Prognostic implications of disappearance rate of biologic markers following radical prostatectomy

Elimination Kinetics of Prostate-Specific Antigen Serum and Urine

The serum half-life of prostate-specific antigen (PSA) was calculated in 66 patients subsequent to radical prostatectomy. Comparing serum half-life to disease outcome in 37 patients after a minimum follow-up of two years, it was found that PSA serum half-life identifies patients with residual disease earlier and more reliably than the presence or absence of detectable PSA levels postoperatively. It is suggested that residual tumor affects the half-life by contributing to the serum level of PSA. When PSA serum half-life was calculated solely in potentially cured patients, we found a half-life of 1.6 days, which is considerably shorter than in previous reports based on patient populations regardless of the outcome of disease in the follow-up.

To elucidate the route of PSA elimination, serial urine PSA levels were determined before and after radical prostatectomy, revealing strong evidence for the assumption that PSA is not eliminated by the kidneys in its unchanged form.

Is it Possible to Provide a Prognosis after Radical Prostatectomy for Prostate Cancer by Means of a Psa Regression Model?

Background

For over 15 years, studies have been done to evaluate the elimination kinetics of the prostate-specific antigen (PSA) after radical prostatectomy. Even though evaluation of PSA regression in the two-compartment model has become established, no clear data are currently available as to whether a statement can be made with regard to tumor prognosis from a computation of the PSA half-life (PSA-HL). This study focuses on the determination of the PSA-HL in the two-compartment model and on its correlation with the biochemical recurrence-free survival. In addition, a computer program is being developed to simplify the determination of PSA-HL.

Material and methods

Seventy-seven prospective patients were examined who subsequently had a radical prostatectomy at our facility without neoadjuvant or adjuvant hormone deprivation. In addition to preoperative measurement of the PSA value (d0), PSA determinations were carried out postoperatively on days 5, 10 and 60, and at four-monthly intervals thereafter (mean follow-up: 16 months). By means of the computer program developed for this purpose, CTK. TumW, the PSA half-lives for the first (d0–d5, PSA-HL1) and second (d5–d10, PSA-HL2) compartments were subsequently determined and their effect on biochemical recurrence-free survival was assessed.

Results

PSA-HL1 and PSA-HL2 were 1.89 (± 0.03) and 3.39 (± 0.14) days, respectively. Whilst PSA-HL1 did not permit any prognostic statement, the median PSA-HL in the second compartment between patients with and without disease progression differed significantly (4.44 versus 3.12 days; p<0.001). Discrimination analysis produced a cutoff of 3.8 days for the second compartment; patients with a PSA-HL2 ≥3.8 days had a significantly worse biochemical recurrence-free survival after 18 months than the other patients (27% versus 93%; p<0.001).

Conclusion

The PSA regression kinetics after radical prostatectomy follows a two-compartment model in which the prognostic value of the PSA-HL1 is limited. When a cutoff of 3.8 days is used, evaluation of the PSA-HL in compartment 2 (d5–10) appears to permit a prognostic statement. Due to the limited postsurgical follow-up, the disease process was only assessed as biochemical recurrence-free survival, and a longer follow-up will be necessary to generate data on progression-free survival.

Prognostic value of modeled PSA clearance on biochemical relapse free survival after radical prostatectomy

PURPOSES

Using population kinetic approach, we modeled PSA decline equations in patients with prostate cancer after radical prostatectomy (RP). We looked for relationships between early PSA decrease profile, characterized by PSA clearance (CL(PSA)) or half-life (HL(PSA)), and the 2-year biochemical relapse free survival (bRFS).

PATIENTS AND METHODS

We performed a retrospective study on 55 patients treated with RP and with at least 2 PSA measurements in the post-operative month. A population kinetic model was investigated with NONMEM. The prognostic factors regarding bRFS were assessed using univariate and multivariate analyses.

RESULTS

The best model describing the PSA post-operative decrease was bi-compartmental and fit patient data well. Median CL(PSA) was 0.034 (terciles were 0.023 and 0.048). The significant prognostic factors associated with a better bRFS with univariate analysis were lower CL(PSA) terciles (2-year bRFS = 100% vs. 85.1% vs. 66.7% if CL(PSA) < 0.023, 0.023 <or= CL(PSA) < 0.048 or CL(PSA) >or= 0.0480, P = 0.006) as well as initial PSA < 7 ng/ml, pT2 stage (vs. pT3), pN0 (vs. pN1) and low main Gleason score (3/5 vs. 4/5). Among these factors, CL(PSA) was the only independent prognostic factor with multivariate analysis regarding bRFS (HR = 0.92, 95%CI = [0.86-0.98], P = 0.0088).

