Status of Current Staging Modalities
DRE is an important tool in staging of patients with prostate cancer, but its usefulness as the sole method of detection is limited because it is observer-dependent and only allows detection of palpable tumors. DRE generally understages up to 50% of extra capsular extension and 14% of seminal vesicle (SV) involvement in localized prostatic cancers. It overstages up to 17% of stage C tumors and fails to diagnose 40% of localized cancers that are not palpable (T1c and transition zone tumors). However, DRE does not require additional costs beyond the physical examination and it is recommended that all patients undergo DRE as an initial staging examination.
Prostate-specific antigen Overall, 70% to 80% of men with a PSA less than 4 ng/mL have organ-confined disease at surgery. Those with a PSA greater than 10 ng/mL have a 50% chance of having organ-confined disease.[6,7] Unfortunately, 60% of men with localized prostate cancer have a PSA value in the intermediate range (4 ng/mL to 10 ng/mL), a finding that limits the usefulness of PSA alone in staging.
Free vs complex PSA Recently, there has been some interest in the role of free-vs-complex PSA in the staging of prostate cancer. Carter and colleagues evaluated the utility of serial measurements of free and total PSA as a predictor of prostate cancer aggressiveness in men diagnosed with adenocarcinoma of the prostate. Data suggested that the percentage of free PSA in sera was predictive of tumor behavior at a time when total PSA levels provided no information on tumor aggressiveness. However, since then, there have been several other studies that have shown a lack of utility of free PSA in staging prostate cancer.
PSA density The combined use of PSA and transrectal ultrasonography (TRUS) to calculate PSAD (PSA [ng/mL]/total prostate volume [mL]) has also been evaluated in the staging of prostate cancer. PSAD has been correlated with final pathology by Ackerman and colleagues and Seaman and colleagues: a cut-off value of less than 0.35 was found to be associated with 90% organ-confined cancers, whereas extraprostatic extension was found in 66% of patients above this level. The major disadvantage of PSAD is the inconsistent measurement of prostatic volume by TRUS. Wolff and associates have recently reported on the efficacy of PSAD in staging. They concluded that PSAD is not an ideal tool to distinguish patients with organ-confined cancer from those with extracapsular tumor extension.
© 2000 Medscape
Cite this: Evaluation of the Patient With Prostate Cancer - Medscape - Sep 14, 2000.