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Signs and Symptoms of Small Intestine Cancer (Adenocarcinoma)
The symptoms of small intestine cancers are often vague and can have other, more common causes. Unfortunately, this means that it’s often at least several months from the time symptoms start until the cancer is diagnosed.
This information is about small intestine cancers called adenocarcinomas. To learn about other types of cancer that can start in the small intestine, see Gastrointestinal Carcinoid Tumors, Gastrointestinal Stromal Tumors, or Non-Hodgkin Lymphoma.
Common symptoms of small intestine cancer
Some of the more common symptoms of small intestine cancer are:
- Pain in the belly (abdomen)
- Nausea and vomiting
- Weight loss (without trying)
- Weakness and feeling tired (fatigue)
- Dark-colored stools (from bleeding into the intestine)
- Low red blood cell counts (anemia)
- Yellowing of the skin and eyes (jaundice)
Often, the first symptom is pain in the stomach area. This pain is often crampy and might not be constant. It may start or get worse after you eat.
Symptoms as small intestine cancer grows
As the tumor gets larger, it can slow the passage of digested food through the intestine. This can lead to increased pain. If the tumor gets large enough, it can cause an obstruction, in which the intestine is completely blocked and nothing can move through. This leads to pain with severe nausea and vomiting.
An intestinal cancer may cause a hole (perforation) to form in the wall of the intestine. This hole lets the contents of the intestine spill into the abdomen. Symptoms of perforation can include sudden severe pain, nausea, and vomiting.
Sometimes a tumor will start bleeding into the intestine. If the bleeding is slow, it could lead to a low red blood cell count (anemia) over time. Symptoms of anemia include weakness and fatigue. If the bleeding is rapid, the stool can become black and tarry from digested blood. Some people may feel lightheaded or even pass out.
A tumor in the duodenum (the first part of the small intestine) can cause jaundice. This can happen if the tumor blocks the bile duct, which can prevent the contents from the liver from entering the intestine.
What to do if you have symptoms
These problems are more often caused by things other than cancer. Still, if you have any of them, especially if they don't go away or are getting worse, have them checked by your doctor to find the cause so it can be treated, if needed.
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- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
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Ciresi DL, Scholten DJ. The continuing clinical dilemma of primary tumors of the small intestine. Am Surg. 1995 Aug;61(8):698-702; discussion 702-3.
Colina A, Hwang H, Wang H, Katz MHG, Sun R, Lee JE, Thomas J, Tzeng CW, Wolff RA, Raghav K, Overman MJ. Natural history and prognostic factors for localised small bowel adenocarcinoma. ESMO Open. 2020 Nov;5(6):e000960.
Doyon L, Greenstein A, Greenstein A. Chapter 76: Cancer of the Small Bowel. In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 6th ed. Philadelphia, Pa: Elsevier; 2019.
Islam RS, Leighton JA, Pasha SF. Evaluation and management of small-bowel tumors in the era of deep enteroscopy. Gastrointest Endosc. 2014 May;79(5):732-40. doi: 10.1016/j.gie.2013.11.003. Epub 2013 Dec 21.
Last Revised: February 9, 2026
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