What is the recommended approach for screening for malignancy?

Screening for Malignancy: Evidence-Based Approach

For average-risk adults, cancer screening should focus on the four cancers with proven mortality reduction: breast, cervical, colorectal, and lung cancer, using age-specific and risk-stratified protocols, while avoiding routine screening for other malignancies unless specific high-risk factors are present. 1

Recommended Cancer Screening by Site

Breast Cancer Screening

• Women aged 45-54 years: Annual mammography 1
• Women aged 55+ years: Transition to biennial mammography (every 2 years) 1
• Women aged 40-44 years: Shared decision-making regarding initiation of annual screening 2
• Clinical breast examination can be performed during routine cancer-related checkups 1
• Screening should continue as long as life expectancy exceeds 10 years 2

Cervical Cancer Screening

• Women aged 21-29 years: Cervical cytology (Pap test) every 3 years 1
• Women aged 30-65 years: Either cytology every 3 years OR cytology plus hrHPV co-testing every 5 years 1
• Screening can be discontinued after age 65 in women with adequate prior negative screening and no high-risk history 2

Colorectal Cancer Screening

• Begin at age 45 for average-risk adults and continue through age 75 1
• Preferred options include:
  • Colonoscopy every 10 years 1
  • Annual high-sensitivity fecal immunochemical test (FIT) or guaiac-based fecal occult blood test (gFOBT) 1
  • Flexible sigmoidoscopy every 5 years 1
  • CT colonography every 5 years 1
  • Multitarget stool DNA test every 3 years 1

Lung Cancer Screening

• Adults aged 50-80 years with ≥20 pack-year smoking history who currently smoke or quit within the past 15 years 1
• Annual low-dose CT (LDCT) is the recommended modality 1

Prostate Cancer Screening

• Requires shared decision-making between patient and provider, as the balance of benefits and harms remains uncertain 2, 1
• If screening is pursued after informed discussion: Digital rectal examination and PSA testing for men over age 50 2
• Testing rates should reflect outcomes of shared decision-making, not population-wide screening 2

Cancers NOT Recommended for Routine Screening

In the absence of high-risk factors, routine screening is NOT recommended for: endometrial cancer, ovarian cancer, oral cancer, or other malignancies, as evidence does not support mortality benefit from population-based screening 2

Screening in Specific Clinical Contexts

Unprovoked Venous Thromboembolism (VTE)

• Limited screening approach is recommended: age-appropriate cancer screening (breast, cervical, colorectal) plus basic history and physical examination 2
• Extensive screening with CT abdomen/pelvis is NOT routinely recommended, as randomized trials have not demonstrated benefit over limited screening 2
• Consider individual risk factors (age, smoking history) when determining screening intensity 2

Autoimmune Encephalitis

• Cancer screening should be considered in most adult patients at presentation, as paraneoplastic and non-paraneoplastic presentations are clinically indistinguishable 2
• Initial approach: CT chest, abdomen, and pelvis with contrast 2
• Additional modalities based on clinical suspicion:
  • Mammogram for breast cancer screening in women 2
  • Transvaginal/transabdominal pelvic ultrasound for ovarian teratoma in young adults with NMDAR-antibody encephalitis 2
  • Testicular ultrasound in males with ataxia or brainstem symptoms 2
  • Whole body FDG-PET scan if initial CT screening is negative but suspicion remains high 2

Critical Principles of Cancer Screening

Balance of Benefits and Harms

• Cancer screening should only be recommended when benefits clearly outweigh harms 2
• Most individuals undergoing screening will not have cancer and therefore cannot benefit, but all are exposed to potential harms 2
• Harms include: physical effects (pain, iatrogenic complications), psychological distress from false-positive results, cascade of additional testing, and financial costs 2

Test Characteristics Required

• Adequate sensitivity and specificity to minimize false-positive and false-negative results 2
• Cancer must be sufficiently common in the screened population to justify the screening effort 2
• Early detection must improve outcomes compared to detection at symptomatic presentation 2

Common Pitfalls to Avoid

• Do not use tumor markers for screening in average-risk populations, as most lack sufficient sensitivity and specificity; they are primarily used for prognosis and monitoring 1
• Do not rely on nonspecific blood tests (complete blood count, inflammatory markers) for cancer screening, as they contribute minimally to cancer diagnosis 3
• Do not perform extensive cancer screening in asymptomatic patients without specific risk factors or clinical indications 2
• Avoid screening tests without proven mortality benefit, as this exposes patients to harms without demonstrated benefit 2

High-Risk Populations

For patients with strong family history, genetic predisposition, or other high-risk features, screening protocols differ substantially from average-risk recommendations and require earlier initiation with different testing modalities 2. These patients should be identified through detailed family history assessment and referred for specialized risk evaluation.