Multiple marker evaluation in human prostate cancer with the use of tissue-specific antigens.

Serum prostate-specific antigen and prostatic acid phosphatase were simultaneously evaluated in 22 healthy males, 29 patients with benign prostatic hypertrophy, and 192 patients with prostate cancers at various stages as well as in 30 patients with cancers other than prostate cancer. Both markers were quantitated by specific sandwich-type, enzyme-linked, immunosorbent assays with the use of specific antiserum reagents. Serum assays revealed a discordance between these two markers; thus expressions of these two biochemically and immunologically distinct prostate-specific proteins may reflect different aspects in the biology of prostate cancer. A combination test with the use of 7.5 ng of prostate antigen and 15.5 ng of prostatic acid phosphatase/ml of serum, respectively, as cutoff values resulted in a positive detection rate of 58% for prostate cancers of stages A (7/12) and B (21/36) each, 68% for prostate cancer of stage C (19/28), 92% for prostate cancer of stage D (106/116), and only 10% for benign prostatic hypertrophy (3/29). None of 52 other cancers or healthy controls was registered as positive. This study demonstrates that a multiple marker test of tissue-specific antigens can be of an additive value in the immunodiagnosis of cancer and may be a logical and effective approach at this time, in light of the unavailability of human tumor-specific markers.

Use of human prostate-specific antigen in monitoring prostate cancer.

The newly reported human prostate-specific antigen (PA) is a specific histiotypic product of human prostate. With the use of a sensitive enzyme immunoassay, the circulating PA in prostatic cancer patients has been evaluated clinically. In 96 patients with advanced stage of disease (D2) and receiving chemotherapies, the pretreatment serum PA levels were found to be of prognostic value with regard to the patient survival. Ten patients with metastatic prostate cancer were monitored for more than 32 weeks by 183 serial PA values and were found generally to respond to the treatment. Additionally, in another group of 32 patients who underwent curative therapies for localized prostate cancer, 161 serum samples were evaluated during periods of 12 to 114 weeks (average 56 weeks). Of these patients, five developed metastases during follow-up, and all were shown to exhibit increasingly elevated PA values, either corresponding to or preceding the clinical diagnosis of disease recurrence. These results suggest that PA is a new marker with potential value to merit further clinical study.

Prognostic importance of prostate-specific antigen for monitoring patients with stages B2 to D1 prostate cancer.

To evaluate the prognostic value of prostate-specific antigen (PA) for detection of tumor growth after definitive therapy, 602 sera from 70 patients with stages B2 to D1 prostate cancer (26 of whom recurred) were analyzed in a blind study. Using Cox's proportional-hazards model, a highly significant association was found between serially measured PA and disease-free survival time (p = 0.0002). A positive predictive value of 100% was found for some markedly elevated PA levels and confirmed recurrence of disease. In fact, this study suggested that once a PA level of 88 ng/ml was reached, there was an average time of less than 2 months before a recurrence was clinically confirmed. Tumor growth in patients who recurred was indicated by a PA elevation before recurrence in 92% (24 of 26) as opposed to 20% (9 of 44) in disease-free patients. Additionally, in these 24 of 26 patients, levels of PA were elevated 12 months (mean lead time) before a confirmed disease recurrence. In patients who were still disease free, serial PA appeared to increase concurrently with putative tumor growth as shown by the initial surgical stage. Generally, the greater the PA level the more advanced was the stage of disease (B2 to D1). These data suggest that PA may be a useful adjuvant marker for monitoring tumor growth in patients with regionally confined prostate cancer.

Prostate-specific acid phosphatase versus acid phosphatase in monitoring patients with prostate cancer.

Serial levels of PAP and AcP activity were compared for their relative values in monitoring 57 early and 33 advanced prostate cancer patients. Several findings regarding the patients' disease status and the enzyme levels have been observed that may be beneficial to therapeutic management of these patients. They are: [1] an elevated PAP activity in disease recurrence and disease progression generally precedes an elevated AcP activity, and thus represents a more sensitive index for patients with early and advanced disease; [2] serial mean levels of PAP activity greater than the mean + 3 SD are more predictive for disease recurrence and progression than are those of AcP activity in both groups of patients; [3] PAP activity is a more sensitive monitor for changes in objective treatment response than is AcP activity; and [4] PAP is more specific than AcP for prostate, thus offering a more reliable marker to identify metastasis of unknown origin, or to confirm metastasis derived from a primary prostate tumor that may have been suggested by other non-prostate-specific marker[s]. In addition, data suggest a favorable prognosis for patients receiving therapy as inferred by a serial mean of PAP activity that is less than mean + 3 SD.

A decade of experience with chemotherapy for prostate cancer.

Chemotherapy for prostate cancer has been demonstrated by the Clinical Trials Program of the NPCP and by other cooperative and individual studies both as single antitumor agents and combinations of agents to provide additional benefit to patients with advanced disease that no longer respond to hormonal therapy, markedly more so than could be provided by a host of palliative and real or synthetic hormonal agents commonly used in this type of patient. There is also some evidence to support the premise that adding antitumor agents to hormones as initial treatment for metastatic disease is more effective than waiting for the ultimate hormone failure, at least in patients with poorer prognosis.

Observations of prolonged use of oral Emcyt in prostatic cancer patients.