CONCLUSION

CL(PSA) determined with 4 PSA concentrations in the first month following the RP may predict the biochemical relapse risk of prostate cancer patients, thus enabling early identification of high-risk patients requiring adjuvant treatment. A prospective validation of these results is required.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Testicular, Prostate, Colorectal, Breast, and Ovarian Cancers

Background: Updated National Academy of Clinical Biochemistry (NACB) Laboratory Medicine Practice Guidelines for the use of tumor markers in the clinic have been developed.

Methods: Published reports relevant to use of tumor markers for 5 cancer sites—testicular, prostate, colorectal, breast, and ovarian—were critically reviewed.

Results: For testicular cancer, α-fetoprotein, human chorionic gonadotropin, and lactate dehydrogenase are recommended for diagnosis/case finding, staging, prognosis determination, recurrence detection, and therapy monitoring. α-Fetoprotein is also recommended for differential diagnosis of nonseminomatous and seminomatous germ cell tumors. Prostate-specific antigen (PSA) is not recommended for prostate cancer screening, but may be used for detecting disease recurrence and monitoring therapy. Free PSA measurement data are useful for distinguishing malignant from benign prostatic disease when total PSA is &lt;10 μg/L. In colorectal cancer, carcinoembryonic antigen is recommended (with some caveats) for prognosis determination, postoperative surveillance, and therapy monitoring in advanced disease. Fecal occult blood testing may be used for screening asymptomatic adults 50 years or older. For breast cancer, estrogen and progesterone receptors are mandatory for predicting response to hormone therapy, human epidermal growth factor receptor-2 measurement is mandatory for predicting response to trastuzumab, and urokinase plasminogen activator/plasminogen activator inhibitor 1 may be used for determining prognosis in lymph node–negative patients. CA15-3/BR27–29 or carcinoembryonic antigen may be used for therapy monitoring in advanced disease. CA125 is recommended (with transvaginal ultrasound) for early detection of ovarian cancer in women at high risk for this disease. CA125 is also recommended for differential diagnosis of suspicious pelvic masses in postmenopausal women, as well as for detection of recurrence, monitoring of therapy, and determination of prognosis in women with ovarian cancer.

Conclusions: Implementation of these recommendations should encourage optimal use of tumor markers.

Total and free PSA kinetics in patients without prostate cancer undergoing radical cystoprostatectomy

BACKGROUND

Radical cystoprostatectomy and radical prostatectomy are the two major operations where prostate is totally and radically removed. Radical cystoprostatectomy is usually performed in patients with invasive bladder cancer. The aim of the study was to examine Total PSA, Free PSA, and Free/Total Ratio elimination kinetics after radical cystoprostatectomy.

METHODS

Serum PSA, Free PSA, and Free/Total Ratio were determined preoperatively, at the time of cystoprostatectomy specimen removal and then at 3, 6, 12, 24, 48, 72, and 168 hr, from seven patients with muscle invasive bladder cancer, who underwent radical cystoprostatectomy. Free and Total PSA concentrations were measured with non-competitive immunological procedures. The elimination rates and half-lives of Total, Free PSA and Free/Total Ratio were studied using a nonlinear regression analysis.

RESULTS

Surgical manipulations caused about 1.5-fold increase of PSA, 5-fold increase in Free PSA and 3-fold increase in Free/Total Ratio. PSA and Free PSA followed a biphasic elimination pattern of a rapid exponential (a) phase with a half-life of 4.27 and 2.14 hr and a terminal, nonexponential (b) phase with a half-life of 63 and 173.2 hr, respectively. Free/Total PSA Ratio followed, also, a biphasic kinetic pattern of a rapid exponential decline with a half-life of 3.34 and a terminal non-exponential increase with a doubling time of 43 hr.

CONCLUSIONS

Comparing PSA kinetics after radical cystoprostatectomy with those of radical prostatectomy, it appears that PSA follows the same elimination pattern in both models. In contrast, Free PSA and Free/Total Ratio elimination kinetics' patterns differ between the two surgical models.

Evaluation of Psa Kinetic after Radical Prostatectomy

The aim of our study is evaluate PSA kinetics after radical prostatectomy for localized prostate cancer.

