睾丸腫瘍における血清marker -血清AFPの理論的および実測減衰線の臨床的意義-

Abstract

Serum AFP is one of the useful markers for testicular tumor. Biological decline of serum AFP by metabolism and actual change of serum AFP of testicular tumor patients are compared. Biological metabolic half life of AFP in human serum is 5 days. If testicular tumor is resected completely, serum AFP level of the patient is calculated by following equation. 10gXt = 10gXo - 0.139t X log e ............... (1) (X0 : initial marker concentration, X t : the concentration at time t in days) Four testicular tumor patients with predetermined histology and stage are investigated. Xo in equation (I) is the serum AFP immediately before orchiectomy or retroperitoneal Iymphnode dissection. The straight line drawn by equation (I) on a hemilogarithm:ic section paper is called theoretical decay curve (TDC) and the line drawn by actual AFP data points is named actual decay curve (ADC). In stage I testicular tumor, ADC slope approximately agrees with TDC in early post orchiectomy period. While, the slope of ADC is milder than that of TDC in stage II after orchiectomy, and in stage III ADC shows also milder slope than TDC after retroperitoneal Iymphnode dissection. Consequently, the results and the theory go well hand in hand, so mild slope of ADC (in comparison with that of TDC) after operation means the existence of the residual tumor tissue. In other words, this method is thought to be useful for the staging and prognostic evaluation of testicular tumors. It is also suggested to be useful for judgement of the effect of therapies that ADC is drawn by data before, during and after chemotherapy and/or radiation therapy and compared with TDC. It is considered to be necessary to draw ADC and TDC also for hCG, another marker of the testicular tumor, but as hCG's half life is very short, more frequent measurements of the marker (hCG) are essential.