Detection and Prevention of Cancer

Core Concepts

Risk factors: modifiable and non-modifiable

Cancer risk factors divide into two groups. Non-modifiable factors include age (most cancers rise with age, reflecting accumulated mutations), inherited genetic variants (see Chapter 30), and, for some cancers, sex and family history. Modifiable factors include tobacco use, excessive alcohol, ultraviolet and ionizing radiation exposure, obesity and physical inactivity, dietary patterns, and certain infections (e.g., human papillomavirus, hepatitis B and C, H. pylori — the "infection-associated cancers"). Most cancers are multifactorial: risk factors add and interact rather than act alone. The nurse's message is honest: reducing a modifiable risk lowers probability — it does not guarantee prevention, and developing cancer is never the person's fault.

Primary prevention: avoiding carcinogens and promoting protection

Primary prevention targets the initiation and promotion phases of carcinogenesis (see Topic 1). Tobacco cessation is the single most impactful intervention — assess tobacco use, advise quitting, and refer to cessation resources at every encounter. Sun protection (shade, protective clothing, sunscreen) reduces skin cancer risk. Vaccination against cancer-associated viruses is primary prevention: HPV vaccines protect against the strains most linked to cervical and other anogenital and oropharyngeal cancers, and hepatitis B vaccination prevents chronic infection that can lead to liver cancer. The nurse educates and supports; the person chooses.

Secondary prevention: how screening works

Screening tests find cancer (or precancer) early in people without symptoms. Common examples include cervical cytology and HPV testing, mammography for breast cancer, stool-based testing and colonoscopy for colorectal cancer, and low-dose CT for lung cancer in defined high-risk groups. The specific tests, ages, and intervals follow current guidelines, which vary by organization, country, and individual risk — nurses must teach from their institution's current recommendations, not from memorized numbers.

The concepts behind every screen matter more than the list: a screen is designed for a population, not a person, so it produces a risk estimate, not a diagnosis. A false positive alarms a healthy person; a false negative misses disease — which is why symptoms always trump a recent normal screen. Screening has harms as well as benefits, which is why guidelines are debated and updated.

Warning signs and the diagnostic workup

Classic warning signs — a lump or thickening, a sore that does not heal, unusual bleeding or discharge, a change in bowel or bladder habits, persistent cough or hoarseness, difficulty swallowing, changes in a mole, unexplained weight loss — are taught with mnemonics such as "CAUTION," which remains a useful study aid though modern guidance emphasizes that any persistent, unexplained change deserves evaluation. The nurse's role: take the symptom seriously, document it, and escalate — never dismiss "it's probably nothing."

When cancer is suspected, diagnosis moves from screening to diagnostic testing: imaging (ultrasound, CT, MRI, PET), and ultimately biopsy — removal of tissue for examination — because only tissue analysis confirms cancer and identifies its type and grade. Biopsy methods include fine-needle aspiration, core needle biopsy, and surgical biopsy; the choice depends on the site and the question. Tumor markers (e.g., PSA, CEA, CA-125, AFP, hCG) are substances that may be elevated with certain cancers, but they are not screening or diagnostic tests in most settings — they are used mainly to monitor treatment response and recurrence. A normal marker does not exclude cancer, and an elevated marker does not diagnose it.

Tertiary prevention and surveillance

After a cancer diagnosis, tertiary prevention aims to reduce recurrence, detect new disease early, and prevent complications: scheduled surveillance imaging and tumor-marker monitoring, management of treatment side effects, lifestyle counseling (tobacco cessation, physical activity), and screening for second primary cancers. This is also the doorway to survivorship care (Topic 4 of this chapter).

Common Confusions