Minimum Residual Disease in Patients Post Radical Prostatectomy for Prostate Cancer: Theoretical Considerations, Clinical Implications and Treatment Outcome

Abstract

<br /> <strong><span style="font-size: small;">Introduction: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Minimal residual disease (MRD) remaining after curative therapy for prostate cancer has the potential for growth and can result in metastasis. Circulating prostate cells (CPCs) and bone marrow micro-metastasis (mM) could represent different types of MRD. We here determined; biochemical failure free survival rates; time to BF after 10 years follow-up; and the presence of CPCs and mM in patients treated with radical prostatectomy (RP) for prostate cancer. </span></span><strong><span style="font-size: small;">Methods and Patients: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">One month after RP, blood and bone marrow were sampled for assessment of CPCs </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">and mM. Cases were classified as: group A, CPC negative and mM negative; group B, CPC negative and mM positive; </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">Group C, CPC positive and mM negative; and Group D, CPC positive and mM positive. Subjects were followed with </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">serial determination of PSA levels, recording the time at which BF occurred defined as a serum PSA >0.2ng/ml. After </span></span><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">ten years of follow-up Kaplan-Meier survival curves were generated and the restricted mean survival time (RMST) for each group calculated. </span></span><strong><span style="font-size: small;">Results: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">A total of 321 men participated, 140 in group A with survival of 92.7% (86.3 to 96.2), 39 in group B with 55.8% (37.2 to 70.9); 54 in group C with 6.41% (1.19 to 18.21) and 88 in group D with 4.96%(1.64 to 11.13%. The RMST (in years) were: group A, 9.47 (9.24 to 9.69); group B, 9.23 (8.87 to 9.58); group C, 4.62 (4.46 to 4.77); and group D, 3.57 (3.52 and 3.63) (p-value</span><strong><span style="font-size: small;">Conclusions: </span></strong><span style="font-family: Times New Roman,Times New Roman; font-size: small;"><span style="font-family: Times New Roman,Times New Roman; font-size: small;">CPC positive men have more aggressive disease, with increased early failure; men who are only positive for mM are at greater risk of late failure. These two forms of MRD represent different clinical entities with respect to biochemical failure and could be used to guide clinical treatment decisions. </span></span></span>