What it can tell you: Whether a cancerous breast lump or thickening is present. When to have it: Generally, your doctor should give you a manual breast exam starting in your early 20s. By the time you’re 30, you should have a manual, clinical exam every year. Recommendations for CBE vary slightly by health organization—here are a few to consider, in addition to consulting your doctor to determine when to start and how often to get a CBE. The National Comprehensive Cancer Network has recommended starting CBE every one to three years starting at age 25, and increasing to yearly exams starting at age 40. Similarly, Memorial Sloan Kettering Cancer Center recommends an annual physical breast exam for all women of average risk between 25 and 40. (It also encourages all women to give themselves self breast checks once a month, starting at age 20, to “become familiar with their breasts so they are better able to notice changes.”) However, the American Cancer Society, does not necessarily recommend regular clinical breast exams as part of a cancer screening routine, since there is research that indicates CBE doesn’t contribute much to early detection in instances when mammography screening is readily available. That said, CBE remains a good way to keep tabs on your body, and women will often receive this check-up every time they visit the gynecologist or at their annual trip to the doctor. Become familiar with the look and feel of your breasts so you and your doctor can recognize if something does change or appears unusual. The Risks: Not all doctors are trained or skilled in this kind of examination. Lumps may be missed, or normal variations in breast tissue may be mistaken for tumors (false positives), leading to needless worry and expensive procedures. RELATED: 10 Key Health Appointments to Schedule Starting in Your 40s and 50s What it can tell you: Suspicious findings from a mammogram come in two forms, calcifications (small white dots) and masses (larger abnormal areas of breast tissue). Calcifications are tiny calcium deposits in the breast tissue; some are normal, but certain patterns of calcification may indicate a tumor and need to be tested further (biopsied). A mass may be biopsied, or it can be examined with ultrasound to find out whether it is just a cyst or even a benign tumor. When to have it: According to the American Cancer Society, “results from many decades of research clearly show that women who have regular mammograms are more likely to have breast cancer found early, are less likely to need aggressive treatment like surgery to remove the breast (mastectomy) and chemotherapy, and are more likely to be cured.” Medical groups generally agree that starting at age 40, healthy women with an average risk for breast cancer should begin mammography screening and consult with their doctor to determine how often. Women 50 and over who have no lumps or other breast abnormalities are strongly advised to have an annual mammogram. To be safe, many doctors recommend starting mammograms at 40 and having them either annually or biennially (every other year). For more specific recommendations, see the Centers for Disease Control and Prevention’s extensive breakdown of breast cancer screening and mammography guidelines for women by health organization and age group. The Risks: False-positive and false-negative results both occur. According to the American Cancer Society, “[a]bout half of the women getting annual mammograms over a 10-year period will have a false-positive finding at some point.” False positives can lead to unnecessary further testing (often an expensive hassle) and undue anxiety. False-negatives are a possibility, too. The National Cancer Institute reports that “screening mammograms miss about 20 percent of breast cancers that are present at the time of screening.” RELATED: 12 Health Stats or Factors You Should Know About Yourself What it can tell you: A 3D mammogram allows doctors and radiologists to see a clearer, more detailed image of the breast and view breast areas from multiple angles. They may be especially helpful for women with dense breast tissue, which can obscure potential cancers in a standard mammogram. DBT has been found to increase both sensitivity (correct identification of someone with cancer) and specificity (correct identification of someone without cancer) of mammography. When to have it: Women 40 and older are encouraged to get yearly mammograms, and should consider 3D mammograms if available. They are becoming more common, but aren’t available at all facilities. More research is underway to determine whether a 3D mammogram alone is more effective at detecting breast cancer than the standard 2D mammogram alone. But studies show, and medical groups agree, that undergoing both exams can reduce the need for follow-up testing, lower the rate of false positives, and catch an increased number of cancers during screening. The risks: Exposure to low-level radiation (though the benefits tend to outweigh the risk of radiation exposure—chat with your doctor if you’re concerned). False positives and missed cancers are also possible. What it can tell you: Ultrasounds are often used as a follow-up to mammography to determine whether a suspicious breast lump apparent in a mammogram is a solid mass or a fluid-filled cyst (which are typically benign and can be drained). A solid mass may require a biopsy to determine if it’s cancerous. (Ultrasound may also be used to guide a needle biopsy.) When to have it: Besides showing whether a lump is a mass or a cyst, ultrasound is often recommended in addition to mammography in women with dense breasts to see if it can help detect cancers that do not appear on mammograms. The Risks: False positives and false negatives are possible. What it can tell you: MRI is used at some centers to screen high-risk women. It’s most helpful for those with dense breasts, where it works better than mammography, which is limited in its ability to reveal lumps in dense breasts. When to have it: Women with risk factors (such as having a mother or a sister who had breast cancer) should consider a yearly MRI scan in addition to a mammogram. If a mammogram has already found a tumor, MRI can help map the extent of the disease and look for other tumors. If a mammogram is questionable, MRI can help rule out a tumor. It’s not recommended, however, as a screening test by itself since it can miss some cancers that a mammogram would find. The Risks: MRI scans are quite expensive and have a high rate of false positives due to their high sensitivity—their ability to pick up even the slightest abnormality regardless of whether or not it’s problematic. Therefore, MRI is not recommended as a regular form of screening for women with average risk of breast cancer. RELATED: How Are You, Really? 14 Personal Health Questions to Ask Yourself on a Regular Basis