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Biomedical subjects

G S Gerber

Publications and source records attributed to G S Gerber.

6 recordsLinked to original sources
PubMed1992

Local staging of prostate cancer by tumor volume, prostate-specific antigen, and transrectal ultrasound.

Conventional methods of staging prostate tumors are highly inaccurate. To improve clinical staging, prostate-specific antigen (PSA) levels (> 10 ng/mL), sonographic tumor volume (> 3 cc), maximum tumor diameter, length of capsular tumor abutment, and overall impression of capsular irregularity suggesting periprostatic tumor spread were assessed in 29 men prior to undergoing radical prostatectomy for clinically localized tumor. After surgery, 18 men had tumor confined to the prostate, while 11 men had histologic evidence of extracapsular disease. Analysis of the parameters measured showed these were the most helpful factors in predicting the presence of extracapsular disease. However, the positive and negative predictive values were only 70 to 90 percent. Therefore, the clinical usefulness of any one measurement alone in determining treatment for the individual patient is limited. However, combining these parameters yields an improved prediction of extracapsular disease. All 6 patients with PSA < 10 ng/mL, tumor volume < 3 cc, and no capsular irregularity on ultrasound had localized disease (neg. predictive value = 100%), while all 7 patients who had more than one of these parameters had extracapsular disease (pos. predictive value = 100%). Thus, using the factors in combination may provide more accurate staging and thereby help in counseling patients regarding therapy.

Humans↗
PubMed1991

Routine screening for cancer of the prostate.

The value of screening for prostate cancer remains unclear. Although digital rectal examination, transrectal ultrasonography, and determination of serum prostate-specific antigen levels may lead to early detection of a malignancy, these procedures have never been shown to reduce disease-specific mortality from prostate cancer. Unfortunately, several potential errors found in uncontrolled trials may suggest benefit from screening where none exists. Only a large, randomized, controlled clinical study demonstrating decreased mortality from prostate cancer can prove that screening is beneficial. Until such a study is performed, patients should be informed of both the potential benefits and the risks of screening and treatment.

Antigens, Neoplasm↗
PubMed1991

Pharmacological erection program using prostaglandin E1.

A total of 72 impotent patients entered into a pharmacological erection program using prostaglandin E1. Of the men 35 (49%) used prostaglandin E1 on a regular basis, while 37 (51%) failed to continue in the program beyond the in-office dose titration period. In patients who continue to use prostaglandin E1 the median duration of drug use is 7 months, with a range of 2 to 28 months. There have been no instances of cavernous fibrosis, systemic reaction or chemical priapism (erection present longer than 4 hours) in any patient. Only 8 men (11%) were unable to achieve an adequate erection with prostaglandin E1 injections. The most common adverse effect of prostaglandin E1 was penile pain after injection. The incidence of severe pain leading to drug discontinuation was 17% (12 of 72 patients) while mild to moderate pain occurred in 22% (16 of 72). Over-all, intracavernous prostaglandin E1 injections appear to be a safe, effective treatment for impotence in most men.

Alprostadil↗
PubMed1990

Prostate specific antigen for assessing response to ketoconazole and prednisone in patients with hormone refractory metastatic prostate cancer.

Serial prostate specific antigen levels were assessed in 15 patients with hormone refractory metastatic prostate cancer treated with ketoconazole and prednisone. Of the men 12 (80%) with continually increasing prostate specific antigen levels before treatment had a decrease in prostate specific antigen with a median duration of response of 3 months. Three patients (20%) had a prolonged response (greater than or equal to 8 months) as seen by a persistently decreasing prostate specific antigen and improvement in bone pain. There appears to be a small subgroup of patients with progressive prostate cancer despite androgen ablation who will benefit from ketoconazole and glucocorticoid treatment. The use of serial prostate specific antigen levels appears to help define this subgroup and avoid the need for multiple radiological procedures to assess response.

Adenocarcinoma↗
PubMed1990

Digital rectal examination in the early detection of prostate cancer.

Screening using digital rectal examination improves the clinical stage distribution of prostate cancer and prolongs survival. Unfortunately, digital rectal examination may not be sensitive enough to detect the small-volume tumors that are most amenable to cure. In several studies, approximately 50 per cent of cancers detected through screening had already spread beyond the prostate. Regardless, the key to demonstrating overall benefit from screening is a diminished disease-specific mortality rate. To date, this has not been shown. Lower mortality rates from prostate cancer can be demonstrated only through a randomized study comparing screened and unscreened populations. Such a study, which has recently been approved and funded by the National Institutes of Health, will require 10 to 15 years to complete. Until that time, the value of screening for prostate cancer by digital rectal examination or any other method will be unknown. Beyond a lack of proved benefit, screening for prostate cancer may be harmful because of the variable natural history of the disease and the morbidity and mortality rates associated with treatment. There exists a large population of patients with pathologically detectable prostate cancer who will never have clinical disease. The detection of some of these tumors may expose those patients to the risks of unnecessary treatment. Large-scale prostate cancer screening studies may ultimately be shown to be advantageous. The sooner this occurs, the earlier aggressive screening can be advocated, similar to screening for breast cancer. However, the temptation to embark on such screening programs without first demonstrating clear benefit should be resisted.

Humans↗