Other methods for improved prostate cancer detection?

Abstract

Investigators are studying many techniques that may improve prostate cancer detection, including: PSA velocity: This is a measurement of the change in prostate-specific antigen (PSA) level over time. A 2006 study found that men who had a PSA velocity >0.35 ng/mL per year had a higher relative risk of dying from prostate cancer than men who had a PSA velocity <0.35 ng/mL per year. More studies are needed to determine whether a high PSA velocity more accurately detects prostate cancer early. PSA density: PSA density considers the relationship between the level of PSA and the size of the prostate. An elevated PSA level might not be suspicious if a man has a very enlarged prostate; however, cancer might be overlooked in a man with an enlarged prostate. Free versus attached PSA: Often used for men who have higher PSA values, free PSA may help determine what kind of prostate problem a man has. With benign prostate conditions (such as benign prostatic hyperplasia), there is more free PSA, whereas cancer produces more of the attached form. Researchers are looking at other ways to measure PSA and use these measurements to determine whether cancer is present. Alteration of PSA cutoff level: A number of studies have used cutoff levels of 2.5 or 3.0 ng/mL, rather than the current cutoff of 4.0 ng/mL. In such studies, PSA measurements higher than 2.5 or 3.0 ng/mL are considered elevated. Researchers hope that using these lower cutoff levels will increase the chance of detecting prostate cancer; however, this method also may increase overdiagnosis and false-positive test results Other Detection Methods MicroRNA patterns: Researchers have found that the pattern of microRNAs in a cell can differ between healthy cells and cancer cells. Some research also suggests that the microRNA patterns in early-stage prostate cancer and late-stage prostate cancer may be different. Nonmutation gene alterations: Research has already shown that certain genes become hypermethylated and inactivated during the development and progression of prostate cancer. Scientists hope to identify DNA methylation changes and protein modifications that could identify prostate cancer early and help predict tumor behavior. Gene fusions: The gene fusions found in prostate cancer involve members of the ETS family of oncogenes. Researchers are investigating whether diagnostic or prognostic tests based on gene fusions can be developed. PCA3: Also known as DD3, PCA3 is a prostate-specific RNA that is reported to be expressed at high levels in prostate tumor cells. A urine test for this RNA, to be used in addition to current prostate cancer screening tests, is currently under study. Differential detection of metabolites: Molecules produced by the body's metabolic processes, or metabolites, may be able to help distinguish between benign prostate tissue, localized prostate cancer, and metastatic prostate cancer. One such molecule, known as sarcosine, may be associated with prostate cancer's invasiveness and aggressiveness. Investigators are determining whether they can develop a test based on sarcosine. Proteo-imaging: Identifying different patterns of protein expression in healthy prostate tissue versus abnormal prostate tissue may help classify early prostate changes that may one day lead to cancer. Protein patterns in the blood: Unique protein patterns in the blood may indicate the presence of prostate cancer. Researchers are studying these patterns to see whether more aggressive cancers can be distinguished from less aggressive ones.