Is blood in urine a common symptom of stomach cancer?

Blood in the urine (hematuria) is not a common symptom of stomach (gastric) cancer. Stomach cancer typically causes digestive-related symptoms such as persistent indigestion, abdominal pain, nausea, feeling full quickly, difficulty swallowing, weight loss, fatigue, and black or bloody stools (from gastrointestinal bleeding), rather than urinary bleeding. ^[1] Stools turning black or containing blood point to bleeding in the stomach or intestines, which is different from blood appearing in urine. ^[2] In advanced stages, symptoms depend on where the cancer spreads (liver, peritoneum, bones), and still predominantly involve abdominal, systemic, or bowel-related signs. ^{[3] [4]}

What stomach cancer usually looks like

• Common early signs include ongoing stomach pain or discomfort, heartburn, bloating after meals, nausea, loss of appetite, and fatigue. ^[1]
• Alarm features include weight loss, vomiting after meals, trouble swallowing, black stools or blood in stool, and anemia. ^[2]
• Advanced (metastatic) symptoms depend on spread: liver involvement can cause right upper abdominal pain and jaundice; peritoneal spread can cause abdominal fluid build-up and bloating; bone spread can cause bone pain. ^{[3] [4]}

What causes blood in urine (hematuria)?

Hematuria has many causes within the urinary tract and kidneys. Seeing red or cola-colored urine can be alarming, and should be evaluated, since causes range from benign to serious. ^[5] Urine can look red from blood, but foods (like beets) or certain medicines can also color urine red, so a checkup is important to confirm true hematuria. ^[6]

Common causes include:

• Urinary tract infection (UTI) or bladder infection, often with burning urination and urgency. ^[7]
• Kidney stones, which can cause severe flank pain and visible blood. ^[7]
• Enlarged prostate (BPH) and prostate issues in older men. ^[8]
• Kidney, bladder, or prostate cancer, particularly when blood is clearly visible without pain; these cancers may be asymptomatic until later stages. ^[9]
• Glomerular (filter) kidney diseases, sometimes after infections and often microscopic blood only. ^[10]
• Recent urinary procedures or trauma (catheter, surgery). ^[10]

Sometimes red urine is not from the urinary tract: vaginal bleeding, semen after ejaculation (prostate issues), or even bowel sources can be mistaken for urinary blood; again, proper evaluation distinguishes these. ^[11]

Could stomach cancer ever lead to blood in urine?

While uncommon, advanced spread into the peritoneum (abdominal lining) can affect nearby urinary structures (bladder or ureters), potentially leading to urinary symptoms or obstruction; this is a secondary effect of widespread disease rather than a primary stomach cancer symptom. ^[12] Stomach cancer primarily causes gastrointestinal bleeding (black stools or blood in stool), not urinary bleeding. ^[2]

How hematuria is evaluated

Doctors first confirm whether the red urine is truly blood and whether the source is urinary:

• Urinalysis and microscopy to detect red blood cells and rule out pigment from foods/medications. ^[13]
• Risk-based workup: visible (gross) hematuria, older age, significant smoking history, or many red blood cells on microscopy raise concern for urinary tract cancers and prompt cystoscopy (camera in bladder) and CT urography (imaging of kidneys/ureters/bladder). ^[14]
• Imaging and specialist referral tailored to suspected causes such as stones or infections. ^{[15] [16]}

Management depends on the cause

• UTI: antibiotics, hydration, symptom relief. ^[7]
• Kidney stones: pain control, hydration, possible procedures if large or obstructing. ^[7]
• BPH/prostate issues: medications or procedures as needed. ^[8]
• Glomerular kidney disease: nephrology-guided treatment based on the specific diagnosis. ^[10]
• Urinary tract cancers: urology-led care including cystoscopy, imaging, biopsy, and oncologic treatment. ^[9]
• If red urine is due to foods or medications, stopping the culprit typically resolves the color change. ^[6]

When to seek medical care

• Any time urine appears red or blood-tinged, get evaluated to confirm the cause. ^[6]
• Urgent care is warranted if blood in urine is accompanied by fever, severe pain, vomiting, shaking chills, or you pass painful clots. ^[17]
• Even small amounts detected only on tests (microscopic hematuria) merit discussion and appropriate follow-up to rule out serious conditions. ^[18]

Key distinctions: blood in stool vs urine

• Blood in stool or black stool suggests bleeding in the stomach or intestines and is a known sign of stomach cancer; this needs prompt medical attention. ^[2]
• Blood in urine points to a urinary or kidney source and is usually unrelated to stomach cancer; it requires a urologic/kidney-focused evaluation. ^[5]

Summary

• Blood in urine is not a typical symptom of stomach cancer, which primarily causes digestive and stool-related bleeding signs. ^{[1] [2]}
• Most hematuria arises from urinary tract issues such as infection, stones, prostate problems, kidney diseases, or urinary tract cancers. ^{[7] [9]}
• Get checked whenever urine looks bloody; management is cause-specific and may involve urology or nephrology. ^{[6] [14]}