Researchers from Sweden look to identify whether certain risk factors present an increased long-term risk of death from breast cancer. Read on to learn more.
The risk of developing breast cancer increases with age, as it tends to develop in women between the ages of 50-69. However, there are also several other risk factors associated with breast cancer, including having a personal history of breast cancer, having a family history of breast cancer and other cancers, having the BRCA gene, having dense breasts, being obese, being of Jewish descent, having undergone extensive hormone replacement therapy (HRT), and more.
The most common type of breast cancer is estrogen-receptor-positive, also known as hormone-sensitive breast cancer. It involves altering the female hormone estrogen and allowing the tumor mass to grow. As the tumor spreads, a woman’s long-term risk of dying from this type of breast cancer is heightened. Although it remains unclear as to why this is so, a probable reason is that the tumor consists of varying degrees of expression of the estrogen receptor, known as intra-tumor heterogeneity.
New study seeks to find the answer
Researchers from the Karolinska Institutet in Sweden sought to identify whether breast cancer patients with increased heterogeneity of the estrogen receptor in their tumor have an increased, long-term risk of dying. The study was published in the Journal of the National Cancer Institute and showed that the risk of breast cancer death is two times as high for patients with increased heterogeneity of the estrogen receptor within the same tumor as opposed to patients with lower heterogeneity. It also revealed that the risk of breast cancer death over 25 years is independent of other tumor markers.
The researchers studied 593 women, all of whom had been diagnosed with post-menopausal estrogen-receptor-positive breast cancer between the years 1976 and 1990. They examined those who had either been treated with tamoxifen and those who had not been treated with systemic therapy following surgery. “Our study shows that patients with high intra-tumor heterogeneity of the estrogen receptor were twice as likely to die up to 25-years after their diagnoses as compared to patients with low heterogeneity. And this was independent of whether or not they'd received tamoxifen and of other known tumor markers,” said Linda Lindström, researcher at the Department of Biosciences and Nutrition at Karolinska Institutet.
Patients with Luminal A breast cancer
The researchers also found that a heightened risk of breast cancer death among patients with increased intra-tumor heterogeneity was also seen among patients with Luminal A breast cancer, a subgroup of estrogen-receptor-positive breast cancer. “Patients with Luminal A breast cancer and high intra-tumor heterogeneity of the estrogen receptor were also twice as likely to die from the disease. This is interesting given that patients with Luminal A breast cancer subtype are generally thought to have a good prognosis. We believe that if validated, these new findings should be useable within the near future,” said Dr Lindström.
Another study and stress
Another particular study, conducted by doctors from the Sahlgrenska Academy in Gothenburg, sought to identify the role of stress in the development of breast cancer. The study suggested that stress relating to family and work increases anxiety and tension, thus leading to a heightened risk of developing breast cancer throughout the course of one’s life.
Doctors examined 1,500 women, ages 38-60, over the course of 24 years. They questioned the women about their stress levels over the last 5 years and conducted follow-up examinations. After gathering their results, the doctors found that stress is two times as likely to trigger breast cancer in women. They also found that other factors - smoking, drinking alcohol excessively, being overweight, having undergone extensive HRT, age of first pregnancy, and age of menopause - contributed to the heightened risk. “This study showed a statistically significant, positive relationship between stress and breast cancer,” said Dr. Osten Helgesson, lead author of the study.
Out of 1,350 women, 456 reported increased levels of stress and 24 of them developed breast cancer. Moreover, 894 women reported low levels of stress or no stress at all and 23 of them developed breast cancer. This in turn led the doctors to conclude that the heightened risk of breast cancer is double among women who are stressed out. Still, Dr. Helgesson noted that the study did not emphasize the amount of stress that was needed to trigger breast cancer. “I would emphasize that more research needs to be carried out before it can be said that stress definitely increases a woman's risk,” he said. A majority of experts believe that because women experience hormonal changes within their bodies, factors such as stress could increase the risk of developing breast cancer. Since breast cancer is driven by the hormone oestrogen, being stressed out could affect hormone levels and therefore affect the growth of healthy cells within the breasts.
Tamoxifen and survival
Today, experts note the importance of the hormone treatment tamoxifen in increasing survival rates among women with breast cancer. They found that taking the medication for 5 years can lead to a 30% decrease in death rate 15 years after breast cancer is initially diagnosed. The results are convincing, but further research still needs to be conducted in order to gather concrete and reliable findings. Although cancers, such as breast cancer, continue to remain an issue among healthcare, doctors are hopeful in furthering survival rates by diagnosing the disease early on and providing better treatment options.
Essentially, it is the sum of all risk factors that define a personal risk of breast cancer, and it is unique for each case. It’s impossible to know your own risk of breast cancer exactly; however, there are several tools available to learn a little bit. To date, the most popular tool is the Gail model. Upon entering relevant information regarding personal and family history, the tool calculates a 5-year and lifetime risk of developing breast cancer. Of course, while one’s increased risk of breast cancer due to personal or family history cannot be changed, there are some adjustments that could prove valuable to those at an increased risk.
An oncologist’s recommendations
“Women should be checked regularly. Every woman over 25 years should be screened annually by a specialist in the field of breast surgery. From the age of 50 and up it is necessary to undergo mammography every two years. This applies to those women as well who do not have a history of breast cancer. Women with a family history or the presence of BRCA mutations are recommended to undergo more frequent examinations. For example, if you know that your mother has breast cancer that was discovered at age 32, then you should begin preventive examinations from the age of 22; ten years before the cancer was diagnosed in your mother,” said Dr. Shani Paluch-Shimon, oncologist.
Beyond the use of medications such as tamoxifen and aromatase inhibitors, good measures include consulting with a breast cancer specialist and:
- Eating a wholesome and healthful diet
- Exercising moderately on a regular basis
- Maintaining a healthy weight
- Limiting alcohol intake
- Avoiding or quitting smoking
- Considering undergoing genetic tests
- Considering undergoing standard imaging tests, such as mammography
- Taking preventative medication or undergoing surgery (for those at high-risk)
It is important to note that each woman’s situation is unique. No procedure or treatment can entirely eliminate the risk of cancer; however, there are approaches to lowering breast cancer risk. Talk to your doctor about your own personal risk of breast cancer and the ideal way to manage it throughout the course of your life.