Tag Archives: cancer screening

Screening for Prostate Cancer

3 Dec

Areas of Uncertainty

A medical Doctor from the Departments of Medicine and Family and Community Medicine, University of New Mexico faces an apparently common problem exposed below:

The answer is far more complex than it appears at first glance:

Screening for Prostate Cancer

Is it useful? but overall is it safe ? Prostate biopsies can lead to death by septicemic shock in those days of increasing resistance to antibiotics. The questions rises more and more interest among men of fifty years of age and over. A recent article in the New England Journal of Medicine, the well known scientific medical journal, describes the state of the art. First of all we must keep in mind that not one prostate cancer equals another in term of prognostic and treatment. In the prostate area, cancer cells don’t necessary mean immediate treatment nor life threat. If screening is useful automatic treatment is not, at least not in all cases. The key word is: watch full waiting (or armed surveillance) in numerous of cases which only the urologists are skill to differentiate. Passed an age that the urologist has to determine given the co morbidities in presence, active treatment would bring more harm and adverse events than positive results.

One thing is granted for sure and has always to be kept in mind: prostate cancer is the second man killer just behind lung cancer. In the fight against this sort of killer primary cares Doctors, surgeons and epidemiologists have still a long uneasy road ahead to ride… and patients have to be patient and above all thing well educated and informed.

Anyway some searchers inferred that mathematically PSA screening should have played a role in 45% to 70% of the overall decline of prostate cancer deaths observed since 1994 but this didn’t resulted from a high level of proof study (not a randomized control trial).

18. Etzioni R, Tsodikov A, Mariotto A, et al. Quantifying the role of PSA screening in the US prostate cancer mortality decline. Cancer Causes Control 2008;19:175-81.
 

Randomly Controlled trials failed by two times to prove that a decline in overall mortality was attributable to screening. But the maximum follow-up is only 9 years. We can not exclude that a favourable effect can still happen beyond 10 year.

24. Holmberg L, Bill-Axelson A, Helgesen F, et al. A randomized trial comparing radical prostatectomy with watchful waiting in early prostate cancer.N EnglJ Med 2002;347:781-9.

According to other searchers 23 to 42 % of screened prostate cancers wouldn’t have cause neither any clinical problem nor the death of the patient during the remaining life time of the patient. Said differently 23 to 42 % of screened cancer were over diagnosis (which is not the same as false diagnosis).

23. Draisma G, Etzioni R, Tsodikov A, et al. Lead time and overdiagnosis in prostate specific antigen screening: importance of methods and context. J Natl Cancer Inst 2009;101:374-83.

Read the entire paper here: nejmcp1103642

 

Breast cancer

1 Oct
Mammakarzinom, ID T1b. Mammography, breast can...

Image via Wikipedia

Mammographic screening induces a 25 percent reduction in breath cancer mortality according to a meta-analysis.

But there is still a controversy about the value of the ratio  Benefit/harm of breath cancer screening among public  health searchers. A norwegian public health searcher states that it is possible that 36% of invasive breath cancer of organised mammography screening programs could be in fact overdiagnosed.

Further research should be to implement on that matter with regard of the human and economic cost of over-diagnosis.

Indeed there is only two possibilities when a cancer is screened by organised program: either it is advanced diagnosis or it is over-diagnosis. In the first case the cancer would have been clinically diagnosed later after the lead time interval. In the second case the cancer would have never been clinically diagnosed during the remaining life time of the women.

Cancer: screening or not screening?

29 Jul

Must all big smokers have a Chest Tomography?

Must all women before 50 have a mammogram every year?

Must all men after 80 be screened for prostate cancer?

Health care journalists push for it as you can see for example in the following videos (beware these following videos are not recommendations but examples of biased reporting, by media, of scientific research results):

Chest tomography for lung cancer

mammogram 1
mammogram 2

Scientists worry about adverse iatrogenic events and high false positive rates that will certainly worry patients creating a new category of patients: the “worried wells”. (in the order there are five categories of patients the sick , the early sick (early detection), the well, the worried well and the worried sick.)

Governmental agencies hesitate before the high number of people needed to screen for saving a single life and try to product guidelines that satisfy everybody.

And people are questioning themselves searching information on the internet and social media.

But I make a proposition for a new preventive action: if tomorrow everybody drive is car at a speed below 40 km per hour it will save a lot of lives (by lowering lethal road crash and air pollution). Are you ready to do that? :-)

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