Clinical significance of serum alkaline phosphatase isoenzyme levels in advanced prostatic carcinoma

Explorative analysis of a score predicting the therapy response of patients with metastatic, castration resistant prostate cancer undergoing radioligand therapy with 177Lu-labeled prostate-specific membrane antigen

OBJECTIVE

Up to 60% of patients with metastatic, castration-resistant prostate cancer (mCRPC) treated with 177Lu prostate-specific membrane antigen (PSMA) radioligand therapy (RLT) achieves a partial biochemical response with a decrease of > 50% in prostate-specific antigen (PSA) levels. The remaining fractions, however, do not respond to RLT. The aim of this explorative analysis was to identify pre-therapeutic factors for the prediction of response.

METHODS

46 patients [age = 68 years (50-87)] with mCRPC who consecutively underwent RLT with 177Lu PSMA [median applied activity = 6 GBq (2.9-6.2)] were included and analysed retrospectively. The association of different clinical and laboratory factors and parameters from pre-therapeutic 68Ga PSMA positron emission tomography (PET) with the outcome of RLT was tested (Fisher's test). Outcome was defined as PSA changes 8 weeks after second RLT [partial response (PR), PSA decrease > 50%; progressive disease (PD), PSA increase ≥ 25%; stable disease (SD), others]. Significant predictive factors were combined in a predictive score.

RESULTS

30% showed a post-treatment PR (median 73% PSA decrease), 35% SD (median 17% PSA decrease) and 35% PD (median 42% PSA increase). Significant predictors for PD were alkaline phosphatase (ALP) > 135 U/l (p = 0.002), PSA > 200 ng/ml (p = 0.036), and maximum standardized uptake value (SUVmax) of the "hottest lesion" in pre-therapeutic PET < 45 (p = 0.005). The predictive score including PSA, ALP and SUVmax could separate 2 distinct groups of patients: ≤ 2 predictive factors (19% PD) and 3 predictive factors (90% PD).

CONCLUSION

The presented predictive score allowed a pre-therapeutic estimate of the expected response to 2 cycles of RLT. As our study was retrospective, prospective trials are needed for validation.

Comparison between CEA, TPA, CA 15/3 and Hydroxyproline, Alkaline Phosphatase, Whole Body Retention of 99mTc MDP in the follow-up of Bone Metastases in Breast Cancer

The development of bone metastases in cancer can be monitored easily using three markers: 24 h urinary hydroxyproline excretion (HOP) (an index of osteoclastic activity), serum alkaline phosphatase (Alk.Ph.) (an index of osteoblastic activity) and 24 h whole body retention of 99mTc-methylene diphosphonate (WBR%) (an index of bone turnover). To evaluate the effectiveness of this group of bone tumor markers in breast cancer we compared it with the following group of three markers which are commonly used in the monitoring of breast cancer and in the follow-up of advanced disease with or without bone metastases: carcinoembryonic antigen (CEA), tissue polypeptide antigen (TPA) and breast carcinoma antigen (CA 15/3).

In 48 patients with bone metastases CEA, TPA and CA 15/3 were shown to be sensitive (79%, 85%, 90% respectively), while HOP, Alk.Ph. and WBR%, which are commonly accepted as reliable markers of bone activity, showed a lower sensitivity (67%, 46%, 75% respectively).

These results may be explained by the lack of osteoclastic or osteoblastic (or both) activity at the time of diagnosis. This explanation is supported by the fact that the bone markers HOP, Alk.Ph. and WBR% were found to be more sensitive than the others in the subsequent follow-up study.

We conclude that in our study, CEA, TPA and CA 15/3 are at first more sensitive than Alk. Ph., HOP and WBR% but during the follow-up Alk.Ph., HOP and WBR% are possibly both more specific and more sensitive

Serum alkaline phosphatase changes predict survival independent of PSA changes in men with castration-resistant prostate cancer and bone metastasis receiving chemotherapy

OBJECTIVES

The association of a change in serum alkaline phosphatase (ALP) with overall survival OS in men with metastatic castration-resistant prostate cancer (CRPC) receiving chemotherapy is unknown. We evaluated the association of changes in ALP within 90 days with OS in men with CRPC and bone metastases treated with docetaxel or mitoxantrone in the TAX327 trial.

