A mammogram is a screening tool used for early detection of breast cancer. Most doctors, and women, understand that early detection is an important factor for successful treatment. Many women undergo mammogram screening on an annual basis, at the recommendation of their doctor. Different research studies have also found annual screening to be beneficial at detecting lumps that are too small too feel through a self-exam or a manual examination by your doctor.
The Benefits of Annual Mammograms
According to the National Cancer Institute, “early detection of breast cancer with screening mammography means that treatment can be started earlier in the course of the disease, possibly before it has spread.”  Studies have shown that regular screenings from mammography can reduce breast cancer deaths, particularly for women over 50. For women under 40, studies have not shown the need for regular screenings.
For all women, no matter whether under or over 50 years old, mammograms are effective at detecting invasive breast cancer, which means it has spread to nearby tissue.
Drawbacks of Annual Mammograms
A recent study, completed by Dr. Archie Bleyer and Dr. Gilbert Welch at the Dartmouth Institute for Health Policy and Clinical Practice, showed that breast cancer was overdiagnosed in 1.3 million women due, at least in part, to annual mammogram screenings. Critics of the study believe that that annual mammograms save lives and should be continued. 
Another drawback is the possibility of receiving a “false positive.” This is when abnormalities are found but no cancer is present. Receiving a false positive result causes undue anxiety and emotional distress. False positives are most common in younger women, those taking estrogen, women with a family history of breast cancer and those who have had previous breast biopsies. Only about 10 percent of women who have an abnormal mammogram will have breast cancer.
The opposite problem, a “false negative” is when the mammogram does not detect any abnormalities, even though cancer is present. The National Cancer Institute indicates that approximately 20 percent of breast cancers are missed during mammogram screenings. This occurs most often when breast tissue is very dense, usually in younger women, because tumors can appear as dense tissue. As a woman ages and breast tissue becomes more fatty, false negatives are less common.
The National Cancer Institute recommends:
- Women age 40 and older should have mammograms every 1 to 2 years.
- Women who are at higher than average risk of breast cancer (for example, because of a family history of the disease or because they carry a known mutation in either the BRCA1 or the BRCA2 gene) should talk with their health care providers about whether to have mammograms before age 40 and how often to have them. 
Other health organizations recommend annual mammograms between the ages of 40 and 50 and biannual mammograms after the age of 50.
Making Your Decision
Before deciding whether you want to have an annual or biannual mammogram, it is best to talk with your doctor. If you have certain risk conditions, such as family history, your doctor may recommend regular mammograms, even before the age of 40.
Keep in mind both the benefits and drawbacks of having annual mammograms and remember, even if you decide to have a mammogram every year, you should continue self-checks and regular check-ups with your doctor. Because mammograms miss about 20 percent of cancers, you want to make sure that you are aware of any changes in your breasts, as soon as possible.
While some studies show that annual screening is not necessary, other studies show it can detect cancer early and can save lives. Both proponents and critics of annual screening point to studies to back up their position. Your decision should be based on being informed of the drawbacks and benefits, your personal risk factors and a thorough discussion with your doctor.
  ”Mammograms” Reviewed 2012, July 24, Staff Writer, National Cancer Institute
 “Study Questions Benefit of Yearly Mammograms,” 2012, Nov 21, Elizabeth Cohen, CNN Health
Published On: November 26, 2012