Cancer Screening, Prevention & Diagnostic Essentials

Screening Guidelines (Average Risk, Asymptomatic)

• Colorectal: Begin at $45$; options
  • Annual stool tests (FIT or gFOBT)
  • Multi-target stool DNA every $3$ yr
  • FSIG every $5$ yr
  • Colonoscopy every $10$ yr
  • CT colonography every $5$ yr; continue through $75$ if life expectancy ≥$10$ yr
• Endometrial: At menopause, educate on unexpected bleeding
• Lung (high-risk smokers): Ages $55$–$74$, ≥$30$ pack-years, quit ≤$15$ yr ago → consider annual LDCT after shared decision-making; smoking cessation remains priority
• Prostate: Men ≥$50$ with ≥$10$ yr life expectancy → informed choice on PSA ± DRE (earlier, $40$–$45$ for high-risk)
• Cancer-related checkup (≥$20$ yr): Skin, oral cavity, thyroid, nodes, testicles/ovaries + lifestyle counseling

Eight Classic Warning Signs

• Change in bowel/bladder habits
• Non-healing sore
• White patches in mouth/tongue
• Unusual bleeding/discharge
• Lump or tissue thickening
• Indigestion or dysphagia
• Change in wart/mole/skin lesion
• Persistent cough or hoarseness

Health Promotion / Risk Reduction

• Avoid carcinogens (tobacco, excess sun, workplace/ environmental hazards)
• Diet: Emphasize colorful vegetables, cruciferous, fruits, whole grains, nuts, legumes, soy; limit fat, processed & red meats, smoked/salt-cured foods
• Physical activity: $150$–$300$ min moderate OR $75$–$150$ min vigorous weekly; >$300$ min optimal
• Sleep $6$–$8$ h nightly; manage stress, schedule regular exams per ACS

Cell Biology & Malignancy Basics

• Normal cells: Controlled, orderly proliferation; immune system removes abnormal cells
• Cancer cells: Loss of differentiation, uncontrolled growth, abnormal mitosis, invade & ignore growth signals
• Non-neoplastic changes (may precede cancer): Hypertrophy, hyperplasia, metaplasia, dysplasia; anaplasia = irreversible primitive state
• Neoplasm = uncontrolled growth; benign (localized, encapsulated) vs malignant (invasive, can metastasize)
• Metastasis routes: Diffusion into cavities or via blood/lymph
• Immune surveillance: T-cells recognize tumor-specific antigens; suppression (age, steroids, poor nutrition, infection) ↑ cancer risk

General Neoplasm Characteristics

• Benign: Slow, localized, encapsulated, mobile, resembles parent tissue, rarely fatal
• Malignant: Rapid, metastasizes, non-capsulated, irregular/immobile, poor resemblance, invades tissue, may recur, fatal if untreated
• Viral/Genetic links: HPV, EBV, HBV, HCV, HIV; inherited predisposition possible

Tumor Grading & Staging

• Grade $1$ (well-differentiated) → Grade $4$ (undifferentiated, most aggressive)
• Clinical Stages: $0$ in situ, $I$ localized, $II$ limited local spread, $III$ regional spread, $IV$ distant metastasis
• TNM system
  • T$x$–T$4$: Primary tumor size/extent
  • N$x$–N$4$: Regional node involvement
  • M$x$, M$0$, M$1$–M$4$: Distant metastasis status

Key Diagnostic Methods

• Biopsy = definitive; types: needle aspiration, punch, shave, incisional, excisional
• Endoscopy: Direct visualization & tissue sampling (bronchoscopy, upper GI, colonoscopy, sigmoidoscopy)
• Imaging
  • Radiography (e.g., chest X-ray, mammography)
  • Radioisotope scans (bone scan detects early metastasis)
  • CT: Cross-sectional detail, small lesion detection
  • Ultrasound: Non-invasive, sound-wave imaging of soft tissue