The dedifferentiation of prostate carcinoma.

Fifty-four patients with prostate carcinoma, each having 2 TURP (transurethral resection of the prostate) procedures separated by 3 to 11 years, were studied to determine whether the histologic appearance of prostate carcinoma remains the same for the life of the host or whether the histological appearance changes with time. Using the M. D. Anderson (MDAH) method of grading prostate carcinoma, 19 of 26 (73%) Grade 1 lesions, 9 of 12 (75%) Grade 2 lesions, and 7 of 8 (88%) Grade 3 lesions dedifferentiated into another grade at the time of the 2nd TURP. Eight cases that were Grade 4 at the time of the 1st TURP, remained Grade 4 lesions at the time of the 2nd TURP. Although 10 Grade 1, Grade 2, and Grade 3 lesions did not change grades, 8 of these 10 cases were less differentiated at the time of the second TURP than they were at the time of the first TURP. Furthermore, no Grade 1 lesions demonstrated evidence of metastases, but 19% of Grade 2 lesions, 55% of Grade 3 lesions, and 80% of Grade 4 lesions demonstrated evidence of metastases. This study suggests that the usual course of prostate carcinoma is dedifferentiation and that with dedifferentiation, the likelihood of metastases increases.