TUMOR-MARKER DOUBLING TIME IN PATIENTS WITH PROSTATE-CANCER - DETERMINATION OF PROSTATE-SPECIFIC ANTIGEN AND PROSTATIC ACID-PHOSPHATASE DOUBLING TIME

To estimate the growth rate of prostate cancer, the doubling times of prostate specific antigen (PSA) and prostatic acid phosphatase (PAP) w ere determined in 51 patients: 44 were refractory to endocrine therapy , and 7 were in an untreated state. Since an exponential increase in P SA and PAP was observed in all patients, the doubling time was calcula ted from a semilogarithmic plot of the respective markers. PSA doublin g time was almost identical with that of PAP. The tumor marker doublin g time in untreated patients was approximately 10 times greater than t hat in the patients who were refractory to endocrine therapy. In endoc rine refractory patients, the tumor marker doubling time in patients w ho showed deterioration of bone lesions was less than that in patients with local regrowth and/or lymph node metastasis. The prognosis of en docrine refractory patients from the time showing tumor marker failure was examined. The group showing the longest time (> 80 days) had bett er prognosis than that shown by the other groups with shorter doubling times. It is concluded that the determination of tumor marker doublin g time is of value for measuring the growth rates of prostate cancer, and for assessing prognosis after relapse.