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Breast cancer is the most common cancer diagnosis in Minnesota, followed by prostate, lung, and colorectal cancer. Each of those three latter diagnoses leads to more total deaths each year than breast cancer. But among Minnesotan women, breast cancer remains the second leading cause of cancer death, behind lung cancer. According to the American Cancer Society, there will be approximately 5,220 new cases of breast cancer diagnosed in the state this year.
“Minnesota is on par with most of the other states with regard to its rates of breast cancer,” says Dr. Sandhya Pruthi, medical director for the Division of Health Education and Content Services at Mayo Clinic. Dr. Pruthi has been the principal investigator for several nationwide multicenter breast cancer chemoprevention trials and engages in cancer education for both patients and health care providers.
Mayo Clinic’s Comprehensive Cancer Center has advanced novel treatments, such as CAR-T cell therapy. At the University of Minnesota, the state also boasts some of the nation’s leading cancer researchers, and the institution regularly attracts grants and funding from the federal government for research projects and the development of new drugs, including new immunotherapies that turn a person’s own immune system against tumors.
New screening guidelines encourage earlier mammograms
In May 2023, the United States Preventive Services Task Force (USPSTF) released updated guidelines urging women to start getting screened for breast cancer every other year beginning at age 40. This marked a change from previous guidelines, which suggested biennial mammograms starting at age 50, with individual choice for younger women based on personal risk.
Other organizations, including Mayo Clinic and the American Congress of Obstetricians and Gynecologists, recommend annual mammograms for women beginning at age 40, while the American Cancer Society recommends annual screenings starting at 45.
Photo by Bill Bartlett
Why the variation among recommendations? “Part of it is how the various organizations weigh risks and benefits, as well as the cost effectiveness of different recommendations,” explains Dr. Anne Blaes, a professor in the Division of Hematology and Oncology at the University of Minnesota. “As an oncologist, I’m happy that the USPSTF has changed their recommendations.”
The benefits of earlier and more frequent screenings are intuitive: Identifying cancer earlier leads to a better prognosis. “When cancers are identified through a screening modality [such as a mammogram], they tend to be more localized and at an early stage,” Pruthi notes. Cancers detected because of a lump or other symptoms are referred to as “interval cancers,” as they’re found in the interval between screenings. These tend to be more aggressive and have worse outcomes, and occur more often when there are longer gaps between mammograms.
Studies have shown that regular mammograms help reduce mortality from breast cancer. Both Pruthi and Blaes note that breast cancer diagnoses are increasing in younger women, with one in six breast cancers occurring in women in their 40s. And according to the American College of Radiology, three out of four women diagnosed with breast cancer have no family history of the disease and are not considered high risk.
Younger women tend to have more dense breast tissue, which can mask tumors. “Having young women with dense breast tissue have annual mammograms is helpful because it’s easier to see if something has changed from one year to the next,” Pruthi says. “I say to my patients, ‘If you’re in your 40s and you have dense breast tissue, I’d rather you be screened every year than every other year.’”
Early, regular screenings may be particularly important for Black women, who face greater breast cancer mortality risk than their white, Asian, and Hispanic counterparts. Research has shown that the rate of breast cancer before age 45 is higher among Black women than white women, and at every age, Black women are more likely to die from breast cancer.
“Black women tend to have more aggressive tumors, even at younger ages,” Pruthi says. “Black women should be screened beginning at age 40, and if they have a family history of breast cancer, they may actually want to start in their 30s.”
However, frequent mammograms also have downsides. They can lead to false positive recalls, in which women are recommended to have additional imaging or biopsies, which reveal no cancer. “That can cause added expense and be really stressful for patients,” Blaes says. Radiation from imaging alone can also lead to increased cancer risk, according to the National Cancer Institute.
Rates of false positive recalls go down as women age, partly because breasts become less dense after menopause (making tumors easier to spot) and partly because previous screening images are often available for comparison.
Screenings can also pick up pre-cancerous lesions. These areas may never turn into invasive cancer but may nonetheless inspire women to pursue aggressive treatments that can affect quality of life. “Many patients will tell you, ‘I’m not comfortable just watching that,’” Blaes says. “Three large national clinical trials are currently assessing surgery versus observation in this subset of women.”
Blaes suggests talking to your primary care doctor about your family history and personal health history to assess your risk and determine the best screening schedule for you.
