PSA tests for men and breast self-examination by women are among two medical screening tests of dubious value.
However neither of these tests has been scientifically proven to reduce mortality rates. PSA levels in the blood can predict mortality from prostate cancer among men known to have the disease but there are no published randomized trials that the earlier detection improves prognosis.The reason: many prostate cancers never develop to the point of causing real problems. Routine testing of otherwise healthy men on a regular basis, therefore, may simply cause many men to be treated unnecessarily, leading to incontinence, impotence, and other problems.
In terms of breast self-examination, a recent large study suggests the technique is ineffective because most malignant lumps are found during activities of daily living, such as washing or dressing, anyway. Regular self-exams just lead to unnecessary surgical biopsies and greater anxiety among women. Specialists believe the same results would apply to testicular self-examination as well and suggests health officials who tout these exams believing they can't hurt are failing to take these adverse effects into account.
Thus researchers conclude saying , "Giving information to people considering screening ... when the only honest information is complete uncertainly is useless. Encouraging people to decide for themselves is ducking the issue."