What laboratory tests are used to screen for cancer?

From the Guidelines

The most effective approach to screening for cancer involves a combination of imaging studies, physical examinations, and blood tests tailored to individual risk factors, age, and family history, as recommended by the American Cancer Society guidelines 1. When it comes to screening for cancer, several tests can be used, including:

• Complete blood count (CBC) to detect leukemia and other blood cancers
• Comprehensive metabolic panel (CMP) to evaluate liver and kidney function
• Tumor markers like PSA for prostate cancer, CA-125 for ovarian cancer, and CEA for colorectal cancer
• Genetic tests for hereditary cancer syndromes However, no single blood test can screen for all cancers, and many tests have limitations in sensitivity and specificity. The American Cancer Society recommends the following screening tests for average-risk, asymptomatic individuals:
• Breast cancer: annual mammography starting at age 40, clinical breast examination (CBE) every 3 years for women in their 20s and 30s, and annually for women aged 40 and older 1
• Cervical cancer: screening should begin approximately 3 years after a woman begins having vaginal intercourse, but no later than age 21, with a Pap test every year or every 2 years using liquid-based Pap tests 1
• Colorectal cancer: annual fecal occult blood test (FOBT) or fecal immunochemical test (FIT) starting at age 50, or flexible sigmoidoscopy every 5 years, or colonoscopy every 10 years 1
• Prostate cancer: men who have at least a 10-year life expectancy should have an opportunity to make an informed decision with their healthcare provider about whether to be screened for prostate cancer using digital rectal examination (DRE) and prostate-specific antigen (PSA) test 1 It is essential to consult with a healthcare provider to determine which screening tests are appropriate for an individual's specific situation, taking into account their risk factors, age, and family history. Regular screening according to age-appropriate guidelines is crucial for early detection, as cancer is most treatable when found early 1.

From the Research

Labs to Screen for Cancer

• Various labs can be used to screen for cancer, including:
  • Tumor markers such as AFP, CEA, PSA, hCG, CA 19-9, and CA 125 2
  • Complete blood counts (CBC) and liver function tests (LFTs) to screen for occult metastatic disease 3, 4
  • Chest x-rays, although their use is no longer recommended by the National Comprehensive Cancer Network guidelines 3, 4
• The use of these labs can help identify cancer at an early stage, when treatment is more effective 5
• However, the use of these labs can also result in additional financial costs, and may not always improve detection of occult metastatic disease 4

Tumor Markers

• Tumor markers such as CA125, CEA, and CA19-9 can be used to diagnose and monitor cancer patients 2, 6
• CA125 has been shown to be a superior prognostic biomarker for colorectal cancer compared to CEA, CA19-9, or CA242 6
• The combination of two or more tumor markers can provide more information about the biological characteristics of the cancer 2

Screening for Specific Cancers

• Mammography, Pap smears, and colorectal cancer screening can be used to screen for breast, cervical, and colorectal cancers, respectively 5
• The use of these screening tests can help identify cancer at an early stage, when treatment is more effective 5
• However, disparities in cancer screening exist, and efforts should be made to increase screening rates among underserved populations 5