Reference — Oncology

Cancer Warning Signs

Early cancer detection significantly improves outcomes. Nurses play a critical role in health education, symptom recognition, and facilitating timely screening and diagnostic evaluation. This reference covers the CAUTION mnemonic, constitutional symptoms, and site-specific warning signs.

Educational use only. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.

CAUTION Mnemonic — American Cancer Society

Letter	Warning Sign	Commonly Associated Cancers	Nursing Education Point
C	Change in bowel or bladder habits	Colorectal, bladder, prostate	Persistent change — not a 1-day episode. Blood in stool or urine: report immediately.
A	A sore that does not heal	Oral, lip, skin (squamous cell)	Any non-healing ulcer, wound, or lesion >3 weeks warrants evaluation
U	Unusual bleeding or discharge	Uterine, cervical, colorectal, bladder, lung	Post-menopausal vaginal bleeding is abnormal and requires immediate evaluation
T	Thickening or lump in breast, testes, or elsewhere	Breast, testicular, thyroid, lymphoma	Teach self-exam: BSE monthly, TSE monthly. Any new or changing lump → evaluation
I	Indigestion or difficulty swallowing	Esophageal, gastric, head and neck, lung	Persistent dysphagia or heartburn unresponsive to treatment warrants endoscopy
O	Obvious change in wart or mole	Melanoma, basal cell, squamous cell carcinoma	ABCDE of melanoma: Asymmetry, Border, Color, Diameter >6mm, Evolution
N	Nagging cough or hoarseness	Lung, laryngeal, thyroid	Cough lasting >3 weeks, hemoptysis, or unexplained hoarseness requires evaluation

Constitutional Symptoms — “B Symptoms”

“B symptoms” is the clinical term for the classic constitutional triad associated with hematologic malignancies. Their presence in Hodgkin lymphoma staging changes stage classification (e.g., Stage IIB vs. IIA) and worsens prognosis.

Fever

Unexplained fever >38°C (100.4°F) not due to infection. Often low-grade and intermittent ('Pel-Ebstein fever' pattern in classic Hodgkin lymphoma).

Hodgkin lymphoma, NHL, leukemia, renal cell carcinoma, hepatocellular carcinoma

Night sweats

Drenching night sweats that require change of clothes or bedding. Distinguish from menopausal hot flashes — cancer-related night sweats are classically severe.

Hodgkin lymphoma, NHL, leukemia, carcinoid, pheochromocytoma

Weight loss

Unintentional loss of ≥10% body weight over 6 months. Cancer cachexia: complex syndrome of anorexia, muscle wasting, and metabolic changes.

Any advanced malignancy; especially pancreatic, gastric, lung, and hematologic cancers

Other constitutional symptoms: fatigue (universal in cancer), anorexia, early satiety, generalized weakness, pruritus (especially in Hodgkin lymphoma and polycythemia vera).

Site-Specific Warning Signs

Cancer Type	Warning Signs	Screening Tool
Breast	New breast lump or thickening, nipple discharge (especially bloody), nipple inversion, dimpling or peau d'orange skin change, axillary lymphadenopathy, breast asymmetry or shape change	Mammogram (USPSTF 2024: biennial age 40–74; ACS: annual age 45–54, then biennial, with option to start at 40); clinical breast exam; breast self-awareness
Colorectal	Change in bowel habits (new constipation or diarrhea), rectal bleeding or blood in stool, dark tarry stools, narrow stools, abdominal pain/cramping, feeling of incomplete evacuation, unexplained weight loss, anemia (fatigue, pallor)	Colonoscopy (every 10 years starting age 45 for average risk); FIT or FOBT (annually); CT colonography
Lung	Persistent cough (new or changed from baseline), hemoptysis, dyspnea, chest pain, hoarseness, recurrent pneumonia or bronchitis, unexplained weight loss, finger clubbing (late)	Low-dose CT (LDCT) annually: age 50–80, 20 pack-year history, current smoker or quit within 15 years (USPSTF 2021)
Prostate	Urinary frequency (especially nocturia), weak or interrupted urine stream, difficulty starting or stopping urination, dysuria, hematuria, hematospermia, back/hip/pelvic pain (bone metastasis)	PSA blood test + digital rectal exam (DRE) — shared decision-making discussion starting age 50; age 45 for high risk (Black men, family history)
Skin (Melanoma)	New mole or changing mole — use ABCDE: Asymmetry, irregular Border, varied Color (multiple shades), Diameter >6mm (pencil eraser), Evolution (any new change). Also: non-healing sore, pearly or waxy bump (basal cell)	Annual skin exam by dermatologist for high-risk patients; monthly self-skin exam
Cervical	Abnormal vaginal bleeding (especially post-coital, between periods, or post-menopausal), unusual vaginal discharge (watery, bloody, foul-smelling), pelvic pain	Pap smear (every 3 years starting age 21); co-test Pap + HPV (every 5 years for age 30–65); HPV vaccine (reduces risk)
Ovarian	Bloating (persistent), pelvic or abdominal pain, difficulty eating or early satiety, urinary urgency or frequency — symptoms often vague and late; frequently presents at advanced stage	No validated population-level screening tool; CA-125 and transvaginal ultrasound used in high-risk women (BRCA1/2)
Testicular	Painless lump or swelling in one testicle, feeling of heaviness in scrotum, dull ache in lower abdomen or groin, gynecomastia (beta-hCG secreting tumors)	Monthly testicular self-examination; ultrasound if abnormality detected

Melanoma ABCDE Rule

Asymmetry

One half does not match the other

Border

Irregular, ragged, notched, or blurred edges

Color

Variation — multiple shades of brown, black, red, white, or blue

Diameter

Larger than 6mm (size of pencil eraser)

Evolution

Any new or changing mole — size, shape, color, or new symptom (bleeding, itching)

NCLEX Pearls — Cancer Warning Signs

✦CAUTION mnemonic: Change in bowel/bladder, A sore that doesn't heal, Unusual bleeding, Thickening/lump, Indigestion/dysphagia, Obvious change in mole, Nagging cough

✦B symptoms: fever + night sweats + weight loss ≥10% body weight — especially associated with lymphoma

✦Post-menopausal vaginal bleeding is ALWAYS abnormal — requires evaluation for endometrial cancer

✦ABCDE of melanoma: Asymmetry, Border, Color, Diameter >6mm, Evolution

✦Ovarian cancer is the 'silent killer' — symptoms are vague (bloating, pelvic fullness) and often present late

✦Lung cancer screening: LDCT annually for smokers age 50–80 with ≥20 pack-year history

✦Painless testicular lump or swelling = testicular cancer until proven otherwise — refer immediately

✦PSA testing requires shared decision-making — a high PSA can indicate cancer, BPH, or prostatitis

✦Nurses promote early detection through patient education, facilitation of screening, and follow-up advocacy

Related Resources

Cancer Fundamentals GuideCancer biology, staging, risk factors, and nursing role

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Radiation Therapy Nursing CareSkin cancer warning signs relate to radiation-induced dermatitis recognition

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Oncologic Emergencies GuideWhat happens when cancer is diagnosed late — emergent complications

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Common Cancer Treatments ReferenceOverview of treatment options once cancer is diagnosed

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Standards & sources

Fact-checked Jun 21, 2026

This page is written to align with Oncology Nursing Society (ONS) · National Comprehensive Cancer Network (NCCN) · American Society of Clinical Oncology (ASCO). It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →