Cancer Warning Signs Mnemonic

Author:Lahav Constantini

Editors:Anna Hernández, MD,Emily Miao, PharmD

Illustrator:Jessica Reynolds, MS

Copyeditor:David G. Walker

What is the “CAUTION UP” mnemonic?

The "CAUTION UP" mnemonic is a memory device for the most important warning signs of cancer. Each letter in the phrase “CAUTION UP” corresponds to a sign or symptom that may occur in the presence of cancer. It’s important to be aware these manifestations are not always related to cancer, and they can be a sign of another underlying medical condition. Knowing and recognizing these manifestations as warning signs of cancer may facilitate an early diagnosis, which is generally associated with better prognosis. 

CAUTION UP mnemonic down the left side, vertically with cancer warning signs written across horizontally.

What does the “C” in “CAUTION UP” mean?

The "C" stands for changes in bowel or bladder habits. Changes in bowel habits may include diarrhea or constipation, difficulty or pain passing stool, as well as the presence of blood in the stool. Changes in bladder habits may include urinary retention or incontinence, pain while urinating, or the presence of blood in the urine. In particular, changes in bowel habits may be linked to gastrointestinal cancers, including colorectal cancer or stomach cancer. On the other hand, changes in bladder habits can occur in prostate cancer and other urogenital cancers. 

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What does the “A” in “CAUTION UP” mean?

The "A" stands for a sore that does not heal even alongside appropriate treatment. Warning signs include sores that are persistent or worsen in terms of size or pain, as well as lesions that take longer than typical to heal. A sore of these characteristics may suggest the presence of skin or oral cancer

What does the first “U” in “CAUTION UP” mean?

The "U" stands for unusual bleeding or discharge from any part of the body, including the nipples and genitalia. Bloody discharge from the nipples may be a sign of breast cancer, whereas unusual or inappropriate vaginal bleeding may be a sign of gynecologic cancer, including uterine and cervical cancer.

What does the “T” in “CAUTION UP” mean?

The "T" stands for thickening or lump in the breast or elsewhere in the body. Lumps are very common and can be found anywhere in the body but are particularly worrisome in the breasts or testicles. In individuals assigned female at birth who are over 50 years old, performing mammography once every two years is recommended for the screening of breast cancer. In individuals at a higher risk of developing breast cancer (e.g., those with mutations in the BRCA1 or BRCA2 gene), breast cancer screening guidelines recommend annual screening with breast magnetic resonance imaging (MRI) as early as 25 years old and the addition of annual screening mammography starting at 30 years old. 

What does the “I” in “CAUTION UP” mean?

The "I" stands for indigestion or difficulty in swallowing. Indigestion refers to a general sensation of discomfort after eating as well as the presence of bloating, nausea, or vomiting. Both indigestion and difficulty in swallowing may indicate mouth, throat, esophagus, or stomach cancer

What does the “O” in “CAUTION UP” mean?

The "O" stands for obvious changes in warts or moles. These changes may indicate some type of skin cancer, such as melanoma. Melanoma typically looks like an abnormal or irregular mole. The main warning signs of melanoma can be assessed using the ABCDE rule. ABCDE stands for Asymmetry in shape; Border irregularities; Color heterogeneity; Diameter over six millimeters; and Evolution, which refers to changes in size, color, or shape over time. The presence of one or more of these features indicates a higher chance of malignancy.

What does the “N” in “CAUTION UP” mean?

The "N" stands for nagging cough or persistent hoarseness that lasts for months or more. These signs, along with changes in the voice and coughing up blood, may be indicative of  throat or lung cancer. Individuals who currently smoke tobacco or those that have smoked tobacco in the past are particularly at risk for these types of cancer.

What does the second “U” in “CAUTION UP” mean?

The second "U" stands for unexplained weight loss, which may be a sign of advanced cancer. Weight loss is usually associated with other symptoms, such as fatigue, generalized weakness, difficulty doing everyday activities, and loss of appetite.

What does the “P” in “CAUTION UP” mean?

The "P" stands for pernicious anemia, which is a medical condition that constitutes a risk factor for stomach cancer. Anemia is a condition where the body has low levels of red blood cells or hemoglobin, which is a protein found in red blood cells important for carrying oxygen throughout the body. Pernicious anemia occurs when the body produces antibodies against a protein called intrinsic factor, which is necessary for the absorption of vitamin B12 from foods. Individuals without enough intrinsic factor may end up with a vitamin B12 deficiency, which affects the body’s ability to make new red blood cells, resulting in pernicious anemia. The persistent inflammation and destruction of the gastric mucosa that leads to destruction of intrinsic factor, can also increase the risk of stomach cancer. 

What are the most important facts to know about the “CAUTION UP” mnemonic?

"CAUTION UP" is a mnemonic device that can help individuals recall some of the early warning signs of cancer. The "C" refers to changes in bowel or bladder habits, "A" refers to a sore that does not heal, the first "U" refers to unusual bleeding or discharge, "T" refers to thickening or lump in breast or elsewhere, "I" refers to indigestion or difficulty in swallowing, "O" refers to obvious changes in warts or moles, "N" refers to nagging cough or persistent hoarseness, the second "U" refers to unexplained weight loss, and "P" refers to pernicious anemia. It is important to note these signs do not necessarily indicate cancer, but they may warrant further investigation to uncover their underlying cause.

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Related links

Breast cancer
Colorectal cancer
Lung cancer
Pernicious Anemia: What It Is, Causes, Signs, Symptoms, and More
Prostate cancer

Resources for research and reference

7 Warning Signs of Cancer. World Health Organization. Accessed March 23, 2022.

Bengtsen MB, Farkas DK, Borre M, Sørensen HT, Nørgaard M. Acute urinary retention and risk of cancer: population based Danish cohort study. BMJ. 2021;375(n2305):n2305. doi:

Breast Self-Exam. National Breast Cancer Foundation. Accessed March 25, 2022.

Cancer - Early Warning Signs Nursing Mnemonic (CAUTION UP). Accessed March 23, 2022.‌

Murphy G, Dawsey SM, Engels EA, et al. Cancer risk after pernicious anemia in the US elderly population. Clinical Gastroenterology and Hepatology. 2015;13(13):2282-2289.e4. doi:

Signs and symptoms of cancer. American Cancer Society. Accessed March 23, 2022. 

Skin cancer facts & statistics. Skin Cancer Foundation. Accessed March 27, 2022.