News from Davis Square Family Practice

Cancer is scary. Nobody wants to get it let alone die from it. For women the most common potentially deadly cancers are breast, lung and colon and for men it is lung, colon and prostate.

There are screening tests for all of these diseases, but that does not mean that each screening test is of equal utility. It would seem obvious to most people that screening men for breast cancer with mammograms would be ridiculous. Yet for many diseases, we screen people without much scrutiny of the test's real value. Without getting too technical, a screening test ideally should be sensitive and have few false positives. A false positive is when the test says you have the cancer but you actually do not have it. Also, if we detect the cancer with the test, are we able to either cure it or add meaningful life for the patient. Another important thing to consider is, how much better is the cure from the cancer itself Every treatment has potential side effects, complications and even death associated with it. In addition, some screening tests may have small but potentially real side effects themselves. For example, there is a small radiation dose from a mammogram.

Lung Cancer

90% of lung cancer is smoking-related. The next highest risk factor of lung cancer is radon exposure. Screening with x-rays has proven nearly useless and CT scans have many false positives and expose people to high doses of radiation if you perform them on a regular basis. It is just best to avoid risk factors. For example, stop smoking and check basements for radon.

Prostate

My feelings about the PSA blood test have modified over the past year. Screening for prostate cancer with a PSA yields many false positives and this is not a good situation. What makes screening even more complicated is that it is difficult to determine who has an aggressive cancer which is more likely to kill them, and prostate biopsies are no walk in the park. Couple that with the fact that the treatment for prostate cancer is not without potentially significant complications. Radiation of the prostate can cause problematic internal colon scarring, and surgery can cause impotence and urinary incontinence. Many long-term studies comparing 'no treatment ' to 'treatment' have shown no significant difference in 10-year survival rates. Perhaps some improvement is death from prostate cancer after 15 years in the treatment group. If you have a family history of prostate cancer, especially early prostate cancer, then perhaps screening is indicated. When you come in for your physical exam around 50 years of age, we should talk about the risks versus the benefits of a PSA blood test.

Breast

There are many varying opinions among the different medical societies as to the proper screening for breast cancer. There are about 200,000 cases of breast cancer diagnosed annually and about 30,000 deaths. The Preventive Service Task Force came out with with some controversial recommendations last year, and I'll summarize them now. They no longer recommend mammograms every 1-2 years for all women between the ages of 40-50. Rather, they suggest discussing individual risk/benefit with your physician. They now recommend mammography every other year between 50-74. They say that the evidence isn't there to recommend for or against mammography for women 75 and older. They recommend against teaching the breast self exam. The feeling is that between the ages of 40-50 the risk of breast cancer is 1 in every 1000 women which is much less than the occurrance in older women and that a lot of unnecessary biopsies are performed in premenopausal women as a result. Breast cancer prior to menopause tends to be a somewhat different entity than postmenopausal cancer. On the other hand, we are treating, and sometimes curing, woman with many years of potential life ahead of them in the premenopausal group. As with prostate cancer screening, a discussion with your clinician is the best course of action when you turn 40 as certain groups of patients are higher risk.

Colon Cancer

Colon cancer is the archetype disease for screening. The colonoscopy will catch a polyp (a tiny clump of cells) when it is small. When caught early and removed, you are 'cured', but when ignored and allowed to spread, it is very difficult to treat. The risks of the colonoscopy (i.e. bowel perforation) are rare. I don't believe that merely checking the stool for occult (microscopic) blood is very sensitive although some authorities say it can suffice. A stool test for cancer cells is available, but it is not as sensitive as the colonoscopy (which should be done every 10 years unless cancerous polyps have been found previously). Colonoscopies generally begin at 50 years of age unless there is a family history of colon cancer and screening may be recommended earlier.

Cancer Screening