Page 133 - Clinical Biochemistry

 EX: Measurement of AFP and hCG is mandatory for germ cell tumors (ovary and testis)
prior to surgical excision because the pretreatment concentration is required to calculate the
half-life of tumor marker decline following chemotherapy.
6- Monitoring Disease Post-treatment to Detect Progression or Recurrence
 In general, a decrease in marker concentrations to normal limits following treatment is a
favorable sign.
 Serial monitoring of tumor marker concentrations post-treatment provides early indication
of disease recurrence, often months before there are clinical signs and symptoms.
Use of Tumor Markers in Specific Malignancies
1- Breast Cancer
Diagnosis:
 Definitive diagnosis of breast cancer requires biopsy and histology. Tissue tumor marker
measurements include those for receptors for estrogen (ER), progesterone (PR)
 Preoperative measurements of CA15-3 and/or CEA are desirable if either marker is going
to be used for post-treatment monitoring.
 A high CA15-3 concentration in a patient with apparently localized breast cancer may
indicate metastasis.
Prognosis:
 The extracellular serine protease urokinase plasminogen activator (uPA) and its
endogenous inhibitor plasminogen activator inhibitor 1 (PAI-1) are the best-validated
tissue prognostic markers for breast cancer.
 Both uPA and PAI-1 promote tumor progression and metastasis
 Increased concentration of the two markers is potent predictor of poor patient outcome.
Therapy Prediction:
 Measurement of ER, the long-established molecular marker for breast cancer, is
mandatory in all newly diagnosed invasive breast cancer patients to determine whether anti-
estrogen endocrine therapy is likely to be effective.
 Patients with ER-positive tumors tend to respond to hormonal therapy, while those with
ER-negative tumors will be treated using other therapies (eg, chemotherapy)
Monitoring:
 Most women who have been treated for breast cancer, are subsequently evaluated at regular
intervals with physical examination, and annual mammography to identify early recurrence
or metastatic disease.
2- Colorectal Cancer