[Circulating prostate cells and bone marrow micrometastasis are determinant in risk and time to biochemical progression in localized prostate cancer.]

INTRODUCTION

Minimal residual disease (MRD) is that which remains after curative therapy for prostate cancer. It has the potential for growth and later cause metastasis. After radical prostatectomy, the detection of circulating prostate cells (CPCs) and bone marrow micro-metastasis could represent different types of MRD. We proposed to determine the biochemical failure free survival rates, the time to biochemical failure after 10 years of follow-up and the presence of CPCs and micro-metastasis in patients treated with RP for pathologically organ confined prostate cancer.

METHODS AND PATIENTS

One month after RP monotherapy for prostate cancer, blood and bone marrow samples were taken to detect CPCs and micro-metastasis. Men were classified as: group A (CPC negative and micro-metastasis negative), group B (CPC negative and micro-metastasis positive), group C (CPC positive and micro-metastasis negative), and group D (CPC positive and micro-metastasis positive). All subjects were followed with serial total PSA levels, recording the time at which failure occurred defined as a serum PSA > 0.2ng/ ml on two separate occasions. After ten years of follow- up for each group Kaplan-Meier survival curves were determined and using an adjusted flexible parametric model (FP), the Restricted Mean Survival Times for groups A, B, C and D were calculated. RESULTS: 191 men participated, 10-year biochemical failure survival rates were; group A (N=114) with a Kaplan-Meier of 98.7%; group B (N=39) 65.1%; group C (N=12) 10.4% and in group D (N=28) 12.8%. The Restricted Mean Survival Times (years) were group A: 9.95; group B: 9.45, group C: 5.11 and group D: 6.18 (p-value <0.001 between groups: A versus C, Aversus D, B versus C and B versus D). Frequency and time to failure was dependent on the type of MRD, those men CPC positive had a significantly higher failure rate and early failure. Those men only micro-metastasis positive had lower failure rate and late failure when compared with men negative for MRD.

CONCLUSIONS

CPC positive men have a more aggressive disease with increased early failure; those men who are only positive for micro-metastasis are at risk for late or delayed failure. These two forms of measuring MRD represent different stages in the disease progression and may be used to guide clinical treatment decisions before increases in PSA levels.

A comparison of 3 on-line nomograms with the detection of primary circulating prostate cells to predict prostate cancer at initial biopsy

INTRODUCTION

The use of nomograms which include the PSA may improve the predictive power of obtaining a prostate biopsy (PB) positive for cancer. We compare the use of three on-line nomagrams with the detection of primary malignant circulating prostate cells (CPCs) to predict the results of an initial PB in men with suspicion of prostate cancer.

METHODS AND PATIENTS

Consecutive men with suspicion of prostate cancer underwent a 12 core TRUS prostate biopsy; age, total serum PSA, percent free PSA, family history, ethnic origin and prostate ultrasound results were used for risk assessment using the online nomograms. Mononuclear cells were obtained by differential gel centrifugation from 8ml of blood and CPCs were identified using double immunomarcation with anti-PSA and anti-P504S. A CPC was defined as a cell expressing PSA and P504S and defined as negative/positive. Biopsies were classified as cancer/no-cancer. Areas under the curve (AUC) for each parameter were calculated and compared and diagnostic yields were calculated.

RESULTS

1,223 men aged>55 years participated, 467 (38.2%) had a biopsy positive for cancer of whom 114/467 (24.4%) complied with the criteria for active observation. Area under the curve analysis showed CPC detection to be superior (p<0.001), avoiding 57% of potential biopsies while missing 4% of clinically significant prostate cancers.

CONCLUSIONS

The CPC detection was superior to the nomograms in predicting the presence of prostate cancer at initial biopsy; its high negative predictive value potentially reduces the number of biopsies while missing few significant cancers, being superior to the nomograms in this aspect. Being a positive/negative test the detection of CPCs avoids defining a cutoff value which may differ between populations.