Very low mammographic breast density worsens the prognosis of breast cancer, according to a recent study from the University of Eastern Finland. Disease free survivals as well as overall life expectancies were significantly shorter in women with very low-density breasts in comparison to women with high density breast tissue. The lower the breast tissue density, the less fibroglandular tissue there is compared to fat tissue.
In the future, these findings may prove significant for the assessment of breast cancer prognosis and treatment planning.
The study involved 270 breast cancer patients at Kuopio University Hospital, aged between 32 and 86 years. Breast tissue density was analysed on the basis of mammographic images obtained at the time of diagnosis. The researchers determined the proportion of dense glandular tissue of the overall breast area. Breast tissue density was categorised as low when the proportion of glandular tissue was below 25%, and as very low when the proportion of glandular tissue was below 10%. The study was a six-year follow up focusing on the effects of breast tissue density and other mammographic features on breast cancer prognosis.
The results indicate that a very low breast tissue density is an independent poor prognostic factor of breast cancer, regardless of patients’ age, menopausal status or body mass index. Out of the women with very low breast tissue density, 70.7% were alive at the end of the six-year follow-up, whereas out of women whose proportion of glandular tissue was higher than 10%, 87.7% were alive at the same time. Lower breast tissue density was also associated with more aggressive higher grade tumours.
The results are particularly interesting because dense breast tissue has long been known to be associated with an increased risk of cancer. “It is difficult to detect small tumours when screening dense breasts, and this results in a higher occurrence of clinically detectable interval cancers. In the U.S., it is nowadays mandatory to let patients know if they have dense breast tissue. This allows them to choose whether they wish to have further tests, for example a screening ultrasound,” says Professor Ritva Vanninen.
Breast Cancer Prognosis
Your prognosis is your outlook or your chance of recovery from breast cancer. New and better treatments are helping people diagnosed with breast cancer live longer than ever before. Still, breast cancer may come back or spread to another part of the body after treatment.
Your doctor will consider many factors when determining your prognosis, including:
the size of the breast cancer
the stage of the breast cancer: whether the cancer is only in the breast or has spread to the lymph nodes or other places in the body
the type of breast cancer
the hormone-receptor status of the cancer
whether the cancer is triple-negative (estrogen-receptor-negative, progesterone-receptor-negative, and HER2-negative)
the rate of cell growth
how likely the cancer is to come back (recurrence)
whether the cancer has just been diagnosed or is a recurrence
your menopausal status
your general health
Doctors often use survival rates to talk about your prognosis. While some people want to know the statistics for others in similar situations, it’s important to remember that each person and each breast cancer is unique. Survival rates usually are based on the outcomes of many, many people diagnosed with breast cancer, but survival rates can’t predict what will happen in your particular situation.
Think about whether you want to know about breast cancer survival statistics before you read beyond this point.
The 5-year survival rate is the percentage of people who live at least 5 years after being diagnosed with breast cancer. Many people live much longer than 5 years after being diagnosed. It’s also important to remember that people diagnosed with breast cancer can die from other causes - stroke or heart attack, for example. The 5-year survival numbers don’t take into account that some people died from something other than breast cancer.
“It could be assumed that dense breast tissue would also be associated with a poorer prognosis in patients with a recently diagnosed breast cancer. However, this was not the case in our study, as low breast tissue density specifically weakened the prognosis.”
Young Women Who Get Breast Cancer Are More Likely to Die
Women who are diagnosed with breast cancer before age 40 have slightly poorer prognoses than older women: Their five-year survival rate is about 82 percent, compared with 85 percent among women ages 40 to 74, according to the American Cancer Society (ACS). Why? “Younger women are more likely to have more aggressive tumors,” explains Lisa Carey, M.D., medical director of the University of North Carolina Breast Center.
Younger women also tend to have denser breast tissue, which makes it harder for mammograms to detect tumors. That said, these women usually don’t get annual mammograms (the ACS recommends yearly screenings beginning at 40), so cases often aren’t caught until the woman herself notices a lump - by which time the cancer is often more advanced. Even then, she’s likely to be blown off by her physician. “It’s common for a 28-year-old to show her doctor a lump, only to have him say, ‘You’re too young to have breast cancer,’” warns Lillie Shockney, administrative director of the Johns Hopkins Avon Foundation Breast Center.
While you can’t control the age at which breast cancer strikes, you can take steps to up your odds of diagnosing it early, which in turn ups your odds of beating it. For starters, if you have a family history of the disease, begin screening 10 years earlier than the age at which your relative was diagnosed, says Shockney. If possible, go to a facility that offers digital mammography, which has higher detection rates than standard mammography in women under age 50, according to the National Cancer Institute (NCI). If you have a strong family history of the disease - two or more first-degree family members, like your mom or sister, have been diagnosed - ask your doctor about more specific diagnostic tests like BRCA gene testing, which looks for hereditary gene mutations that are linked with breast cancer. And know that even if you don’t have breast cancer in your immediate family, you may still be at risk if you have relatives with hormone-driven cancers like prostate or ovarian cancer, which are also linked to BRCA gene mutations.
Masarwah A1, Auvinen P, Sudah M, Rautiainen S, Sutela A, Pelkonen O, Oikari S, Kosma VM, Vanninen R. Very low mammographic breast density predicts poorer outcome in patients with invasive breast cancer. European Radiology. 2015 Mar 4 (Published ahead of print).
University of Eastern Finland