Testis cancers produce hormones that can be measured in the blood. These measurements are extremely reliable tumor markers. The three main markers are HCG, lactate dehydrogenase (LDH) and alpha-fetoprotein (AFP). They are so dependable that any increase above normal blood levels indicates a testis tumor recurrence . This is true even if there is no evidence of cancer by physical examination and x-ray examinations.
The Uses of Tumor Markers These markers are used to monitor the response to therapy. If the tumor markers decrease or return to normal levels after treatment, there is obviously a response. An increase is a sign of disease progression or failure to respond.
If the levels increase, signifying relapse, chemotherapy or sometimes surgery is needed (the cure rate for "marker relapse" is excellent, approaching 100 percent). But normal levels do not guarantee the complete absence of testis cancer, since microscopic deposits may still exist. This is why follow-up requires chest x-rays and CT scans. When masses are seen on CT scans and x-rays, particularly in the abdomen when measuring more than 1.2 in. (3 cm), they are likely to be malignant . Smaller masses when accompanied by an increase in the marker level also indicate that more treatment is necessary. If the markers are normal, small masses may well be only remaining scar tissue or benign teratoma.
The rate of disappearance of a marker from blood can also be predicted by its "half-life"—the time it takes for the amount of a marker in the bloodstream to be reduced by half. The half-life for HCG is about 30 hours, and five to seven days for AFP. Physicians using these formulas can determine to some degree whether the
