Mammography is a widely used imaging method that uses X-rays to examine the breast for early detection of cancer and other breast changes. While mammograms are a standard part of breast health, many people have concerns about the procedure. This article explores some common downsides associated with mammography.
Discomfort and Pain During the Procedure
Many individuals experience physical discomfort or pain during a mammogram. During the procedure, the breast is compressed between two plates. This compression is necessary to spread out the breast tissue, which helps create clearer images and reduces the amount of radiation needed.
The level of discomfort can vary significantly among individuals. Factors influencing this include breast sensitivity, which can be heightened by hormonal changes, and the skill of the technologist. Breast structure, such as dense or fibrocystic breasts, can also contribute to increased pain. Some people report soreness after the procedure, though it subsides quickly.
Concerns Regarding Radiation Exposure
Mammograms involve the use of low-energy X-rays, which is a form of ionizing radiation. This raises concerns for some about the potential risks.
A typical screening mammogram delivers approximately 0.4 mSv of radiation per view. To put this into perspective, a single mammogram’s radiation dose (0.4 mSv) is comparable to about seven weeks of natural background radiation exposure. The average American receives about 3.1 mSv of background radiation annually from natural sources. While the risk from a single mammogram is considered small, the cumulative exposure over many years of annual screening is a consideration for some individuals.
Limitations and Accuracy Challenges
Mammograms, despite their utility, have limitations and accuracy challenges, leading to both false-positive and false-negative results. A false-positive occurs when a mammogram indicates an abnormal finding that is not cancer. These results can cause emotional distress and anxiety, often necessitating further tests like imaging or biopsies, which carry risks and costs. After 10 years of annual screenings, 50-60% of women can expect at least one false-positive result.
Conversely, a false-negative result means breast cancer is present but undetected. This can create a false sense of security, potentially delaying diagnosis and leading to later-stage detection with more complex treatment implications. Screening mammograms may miss approximately 1 in 8 breast cancers.
Dense breast tissue significantly contributes to both false-positive and false-negative results. On a mammogram, dense tissue and cancerous masses both appear white, making distinction difficult. About half of all women over 40 have dense breast tissue, which can reduce mammography sensitivity, making it more likely to miss cancer.
Understanding Overdiagnosis
Overdiagnosis refers to detecting cancers that would never have caused symptoms or threatened a person’s life if left untreated. These are often slow-growing or non-aggressive cancers that might never have progressed clinically. This phenomenon is considered an inherent outcome of screening, as it aims to detect cancers at their earliest stages.
The primary harm of overdiagnosis is overtreatment. Individuals diagnosed with these non-threatening cancers often undergo unnecessary and potentially harmful treatments like surgery, radiation, or chemotherapy. These treatments can result in side effects, psychological distress, and a reduced quality of life, without providing a survival benefit.
Ductal carcinoma in situ (DCIS), a non-invasive form of breast cancer, is frequently cited in discussions of overdiagnosis. The incidence of DCIS has increased significantly with the rise of mammography screening, accounting for 20-25% of all breast cancer diagnoses. Many DCIS lesions are indolent, meaning they would not progress to invasive cancer or cause harm. Distinguishing between cancers that require intervention and those that would remain harmless is a complex challenge in current breast cancer screening practices. Estimates for overdiagnosis rates vary widely, from 5% to over 30% of diagnosed cases, due to differing definitions and study methodologies.