Overall, 10 (22%) had undetectable serum PSA levels and 30 patients (65%) had PSA of less than 1ng/ml at the time of disease progression. Of the 25 men who had undergone radical prostatectomy, 7 were hormone na�ve at the time of progression. The median increase in PSA was 0.25ng/ml at the time of progression. In 19 patients, there was no increase in PSA from the nadir level at the time of progression. The median PSA doubling time for the cohort was 7.6 months.
Atypical variants of CaP were identified in 21 of 46 patients; including 9 with ductal CaP, 8 with small cell variant, 2 with neuroendocrine tumors and 2 men with sarcomatoid tumors. Metastatic progression was most commonly in the bones, followed by liver, retroperitoneal lymph nodes and lungs. Progression was identified by bone scans, CT or MRI.
In patients with CaP variants, monitoring in addition to PSA may have value.
Occasionally prostate cancer cells make little or no PSA. As this study points out, it is usually the rarer forms that do this.