Marker half-life analysis as a prognostic tool in testicular cancer.

In a retrospective study we compared the actual half-life of the serum tumor markers alphafetoprotein and human chorionic gonadotropin to the clinical course of patients who underwent an operation or chemotherapy for germ cell cancer. Of the 7 patients with residual disease postoperatively 5 had abnormal half-life values and in 3 this knowledge would have been of clinical value. Only 1 of 10 patients with a complete response to chemotherapy had an unfavorable actual half-life compared to 17 of 19 with a less than complete response. Prolonged marker decay rates during the first month of chemotherapy reflected ineffective chemotherapy and appeared to be independent of tumor bulk. Postoperatively, actual half-lives probably are useful prognostically only if the values are abnormal. Similar calculation may be of prognostic value early in the course of induction chemotherapy.