[Role of rectal exploration, suprapubic and transrectal prostatic ultrasonography, and PSA in the diagnosis and follow-up of prostatic carcinoma].

BACKGROUND AND AIM

The aim of this study was to evaluate the advantages and limits of the various examinations, namely rectal exploration, suprapubic and transrectal scan and PSA, used in the diagnosis and follow-up of prostatic carcinoma.

METHODS

The study was carried out in 21 cases of histologically confirmed prostatic carcinoma in patients aged between 57 and 82 years old (mean age: 69.5) referred to the authors' attention between January 1990 and August 1993.

RESULTS

With regard to the diagnosis, rectal exploration showed a sensitivity of 80.9%, suprapubic scan 95.2%, transrectal scan and PSA 100%. During the follow-up, patients were divided into operated (9) and non-operated (12) groups. Of the 9 patients undergoing radical prostatectomy, 5 showed residual locoregional disease; of the other 4 who had undergone a complete removal of the gland, one subsequently reported local recidivation. In those patients with residual disease, rectal exploration showed a postoperative sensitivity of 20%, nil sensitivity in the case of local recidivation and 100% specificity in successfully operated patients. Suprapubic scan showed a sensitivity of 60% in patients with residual disease, nil sensitivity in the case of local recidivation and 100% specificity in successfully operated patients. Transrectal scan and PSA revealed 100% sensitivity and specificity in all cases. These patients who were not operated owing to the presence of metastases at the time of diagnosis were divided into those who responded to hormone and chemotherapy (3 total responses, 6 partial responses) and patients who did not respond to this type of treatment (3 non-responders). In the cases of total response, all the tests used obtained 100% specificity. Serum levels of PSA were higher than the threshold value owing to the persistence of metastases. In the cases of partial response to treatment, rectal exploration revealed 50% sensitivity, suprapubic scan 83%, and transrectal scan and PSA 100%. Sensitivity to the four methods used was 100% in all non-responders.

CONCLUSIONS

From the results obtained it can be affirmed that the diagnosis of prostate pathology should start with rectal exploration and in the event that this method suggests the probable benignity of the lesion, the diagnostic process should conclude with a suprapubic scan. If rectal examination or suprapubic scan reveal a suspected malignancy, it is essential to perform a transrectal scan or PSA assay which has a high level of sensitivity and specificity for values over 10 ng/ml. During follow-up the only tests which show a high level of sensitivity are transrectal scan and PSA, whereas suprapubic scan and rectal exploration are not reliable in view of the high percentage of false negatives observed. The follow-up of those patients who were not operated and responded totally or partially to treatment must be carried out exclusively using transrectal scan and PSA assay. Suprapubic scan enables the evolution of the neoplasia to be followed over time in those patients who did not respond to treatment.