Small cell and anaplastic prostate cancer: correlation between CT findings and prostate-specific antigen level

To evaluate the computed tomographic (CT) findings in patients with the anaplastic clinical variant of prostate cancer and to correlate these with prostate-specific antigen (PSA) levels.

Twenty-seven men with the anaplastic clinical variant of prostate cancer, including 12 patients with small cell cancer of the prostate, underwent CT before platinum-based chemotherapy. CT findings were retrospectively reviewed for the extent of disease in the abdominal and pelvic lymph nodes, liver, bone, and prostate. CT findings were correlated with baseline PSA levels.

The overall mean PSA level was 59.9 ng/ml +/- 23.3 (range, 0-583 ng/ml; median, 4 ng/ml), with a mean PSA level in the small cell cancer subgroup of 12.3 ng/ml +/- 9.0 (range, 0-110 ng/mL; median, 1.7 ng/mL). Twenty-six patients (96%) had metastatic disease evident at CT, but only nine (33%) had PSA levels greater than 10 ng/mL. The mean PSA level in patients with pelvic lymphadenopathy was 12.8 ng/mL +/- 7.9 (median, 1.6 ng/mL); that in the small cell cancer subgroup was only 2.8 ng/ml +/- 1.4 (median, 1.6 ng/ml). Whereas 19 (70%) of all patients had osseous metastases and an average PSA level of 73 ng/ml +/- 32(median, 9.1 ng/mL), the seven (58%) with small cell cancer and bone metastases had an average PSA level of 18 ng/mL +/- 13 (median, 4 ng/mL).

Unlike patients with advanced typical adenocarcinoma of the prostate, patients with the anaplastic clinical variant of prostate cancer often have extensive metastatic disease at CT despite relatively low PSA levels.