Shifting Patterns in Breast Cancer Risk in Caribbean Women
Article Summary
- Sylvester Comprehensive Cancer Center leads a major global effort to understand risk factors for breast cancer in the Caribbean population, which is disproportionately affected by the disease.
- The latest study examines reproductive risk factors, showing shifts over time in pregnancy rates and age at a girl’s first period.
- These shifts are linked to earlier age at diagnosis and emphasize the need to target other modifiable risk factors.
Breast cancer takes a major toll on Caribbean women. Patients in the region are commonly diagnosed at a younger age than in the U.S., and they have one of the highest mortality rates in the world from the disease.
Researchers at Sylvester Comprehensive Cancer Center, part of the University of Miami Miller School of Medicine, are investigating the drivers of breast cancer in Caribbean women in collaboration with a network of colleagues across the region.
Breast Cancer and Childbirth
In a new study, the researchers explored shifting patterns in risk factors related to reproductive health. The findings show that women more recently diagnosed with breast cancer have had fewer babies than previous generations, and they experienced their first periods at an earlier age.
Having an earlier age for the first period, known as menarche, and giving birth to fewer children are known to increase the risk for breast cancer.
“These changes are compounding the already known increased risk for developing these aggressive diseases,” said Sylvester researcher Sophia George, Ph.D., who was raised in Dominica, a Caribbean country.
The findings put a renewed emphasis on public health messages targeting modifiable risk factors for breast cancer in the region, including diet and exercise, said Dr. George, who is an associate professor in the Division of Gynecological Oncology at the Miller School. Dr. George is the corresponding author of the study.
The findings also highlight how socioeconomic development and accompanying lifestyle changes influence reproductive patterns and breast cancer. The research was published by JAMA (Journal of the American Medical Association) Network Open.
Breast Cancer Risks for Caribbean Women
The research is part of a larger endeavor launched by Sylvester examining risk factors for breast and ovarian cancer in Caribbean women, the Caribbean Women’s Cancer Study (CWCS).
The new study enrolled 995 women diagnosed with invasive breast cancer as part of the CWCS in The Bahamas, Barbados, Cayman Islands, Dominica, Haiti, Jamaica and Trinidad and Tobago. The researchers analyzed data from four cohorts born in different decades: before 1950, from 1950 to 59, 1960 to 69, and on or after 1970.
With each cohort, women diagnosed with breast cancer had a lower age at menarche, fewer pregnancies and fewer full-term pregnancies. Only 33% of women born before 1950 experienced menarche at age 12 years or younger, whereas 57.9% of those born after 1970 did.
It’s absolutely necessary for us to understand the population that we serve.
—Dr. Sophia George
Lower birth rates and earlier menarche, which are thought to be influenced at least partly by diet, go hand in hand with socioeconomic growth. These two factors also increase the number of years a woman is exposed to estrogen and other hormones that promote breast cancer.
Similarly, in the new study, women whose menarche occurred at age 12 or younger were diagnosed on average at age 45 with breast cancer, compared to age 49 in women whose menarche occurred at age 15 or older. Women who had never given birth were also diagnosed at an earlier age than women who had experienced three or more full-term pregnancies.
While there were differences among countries, the data overall also showed a trend towards a decreased age at breast cancer diagnosis.
Public Health Implications
The findings add urgency to public health interventions designed to reduce breast cancer risk, said the researchers.
“Proactive interventions in the areas of lifestyle, exercise patterns, obesity and diet, including alcohol intake, need to be pursued to determine whether these shifts in reproductive patterns could be modified to benefit these patients,” said Jameel Ali, M.D., a study collaborator at St. James Medical Complex, North Northwest Regional Health Authority, Port-of-Spain, Trinidad and Tobago.
The impact of the new research on the public health sector will be “significant,” added collaborator Hedda Dyer, M.B., Ch.B., at the Ross University School of Medicine, St. Michael, Barbados.
“This study further emphasizes the importance of research in crafting local public health policies. As we continue to see an increase in research focused on the Caribbean basin, this article will certainly move the needle forward,” said Dyer.
Power of Collaboration
Limitations of the study include assessment only of women who survived breast cancer at the time of enrollment and the lack of a control group of women unaffected by breast cancer, said Dr. George.
Meanwhile, CWCS research will continue to assess risk factors for breast cancer in the Caribbean population. African women and women of African ancestry, the most common ethnic group in the Caribbean, similarly suffer disproportionately from the disease, noted Dr. George. A CWCS study previously showed that genetic causes of breast cancer are common in the Caribbean population.
Other researchers at Sylvester and the Miller School involved in the study include:
• Maurice Junior Chery, M.D.
• Priscila Barreto-Coelho, M.D.
• Alexandra Diaz-Barbe
• Leah V. Dodds
• Patricia P. Jeudin, M.D., associate professor in the Division of Gynecologic Oncology at the Miller School
• Matthew Schlumbrecht, M.D., M.P.H., professor of gynecological oncology at the Miller School
• Isildinha M. Reis, Ph.D., research professor of public health science at the Miller School
• Judith Hurley, M.D., from the Division of Medical Oncology, who initiated the CWCS
First author Alex Sanchez-Covarrubias, M.D., M.S., a Ph.D. student in Dr. George’s lab, said that the study will have an impact on each community studied and beyond. There are about 45 million people in the Caribbean. Millions have emigrated outside the area. The findings are also relevant for the large Caribbean population in South Florida, said Dr. George. Research that affects the local community is a major emphasis at Sylvester.
“It’s absolutely necessary for us to understand the population that we serve,” she said.
Tags: African Caribbean Cancer Consortium, breast cancer, Dr. Isildinha Reis, Dr. Judith Hurley, Dr. Matthew Schlumbrecht, Dr. Patricia Jeudin, Dr. Sophia George, USNWR Oncology