MATERIALS AND METHODS

Eligible patients included those with bony metastatic disease, baseline ALP ≥ 120 u/L (upper limit of normal) and ≥2 post-therapy measurements of ALP available. Survival was estimated using the Kaplan-Meier method and prognostic potential of change in ALP was evaluated using Cox proportional hazards regression. Surrogacy was calculated by the Likelihood Reduction Factor.

RESULTS

601 patients met the eligibility criteria. By day 90, 159 patients had ALP normalization (<120 u/L) and 442 patients did not normalize. Normalization of ALP remained prognostic for OS after adjusting for PSA decline ≥ 30% by day 90 (HR 0.79, 95% CI = 0.65-0.97, P = 0.022). Increase in ALP remained prognostic for OS when adjusting for PSA increase ≥ 50% by day 90 (HR 1.69, 95% CI = 1.33-2.14, P < 0.001). ALP changes did not meet criteria for surrogacy for OS.

CONCLUSIONS

For men with CRPC, bone metastasis and high baseline ALP receiving docetaxel or mitoxantrone chemotherapy, normalization of ALP by day 90 was predictive of better survival independent of ≥30% PSA declines. An increase in ALP by day 90 was also predictive of poor survival independent of ≥50% PSA increase. Given the ready availability of ALP, the validation of our data is warranted.

Prostate-specific antigen and other markers of therapeutic response

Several new agents and combinations demonstrate significant activity in the treatment of patients with hormone refractory prostate cancer. Prostate-specific antigen (PSA) is being used increasingly as the key marker of a therapeutic response in trials of new agents. This article reviews data that support this marker as a surrogate endpoint, and it discusses the issues around the appropriateness of PSA as an intermediate marker with evolving noncytotoxic agents. Other biomarkers of prostate cancer progression are not uniformly elevated in men with advanced disease; to date, they are of limited clinical use. This article also discusses the rationale and results of novel and alternative biomarkers of prostate cancer progression.

Aminoterminal propeptide of type I collagen and bone alkaline phosphatase in the study of bone metastases associated with prostatic carcinoma

The aim of this work was to evaluate the usefulness of serum aminoterminal propeptide of type I collagen (PINP) in the early detection of bone metastases associated with prostatic carcinoma. The results were compared with those of bone isoenzyme of alkaline phosphatase (bAP). Levels of total alkaline phosphatase (TAP) and prostatic specific antigen (PSA), related to the existence of bone metastases, are also evaluated. Fifty-five male patients aged 70-80 years were studied. Nine presented a benign prostatic hyperplasia (BPH) and the rest clinically confirmed prostatic cancer. Cancer patients were classified in accordance with the staging grouping of the International Union Against Cancer/American Joint Committee on Cancer TNM 1992 Revision: stage 0 or BPH (n=9), I (n=6), II (n=12), III (n=18) and IV (n=10). According to this classification, patients of groups BPH, I, II and III have no evidence of metastases. Those of stage IV present any type of metastases. In the case of this work, all patients of group IV presented bone metastases. Some patients of group BPH, I and II were untreated. The rest of the patients were under treatment (radical prostatectomy, telecobaltotherapy or hormonal therapy) for a period of between 6 months and 15 years. Serum PSA (Quimioluminiscence, IMMULITE), PINP (RIA, Orion Diagnostica), bAP (IRMA, Tamdem R-Ostase, Hybritech), and TAP (autoanalyzer) were determined. We found the following sensitivities and specificities (relating the presence of bone metastases to values higher than the upper limit of normality and, in the case of PSA, to values higher than 100 microg/L): (1) PINP: 100% (10/10) and 87% (39/45), (2) bAP: 90% (9/10) and 82% (37/45), (3) TAP: 60% (6/10) and 93% (42/45), (4) PSA: 40% (4/10) and 100% (45/45). These results suggest that PINP and bAP are adequate biochemical markers of bone formation to be used in the detection of bone metastases in prostatic carcinoma, improving the sensitivity and specificity of TAP and PSA. With respect to PINP, bAP presents the disadvantage of its cross-reactivity with liver isoenzyme.

