However, because of the lack of convincing evidence of benefit from screening for lung cancer, periodic chest x-rays and sputum cytology are not recommended. PSA is being increasingly used for prostate cancer detection. Serum PSA levels correlate with the clinical stage of prostate cancer and the volume of cancer in a gland. Although PSA screening is widely used, controversy remains about whether it reduces mortality from prostate cancer. The test may detect medically inconsequential tumors and lead to unnecessary treatment and substantial morbidity.
Trials are under way to determine the benefits of various prostate cancer detection methods.
The current guidelines can be expected to evolve with the accrual of new knowledge and new technological advances. For example, the technical quality of mammograms and their interpretation are critical factors in their usefulness. Mammographic detection of cancer is more problematic in the dense breast tissue of younger women, whose tumor growth rates are generally more rapid. After analyzing the same body of evidence from randomized mammography studies, expert committees have reached different conclusions regarding routine mammographic screening of asymptomatic women 40 to 49 years of age. The American Cancer Society, National Cancer Institute, and other groups have recommended annual mammography for women beginning at 40 years of age, but the NCI Consensus Panel did not.