MedWire News: An individualized approach to prostate cancer screening that relies on pre-biopsy information in addition to prostate-specific antigen (PSA) test results, could reduce the number of unnecessary biopsies, study findings show.
This approach misses very few prostate cancer cases for which diagnosis at a subsequent screening visit might be too late for curative treatment, say Monique Roobol and colleagues.
“A key question is whether all biopsy-detectable prostate cancers should be detected, knowing the numerous studies of overdiagnosis and overtreatment caused by the detection of non-life-threatening or indolent prostate cancer,” says the team, from University Medical Center in Rotterdam, The Netherlands.
The researchers assessed the reduction in potentially unnecessary prostate biopsies using risk profile-based cut-off values as an indicator for biopsy in men with a prostate-specific antigen (PSA) level of 3 ng/ml or more.
Among a cohort of 2147 men, a total of 1850 were biopsied after initial screening and 541 prostate cancers were detected, 44% of which were likely to be indolent. The overall number of cancers found per biopsy done (positive predictive value [PPV]) was 29%.
Of 1359 men available for repeat screening, 568 underwent re-biopsy and 225 prostate cancers were detected.
The researchers calculated the patients’ positive biopsy probabilities based on pre-biopsy information such as age, results of digital rectal examinations, and prostate volume, and deduced a strategy where those with a probability below 12.5% would not have received prostate biopsy, and those whose probability was above would have undergone biopsy.
This strategy would have reduced biopsy rates by 33% and 37% in initially and repeat-biopsied men, respectively, they report. PPV’s would have risen to 38% among the initially screened cohort, and risen from 19% to 25% in the repeat-biopsy cohort.
A total of 14% of all prostate cancers would have been missed at initial screening using this strategy, among which 70% would have been considered indolent and 4% important.
However, prostate cancer in 90% of patients whose disease progressed during follow-up and in 17 of the 18 men who died from the disease would still have been picked up at initial biopsy, with similar rates seen among men who underwent repeat biopsy.
“Instead of trying to detect as many prostate cancer cases as possible by means of lowering biopsy thresholds or repeat biopsy procedures or screening visits, it seems necessary to find ways to detect only those cancers that need to be treated before they become life threatening,” say Roobol et al.
“This study can be considered a plea for a more individualized screening algorithm,” the team concludes.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
My thoughts
Yet another study stating that there are too many biopsies being done. Then in the same breath saying that at the current time we are unable to determine pre biopsy if the cancer is one we should find (an aggressive one) or one that is indolent (not aggressive). So… you are the patient and you are there in front of your doctor and told your PSA is high. What do you do? Well, I can tell you what you do. You have the biopsy to see which you are or if you have it at all. So although this article is interesting and timely, it does nothing to guide the patient or the doctor in determining who should have a biopsy. Throw in malpractice issues i.e. an aggressive prostate cancer that just happens not to produce PSA but is still very aggressive. The doctor misses it untill it is too late, the patient rightfully asks why was a biopsy not done in a timely fashion and angry that a cancer was missed. This is not the rule and is uncommon but again, if the odds are one in a hundred and you are the one.. then its 100%. As a urologist some decisions are protective for me and the patient and this is one of them.
Prostate Diaries 