The Dilemma of Serum Tumor Marker (STM) Flares.

UNLABELLED Serum tumor marker (STM) estimation is often used in clinical practice in monitoring response to treatment and as a predictor of treatment failure and relapse. However, there are pitfalls in interpretation, particularly in the immediate post treatment period, when a rise in titre could be observed, the phenomenon being termed as "flare". A literature search was done to examine this phenomenon for some of the commonly used serum tumor markers in malignancies. This phenomenon has been documented with respect to AFP, beta HCG, CEA, AC 15.3, PSA, CA 19.9 and CA 125 with or without other evidence of progression. Based on this review, a practical approach is suggested so that the clinician is not misled into changing a potentially effective treatment regime. A practical approach would be to correlate serum tumor marker values with other clinical and radiological parameters, and not to rely exclusively on serum marker values to guide therapy. KEYWORDS serum, tumor markers, flares, STM, pseudoprogression.