8 Questions
Which tumor marker is considered reliable for cancer screening?
PSA (with digital rectal examination)
Which tumor markers are considered reliable for early detection of cancer?
AFP (fucosylated)
Why are tumor markers generally unreliable for staging of tumors?
There is an overlap in tumor markers values between stages
What is the most widely accepted indication for measuring tumor markers?
Monitoring and follow-up of tumor for recurrence
After how many consecutive measurements spaced 1 month apart is a significant change in tumor marker levels generally considered?
3
Measurement of tumor markers should be postponed for at least 1 month after which procedures?
Surgery and biopsy
Which of the following markers are indicative of a good therapeutic response in breast cancer?
Estrogen and progesterone receptors
When measuring tumor markers, why must you inform the lab if the patient is receiving treatment with monoclonal antibodies?
Treatment with monoclonal antibodies can interfere with test results
Study Notes
Characteristics of Ideal Tumor Markers
- Tumor markers are unreliable for screening of tumor due to low sensitivity, except for PSA when used with digital rectal examination.
- Tumor markers are unreliable for early detection of tumor due to low sensitivity and specificity, except for PSA (Free, density), AFP (fucosylated), HCG, and monoclonal Immunoglobulin.
Limitations of Tumor Markers
- Tumor markers are unreliable for staging of tumor due to overlap in tumor marker values between stages.
Monitoring and Follow-up of Tumor for Recurrence
- Measuring tumor markers is the most widely accepted indication for monitoring and follow-up of tumor for recurrence.
- Significant changes in tumor marker levels require a 25% increase in three consecutive measurements taken 1 month apart.
- After marker levels return to the reference range, repeat testing is done every 3 months for 1-2 years, and every 6 months thereafter.
- Increased PSA and HCG levels are used to initiate therapy for recurrence, while other markers require confirmation of recurrence before treatment.
Prediction of Therapeutic Response
- Only a few markers, such as estrogen and progesterone receptors (steroid receptors) in breast cancer, indicate a good response to therapy.
Important Notes
- Measurement of tumor markers should be postponed for at least 1 month after surgery, biopsy, or digital rectal examination (in case of PSA measurement).
- Inform the lab when patients receive treatment with monoclonal antibodies.
- Avoid measuring tumor markers when there is damage to the organ clearing or producing the markers.
Learn about the ideal characteristics of tumor markers for cancer screening and early detection, including sensitivity and specificity.
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