More young women are developing breast cancer, and doctors are scrambling to find out why.
The incidence of breast cancer in women under 50 has increased by more than 15% over the past 20 years. Almost all of this increase is driven by an increase in estrogen receptor-positive breast cancer (ER+), a tumor subtype that requires the action of the hormone estrogen. Grow and spread.
Estrogen receptor-positive breast cancer is the most common type in all age groups. This particular type of breast cancer is causing a surge almost exclusively in young women, leading some doctors to link this trend to the fact that more people in the U.S. are getting their periods earlier and having their first child later. I suspect that you are doing so.
“Women are exposed to more estrogen throughout their lives,” says Dr. Alexandra Thomas, a medical oncologist at Duke Health. “That’s probably a big part, but we don’t know why we’re seeing an earlier period.”
Although many factors may be behind this increase, including obesity, alcohol consumption, genetics, and hormonal contraception, the role of early puberty in women’s breast cancer risk is gaining attention. The age at puberty for girls has declined in recent decades, especially among blacks and Asian Americans.
“This research is still in its early stages,” says Dr. Adetunji Toriola, a molecular epidemiologist at the University of Washington Siteman Cancer Center. “But we know from previous research and the work of others that we know of certain factors that may be causative. We know that these reproductive factors are associated with breast cancer. I know it may be.”
Menstruation comes earlier and motherhood is delayed
Although it has long been known that significantly earlier onset of puberty increases the risk of developing breast cancer, little research has been done on the effect of age at diagnosis.
A study published earlier this year in JAMA Network Open found that women born between 1950 and 1969 had an average age of menarche of 12.5 years. Less than 9% had menarche (the scientific term for a girl’s first menstrual period) before the age of 11, which is considered early. Only 0.6% of these women reached menarche before age 9, a very early age.
On average, girls born between 2000 and 2005 reached menarche just before they turned 12, six months earlier than girls born 40 to 50 years earlier. The proportion of early menarche and very early menarche also increased, jumping to 15.5% and 1.4%, respectively.
“When menstruation begins before age 11, the risk of breast cancer increases, and now the average age (of menarche) continues to decline,” says Eleonora, Director of Breast and Gynecologic Oncology at Valley Health System. Dr. Teplinski says: In New Jersey.
Research shows that for every year a girl gets her period younger, her lifetime risk of breast cancer increases by about 5%. Early breast development also increases the risk of breast cancer. A study of nearly 50,000 women found that girls whose breasts developed before age 10 had a higher lifetime risk of developing breast cancer than girls whose breasts started developing at age 12 or 13. It turned out to be 23% higher.
When a woman begins menstruation, her ovaries release estrogen and progesterone. Both may play a role in increasing a woman’s risk for hormone-sensitive subtypes of breast cancer. Breast cancer usually grows slowly and is easy to treat. According to the American Cancer Society, about 75% of breast cancers are sensitive to at least one hormone, usually progesterone or estrogen.
At the same time, women are having children later in life or choosing not to have children.
Dr. Anne Partridge, co-founder and director of the Young Breast Cancer Program at Dana-Farber Cancer Institute, says that childbirth may temporarily increase a woman’s risk of breast cancer, but the long-term risk is slightly lower. He said he would.
Women stop their menstrual cycles during pregnancy, but “that has to do with not only how many cycles the person has been exposed to, but also the timing of the pregnancy, and has nothing to do with estrogen,” says Partridge. he says.
Rather, it may have something to do with changes that occur in the breasts after giving birth, as a woman’s mammary glands return to their pre-pregnancy state. This increased risk is higher for women who give birth later in life.
“Women who have children before age 30 have a reduced long-term risk of developing breast cancer,” Dr. Partridge said. “We don’t know why, but the older you are at your first pregnancy, the higher the risk in the short term.”
Partridge added that the reason is unclear, but it may have something to do with the fact that younger bodies are generally better at quelling inflammatory responses and repairing damaged DNA.
What we know about breast cancer in young women
Doctors are still scratching the surface of why breast cancer is more common in younger people.
“Women either don’t have children or have children later in life. They’re not breastfeeding as much, which increases their risk of breast cancer. But that’s not all.” Mr. Key said. “We know obesity and a sedentary lifestyle are to blame, but why are we suddenly seeing this increased risk?”
Teplinski said more research is needed into the link between environmental toxins, such as chemicals known as endocrine disruptors, and breast cancer.
A study published earlier this year in the journal Frontiers in Toxicology found that about 200 chemicals linked to breast cancer are used in food packaging, including cardboard. Some recent studies suggest that using estrogen-only contraception may slightly increase a woman’s risk of breast cancer.
Obesity may be another factor in early diagnosis of breast cancer, but the association is complex. Obesity is thought to be one of several factors that can cause early puberty. It can also increase your risk of breast cancer by as much as 30%, but research suggests this is limited to postmenopausal women, especially those who have difficulty regulating their blood sugar levels.
Triola, of the University of Washington, said this shows that obesity is likely not a factor in the increased incidence of breast cancer in young women.
Triola said most of the research being done on lifestyle factors and breast cancer has been done on women of all ages, so it’s difficult to identify specific factors in younger women.
Additionally, she hopes more clinics will adopt risk prediction models, such as the Tyler-Cusick risk assessment, which take into account not only a woman’s personal and family breast cancer history and mutations, but also other factors such as early puberty. He added that it should.
“These are a comprehensive overview of a woman’s risk of developing breast cancer,” says Triola. “These take into account all risk factors and will give women a better indication of what actions and tests they should undergo.”
