Background: Adenocarcinoma of the prostate with seminal vesicle involvement indicates a rather poor prognosis. The aim of this study is to evaluate the route of seminal vesicle involvement via lymphaticovascular or local extension, as a possible way which may determine the extent of disease as systemic or local.
Methods: In a retrospective study of 32 patients who underwent radical prostatectomy for localized cancer of the prostate, medical records and imaging studies were reviewed, and the histopathological slides of the resected specimens were rechecked.
Results: Of 32 patients, 12 (37.5%) had seminal vesicle involvement. Seven patients had involvement of bilateral seminal vesicles and five had unilateral involvement. Tumor cells invaded the muscle portion of seminal vesicle from the adjacent prostatic tissues in all 12 patients. Four of the seven patients with involvement of bilateral seminal vesicles developed bony metastasis 7 to 12 months after operation. No patient with unilateral involvement of seminal vesicle was found to have disease progression to bony metastasis during follow-up for as long as 39 months.
Conclusions: The route of seminal vesicle involvement in prostate cancer was through local extension in all of our patients. Involvement of bilateral seminal vesicles may have more chances to develop bony metastasis than unilateral involvement. Further study with a large number of patients is necessary to clarify the issue regarding the route of seminal vesicle involvement in adenocarcinoma of prostate.