Page 131 - Clinical Biochemistry

Clinical Applications of Tumor Markers
 Screening for Cancer
 Diagnosis of Cancer
 Assessing Prognosis
 Prediction of Treatment Response
 Monitoring Response During and/or Shortly After Treatment
 Monitoring Disease Post-treatment to Detect Progression or Recurrence

1- Screening for Cancer
 The aim of screening is to detect unsuspected disease in asymptomatic subjects.
 Successful population screening for early colorectal cancer using a fecal

immunochemical test for hemoglobin (FIT) is routine in some countries.
 Screening patients at high risk of hepatocellular carcinoma (HCC) with ultrasound (US)

with or without alpha- fetoprotein (AFP).
 Ovarian cancer screening by CA-125.
 There is continuing debate about whether to screen for prostate cancer using PSA marker

2- Diagnosis of Cancer
 Tumor markers are not helpful for diagnosis in patients with nonspecific symptoms and

cannot replace a biopsy for establishing the primary diagnosis of cancer.
 However, in carefully selected undiagnosed patients who are at high risk of malignancy

increase concentrations of tumor markers may be informative and facilitate diagnosis
 In general, the higher the serum tumor marker value, the greater the probability of

malignancy, but conversely it is essential to remember that results within the reference

interval never necessarily exclude malignancy.
 Serum AFP testing as an adjunct to ultrasound for hepatocellular carcinoma (HCC) in

patients with cirrhosis who are at high risk of developing HCC
 Differential diagnosis: CA125 contributes (with menopausal status and ultrasound

findings) for the calculation of the “risk of malignancy index,” which is used to differentiate

patients with benign and malignant pelvic and ovarian masses.

3- Assessing Prognosis
 Prognostic markers predict the likely outcome of disease with respect to risk of relapse or

disease progression.
 A marker of good prognosis is suggestive of prolonged survival and/or the possibility of

cure.
 A marker of poor prognosis indicates an increased probability of early recurrence.