Prostatic carcinoma: detection and staging using suprapubic US.

Eighteen patients with pathologically proved carcinoma of the prostate were examined with suprapubic ultrasound (US) to assess the capability of the modality in the detection and staging of the disease. Five of the patients were evaluated for recurrent disease. A detailed, retrospective, echo-textural analysis of the prostate and periprostatic structures was performed. The most frequently encountered US findings were recorded and used as criteria in the diagnosis and staging. Most diagnostic of the echo patterns were the presence of a large (greater than 6 mm) focal density within the peripheral zone that was as bright as or less bright than the density of the capsule, a mixed or diffuse pattern, and loss of integrity of the capsule, seminal vesicles, or bladder. Using these criteria, we were able to correctly diagnose 17 of 18 cases, with an accuracy rate of 94%. US was also used to assess the extent of local disease in carcinoma of the prostate. The US staging was compared with the staging by digital rectal examination and by clinicopathologic results. We correctly staged 15 of 18 cases (83%) with US, while the rectal examination helped to stage correctly only 10 of 18 cases (56%). All errors were due to understaging. We find suprapubic US to be very helpful in the diagnosis and staging of prostatic cancer. Since there is some overlap between the findings in benign and malignant disease, we cannot recommend US as an alternative to prostate biopsy. Further experience in detection and staging with prospective studies may be necessary before final conclusions can be made.