Materials and Methods

We evaluated PSA kinetic in 101 patients who underwent radical prostatectomy for localized prostate cancer. Only patients in whom one or more measurable PSA values available postoperatively (from day 2 to day 10) were included in our study group. We calculated the PSA half-life after radical prostatectomy.

Results

The median PSA half-life after radical prostatectomy was 2.2 days (range 0.97 to 6.73 days). We found a statistical difference in PSA half-life between patients with and without positive surgical margins; the group with positive surgical margins showed a slower reduction of PSA than the other, probably due the presence of residual cancer tumor. Conclusions. PSA half-life differs during the beta-phase after radical prostatectomy, it is longer in patients with positive surgical margins than those with negative surgical margins. This difference is probably due to the presence of residual prostate cancer after surgery.

A case of serum CEA disappearance curve after resection of breast carcinoma

Carcinoembryonic antigen (CEA) elimination kinetics after tumor resection were measured in a case of breast cancer. A 45-year-old woman with a left breast carcinoma underwent surgery after neoadjuvant chemotherapy. The serum CEA level before surgery was 34.3 ng/ml. After sequential monitoring of serum CEA levels, postoperative serum CEA elimination kinetics were calculated using non-linear least square analysis with the fitting equation C(t)=(C0-Cp)exp(-kt)+Cp, where C(t) was the postoperative CEA level, t was the number days after surgery, C0 was the CEA level at postoperative time zero, Cp was the CEA at plateau, and k was the rate constant of elimination. Cp was calculated as 6.9 ng/ml, which was above the cut-off level and indicated residual malignancy. After adjuvant chemotherapy, CEA normalized to 1.8 ng/ml. In breast cancer patients with high preoperative serum CEA levels, our analytical method for CEA elimination might be useful for the detection of residual malignancies.

Time course of carcinoembryonic antigen after resection of lung cancer: a predictor of recurrence

We investigated whether the early postoperative time course of carcinoembryonic antigen (CEA) level after resection of lung cancer could be used to predict patients' prognosis. Fifty-three lung cancer patients were included in this study. Postoperative serum CEA levels were calculated by means of non-linear least-squares fitting to the equation C(t) = (C(0)-C(p))exp(-kt) + C(p), where C(t) is postoperative CEA level, t is days after surgery, C(0) is CEA level at postoperative time 0, C(p) is CEA level at plateau, and k is the rate constant of elimination. Postoperative CEA production (P(p)) was calculated as C(p) multiplied by k. C(p) and P(p) represent the numbers of residual tumor cells after surgery. More residual tumor cells yield higher values of C(p) and P(p), and result in earlier recurrence.

RESULTS

Kinetic parameters could be obtained for 30 patients whose preoperative CEA levels were sufficiently elevated. Cutoff levels as predictors for recurrence were 1.1 ng/ml for C(p) and 0.9 ng/ml/day for P(p). The accuracy of prediction of recurrence using these cutoff levels was 79% with C(p) and 89% with P(p). A very poor prognosis was observed for patients with P(p) over 0.9 ng/ml/day.

CONCLUSION

Analysis of the time course of changes in CEA levels after resection of lung cancer appears to be useful for predicting patient prognosis. C(p) and P(p) are very precise predictors of recurrence.

Elimination of serum free and total prostate-specific antigen after radical retropubic prostatectomy

Elimination kinetics of serum total and free prostate-specific antigen were studied for a ten days course after radical retropubic prostatectomy on 11 patients suffering from organ confined prostate cancer. Samples were taken before operation, immediately after finishing the operation and 1, 2, 3, 4, 5, 6 h after prostatectomy and then once a day for the following ten days. The measurements were performed with AxSym assays from Abbott Laboratories. The elimination of both total and free prostate-specific antigen followed a biphasic kinetics. In the fast phase, the average of the individual elimination half-lives of total and free prostate-specific antigen amounted to 6.3 h (SD = 6.1 h; range: 0.55 to 37.1 h) and 0.57 h (SD = 0.18 h; range: 0.22 to 0.89 h), respectively. In the slow phase, total prostate-specific antigen disappeared with an average half-life of 85.6 h (SD = 11 h; range: 47.2 to 261.7 h) and free prostate-specific antigen with an average half-life of 14.4 h (SD = 10.4 h; range: 2.4 to 30.3 h). These results might be significant for the use of free and total prostate-specific antigen and its ratio as a diagnostic and prognostic tool.