Experiences resulting from Emcyt therapy in patients with both newly diagnosed and hormone refractory advanced prostate cancer, as well as on adjuvant to surgery or radiotherapy in earlier disease are presented. Data from trials of the National Prostatic Cancer Project (NPCP) and a series from Roswell Park Memorial Institute (RPMI) were divided into short-term (up to twenty weeks and up to fifty-two weeks in adjuvant trials) and long-term therapy. Baseline disease and patient characteristics and toxicities encountered in these two treatment-duration groups were compared. Patients in a more favorable health or disease status and/or responded to therapy were more frequently in the long-term group. Patients in the long-term group tended to have higher over-all incidences of toxicity; and although many had occurrences begin as early as those in the short-term group, they were able to tolerate the therapy for relatively long periods. The agent is thus both effective and can be given safety for long periods of time.

Chemotherapy in metastatic, hormone refractory prostatic cancer using chlorambucil in combination with prednisolone versus conjugate, prednimustine (Leo 1031).

Chlorambucil plus prednisolone were administered to 11 patients with metastasis hormone refractory prostatic cancer, and the results were contrasted with a previously reported series of 23 similar patients treated with the chemical conjugate of these two agents, known as prednimustine or Leo 1031. The conjugated form of treatment (Leo 1031) had a limited therapeutic advantage, in that 3 patients experienced shrinkage of an enlarged prostate, 2 of whom also had elevated acid phosphatase levels return to normal and 5 others experienced only subjective improvement. There were, however, more adverse side effects in this group than those noted in patients treated with the combination of agents. Patients treated with the combination of drugs experienced no appreciable tumor shrinkage and none had acid phosphatase return to normal, although some reduction was noted in 8 of 11 patients who had elevated levels initially. Two of the 11 patients were considered stable for twelve months and one other remained ambulatory with mild pain for six months. Thus, to the degree that these studies permit, it is judged that the conjugated agent may have some limited therapeutic advantage not observed when the unconjugated agents were used.

Relationship of prior hormonal therapy to subsequent estramustine phosphate treatment in advanced prostatic cancer.

The relationship of prior hormonal therapy to subsequent response on estramustine phosphate (Estracyt) was examined in 107 patients with advanced prostatic cancer treated in two different Phase II chemotherapy trials. In both trials patients with the longest prior hormonal treatment were the least likely to respond to estramustine phosphate. Patients in the series from the National Prostatic Cancer Project with a response classification to prior hormonal therapy had only a 26 per cent response to subsequent estramustine phosphate therapy, whereas 40 per cent of those with no prior response to hormonal therapy responded to estramustine phosphate. This latter group had the shortest average disease duration from diagnosis. The sample of prostate cancers studied appeared to include groups that were sensitive to both hormones and cytotoxic activity as well as to either of these two alone. These data support the contention that estramustine phosphate may act both as an estrogenic and a cytotoxic agent.

Value of new fluorescent immunoassay for human prostatic acid phosphatase in prostate cancer.

A new solid phase fluorescent immunoassay for human prostatic acid phosphatase in prostatic cancer has been evaluated. This technique is rapid, quantitative, and sensitive. In more than 133 patients studied by the National Prostatic Cancer Project, positive results were obtained in patients with localized, nonmetastatic disease as confirmed by clinical testing, surgical staging, and careful inspection of all pelvi lymph node material in appropriate cases. That this can occur even in Stage A2 patients may alter current concepts on the staging or, even further, on the therapy of prostatic cancer.

Prostatic cancer. Treated at a categorical center, 1980-1983.

This report covers the experience from 537 patients with prostatic cancer seen at Roswell Park Memorial Institute (RPMI) from 1980 through 1983. This is a look at experiences in the early 1980s and is a continuation of the series covering the decades of the 1950s, 1960s, and 1970s. Referrals continue to dominate the series (85% of cases) but are now only slightly younger (65 years) than in-house diagnoses (66 years), of which one third were diagnosed at autopsy. Survival rates in this series, although limited in follow-up, were similar at two years to those in the 1970s and in the extensive series collected by the survey of the American College of Surgeons. Multiple primary tumors were observed in 22 per cent of this series, most frequently involving the bladder in addition to the prostate. Treatments continue to involve chemotherapy earlier in the course of disease as part of a succession of therapeutic modalities that include transurethral resection of prostate (TURP) or prostatectomy, lymph node dissection, external irradiation, castration, and hormones.

Criteria for evaluating patient responses to treatment modalities for prostatic cancer.

Criteria for evaluating response to therapy for both early and late stages of prostate cancer, as developed by the National Prostatic Cancer Project, are presented and discussed. Detection of bone metastases and monitoring of changes in existing bone lesions are critical to these criteria for early and late disease, respectively. The prognosis, or survival experience, of groups of patients for each response category is also discussed.

The influence of site of metastasis on tumour growth and response to chemotherapy.

Drug screening trials and general treatment of solid tumours in advanced cancer patients have been concerned only with the site of primary origin, regardless of where metastases might have seeded. Since the environment for tumour growth can differ appreciably at various anatomical sites, an investigation was undertaken to determine the effect of metastatic site on response to chemotherapy. Data from 1961 to 1965 of the screening trials of the Eastern Clinical Drug Evaluation Program were utilized. Response and location data extensive enough for analysis represented 6 sites of primary origin and 6 metastatic site groups, totalling 1687 lesions. Analysis of percentage reduction in tumour size after chemotherapy regimens of up to 60 days revealed a significant amount of variation associated with metastatic sites and a non-significant amount associated with sites of primary origin. Advanced primary tumours showed marked variation in responsiveness and some showed a difference in response to different drug groups. Generally, metastases responded better than the advanced primaries from which they were derived, except for those from breast tumours.