Study Suggests Re-evaluation Of Prostate Cancer Screening by Gina Shaw You canít blame a guy for being confused. Since the late 1980s, the standard screening for prostate cancer has been the prostate-specific antigen (PSA) test, which measures bloodstream levels of a protein manufactured by the prostate. The prostate pumps out more of this protein when cancer is present. Up until recently, men were advised to begin getting PSA tests at age 50, and to get a biopsy to check for prostate cancer if the PSA level reached 4.0 (measured in nanograms per milliliter) or higher. But a study published in the New England Journal of Medicine in late May showed that setting the biopsy cutoff point at 4.0 misses prostate cancers in about 15 percent of men over 60, including about 2 percent of cases that look highly aggressive under the microscope. The study highlights a continuing debate among prostate cancer researchers that has left many men wondering and worried. How should prostate cancer risk be assessed, and when should biopsies be done? Dr. William Catalona, who established and directed the largest single-institution prostate cancer-screening program in the United States, is director of the Clinical Prostate Cancer Program at Northwestern Universityís Robert H. Lurie Comprehensive Cancer Center. The problem, he explained, is that although prostate cancer can be relatively ìindolentî and slow-growing in many men, there hasnít been any way to detect which men have a more aggressive and lethal form of the cancer. ìYou hear a lot of people say that everybodyís going to get prostate cancer if they live long enough, and relatively few men die from it,î he said. ìBut one in six men will be diagnosed with prostate cancer in their lifetime. Only about 16 percent of men who get prostate cancer will die from it, but because itís such a common cancer, itís the second leading cause of cancer death in men. And death from prostate cancer is horrible.î On the other hand, said Dr. H. Ballentine Carter, a prostate cancer researcher at Johns Hopkins University, many other small prostate cancers are relatively indolent. ìHuge numbers of small cancers never present a threat to a person,î he said. ìWe donít have a marker right now that can tell us which ones are going to be harmful and which ones are not.î Treating all prostate cancers aggressively may leave some men who have slow-growing, non-threatening tumors suffering more from the side effects, such as incontinence or impotence, than they might have from the actual disease. In May, the National Comprehensive Cancer Network (NCCN)óa group of the nationís most renowned cancer research and treatment facilitiesóannounced that it would change its recommended prostate cancer screening guidelines. Instead of beginning prostate cancer screening at age 50, the NCCN now suggests that all men have a baseline PSA test at age 40, repeating the test at age 45, and that the cutoff level for a biopsy be lowered from 4.0 to 2.5. Catalona, who serves on the panel that set the new guidelines, said he would have gone even further, recommending annual PSA screening beginning at 40. ìLooking at years of data on thousands of men with prostate cancer in our research studies, you never know when the PSA level will start to rise. A man can have levels of 0.6 for a couple of years, and then the next year it will be 1.2 and 3 the next year,î he said. ìI see patients whose levels are 2.5 one year and 11 the next. Itís such an easy test, and I think that thereís no need to wait five years to repeat it. You may miss some of those men.î Catalona and Carter agree that whatís really needed is a more accurate way to identify the men whose cancers are most aggressiveówho face the greatest risk of prostate cancer deathóas early as possible. In an upcoming New England Journal of Medicine article due out this summer, Catalona and lead author Dr. Anthony DíAmico, chief of genitourinary radiation oncology at the Dana-Farber Cancer Institute in Boston, suggest that the rate of rise in PSA levels can help to provide an answer to that question. ìOur study shows that more important than any single PSA value is the trend over time,î said Catalona. ìIn a typical man, the PSA level is low and stays flat. Beginning about a year before they develop cancer, it begins to rise at a steeper rate. A very rapidly rising PSA, around two units in a year, predicts a very high rate of death from prostate cancer.î Using this information, he said, doctors may soon be able to ìstratifyî the threat from prostate cancer. ìBy testing men early enough and monitoring the rate of rise in their PSA levels, we can identify those men who have highly lethal cancers, those who have less lethal cancers but which are still dangerous and are curable, and those who have very indolent cancers that arenít threatening.î Ultimately, Catalona noted, there may be still more accurate prostate screening tests, including one now being studied called the pro-PSA test, but those arenít yet available. Know your PSA numbers and know the trend line, Catalona advises. ìYesterday, I saw two patients with prostate canceróone whose PSA was six and one whose PSA was nine,î he said. ìI asked them when they were first tested, and they said years ago. When I asked what their numbers had been, they said they didnít knowóthe doctor had just told them it was fine. When you start getting tested, know what your PSA level is and keep a record of your own. If it starts to take off on you, thatís a red flag.î Gina Shaw is the medical writer for The Washington Diplomat.