Objectives: To report the results of a retrospective study of 2290 ProstaScint scans of 2154 patients with prostate carcinoma done at 15 institutions.
Methods: The results were analyzed by logistic regression after stratification of the patients into four groups: group 1, newly diagnosed; group 2, after radical prostatectomy with a rising prostate-specific antigen (PSA) level; group 3, after radiation therapy with a rising PSA level; and group 4, after hormonal therapy.
Results: The PSA level and ProstaScint scans positive in the prostate bed (P <0.001) and for pelvic metastases (P <0.001), but not for extrapelvic metastases, correlated significantly in group 1 patients. In group 2, the association for detecting fossa recurrence was weaker (P = 0.033) and was insignificant for pelvic and extrapelvic metastases. Patients in group 3 also exhibited a weak PSA-ProstaScint association for detecting fossa recurrence (P = 0.038), and was insignificant for pelvic and extrapelvic metastases. No significant PSA-ProstaScint correlation was found in patients in group 4 for fossa recurrence, pelvic or extrapelvic metastases. The distribution of positive ProstaScint results among the prostate/prostate bed, pelvic nodes, and extrapelvic nodes was nearly equal for all groups, except that a significantly greater percentage of extrapelvic metastases was found in the hormonal group (group 4). The ProstaScint results were independent of the Gleason score for 260 patients before and 285 patients after therapy.
Conclusions: The results of this study underscore the complementary diagnostic value of ProstaScint to PSA level and Gleason score as an independent indicator of prostate cancer recurrence and metastases and in identifying extrapelvic metastases in both newly diagnosed and recurrent prostate cancer.