Diagnostic performance of malignant prostatic cells detection in blood for early detection of prostate cancer: comparison to prostatic  biopsy.
OBJECTIVE
Serum prostate specific antigen and digital rectal examination are the tests used as screening tests to detect prostate cancer. However, only approximately 30% of men with suspicion of cancer have it confirmed on prostate biopsy, and not all of these need treatment. Detection of circulating tumor cells in localized prostate cancer has given variable results, but it could be a useful complementary screening tool to detect prostate cancer in men with abnormal screening tests before the evaluation with prostate biopsy. To evaluate the diagnostic yield of the detection of mCPC as a complementary PC screening test in a population fulfilling criteria for a prostate biopsy for suspicion of PC.


METHODS
A prospective screening study of consecutive patients aged 45-80 years presenting to the urologist for PC screening. Inclusion criteria were PSA >4.0 ng/ml, PSA velocity >0.35 ng/ml/year and/or DRE suspicious for cancer. Patients fulfilling inclusion criteria had blood taken for mCPC detection and then underwent 12-core transrectal prostate biopsy. Double immune-histochemical staining with anti-PSA and anti-P504S was used to detect mCPC. Both cytologist and pathologist were blinded to the results of the biopsy, mCPC results and clinical details. The diagnostic yield of the presence or absence of mCPC was evaluated; the prostate biopsy was classified as cancer or no -cancer.


RESULTS
228 men participated, with a mean age of 66.8 ± 8.8 years and a median serum PSA of 5.15 ng/ml. 28.6% of the biopsies were positive for PC, and mCPC were detected in 31.0%of all cases. Sensibility, specificity and negative predictive value were 86.2%, 90.8% and 94.3% respectively. The negative and positive like-lihood ratios were 9.36 and 0.15. In men with a PSA <4.0ngml, 13.3% had cancer detected on biopsy, with a sensibility and specificity for mCPC detection of 83.3% and 84.6% and negative predictive value of 97.1%. All the mCPC determinations were interpretable. There were 9 false negative cases, all with small low grade tumors.


CONCLUSIONS
The use of mCPC detection could be useful as a complementary prostate cancer screening test, especially for excluding cancer, including patients with a serum PSA <4.0 ng/ml.
Hospital de Carabineros de Chile, Santiago de Chile, Chile. nigelpetermurray@gmail.com
Nigel P
NP
Murray
E
E
Reyes
P
P
Tapia
N
N
Orellana
R
R
Dueñas
C
C
Fuentealba
L
L
Badinez
D000368:Aged; D000369:Aged, 80 and over; D055088:Early Detection of Cancer / Q000379:methods*; D005188:False Negative Reactions; D005189:False Positive Reactions; D006801:Humans; D007150:Immunohistochemistry; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011467:Prostate / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000032:analysis; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology*
D017430:Prostate-Specific Antigen