Evaluation of PSA, free PSA, PSMA, and total and bone alkaline phosphatase levels compared to bone scans in the management of patients with metastatic prostate cancer

BACKGROUND

Metastatic prostate cancer clinical evaluation is difficult. A revaluation of new prostate markers with regard to bone scans was performed.

METHODS

Serial markers, including bone alkaline phosphatase (BAP), total alkaline phosphatase (TAP), prostate-specific antigen, total (PSA) and free (fPSA), and prostate-specific membrane antigen (PSMA), were obtained in patients under evaluation and treatment for possible or known metastatic prostate cancer. These were correlated with bone scan results (BSR).

RESULTS

Seventy patients were observed from mid-October 1996-January 1997, during which time 171 serum samples were obtained and correlated with semiquantitative bone scan status. PSA and fPSA provided some correlation with BAP and BSR, but only at high levels (> 16-50 ng/ml). Receiver-operating curve (ROC) analysis demonstrated that BAP and TAP had a significant discriminating ability for positive and negative bone scans (> .78), compared to PSMA, PSA, and fPSA. However, percent BAP and TAP only correlated with BSR at a level above six lesions. As the lesions detected by BSR increased, the correlation increased.

CONCLUSIONS

BAP is a valuable marker for clinical response evaluations to use in the serial follow-up of patients with metastatic prostate cancer, and correlates well with the bone scan as the number of lesions increase to > 6. PSA or fPSA show comparable results, but only at high levels (> 16-50 ng/ml).

Weekly chemotherapy in advanced prostatic cancer

This randomised phase II study was performed in order to evaluate the effectiveness of a weekly chemotherapy regimen in advanced prostatic carcinoma patients (stage D2) refractory to hormonal therapy. Seventy-two cases were studied: they were randomised in a 2:1 ratio to receive either epirubicin (30 mg m-2 weekly) or doxorubicin (25 mg m-2 weekly); 48 patients received epirubicin and 24 received doxorubicin. After 12 courses of chemotherapy, the 45 evaluable patients in the epirubicin arm showed a response rate of 37.7% and the 21 evaluable patients in the doxorubicin arm showed a response rate of 33.3% (P = 0.51). Pain intensity, bone and prostatic tumour markers rapidly and significantly decreased in responders. An improvement in physical symptoms, functional conditions and in emotional well-being was observed in the majority of the treated patients. The histological analysis of bone metastases, performed before and after 12 courses of chemotherapy showed a significant reduction in neoplastic invasion and in new bone formation in responders. Cardiac performance worsened in five out of 45 patients and in ten out of 21 during the first 12 courses of epirubicin or doxorubicin respectively (P = 0.014). The median survival was 12.5 months in the epirubicin arm and 8.0 months in the doxorubicin arm (P = 0.042). Our data indicate that in advanced prostatic carcinoma, a weekly epirubicin regimen may give rapid palliative results, similar to that of doxorubicin, but with less side-effects.

Prostate-specific antigen: questions often asked

In conclusion, an effective new marker for prostatic tissue has been identified and is commonly known as PSA. A review of the literature indicates that although PSA is not tumor specific, its organ-site and cell-type specificity provide the basis for making PSA the marker of choice for use in patients with prostate cancer. The clinical utility of PSA includes monitoring therapeutic efficacy, screening and early diagnosis in high-risk patients, prognosis, staging, and tumor volume evaluation, prediction of disease progression, detection of recurrent disease after radical prostatectomy, and the differential diagnosis and confirmation of tissue for prostatic origin. PSA is not a "magic bullet" for patients with prostate cancer. Many questions must still be answered. For example, with an increase in sensitivity for screening of high-risk populations, how does the urologist/oncologist determine which patients with latent curable early cancer will develop into clinically significant metastasis? Is PSA a more reliable method for detection of early prostate cancer than rectal examination? What procedure should be followed for an asymptomatic patient who presents a 35 ng/ml level of PSA during a routine physical examination? Clearly, further studies are required to answer these questions as well as to assess the malignant potential of the prostatic tumor cell. For now, the combination of PSA, rectal examination, and transrectal ultrasonography guided needle biopsy would appear to be the method of choice to decrease the yearly fatalities due to cancer of the prostate.