Analysis of the early postoperative serum carcinoembryonic antigen time-course as a prognostic tool for bronchogenic carcinoma

BACKGROUND

The serum kinetics of carcinoembryonic antigen (CEA) after resection of lung carcinoma are not well characterized. Its prognostic implications remain unclear. This study was designed to clarify the correlation between postoperative CEA time-course and patient prognosis.

METHODS

The authors analyzed early postoperative CEA time-course in 31 lung carcinoma patients using nonlinear least square analysis with the following three equations: Equation 1: C(t) = C(0); Equation 2: C(t) = C(0)exp(-kt); and Equation 3: C(t) (C(0)PLAT)exp(-kt) + PLAT, in which t: postoperative day; C(t): postoperative CEA; PLAT: postoperative CEA at plateau; C(0): CEA at postoperative Day zero; and k: rate constant of elimination. The equation that yielded the least Akaike's information criterion was adopted as the best fitting regression equation for each patient. When Equation 3 was adopted, postoperative CEA production (PROD) was calculated as PLAT multiplied by k.

RESULTS

Equations 1, 2, and 3 were adopted for 16 (Group 1), 0, and 15 (Group 2) patients, respectively. In Group 1, no decrease in serum CEA level after surgery was detected and CEA production appears to have been little or none. In Group 2, biologic CEA half-life was 1.1 +/- 0.7 days and was not useful for predicting patient prognosis. Tumor recurrences were observed in 9 of the Group 2 patients 19 +/- 9 months postoperatively and there was no significant difference in PLAT or PROD between patients with and without recurrence. Early recurrence within 6 months after surgery was recognized in 5 (early-REC) of the 15 Group 2 patients, in whom there was a tendency for PLAT to be higher than in the other 10 patients without recurrence (early-NON) (early-REC: 3.8 +/- 4.9 ng/mL; early-NON: 1.5 +/- 1.1 ng/mL; P = 0.08). PROD was significantly higher in early-REC than in early-NON (early-REC: 3.5 +/- 4.2 ng/mL/day; early-NON: 0.8 +/- 0.4 ng/mL/day; P < 0.05).

CONCLUSIONS

Although PROD is more sensitive than PLAT, both parameters appear to be useful as prognostic tools for predicting early recurrence after resection of lung carcinoma. This is probably because they represent the number of residual tumor cells immediately after surgery.

A guide to the interpretation of serum prostate specific antigen levels

OBJECTIVE

To review the factors that affect the concentration of prostate specific antigen (PSA) in the serum.

RESULTS

The discussion includes the structure of PSA; its distribution and metabolism; various analytical aspects of PSA measurements; the effects of clinical manipulations on PSA, including digital rectal examination, transrectal ultrasound, cystoscopy, biopsy and transurethral resection of the prostate; factors affecting PSA levels in health, in benign disease, and in prostate cancer; the effect of various treatments on PSA; and the issue of reference ranges.

CONCLUSION

Laboratory staff and physicians must take many factors into consideration when interpreting PSA results.

Clearance of serum PSA after open surgery for benign prostatic hypertrophy, radical cystectomy, and radical prostatectomy

OBJECTIVE

To study the clearance of serum prostate-specific antigen (PSA) after several types of prostatic tissue ablation.

METHODS

Serum PSA levels were measured (YANG Proscheck ultrasensitive assay) just before surgery, immediately after specimen removal, then twice weekly for 5 weeks or until it was undetectable (< 0.05 ng/ml) in patients undergoing radical cystoprostatectomy for bladder cancer (n = 10), or radical prostatectomy for T1 T2 prostate cancer (n = 18) and daily for 6 days after open surgery for benign prostatic hypertrophy (BPH) (n = 10).

RESULTS

Open enucleation for BPH: the immediately postoperative PSA level was 6 times its preoperative value. It decreased following a monoexponential curve with a very short half-life of 0.55 +/- 0.39 days, range (0.14-1.3), reaching a value lower than the preoperative level in all cases, except one by day 3. After radical cystoprostatectomy: the decrease of serum PSA is monoexponential with a half life of 1.92 +/- 1.2 days (0.57-4.24) reaching undetectable level (< 0.05 ng/ml) in all patients by day 21. After radical prostatectomy: 11/18 patients (61%) showed a one-component exponential decrease in PSA with a half-life of 2.5 +/- 1.33 days (range 0.97-4.6 days), and 7/18 showed a two-component exponential decrease with a first half-life of 0.94 +/- 0.8 days and a second of 7.62 +/- 6.35 days); 100% of the patients reached undetectable serum PSA by day 28 in the first group compared to 14.2% of the patients with a two component exponential decrease (P < 0.01). There was no difference between these groups as far as preoperative PSA levels and specimen pathology were concerned.

