Hematuria and cancer
Hematuria refers to the abnormal presence of blood in urine, which can be a crucial indicator of underlying health issues, including cancers of the bladder, kidney, prostate, or urethra. It can manifest as either gross hematuria, where urine appears visibly red, or microscopic hematuria, detectable only under a microscope. Various risk factors can increase the likelihood of hematuria being associated with cancer, particularly in males over the age of 40, those with a significant family history of urothelial cancer, or individuals showing high counts of red blood cells in urine examinations.
The causes of hematuria are diverse, ranging from benign factors like exercise or menstrual bleeding to more serious conditions such as infections, kidney stones, or malignancies. While hematuria itself is not a definitive screening tool for tumors, its presence necessitates further investigation to rule out severe underlying conditions. Screening typically involves a combination of physical examinations, urine tests, and imaging techniques. The prognosis for hematuria varies widely, influenced by the underlying causes, and an appropriate evaluation is essential for determining treatment and potential outcomes.
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Hematuria and cancer
ALSO KNOWN AS: Blood in the urine
RELATED CONDITIONS: Cancers of the bladder, kidney, prostate, or urethra
DEFINITION: Hematuria is the abnormal presence of blood in the urine. Hematuria can originate from anywhere in the urinary tract. Macroscopic or gross hematuria occurs when urine is visibly red with intact red blood cells on a microscopic exam.
Risk factors: The presence of heme or red blood cells in microscopic or gross amounts in the urine is a sign requiring interpretation within the context of the patient’s presenting symptoms to rule out kidney disease, urinary tract infection, or bladder cancer. Individuals with hematuria are more likely to be diagnosed with cancer if they are male, over forty, have more than twenty-five red blood cells per high power field, or have a family history of urothelial cancer.
Etiology and the disease process: The cause of hematuria may range from transitory and insignificant to increasingly serious. The blood may be from excessive or strenuous exercise, menstrual bleeding, hemorrhoids, trauma, infection, stones or calculi, obstruction, illicit or prescription drug use, poisoning, or tumors. Hematuria is among the most common and earliest indications of cancers of the bladder, kidney, prostate, or urethra.
Incidence: Asymptomatic microscopic hematuria varies from 2 to 31 percent, with higher rates in men over the age of sixty and former or current smokers. Around 28 percent of patients with hematuria are diagnosed with urinary tract cancer, primarily bladder cancer.
Symptoms: Hematuria may be asymptomatic or may manifest in urine that is smoky, pink, bright red, or dark red (although urine may appear clear and still result in a diagnosis of hematuria).
Screening and diagnosis: The American Urological Association defines hematuria and updated its criteria for hematuria evaluation in 2020. Blood in urine is detected as intact red blood cells under the microscope or as the heme subunit of the hemoglobin molecule in a routine chemical evaluation of urine. Screening involves a routine urinalysis in each of the three distinct testing phases:
- Physical examination (the urine sample may appear in color and clarity from transparent to smoky, pink, bright red, or dark red.
- Microscopic examination (identifies and counts the blood cells per high-power field)
- Biochemical examination (to determine the presence or absence of blood in the urine; relies on the peroxidase activity of the heme moiety, which leaks from the red blood cell or muscle tissue in the form of myoglobin into the urine)
Because hematuria can originate from a wide variety of causes, the presence of red blood cells in the urine is not a useful screening tool to detect urinary tract tumors. Once hematuria has been detected, the clinician must find the cause. Often, the diagnosis of cancer begins with ruling out all other possible sources of blood in the urine.
Definitive diagnosis may require one or more exploratory and confirmatory procedures—urine cytology; intravenous urography (IVU), a radiology procedure that uses an injected dye to show the kidneys, ureters, and bladder; ultrasonography; computed tomography (CT); magnetic resonance imaging (MRI); or a cystoscopy with biopsy.
Treatment and therapy: Treatment depends on the underlying cause.
Prognosis, prevention, and outcomes: Hematuria requires evaluation within the context of the patient’s history and physical examination. Asymptomatic, microscopic hematuria may range from insignificant to life-threatening. Risk factors for significant disease in patients with microscopic hematuria include smoking, occupational exposure to chemicals, analgesic abuse, urinary tract infection, and a history of urologic disorders.
Bibliography
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