The story so far:
In September, the Food and Drug Administration (FDA) of the United States, the country’s apex public health body implemented a rule that required mammogram reports to include information about breast density. This was aimed at ensuring that women are informed about the risks of breast density and can talk to their doctors about possible next steps including other imaging tests.
What is dense breast tissue?
Breasts comprise three types of tissue: fatty tissue, glandular tissue and fibrous connective tissue. Breast density, as per the American Cancer Society, is a measure of how much fibrous and glandular tissue (also known as fibroglandular tissue) there is in your breast, as compared to fatty tissue. This is not related to breast size or firmness. A person with dense breast tissue has more fibrogladular tissue relative to fatty tissue.
There are four categories of breast density: Category A: Breasts are almost entirely all fatty tissue; Category B: Breasts have scattered fibroglandular tissue, but the majority is fatty tissue; Category C: Many areas of the breast have dense fibroglandular tissue (heterogeneously dense) while some areas have fatty tissue; and Category D: Extremely dense breast tissue, almost all of the areas have dense tissue
Having dense breasts is not uncommon. It is also a factor of ageing: for many women, breasts become less dense as they get older, says Arvind Krishnamurthy, professor and head, surgical oncology, Cancer Institute, Adyar, Chennai. A 2018 research paper in the Breast Journal by Tulika Singh et al from PGIMER, Chandigarh that evaluated breast density in the Indian population and its relationship with age, found that in 6,132 screening mammograms, 22% of patients between 40 and 49 years old had dense breasts. This percentage decreased to 9% of women in their 50s. Only 7% of women in their 60s and 8% of women in their 70s had dense breasts.
Why does breast density matter?
There are two main reasons: The first is that dense breast tissue makes it harder to detect signs of cancer on a mammogram. This is because dense breast tissue looks white on a mammogram. Masses and cancers in the breast can also look white, making them harder to see, if the breast is dense. Fatty tissue however, looks almost black on a mammogram, making it easier to spot a white tumour/mass, says the American Cancer Society.
However, Bhawna Dev, professor lead consultant, breast imaging and interventions, Sri Ramachandra Medical College, Chennai, says newer technology such as tomosynthesis has decreased the chances of missing cancers as the imagery is more detailed. Digital mammograms, which are also common these days, have better sensitivity compared to conventional mammograms, making them more accurate. There still remain chances though, she says, that small cancers may be missed in the case of extremely dense breasts.
Under the new FDA rule, patient summaries in mammograms will now include the statement: Dense tissue makes it harder to find breast cancer on a mammogram and also raises the risk of developing breast cancer. For women with breast tissue, the disclosure reads: “In some people with dense tissue, other imaging tests in addition to a mammogram may help find cancers. Talk to your healthcare provider about breast density, risks for breast cancer, and your individual situation.”
The second reason breast density is significant is because it is associated with an increased risk of breast cancer. “Multiple studies have shown that increased density is an independent risk factor for breast cancer; however, it must be noted that increased breast density is not associated with increased mortality from breast cancer,” says Dr. Krishnamurthy.
Only a mammogram can tell you if you have dense breasts. It is not something you can self diagnose.
What is the breast cancer situation in India?
Breast cancer is the most common cancer in women in India, accounting for about a quarter of all cancers. It also accounts for the highest number of cancer-related deaths in the country.
In India, says Anita Gadgil, general surgeon and breast cancer (early detection and screening) researcher with The George Institute for Global Health, India, mammography screening for all women is not carried out. As per the Indian Council of Medical Research’s (ICMR) Consensus Document for Management of Breast Cancer, 2016, population-wide mammographic screening programme of asymptomatic women is neither feasible in India, nor may it be useful. The document adds that opportunistic screening may be considered for some high risk and concerned women in India.
Affordability of and access to a mammogram are out of reach for a large section of the female population in a limited-resource, high population country like India, says Dr. Gadgil. “Since breast cancer occurs at a younger age in Indian women, compared to the West, and younger women have denser breasts in general, it may also be difficult to find small cancers even if a mammogram is done. The recommendation in India is a clinical breast examination with trained healthcare providers and increasing awareness at the community level.” There is evidence to show that this too can save lives.
Who needs additional screening?
However, women who have any symptoms related to the breast or those who have one or more risk factors should consult a doctor and then get a mammogram done if required, emphasise doctors.
The risk factors include: a family history of breast cancer; starting menstrual periods before the age of 12 or going through menopause after age 55; alcohol use; obesity; having your first child after age 30 and having never been pregnant; certain inherited DNA changes; menopausal hormone therapy and dense breast tissue among others.
Should all women whose mammogram indicates dense breasts get additional screening? Not necessarily, says Dr. Krishnamurthy. Women who have a high risk of breast cancers will benefit from additional imaging such as tomosynthesis, an MRI of the breast or an ultrasound as deemed clinically necessary by their treating physician.
Published – November 02, 2024 11:10 am IST