CONCLUSION

Serum clearance of PSA after extirpative prostatic surgery is closely related to the type and indication of procedure used. Radical cystoprostatectomy is probably the best model in which to study the pharmacokinetics of PSA.

PSA and radicai prostatectomy

PSA represents a very reliable marker in the evaluation of prostatic cancer patients. Particularly in those who have undergone radicai prostatectomy, finding dosable values of serum PSA, that theoretically shouldn't occur, must be regarded as the persistence, at least, of residuai prostatic tissue. An increase of such concentrations raises doubts of locai recurrence or metastatic disease. Every effort must be made to demonstrate this event as soon as possible in order to apply an adjuvant treatment. Non-disappearance of serum PSA at 3 months after surgery has to be inevitably considered as a lack of surgical radicality.

Molecular forms of prostate-specific antigen and the human kallikrein gene family: a new era

Without question, much has been learned about the glycoprotein PSA in recent years. By increasing our understanding of this tumor marker's biochemical and physiologic properties, we will be able to improve its clinical utility. The discovery of the various molecular forms of PSA represents a significant advancement. Knowing the concentration and ratio of these PSA forms will be valuable in deciding which patients require further evaluation with transrectal ultrasound and prostate biopsy and which men can be monitored safely without undergoing further invasive testing. This information will be most valuable in treating the patient with a mildly elevated serum PSA level. Although assays are not yet available to detect specifically hK2, the striking similarities of hK2 to PSA, including selective expression in the prostate, suggest that this marker may also prove useful in prostate cancer management. Indeed, a new era of PSA testing has been entered, and the entire field of prostate cancer will benefit.

The effect of orgasm on prostate-specific antigen

To identify the effect of orgasm on serum prostate-specific antigen (PSA) levels, a prospective trial before and after orgasm was performed in 14 healthy colleagues aged 32-62 years (mean, 44.4 years) with no evidence of prostatic disease. PSA determinations were performed on serum samples obtained before and after orgasm. Significant changes in PSA levels after orgasm were found (P = 0.002, analysis of variance). We conclude that the impact of orgasm on PSA levels should be taken into account when the latter are used for the detection of prostatic disease.

Systematic biopsies accurately predict extracapsular extension of prostate cancer and persistent/recurrent detectable PSA after radical prostatectomy

OBJECTIVES

To determine if methodic analysis of systematic echo-guided biopsies associated with prostatic-specific antigen (PSA) and PSA density can accurately predict the actual pathologic stage of prostate cancer (Ca P).

METHODS

One hundred patients with clinically localized (T1, T2) Ca P who underwent radical prostatectomy (RP) were preoperatively staged by digital rectal examination (DRE), measurement of serum PSA (Yang Pros-check) and PSA density (PSAD), and transrectal echo-guided systematic biopsies (three in each lobe aiming to sample prostatic capsule) to evaluate T stage, Gleason grade, number of positive biopsies, and presence of cancer in the periprostatic tissues. Radical prostatectomy specimens were processed following the McNeal method. The PSA levels were measured every month for 2 years.

RESULTS

Extracapsular disease was detected on the specimen in 45% of the patients, persistent/recurrent detectable PSA in 47% (mean follow-up 18 months). Clinical stage T2 B, presence of Gleason grade 4, PSA > 25 ng/mL, PSAD > 0.6, number of positive biopsies > 66% of the total number of cores taken had a positive predictive value (PPV), respectively, of 72%, 66%, 80%, and 87%. Periprostatic tissue was evaluable on the core biopsies in 77% of the cases. Presence of cancer in the periprostatic fat on the core biopsies had a PPV of 94% for extracapsular disease/biological recurrence.

CONCLUSIONS

The presence of extracapsular cancerous tissue on prostatic core biopsies accurately predicts extracapsular extension of Ca P. Therefore, care should be taken when performing prostate biopsies to sample the prostate capsule and surrounding tissues to obtain a more accurate staging of the disease. The second best predictor of extracapsular disease is the percentage of positive biopsies.