Nondetected tumor (pT0) after prolonged, neoadjuvant treatment of localized prostatic carcinoma

135 patients with stage T1-3N0M0 prostatic carcinoma were submitted to prolonged PSA-monitored neoadjuvant endocrine treatment (PPNET). The rate of pT0 reports was three times higher (15%) than after the standard 3-month therapy (5%). The present work was done to elucidate the initial characteristics of these tumors, to see if additional workup of these prostatectomy specimens is able to detect tumor vestiges and, if so, to describe their morphology.

The original clinical and histopathological data of 20 pT0 cases were reviewed and an additional histopathological workup of the prostatectomy specimens was done.

The majority of patients had initially small (9 patients cT1, 8 patients cT2, 3 patients cT3) and well-differentiated tumors (18 patients Gleason score <7). Microscopic assessment of 4,503 slides revealed very small tumor remnants (mean volume 0.2 ml) in 13 of the 20 prostatectomy specimens. Severe tumor regression was seen in 3 cases, slight to moderate regression in 10 cases.

A pT0 report following detailed routine histopathological workup has to be regarded as a maximal therapeutic effect, but not as tumor elimination. PPNET clearly increases the rate of pT0 reports, implicating that the conventional 3 months of pretreatment does not exploit the possibilities of neoadjuvant therapy.