Women with breast cancer who are 35 and under are at the greatest risk of any age group for their cancer to spread.
That’s what researchers said at the sixth International Consensus Conference for Advanced Breast Cancer while discussing their study on the concept.
The first global study of its kind, the research is a meta-analysis of 400 studies and found that the risk of breast cancer spreading to other body parts ranges from 6% to 22%. Altogether, the studies contained data on tens of thousands of women across North and South America, Europe, Africa, Asia and Oceania. For women 35 and younger, the risk is 12.7% to 38%, compared to 3.7% to 28.6% for women age 50 and older, reported The Guardian
“The data shows that people diagnosed with primary breast cancer aged 35 years or younger have the greatest chance of developing secondary breast cancer. The study also highlights that the size of the tumor, the type of breast cancer and the length of time since primary diagnosis can impact a person’s risk,” said Kotryna Temcinaite, senior research communications manager at the charity, Breast Cancer Now, in a statement.
Most women are diagnosed when cancer is confined to the breast or has only spread to nearby tissue. Secondary breast cancer can develop many years after an initial cancer diagnosis is made and sometimes does not spread but comes back in a different part of the body several years after initial treatment has ended. Treatment at this point becomes much harder and the risk of dying is higher, according to Dr. Eileen Morgan, of the International Agency for Research on Cancer (IARC), who presented the study.
"Historically, cancer registries have not routinely collected information on cancer recurrence and no guidelines to define these have been established," she told HCB News. "We plan to investigate how studies have previously defined metastatic recurrence to help inform cancer registries on how this can be done."
Patients with larger tumors when initially diagnosed are also at increased risk, as are those with specific forms of the disease. For instance, patients diagnosed with type luminal B have a 4.2% to 35.5% risk of their cancer spreading, compared to those with luminal A cancer, who have a 2.3% to 11.8% risk.
The risk is broad, according to Morgan, and can be influenced by a whole range of factors, including initial treatment, subtype of cancer and at what stage patients are diagnosed. While a firm reason has not yet been established, she says that women under 35 may have a higher risk of metastasis “because younger women have a more aggressive form of breast cancer or because they are being diagnosed at a later stage.”
Little is known about the risk of secondary breast cancer and where the disease spreads to other parts of the body and becomes incurable. Through their study, the researchers have provided the first reliable estimate of how many breast cancer patients may develop metastasis in contemporary cohorts and identify groups who are at higher risk. In the second part of their study, they will explore better ways in which cancer registries can collect adequate data about relapses to have a better idea of the number of patients in each country with metastatic cancer, said Dr. Shani Paluch-Shimon, a member of the Scientific Committee for ABC 6, director of the breast unit at Hadassah University Hospital in Israel, who was not involved with the research.
“It will help us identify at-risk groups across different populations and demonstrate how the disease course is changing with contemporary treatments,” she said. “It will also help us understand what resources are needed and where, to ensure we can collect and analyze quality data in real time, as this is key for resource allocation and planning future studies.”
In addition to age being a determinant in whether breast cancer spreads, certain races are also at an increased risk of developing the disease in the first place. Black women have higher rates of aggressive cancers at younger ages than white women, with treatment for those types not as effective. While current guidelines recommend women start getting mammograms biennially between 50 and 74, a recent study says that performing mammograms on Black women starting at age 40
may lead to more equitable survival outcomes for them, compared to white women who begin screening at 50.
Researchers at the University of Michigan who carried out the study found that initiating mammograms for Black women at 40 reduced mortality the greatest and decreased mortality disparities by 57%. “One of the major issues in health equity research is that disparities have been described for decades, but there has been less attention on actually rectifying disparities. Funding and other resources are needed to support research to address disparities,” said lead author Dr. Christina Hunter Chapman, adjunct assistant professor in the department of radiation oncology at the University of Michigan. She adds that policy changes on societal levels are also required.
Morgan says that understanding the factors that influence rates of recurrence can show what treatments have lower or higher risk of recurrence. She and her colleagues at the IARC are working closely with a number of cancer registries and collaborators at NCI to develop guidelines for the collection of breast cancer recurrence data.