[Early changes in serum alpha-fetoprotein after chemotherapy in advanced testicular tumors]

The serum levels of alpha-fetoprotein (AFP) are known to undergo acute changes (paradoxical elevation) after effective chemotherapies for testicular germ cell tumors. In order to understand the clinical significance, the changes of the serum AFP levels after PVB therapy for testicular germ cell tumors were analyzed, and their relationship to the treatment effects was investigated in this retrospective study. Thirty-one patients with testicular germ cell tumors (11 with stage I, 7 with stage II, and 13 with stage III) which had been treated by PVB therapy were evaluated. The measurement of the serum AFP levels was performed by radioimmunoassay on Day 1 (the initiation day of the PVB therapy), thereafter on Day 8 and Day 22. The half-life (t1/2) or doubling time (t2) of the serum AFP were calculated. In patients with stage I disease, the serum AFP levels declined nearly according to its biological half-life between Day 1 and Day 22 after termination of chemotherapy (t1/2 = 6.2 days). In patients with stage II or III disease, the changes of the serum AFP levels were not consistent with the treatment results between Day 1 and Day 8. Namely, complete responders revealed a prolonged decline of the serum AFP levels (t1/2 = 63.0 days), partial responders a transient rise of the serum AFP levels (t2 = 49.5 days) and non-responders a sudden rise of the serum AFP levels (t2 = 9.9 days). On the contrary, the serum AFP levels changed in accordance with the treatment effects between Day 8 and Day 22. Early changes of the serum AFP levels were seen in patients with stage II or III disease between Day 1 and Day 8 after chemotherapy. It was indicated that the measurements of the serum AFP levels during this period were not useful for the evaluation of the treatment effects in these patients. Furthermore, it was suggested that the early changes of the serum AFP levels possibly correlate with the poor response. The mechanism of the early changes of the serum AFP was also discussed.