Why a Randomized Study Is Needed to Prove That Screening Is Effective

Your name: Your e-mail address: Your friend's e-mail addresses:

(separate multiple addresses with comma)
Indicates required field
Message (limit 100 characters)
Enter answer below:

(Why the math? It protects against spam)
=
Send
Cancel
Your message has been successfully sent!

Unfortunately, you simply cannot compare men who have been screened with those who have not because those who are screened are likely to survive prostate cancer longer and to live longer for reasons other than screening.

• Those who choose to be screened have been shown to be healthier and to have healthier lifestyles, thus are likely to have less disease, possibly including prostate cancer.
• Those who are screened are diagnosed earlier in the course of the disease so it appears that they live longer with the disease when in fact it is just because it was found earlier; in this case, treatment may appear to improve survival when it really does not.
• Cancers detected by screening may appear to improve survival because they are more likely to be slow growing. Slow-growing tumors can be detected over a longer period of time, therefore more likely to be detected by screening. And, regardless of how well treatment works will result in better survival.

When men are randomly assigned to screening or no screening, there will be no difference in their health or lifestyles, and the slower-growing and faster-growing tumors will be balanced out between groups. The result is that we can finally tell if screening really does work to improve prostate cancer outcomes.