Courtesy of Mayo Clinic
Managing risk amid rising rates
As breast cancer diagnoses rise in younger women, experts point to several hypotheses for the cause. “Is some of it environmental? Is it related to the fact that we have a more overweight population and weight is associated with breast cancer? There’s ongoing research, but I don’t think it’s one simple thing,” Blaes says.
In September 2021, the University of Minnesota was awarded a grant of approximately $2.1 million from the National Cancer Institute (NCI) to investigate environmental exposures to radon, Per- and Polyfluoroalkyl Substances (PFAS), and glyphosate, a widely used herbicide. These chemicals of concern are suspected risk factors for certain cancers.
With additional support from the Masonic Cancer Center, UMN Medical School, and UMN School of Public Health, the NCI grant is funding a study at the University of Minnesota called the 10,000 Families Study. “It’s a collaboration between epidemiologists and cancer prevention researchers looking at exposures and cancer development,” Blaes explains. The study is actively recruiting families across Minnesota, aiming to attract people from a diverse range of ethnicities, ages, races, and geographical locations around the state. Researchers will follow participants over time and track how genetics and environmental exposures affect long-term health outcomes. (Visit 10kfs.umn.edu to learn more about eligibility.)
In the meantime, there are known ways to reduce one’s personal risk. While some risk factors, such as age and genetic mutations, aren’t modifiable, there are plenty of others that are. “Many of the younger women getting breast cancer don’t even have the hereditary BRCA mutation. They had their babies young and breastfed them, which are common risk-reducing factors. So I wonder about lifestyle,” Pruthi says.
Obesity and alcohol use are established risk factors for breast cancer, as is lack of physical activity. “I counsel my patients about healthy weight and healthy diet. Research shows that the Mediterranean diet does reduce breast cancer risk,” Pruthi says. Regular exercise (at least 150 minutes per week of moderate-intensity activities such as walking or jogging) and limiting alcohol intake to one or fewer drinks per day are also protective.
Pruthi notes that 75% of breast cancers are hormone-dependent tumors, so managing hormones is another important element in reducing risk. The question of how hormone replacement therapy (HRT) for menopausal women affects breast cancer risk has been contested in recent years. The Women’s Health Initiative (WHI) observational study suggested HRT was associated with an increased risk of breast cancer, but the average age of diagnosis among women in the study was 60—well after the average age of menopause (51, according to Mayo Clinic).
“I tell women if they are at average risk [for breast cancer] and are experiencing severe quality of life issues during their menopausal transition, then short-term HRT for three to four years is fine to use. As soon as we start getting to age 55 or 56, we need to taper off to avoid contributing to the higher-risk, hormone-dependent type of breast cancer,” Pruthi says.
Blaes agrees: “If you need HRT when you first go into menopause, it’s appropriate, but you want the lowest dose possible and for the shortest period of time.”
Supporting survivors
According to the American Cancer Society, the combined five-year survival rate for all stages of breast cancer is 91% and rising, thanks to constant advances in treatment. Even triple-negative breast cancer, one of the most aggressive types, is becoming more treatable. Clinical trials at the University of Minnesota tripled treatment response rates for this type of breast cancer by using immunotherapy in combination with chemotherapy. “That’s phenomenal in terms of curing a larger number of patients,” Blaes says.
But even after being cured, breast cancer survivors often need ongoing support. “People can be at risk for things like changes in muscle mass and bone health, or neuropathy from chemotherapy drugs,” Blaes says. Some may also experience heart complications, mental health challenges, or menopausal symptoms such as hot flashes, vaginal dryness, and bone and muscle aches..
The University of Minnesota has a cancer survivorship clinic and long-term follow-up clinic that help survivors navigate these challenges. They also offer webinars and individual support to help survivors learn how to improve sleep, manage anxiety and depression, stay physically active, eat a healthy diet, quit smoking, and optimize blood pressure and cholesterol.
Here, too, research promises to unlock new advances in quality of life. Supportive care and survivorship trials at the University of Minnesota are looking at everything from cannabis use among cancer survivors to the cardiovascular impacts of cancer treatments to the cancer experience in underserved and minority populations.
Thanks to the efforts of Minnesota’s leading researchers and clinicians, breast cancer outcomes should continue to improve in our state and beyond.
