothelial cells that line the urethra, bladder, ureters, and renal pelvis. Almost all bladder cancers are urothelial carcinomas.
What does non-muscle-invasive bladder cancer mean?
Non-muscle-invasive bladder cancer is cancer that has not reached the muscle wall of the bladder. Most bladder cancers are non-muscle-invasive. Muscle-invasive bladder cancer has spread through the lining and into the muscle wall or beyond it.
What is a major risk factor for bladder cancer?
Using tobacco, especially smoking cigarettes, is a major risk factor for bladder cancer. Your healthcare team can explain other risk factors and steps that may lower your risk.
How is the bladder connected to the kidneys?
The kidneys filter and clean the blood and make urine. The urine passes from each kidney through a tube called a ureter into the bladder, where it is stored until it leaves the body through a tube called the urethra.
Questions to ask your doctor
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Sources last checked: 2026-07-21 what this meansLast updated: 2026-07-21Next planned review: 2027-07-21
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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