Document Type: Research Articles
CTC Unit, Faculty of Medicine, University Finis Terrae, Santiago, Chile.
Urology Service, Hospital de Carabineros de Chile, Santiago, Chile.
Faculty of Medicine University Diego Portales Santiago, Santiago, Chile.
Objective: The biological characteristics of circulating prostate cells (CPCs) are probably more important than their
mere presence. CD82 is a tumor suppressor, we present the outcome of radical prostatectomy (RP) in men with CD82
positive CPCs. Methods and Patients: consecutive men treated with RP were studied, age, total PSA, Gleason, stage, the
presence of extra-capsular extension, positive surgical margens and infiltration of the seminal vesicles and lymph nodes
were registered. Biochemical failure was defined as a PSA >0.2ng/ml. Immediately before the RP, 8ml of venous blood
was taken to detect CPCs. Mononuclear cells were separated using differential gel centrifugation and CPCs identified
using immunocytochemistry with anti-PSA and anti-CD82. The men were divided into three groups; 1) CPC (-), 2)
CPC (+) CD82 (+) and 3) CPC (+) CD82 (-). The groups were compared with respect to clinical-pathological findings
and biochemical free survival using Kaplan Meier and Cox regression models. Results: 285 men, mean age 65.9 years
participated, 61 (21%) were CPC (-); 57 (20%) were CPC (+) CD82 (+) and 167 (59%) were CPC (+) CD82 (-). Group
1 had low grade small volume cancer, in Group 2, low grade but a larger volume than Group 1 and Group 3 high grade
cancer. Kaplan Meier biochemical free survival curves at 36, 60 and 120 months were; Group 1 98%, 96% and 90%;
for Group 2 93%, 93% and 69% and for Group 3 62%, 44% and 16% respectively. Conclusions: Kaplan Meier survival
curves for Group 1 and Group 2 were similar, although Group 2 men had higher PSA values, more advanced staging
but a similar Gleason score. Group 3 men had a worse prognosis. The results support that biological characteristics of
CPCs are more important than their mere presence identifying men with a high risk of biochemical failure.