What are the recommended lab tests and procedures for a patient undergoing cancer screening, considering their individual risk factors and medical history?

Cancer Screening Lab Work

For average-risk adults in the general population, cancer screening lab work should include complete blood count, liver function tests, and urinalysis as baseline tests, supplemented by age- and sex-appropriate screening including fecal occult blood testing starting at age 50, PSA testing for men after shared decision-making at age 50, and CA-125 with pelvic ultrasound for women with specific risk factors. 1

Standard Laboratory Panel for General Cancer Screening

Basic screening labs should include the following for all adults undergoing cancer evaluation: 1

• Complete blood count to detect anemia (suggesting gastrointestinal or other bleeding sources) 1
• Liver function tests to identify hepatic involvement or dysfunction 1
• Erythrocyte sedimentation rate and/or C-reactive protein as inflammatory markers 1
• Serum protein electrophoresis with free light chains to screen for hematologic malignancies 1
• Urinalysis to detect hematuria or other urinary tract abnormalities 1

Age- and Sex-Specific Screening Tests

For Men and Women Age 50+

Colorectal cancer screening requires one of the following approaches: 1

• Annual fecal occult blood test (FOBT) or fecal immunochemical test (FIT) with at least 50% sensitivity for cancer, performed at home with proper collection technique (not single-sample digital rectal exam in office) 1
• Colonoscopy every 10 years as the preferred method for those with family history 2, 3
• Flexible sigmoidoscopy every 5 years combined with annual FOBT 1, 3

For Women

Cervical cancer screening follows this algorithm: 1

• Ages 21-29: Pap test every 3 years 1
• Ages 30-65: HPV DNA test plus Pap test every 5 years (preferred) OR Pap test alone every 3 years 1
• Age >65: Stop screening if 3 consecutive negative Pap tests or 2 consecutive negative HPV/Pap tests in last 10 years 1

Breast cancer surveillance requires: 1

• Annual mammography starting at age 40 until good health no longer permits treatment 1
• Clinical breast examination annually prior to mammography 1

Endometrial cancer requires no routine screening labs, but women at menopause should be counseled to report any vaginal bleeding or spotting immediately 1

For Men

Prostate cancer screening requires shared decision-making discussion at age 50 for men with ≥10-year life expectancy: 1

• PSA blood test with digital rectal examination after informed consent about benefits, risks, and uncertainties 1
• Testing should not occur without this informed decision-making process 1

Enhanced Screening for High-Risk Individuals

For patients with specific cancer risk factors (family history, genetic syndromes, or high-risk clinical features), add: 1

• CA-125 blood test for ovarian cancer risk 1
• Prostate-specific antigen if not already part of routine screening 1
• CT scan of neck, thorax, abdomen, and pelvis for comprehensive anatomic evaluation 1
• Pelvic or transvaginal ultrasonography for ovarian cancer screening 1

Family History-Based Modifications

For individuals with first-degree relative diagnosed with colorectal cancer before age 60: 2

• Begin colonoscopy at age 40 or 10 years before relative's diagnosis age (whichever is earlier) 2
• Repeat every 5 years (not 10-year intervals) 2

For individuals with first-degree relative diagnosed at age 60 or older: 2

• Begin screening at age 40 using average-risk options 2
• Colonoscopy every 10 years or annual FIT 2

For two or more first-degree relatives with colorectal cancer at any age: 2

• Begin colonoscopy at age 40 or 10 years before youngest diagnosis 2
• Repeat every 5 years 2
• Consider genetic counseling for Lynch syndrome if multiple relatives affected, especially with early-onset disease 2

Critical Pitfalls to Avoid

Do not perform single-sample FOBT collected on fingertip during digital rectal exam—this is inadequate and not recommended 1

Do not use guaiac-based toilet bowl FOBT tests, as immunochemical tests are superior in sensitivity and patient-friendliness 1

Do not repeat FOBT in response to initial positive finding—refer directly for colonoscopy 1

Do not perform routine endometrial imaging in asymptomatic postmenopausal women on tamoxifen—only evaluate if vaginal bleeding occurs 1, 4

Verify family history details whenever possible, as this information is often incomplete or inaccurate and critically determines screening intensity 2

Emerging Technologies

Multi-cancer blood-based screening tests (CancerSEEK, Galleri, PanSeer) are under investigation but not yet validated for general population screening 5, 6

PET/CT scanning may identify occult primary tumors with 84% sensitivity and specificity in patients with known metastatic disease, but is not recommended for asymptomatic screening 1