Urokinase-type plasminogen activator as a marker for the formation of distant metastases in prostatic carcinomas

Plasma levels of urokinase-type plasminogen activator have been investigated in 80 patients with prostatic carcinoma by means of a radioimmunoassay. A total of 30 patients with disseminated prostatic carcinoma had significantly elevated levels of urokinase-type plasminogen activator, whereas the plasma levels in patients without metastases did not differ from a healthy age matched control group. Sensitivity of elevated urokinase-type plasminogen activator levels in patients with prostatic carcinoma for the presence of metastases was 80 per cent. Therefore, urokinase-type plasminogen activator appears to be a reliable marker for the formation of metastases in prostatic carcinoma.

Prostate specific antigen in the preoperative and postoperative evaluation of localized prostatic cancer treated with radical prostatectomy

The usefulness of prostate specific antigen to predict final pathological stage was studied in 178 consecutive patients. Prostate specific antigen was determined preoperatively in all patients by a monoclonal immunoradiometric assay. All pathological specimens were examined for capsular penetration, seminal vesicle involvement and lymph node involvement. Prostate specific antigen correlated directly with capsular penetration (p less than 0.002), seminal vesicle involvement (p less than 0.02) and lymph node involvement (p less than 0.05). However the diagnostic accuracy of an elevated serum antigen level on an individual basis was only 55 per cent for capsular penetration and 50 per cent for seminal vesicle involvement and lymph node involvement. With a log-linear regression model, the half-life of prostate specific antigen was calculated to be 3.15 +/- 0.09 days. From the equation PSA (t) equals PSA (2) e[-0.2197(t-2)], prostate specific antigen can be used to detect residual cancer on day t in the immediate postoperative period. With respect to long-term followup, 127 patients have been monitored for longer than 2 months postoperatively with prostate specific antigen (mean followup 2 years, range 2 months to 8.6 years). Of the 101 patients who had favorable pathological findings at operation (organ-confined cancer or capsular penetration only) 92 (91 per cent) had a followup antigen concentration in the female range (0.0 to 0.2 ng. per ml.), whereas only 5 of 26 men (19 per cent) with either seminal vesicle involvement or lymph node involvement had an antigen value that was less than 0.2 ng. per ml. All patients with a documented clinical recurrence (8 of 127, 6 per cent) had an elevated followup serum prostate specific antigen concentration. These findings suggest that preoperative levels of prostate specific antigen are not sufficiently reliable to predict final pathological stage on an individual basis in patients with early prostatic cancer, and that the antigen is a sensitive tumor marker for the detection of residual disease after radical prostatectomy and subsequent recurrence of tumor on long-term followup.

Carcinoma of the prostate. Hormonal therapy

A selective review of the literature regarding hormonal therapy for patients with carcinoma of the prostate is presented to assess the current status of the following: therapeutic advantages, disadvantages and risks of alternate approaches to hormonal therapy; observations to predict the magnitude and duration of response to therapy; indications for initiating hormone therapy; the short-term and long-term effects of therapy; and role of hormone therapy in patients with recurrent tumor activity after initial hormonal measures.

Bone imaging and serum phosphatases in prostatic carcinoma

One hundred and twenty-seven patients with locally advanced prostatic cancer were evaluated for the presence and progress of bone metastases before and during hormonal therapy, by serial radionuclide imaging and frequent measurement of plasma acid (tartrate-labile) and alkaline phosphatase. For comparison, serial changes in imaging and phosphatases were classified in each patient into one of six groups. Of 71 patients with negative imaging before treatment, 82% had normal alkaline phosphatase levels and 83% had normal acid phosphatase levels. Of 56 patients with bone metastases at presentation, false negative alkaline and acid phosphatase levels were noted in 18% and 36% respectively, though a few patients eventually developed abnormal levels. Serial plasma biochemistry and particularly alkaline phosphatase showed a response to treatment which was not always obvious on imaging. An assessment of the hepatic component of alkaline phosphatase by reference to plasma gamma glutamyl transpeptidase and isoenzyme electrophoresis was helpful in the evaluation of a false positive result but unnecessary where imaging was positive and phosphatase elevated. It is concluded that serial alkaline phosphatase estimation is essential in the follow-up of patients with prostatic cancer and bone metastases, and probably renders serial imaging studies superfluous once the presence of skeletal metastases has been proven. By comparison, acid phosphatase is a much less effective marker.

