Lack of Correlation Between Prostate-Specific Antigen and the Presence of Measurable Soft Tissue Metastases in Hormone-Refractory Prostate Cancer

Abstract

Appropriate staging procedures for patients with hormone-refractory prostate cancer are poorly defined. In particular, there are no studies correlating prostate-specific antigen (PSA) with more traditional methods of staging. We have evaluated the abdominal/pelvic CT scan, bone scan, and PSA results following initial diagnosis of hormone-refractory prostate cancer in 177 consecutive patients (median age = 63.1 years, range 45-80). Thirty-four patients (19.2%) had measurable lesions (> or = 2 cm) on CT scan compatible with metastatic disease. Of the patients with measurable lesions, 29/34 (85.3%) had retroperitoneal and/or pelvic adenopathy; 5 patients (14.7%) had measurable lesions in the liver. Other sites of metastatic disease were detected in less than 1% of the patients receiving scans. All patients had bone scan abnormalities compatible with metastatic disease. Results of these imaging studies were then compared to PSA serum concentration (Abbott IMx). The mean PSA concentration was not different in those patients with soft tissue disease as compared to those without soft tissue involvement and there was no correlation between PSA concentration and the presence or absence of measurable soft tissue disease. In contrast to previously published studies in hormone-naïve prostate cancer patients, these studies in hormone-refractory patients indicate that the detection of metastatic disease by standard radiological procedures cannot be predicted by measurement of serum PSA.

Prostate Cancer Clinical Trial End Points: “RECIST”ing a Step Backwards

“…As a screening method for active treatments, many trials report the proportion of patients who achieve a defined posttherapy change (e.g., the proportion showing a 50% or 80% decline from baseline) as suggested by the Prostate Specific Antigen Working Group (18), while monitoring all sites of disease to ensure concordance (6). Whether a posttherapy decline in PSA can serve as a ''surrogate'' for clinical benefit, however, remains controversial (53 -55).…”

Circulating Tumor Cells in Patients with Castration-Resistant Prostate Cancer Baseline Values and Correlation with Prognostic Factors

“…Bone scans are notoriously unreliable because the delayed kinetics of bone remodeling after cancer therapy has been largely supplanted by PSA (4). Measurable disease in CRPC is present in <25% of patients and thus limits the usefulness of radiographs in monitoring clinical response (5).…”

Epirubicin carboplatin and 5-fluorouracil (ECarboF) chemotherapy in metastatic hormone refractory prostate cancer

“…Poor response rates of 10 -15% to single agents with a median duration of response of 6 -9 months have been quoted (Brausi et al, 1995). However, early studies in the pre-PSA era often relied on acid phosphatase levels and patient symptoms as markers of response, as only 20% of patients with metastatic prostate cancer, have measurable soft tissue disease (Figg et al, 1996). Post-therapy PSA levels have become widely accepted as a surrogate end point in the evaluation of treatment Defined as 450% fall in initial level maintained for at least 4 weeks from completion of chemotherapy.…”