Are poor eating habits and other lifestyle factors early in life contributing to an increase in cancer rates at younger ages? According to a recent study conducted by researchers at Harvard T.H. Chan School of Public Health and Brigham and Women’s Hospital in Boston, the number of cancers diagnosed in people under 50 is rising, and early exposure to risk factors may be a key link.
“The results of the study mirror what we’re seeing in the community,” said Dr. Gregory Britt, board-certified hematologist and medical oncologist at Rocky Mountain Cancer Centers. “A study like this is confirmation of what a lot of us have been seeing in our practices. It’s a call to action around screening and awareness.”
The study, which was published in September in Nature Reviews Clinical Oncology, found 14 types of cancer are steadily increasing in younger people in many countries around the world:
- Breast cancer
- Colorectal cancer
- Endometrial cancer
- Esophageal cancer
- Extrahepatic bile duct cancer
- Gallbladder cancer
- Head and neck cancer
- Kidney cancer
- Liver cancer
- Bone marrow cancer
- Pancreatic cancer
- Prostate cancer
- Stomach cancer
- Thyroid cancer
Researchers believe that several lifestyle-related risk factors may be contributing to the increased incidence rate of early-onset cancers, including:
- Consuming alcohol
- Eating highly processed foods
- Lack of exercise
- Sleep deprivation
“The habits you develop in youth carry over into adulthood,” Dr. Britt said. “We’re starting to see the effects of those practices that are starting early in life. Obesity in youth has become a problem. Diet plays a big role, as do sedentary lifestyles.”
Increasing evidence suggests eating a diet high in processed foods may lead to a higher risk of developing certain cancers. A British study found that the consumption of ultra-processed foods (UPFs) is linked to a greater likelihood of developing ovarian and brain cancers. But other food choices that have become common in recent decades may also be contributing to increased cancer cases.
“I think our ‘fast food’ culture is catching up with a lot of people around the globe,” Dr. Britt said. “Fatty diets, less fruits and vegetables, and more processed and red meats are likely prime contributors.” Other dietary factors include consumption of sweetened beverages, low vitamin D intake, and excessive alcohol consumption.
Increased Colorectal Cancers
Of the 14 cancer types identified in the study, eight are correlated to the digestive system, including colorectal cancer. Other studies have also revealed a significant rise in the diagnosis of colorectal cancer in younger people.
The U.S. Preventive Services Task Force (USPSTF) reports that an estimated 10.5% of newly diagnosed colorectal cancer cases occur in patients under 50 years old. In fact, between 2000 and 2016, the number of adults between the ages of 40 and 49 diagnosed with colorectal cancer rose by 15%.
“Diets have been getting worse for decades, and we’re starting to see the effects in the colorectal tract,” Dr. Britt said. The study also revealed that several other risk factors that develop during adolescence and young adulthood likely play a role in early-onset colorectal cancer, including lack of exercise and a sedentary lifestyle, metabolic syndrome, and type 2 diabetes.
The trend of early onset colorectal cancer has become a very serious public health concern that prompted the American Cancer Society to change its screening recommendations for colorectal cancer. In 2018, the age for starting screening dropped from 50 to 45. In 2021, the USPSTF followed suit, also adjusting its guideline to begin screening at age 45. However, many people in the general public, as well as people in the medical community, still abide by the old guidelines.
“I’m still often surprised that patients are not being offered colorectal cancer screening at age 45 for average risk individuals,” Dr. Britt said. “Being on the frontline as a community oncologist, I unfortunately encounter a lot of patients on a routine basis who are in their forties and present with pretty severe colorectal cancers, some of which are stage four upon presentation.”
Additionally, patients at high risk of developing colorectal cancer should begin screening much earlier in some cases, even as early as in their twenties. “Getting awareness out is key,” Dr. Britt said.
Risk Factors for Breast Cancer
According to the study, breast cancer is also being diagnosed at earlier ages. Lifestyle and reproductive factors may play a part in the development of premenopausal breast cancer, including:
- Fatty diet during adolescence and young adulthood
- Alcohol consumption
- Sedentary lifestyle
- Oral contraceptive use
- Menstruating at a younger age
- Nulliparity or older age at first birth
- Never breastfeeding
- Having certain genetic mutations, such as the BRCA gene
- Having a strong family history of breast cancer
“Throughout my career, I have seen patients in their thirties and forties be diagnosed with breast cancer,” Dr. Britt said. “While some are genetically driven, there has been an increase in sporadic cancers, which are likely linked to changes in lifestyles that have occurred over time.”
These include delaying having children until an older age, not having children, and choosing not to breastfeed.
“For breast and other cancers, alcohol consumption is also a key factor,” Dr. Britt said. “Rates of anxiety and depression are probably higher now than they’ve ever been, which can lead to drinking alcohol becoming a part of daily life. I think we will see more alcohol-related cancers in the future.”
By discussing all risk factors with patients, even those that are beyond patients’ control, physicians can raise awareness to ensure women are regularly screened for breast cancer beginning at the appropriate age based on their individual situation. Breast cancer death rates have declined steadily since 1989 due in part to enhanced awareness and screening.
The American Cancer Society recommends women at average risk between the ages of 40 and 44 talk to their physician about whether to begin yearly mammograms, while all women between ages 45 and 54 should get screened every year. Those 55 and older can switch to every other year or continue on an annual basis. However, women at high risk may need to begin mammograms at an earlier age. African American women, for example, are at a much higher risk to be diagnosed with breast cancer in their younger years and with a much more aggressive form.
Awareness and Survivorship Care
In addition to talking to patients about their individual risk factors and what they can do to help prevent cancer, as well as the importance of early detection, physicians can use the study as a springboard for survivorship care as well. Survival rates for many types of cancer have increased, in large part thanks to screening and early detection.
“In many cases, patients with early onset cancers, such as breast cancer, colorectal cancer, uterine cancer, head and neck cancers, and others can be cured,” Dr. Britt said. “But it’s not uncommon for these patients to present years later with another cancer. Once these patients return to normalcy, we want to make sure they are doing everything possible to prevent another cancer in the future.”
Dr. Britt stresses that in addition to talking to patients about making healthy lifestyle changes, it’s also important to counsel them on how to talk to their family members and what their diagnosis might mean for them, as well as to discuss family history with all patients.
“It’s really important to take careful family histories of patients, because genetics play an important role as well, and sometimes that gets overlooked,” Dr. Britt said. “By taking a couple of minutes to talk to patients about their family history, you might find patients that are candidates for genetic testing.”
Dr. Britt is hopeful studies like this will begin to turn the tide. “It’s possible that things will get a little worse before they get better, because societal behaviors take a long time to change. But I think people are beginning to pay more attention and trying to make healthier choices.”
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