Is a Mammogram Enough to Diagnose or Predict Breast Cancer? 

Olivia Munn brought significant attention to breast cancer detection methods in 2024 when she shared her battle with the disease. This disclosure has prompted conversations about the limitations of traditional screening tests like mammograms and genetic tests.

Early in 2023, she received negative results for both a genetic test for cancer-linked genes and a mammogram, often considered the gold standard for breast cancer detection. 

However, just two months later, she received the diagnosis of aggressive breast cancer. The credit for potentially saving Munn's life goes to her doctor's proactive approach. After her negative mammogram result, the doctor utilised a Breast Cancer Risk Assessment (BCRA) score to assess her risk level, which indicated a higher-than-average risk. 

Munn's social media posts highlighted the importance of a "Breast Cancer Risk Assessment Score" (BCRA Score). "Because of that score, I was sent to get an MRI, which led to an ultrasound, which then led to a biopsy," she explained in her social media post. This score considers factors beyond genetics, such as age, family history, and even the age at which you had your first child.

The tests identified cancer in both of her breasts. Munn underwent a double mastectomy and a total of four surgeries over ten challenging months (as documented in her Instagram posts). 

A mammogram is a screening test that is a tool for cancer detection in the breast. It is an X-ray examination where the breasts are compressed onto a firm surface to allow for breast tissue examination. The X-ray produces black-and-white images that will be reviewed for detection of any abnormalities. A mammogram may help find cancer before the patient experiences any symptoms, allowing the patient to begin breast cancer treatment at an early stage.

Mammograms are a great tool for early breast cancer detection, but they aren't perfect. Studies show they can miss cancers, especially in younger women with dense tissue. They can also lead to unnecessary tests due to false positive results. 

Dr. Anil Thakwani, MBBS MD - Radiation Oncology FCSS NUTAS, says, “Dense breast tissue, especially common in younger women, can appear white on mammogram images, mimicking tumours and masking real ones. Additionally, fast-growing cancers can develop quickly, potentially escaping detection between annual mammograms; these reasons can lead to mammograms sometimes failing to detect aggressive forms of breast cancer, as seen in cases like Olivia Munn's.”

“We cannot entirely depend on a mammogram for cancer detection,” he adds.

According to Dr Thakwani, these limitations emphasise the importance of a personalised screening approach. To create the best plan, the doctor will consider factors like age, family history, and breast density. This might include additional tests like ultrasounds or MRIs or utilising a Breast Cancer Risk Assessment Score for further guidance. 

Missed cancers on mammograms (false negatives) can be a significant concern. They delay diagnosis, allowing cancer more time to grow and potentially spread before it's finally detected. This delay can have a ripple effect on treatment outcomes. Dr Thakwani explains that women with false-negative mammograms are much more likely to be diagnosed with advanced-stage breast cancer, often requiring more aggressive treatments with harsher side effects. These treatments can significantly impact a patient's quality of life.

Dr Thakwani explains ultrasound, using sound waves for detailed images, works well for women with dense breasts where mammograms might miss something. MRI, with its powerful magnets and radio MRI waves, can detect some cancers even mammograms miss and might be recommended for higher-risk women. Apart from these, BCRA tools can be beneficial. We can consider these additional methods to improve detection rates for breast cancer. 

The Breast Cancer Risk Assessment (BCRA) tool is a questionnaire that estimates a woman's lifetime risk of developing breast cancer.  Unlike a mammogram, it doesn't diagnose cancer but provides a risk score that helps doctors personalise your screening plan.

Dr Thakwani says, “Things like family history, age of first menstruation, and childbirth history are considered when assessing a patient with the BCRA tool."

Following Olivia Munn's lead and considering a BCRA tool can be a wise move. A high score might warrant more frequent mammograms or additional tests like ultrasounds or MRIs. Dr Thakwani says, “Knowing your risk allows for a proactive approach: increased self-awareness, prompt reporting of changes, and potentially earlier detection with better treatment outcomes (like in Munn's case). While the BCRA tool has limitations in accuracy and doesn't replace genetic testing, it can be a valuable first step in creating a personalised plan for optimal breast health.”

Breast Cancer Risk Assessment (BCRA) scores aren't a one-size-fits-all approach. Dr Thakwani informs they are typically recommended for women with a higher baseline risk, such as those with a family history of breast cancer in close relatives or a personal history of certain breast conditions.

The BCRA tool's accuracy can vary depending on ethnicity, and for women with a low baseline risk, the potential anxiety from a high score might outweigh the benefit.

Several additional risk assessment methods may be considered for a more nuanced assessment. Dr Thakwani elaborates the Gail Model factors in age, family history, ethnicity, and reproductive history to approximate a woman's risk of developing breast cancer within the next five years and over her lifetime. The Tyrer-Cuzick (IBIS) Model focuses on family history and genetic risk factors to provide another estimate of breast cancer risk. 

Dr Thakwani advises conducting comprehensive tests if there's even a slight suspicion of cancer. This proactive approach enables early detection for prompt treatment and reduces the risk of cancer progression. Olivia Munn's case highlights the significance of thorough testing, where her doctor wisely utilised BCRA, MRI, and ultrasound to diagnose her cancer despite limitations in mammograms. It's crucial to note that while mammograms have their limitations, they still play a vital role in cancer detection and should not be disregarded entirely.

It is advisable to use both mammography tests and ultrasound for screening. An ultrasound detects lesions better in denser breasts. A breast MRI has higher sensitivity for detecting breast cancer and is recommended for those who have an increased risk from genetic mutations, a strong personal or family history of breast cancer, or to clarify uncertain findings detected in a mammogram or ultrasound.

Medically reviewed by:

Dr Akash Dhuru, Surgical Oncologist