Comparison of estramustine phosphate, methotrexate and cis-platinum in patients with advanced, hormone refractory prostate cancer

In this clinical trial of men with advanced prostatic cancer no longer responsive to hormone therapy 189 were randomized to receive estramustine phosphate, methotrexate or cis-platinum. Response evaluations were done in 158 cases. Objective response rates (complete, partial or stabilization of disease) were 34 per cent for estramustine phosphate, 36 per cent for cis-platinum and 41 per cent for methotrexate. Subjective parameters indicated a substantial advantage for pain improvement with methotrexate or cis-platinum over estramustine phosphate. Probabilities of continued response indicated some advantage for methotrexate and median response durations at this time were twice as long for methotrexate (32 weeks) as for cis-platinum (16 weeks), with estramustine phosphate intermediate (23 weeks). Survival rates for the original treatment randomization groups were not different at this time. Side effects of estramustine phosphate consisted primarily of nausea and vomiting and/or anorexia but to a lesser extent than with cis-platinum. These effects were somewhat less for methotrexate, for which the major side effects were stomatitis and leukopenia, as well as hepatic toxicity reflected by elevated serum glutamic oxaloacetic transaminase levels. Other side effects of cis-platinum were less than for methotrexate (no stomatitis), except for signs of renal toxicity (elevations in blood urea nitrogen and serum creatinine), which were greater. Methotrexate had a relatively high level of activity against metastatic, progressive, hormone nonresponsive prostatic cancer, with side effects that were substantial but manageable.

Serial spot hydroxyproline/creatinine ratios in metastatic prostatic cancer

Analysis of urinary hydroxyproline levels offers a marker to monitor osseous involvement in patients with metastatic malignancies. Such a marker is needed in patients with prostatic cancer when bone metastases predominate. Thirty-two men with stage D2 prostatic cancer were monitored by bone scan, acid and alkaline phosphatase values, and urinary hydroxyproline, beginning from 4 to 36 months after initiation of hormonal manipulation and/or systemic chemotherapy. In patients with disease progression determined by bone scan serial urinary hydroxyproline values progressively increased and were significantly elevated compared to urinary values obtained from patients with a stable or improving scan (p less than 0.001). Simultaneous alkaline phosphatase determinations showed less significant differences between patient groups. Acid phosphatase did not reliably indicate osseous response to therapy. These data suggest that urinary hydroxyproline values are predictive as an early objective sign of osseous response in patients receiving therapy for stage D2 prostatic cancer.

A comparison of estramustine phosphate versus cis-platinum alone versus estramustine phosphate plus cis-platinum in patients with advanced hormone refractory prostate cancer who had had extensive irradiation to the pelvis or lumbosacral area

Single and combination chemotherapy was compared in a clinical trial for men with advanced, metastatic prostate cancer who had received prior pelvic irradiation and had had progression of disease despite hormonal therapy. The 149 patients were randomized to receive estramustine phosphate or cis-platinum alone or in combination. Of the 149 patients 25 (17 per cent) were excluded from the study but 124 were evaluated for response and survival. Entry variables were distributed similarly among patients in each treatment arm. There were no complete or partial responders but there were nearly twice as many patients whose disease was stabilized (33 per cent) on the combination regimen compared to estramustine phosphate (18 per cent) and about a third more than for cis-platinum (21 per cent). Analysis of survival revealed some advantage for patients on combination therapy. Major toxicities for all treatments were nausea and vomiting (62 to 88 per cent) and accompanying anorexia (72 to 95 per cent). Azotemia developed in 45 per cent of the patients receiving combination therapy. In addition an elevation in serum creatinine occurred in 22 per cent of the patients receiving combination therapy and in 17 per cent of those receiving cis-platinum alone. Myelosuppression occurred infrequently.

