Screening vs. clinical detection: prostate cancer in China
Posted Jan 30 2010 12:00am
A newly published study has compared the clinical and pathological characteristics of screen-detected and clinically diagnosed prostate cancers in Chinese men.Hua et al. report data from a two-part study carried out in Nanjing.
In the first part of this study, they collected data on 82 men who had clinically diagnosed prostate cancer but who had never had any form of prior test for prostate cancer risk. They then compared the data from these men with clinically detected disease to the data from 8,562 men aged ≥ 50 years who were screened for prostate cancer using PSA testing 0ver an 18-month period between July 2004 and December 2005. In the screening portion of the study, participants with a serum PSA ≥ 4.0 ng/ml were recommended for transrectal ultrasonography (TRUS)-guided prostate needle biopsy. (The abstract of the paper does not provide any details about numbers of biopsy cores.)
Comparison of the clinical and pathological features of the screened versus clinically diagnosed cancers showed the following:
719/8,562 of the screened men (8.4 percent) had PSA levels ≥ 4.0 ng/ml.
Biopsies were actually carried out on only 295/719 men with a PSA ≥ 4.0 ng/ml, and 58 prostate cancers were detected.
The biopsy rate, positive predictive value (PPV), and detection rate were 41.0, 19.7, and 0.68 percent among the screened population, respectively.
Patients with prostate cancer but with PSA levels < 20 ng/ml were significantly more common among the screened group (55.2 percent) than among the clinically detected group (22.4 percent).
The same was true for patients with Gleason scores < 7 (60.3 vs. 34.1 percent), organ-confined tumors (87.9 vs. 26.8 percent), and opportunities for radical prostatectomy (50.0 vs. 18.3 percent).
Now there are clearly “problems” with this study. For example, only 41 percent of the men who had an elevated PSA test actually went on to have a biopsy, so we have no idea what the rate of prostate cancer was in these 424 men. On the other hand, this study clearly confirms what has been known for some years in non-Chinese populations — that PSA screening is effective for early detection of prostate cancer in men ≥ 50 years of age, and that such screening is associated with lower PSA levels, fewer Gleason scores of 7-10, earlier clinical stage, and greater chances for curative treatment. In other words, screening can “stage-shift” prostate cancer in China from an advanced stage at diagnosis to stage with a high chance for curative therapy, just as it has in other parts of the world.
Of course, if prostate cancer screening becomes commonplace in China, the world’s most populous nation will also have to face up to the question of the most appropriate way to manage men with early-stage, screen-detected prostate cancer.
A newly published study has compared the clinical and pathological characteristics of screen-detected and clinically diagnosed prostate cancers in Chinese men. Hua et al. report data from a two-part study carried out in Nanjing.
In the first part of this study, they collected data on 82 men who had clinically diagnosed prostate cancer but who had never had any form of prior test for prostate cancer risk. They then compared the data from these men with clinically detected disease to the data from 8,562 men aged ≥ 50 years who were screened for prostate cancer using PSA testing 0ver an 18-month period between July 2004 and December 2005. In the screening portion of the study, participants with a serum PSA ≥ 4.0 ng/ml were recommended for transrectal ultrasonography (TRUS)-guided prostate needle biopsy. (The abstract of the paper does not provide any details about numbers of biopsy cores.)
Comparison of the clinical and pathological features of the screened versus clinically diagnosed cancers showed the following:
Now there are clearly “problems” with this study. For example, only 41 percent of the men who had an elevated PSA test actually went on to have a biopsy, so we have no idea what the rate of prostate cancer was in these 424 men. On the other hand, this study clearly confirms what has been known for some years in non-Chinese populations — that PSA screening is effective for early detection of prostate cancer in men ≥ 50 years of age, and that such screening is associated with lower PSA levels, fewer Gleason scores of 7-10, earlier clinical stage, and greater chances for curative treatment. In other words, screening can “stage-shift” prostate cancer in China from an advanced stage at diagnosis to stage with a high chance for curative therapy, just as it has in other parts of the world.
Of course, if prostate cancer screening becomes commonplace in China, the world’s most populous nation will also have to face up to the question of the most appropriate way to manage men with early-stage, screen-detected prostate cancer.