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This article appeared in The Home News Tribune on May 22 2007.
Cancer screenings: What, when and why?
By Anise Kachadourian, M.D.
Some of my cancer patients brag that they haven't been to a doctor in 30 years.
These patients grew up believing that you went to a doctor when you felt sick or when you had symptoms. Go to a doctor to screen for something, especially something as scary as cancer? Why would you do that? Unfortunately, many people still hold that view.
Cancer remains a scary word. Screenings, no matter how good, are not 100 percent. There is the possibility of false positives, complications that can arise from biopsies, and, of course, the anxiety. Still, we have the ability of finding cancers at very early stages, when they are the most curable. And we have some good screening tools that have been shown to reduce death in certain types of cancers, particularly colon, breast and prostate cancer.
That's the good news. Unfortunately, the screening story for the leading cancer killer, lung cancer, is not as clear cut. Lung cancer is the leading cancer killer, yet we do not have an effective screening tool that has conclusively been shown to reduce deaths from lung cancer. While screening with chest X-rays, low dose computerized tomography or sputum cytology can find lung cancer at an earlier stage than would be detected in the unscreened population, there is poor evidence that any screening for lung cancer would decrease death from lung cancer.
But we do have strong evidence that screening for colon, breast and prostate do, in fact, reduce death from these cancers.
Colon cancer
Colon cancer is the second leading cause of cancer deaths in the United States, yet national rates of colon screenings are low. The exciting news is that the death rate from colorectal cancer has been declining in recent years, by about 2 percent per year, thanks to screening. If more people were screened, the death rate could probably be cut by half.
Most of the time, colorectal cancer begins as a polyp in the lining of the intestine, progressing slowly and possibly turning malignant. Tests that examine the colon can find these polyps and doctors can snip them out before they become cancers. The tests can also reveal early tumors that can be removed.
Polyps that are sitting in the colon do not necessarily mean the start of cancer, but if the polyp is a villous adenoma, there is a greater chance that it could turn to cancer.
The recommendation is for men and women to be screened for colorectal cancer at 50 years or age or older, sooner if you are at higher risk. Who is at a higher risk? You have a higher risk if you have a first-degree relative — mother, father, sister, brother — who has colon cancer. The risk also increases if you have inflammatory bowel diseases, such as Crohn's disease, ulcerative colitis, or a gene mutation that causes polyps.
There are several screening methods. One is a fecal occult blood test, or the newer version called fecal immunochemical test, which looks for blood in the stool. Polyps are less likely to bleed than cancers, so tests for blood in the stool are more likely to find cancers than they are to detect polyps. And often the first site of blood loss is in the colon. A fecal test should be done annually, but should never be relied on alone. If blood is found, the screen is generally followed by a colonoscopy.
Breast cancer
While we know the benefits of mammography and a yearly clinical breast examination, I tell patients that they are more likely to find a lump before the doctor finds it. Many women shy away from these tests, but I also caution that not every lump is cancer. Make breast self-examination a priority. Do it every month.
While a good tool, mammograms are not 100 percent. Breast implants can throw off a mammogram. Large breasts can distort a mammogram. That is where MRI or ultrasound can help if you have felt something.
A yearly mammogram is an important screening for women beginning at age 40 with no family history of breast cancer. The evidence is strongest for women ages 50 to 69, the age group generally included in screening trials and at higher risk.
In addition to family history, women who are at higher risk for breast cancer are those whose period started earlier or who began menopause later. Women with a late first pregnancy are at higher risk, as are those who have never been pregnant.
Prostate cancer
There is no standard or routine screening for prostate cancer. Many doctors use the prostate-specific antigen (PSA) test and digital-rectal exam. The PSA test is really a tumor marker and was never meant to be used for screenings.
When PSAs were developed, they were used to follow patients already diagnosed with prostate cancer. But these days, many physicians use the PSA as a screen. According to the US Preventive Services Task Force, the evidence is insufficient to recommend for or against routine screening using PSA. While the test detects cancer at earlier stages, it is not clear whether this early detection actually improves overall survival. That is because prostate cancer is an illness of longevity. That is, if men live long enough, a high number of them will develop prostate cancer.
Men who are at greater risk of prostate cancer are those with a family history. That is, if a first-degree relative had it. Another risk factor for prostate cancer is an enlarged prostate.
The overall screening recommendation for men is for a digital rectal exam and a PSA at age 50.
Anise Kachadourian, MD, is a hematologist-oncologist affiliated with Robert Wood Johnson University Hospital at Rahway. Her practice is in Roselle, New Jersey.
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