Significance of alkaline phosphatase and chemotherapy for head and neck carcinoma

As an adjunct to surgical treatment and radiation therapy, chemotherapy is becoming another major treatment for head and neck malignancies. While response rates have reached as high as 75% in some series, chemotherapy is time-consuming, expensive, and not without risk to the patient. If a subpopulation that would benefit from its use could be identified, this new modality could be applied on a more rational and selective basis. Recent work has suggested a prognostic role for serum alkaline phosphatase in carcinoma of the head and neck. In an attempt to verify this work, a study of 101 patients treated with an induction chemotherapy protocol for squamous cell carcinoma of the head and neck was undertaken. Alkaline phosphatase and other variables possibly related to alkaline phosphatase were studied in detail. We are unable to verify a prognostic role for alkaline phosphatase.

The use of serum isoenzymes of alkaline and acid phosphatase as possible quantitative markers of tumor load in prostate cancer

The tumor burden of 98 patients with metastatic prostatic cancer was compared longitudinally with the activities of bone (BAP) and liver isoenzymes (LAP) of alkaline phosphatase, total acid phosphatase (AcP), and prostate-specific acid phosphatase (PAP). A quantitative association between these enzyme markers and the tumor mass was suggested by comparing the enzymes with 1) both the treatment response and the estimation of metastasis by radionuclide bone scanning; 2) metastasis based upon radiographic evidence. In addition, an apparent extensive pretreatment bone tumor load was predictive for an elevated BAP activity, which was also a suggestive poor prognosis as previously reported. An elevation of PAP, in contrast to AcP, may precede the clinical disease progression in some patients. Data presented in this report have indicated that the levels of these enzymes compared well with the extent of tumor involvement and therefore may be considered suitable as adjuvant and even quantitative biochemical markers of bone and liver metastasis.

Carcinoplacental isoenzyme (Regan) in carcinoma of the prostate. National Prostatic Cancer Project

Serum samples were examined for the placental-like "Regan" isoenzyme of alkaline phosphatase in two groups of patients with advanced cancer of the prostate from clinical trials of the National Prostatic Cancer Project. In the first group, 98 samples from 76 patients over three consecutive months revealed elevated isoenzyme activity in 14 (18%) of the patients, a frequency similar to those reported for some other tumor types. Four of these patients whose serum demonstrated the "Regan" isoenzyme had samples taken more than once, and their sera had negative readings when taken a month or more before or after the sample that was positive for the isoenzyme. Comparisons of general disease and patient characteristics for patients whose sera were positive or negative for Regan isoenzyme revealed no demonstrable relationships. The second group consists of 72 samples received from 52 study patients with metastatic lesions under treatment from August 1, 1979 to November 16, 1979. Fifteen patients had sufficient serial values. In this study to date, the relationship with clinical response to treatment is inconclusive, although elevated levels of the isoenzyme appear to occur in patients with metastatic disease with bony lesions that are clinically in progression, as well as in those apparently responding to chemotherapy.

Overview of past and current philosophy of prostatic cancer

Carcinoma of the prostate is the second most common cancer in men, yet no significant change in overall survival has occurred since the original description of the results of castration by Huggins and Hodges. Many important questions about the disease remain unanswered. The cause of prostatic cancer is unknown, and few specific environmental or viral agents have been linked with the tumor. Increased recognition of the importance of frequent digitial rectal examination has resulted in more tumors being diagnosed in early stages. Developments in sonography suggest that it may be useful in detecting the presence of prostatic cancer and whether extraprostatic extension has occurred. Recent inprovements in the sensitivity of prostatic acid phosphatase assays have been made, but their use as a screening tool remains limited. In patients with clinical stage B lesions that are microscopically confined to the prostate, treatment by radical prostatectomy appears to confer greatest survival. The exact role of radiotherapy remains to be defined. However, when the tumor extends beyond the prostate and is localized to the pelvis, external beam ro interstitial radiation is appropriate. Pelvic lymphadenectomy has significant morbidity, but less invasive methods of pelvic nodal evaluation are less accurate. Lymphadenectomy has not been shown to have any therapeutic effect. Whether hormonal therapy improves survival needs further investigation, and efforts must continue to develop means of predicting hormonal responsiveness. Those patients unlikely to respond to hormonal therapy should be treated with early chemotherapy.