Not long ago, 20 years has been dedicated to prostate cancer research scientist at Stanford University Stamey Urology striking phrase, PSA (prostate specific antigen) screening in the diagnosis of prostate cancer has been scenery is not, PSA era is over? serum PSA level was used as marker for prostate cancer, began in the 20th century, early 80s, with the development of medicine in recent years, the early diagnosis of prostate cancer increased year by year. 4ng/ml greater than the current general PSA , or PSA greater than in the United States to accept the proposal 2ng/ml prostate biopsy, which, in the male prostate survey of experts on the PSA when screening for prostate different opinions on this issue, some experts have suggested that men generally start at age 50 PSA screening should be conducted annually and, if prostate cancer risk factors (such as black, or family history of prostate) should also be re-screened in advance the age. There is no evidence of significant PSA screening really save the patient. (1) PSA and prostate cancer-related changes of 20 years based on the assertion Stamey, is derived from a PSA level of his relationship with the prostate cancer research. The results of the 2009 annual meeting of American Urological. The study included 1983-2003 Stanford University received radical prostatectomy 1317 cases, according to the diagnosis and treatment time will be divided into 4 groups (5 years, group 1), tumor pathology (size, grade, etc.) and clinical findings (digital rectal examination, PSA level ) to compare the correlation between. The results show that in the first 5 years (1983-1988) PSA level and prostate cancer the correlation between the severity of a better, PSA level is higher, the greater the tumor volume, the more aggressive strong, to the last 5 years (1999-2003) correlation between the two has been very small, PSA and prostate volume and not only volume-related prostate cancer. The study, PSA is not a perfect marker for prostate cancer in use of PSA screening beginning of the severity of prostate cancer was only 42% predictive ability, then the correlation between the two is even more rapid decline in the last 5 years has dropped nearly 2%, can be ignored.
why the above phenomenon? Johns Hopkins University, Professor Carter explains: ?In the beginning use of PSA screening, general screening for the presence of objects that are already large group of cancer patients, and thus in the PSA and the tumor size (disease severity) a good correlation between. Now, due to improved screening rates, we are very small tumors were detected in prostate cancer has not caused structural changes, changes in serum PSA may not be significant, resulting in the correlation between PSA and tumor decreased.
(2) prostate cancer: high prevalence and low mortality
Stamey that, PSA is 2ng/ml-10ng/ml (or 20 ng / ml) of men Many of the high PSA because of benign prostate hyperplasia, such as biopsy of these patients, which often can be detected in prostate cancer because of the prevalence of prostate cancer and age related. The incidence of prostate cancer increased with increasing age. In the 70-80 years old, may be increased to 70%. Live a long time as long as men are likely to end prostate cancer. But its mortality rate is much lower, In the United States over the age of 65 226 cases of prostate cancer mortality rate / 10 million, the possibility of dying from prostate cancer, only 0.2%. American Urological Association said in a statement, the PSA level and digital rectal examination results and a complete medical history are combined to make the best decision for prostate biopsy.
(3) PSA check whether obsolete, what is the value?
a present that is still useful in the clinical value of PSA for the treatment and recurrence monitoring. Either prostate cancer or benign prostatic hyperplasia, no matter which treatment method (surgery or radiotherapy), PSA levels in monitoring treatment success and the role of disease recurrence are beyond question.
Second, the challenged prostate cancer screening, PSA is not without benefits, the key is how a reasonable application. Professor Carter can be used for PSA levels of PSA screening and prostate cancer is relatively good correlation between the population (ie, relatively minor age, male). The reason is the low rate of benign prostatic hyperplasia of these people, even if there is proliferation, the degree of light. Carter recommends PSA screening for men age 40 to age 45 be tested once again after 50 years tested once a year, should be together all of these findings the trend observed PSA levels, but men over the age of 70, PSA screening meaningless.
(4) Points Summary
a prostate cancer screening has been considered the ?gold standard? of PSA in the diagnosis of prostate cancer is decreasing, specificity is not high, prone to false-positive, the sensitivity of urinary scientists look forward to highly specific marker for prostate cancer appears.
two current research related to prostate cancer diagnostic marker 1 (PCADM-1), serum PSA precursor (pro PSA), and early prostate cancer antigen -2 (EPCA-2) and so can the earlier diagnosis of prostate cancer, the sensitivity was 94%, specificity of 92%, can be distinguished on the basis of detection of malignant and benign prostatic hyperplasia. In 2 years this method can replace the traditional PSA test, a revolutionary change in prostate cancer diagnosis.
link: PSA is a glycoprotein produced by the prostate, usually very little into the blood, and only in the prostate structural disorder, such as benign prostatic hyperplasia or prostate cancer extrusion damage, make PSA by the prostate Xian bubble into the bloodstream. Therefore, the value of serum PSA reflects changes in the prostate itself.
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