You’d be hard-pressed to find someone who’s never worried about their cancer risk ― especially since so many things in our day-to-day lives, from alcohol to the sun’s rays, are known to cause or increase the risk of the disease.
Now, new research conducted by the American Cancer Society has found that millennials and members of Generation X are more likely than older generations to get 17 certain kinds of cancer. The study was published in The Lancet Public Health.
Researchers looked at data from 23,654,000 people ages 25 to 84 who were diagnosed with 34 different kinds of cancer in all. They also looked at data from 7,348,137 people who died from 25 different kinds of cancer in total. The data spanned from Jan. 1, 2000, to Dec. 31, 2019.
Participants were born between 1920 and 1990, and researchers looked at each birth cohort in five-year intervals to consider things like age, environmental factors and lifestyle patterns. Those who were considered Gen X in the study were born between 1965 and 1980, while those classified as millennials were born between 1981 and 1990.
These are the 17 types of cancers that are increasing in Gen Xers and millennials:
- oestrogen receptor-positive breast cancer
- ovarian cancer
- cardia gastric (a stomach cancer)
- small intestinal cancer
- liver and intra-hepatic bile duct cancer in women
- non-HPV-associated oral and pharynx cancers in women
- colorectal cancers
- uterine corpus cancer (endometrial cancer)
- kidney and renal pelvis cancer
- pancreatic cancer
- anal cancer in men
- myeloma (which affects the white blood cells)
- non-cardia gastric cancer (a stomach cancer)
- testicular cancer
- leukemia
- Kaposi sarcoma (a cancer of the blood and lymph vessels) in men
- gallbladder and other biliary cancer
Researchers also found that nine of these cancers – oestrogen receptor-positive breast cancer, colorectal cancers, endometrial cancer, non-cardia gastric cancer, gallbladder and other biliary cancer, testicular cancer, ovarian cancer, anal cancer in men and Kaposi sarcoma in men — are on the rise among millennials and Gen Xers after having declined in older generations.
According to experts, the most alarming increases in Gen Xers and millennials were in kidney, small intestinal and pancreatic cancers in both men and women, and in liver cancer in women. Rates for these kinds of cancer were two to three times higher for people born in 1990 when compared to people born in 1955.
When it comes to cancer deaths, rates increased in cases of liver cancer in women, and colorectal cancer, testicular cancer, gallbladder cancer and endometrial cancer for men and women.
It’s not clear why this is happening, but experts have some theories.
“For a young adult to develop cancer in general ― that would be, if it’s not from an inherited genetic predisposition ― that’s probably from exposures that occurred early in life, because it takes a while for cancer to develop after exposure,” said Dr. William Dahut, the chief scientific officer at the American Cancer Society. Dahut was not affiliated with the study, but he oversees the American Cancer Society’s research arm.
Experts say part of these early-life exposures and experiences that increase cancer risk include underlying conditions like obesity. Dahut pointed out that 10 of the cancers on the list are obesity-related, including colorectal cancer, oestrogen receptor-positive breast cancer and pancreatic cancer.
“When we look at changes in obesity in the last 20 years, and knowing that many of these cancers [are] at least related to obesity, that’s clearly one of the factors,” Dahut said. “There are probably others, too.”
Since 1990, obesity rates have doubled in adults and quadrupled in children around the world, according to research published in The Lancet. Of course, not all of this can be attributed to unhealthy habits. Obesity can also be due to genetics, a metabolic disorder, or a host of systemic issues that make it harder for lower-income people to afford or even get physical access to nutritious food.
“There’s something about our collective environment and diet and lifestyles that is dangerous,” said Dr. Lidia Schapira, a medical oncologist at Stanford Health Care in California who was not affiliated with the study.
To prioritise your health, it’s important to know your personal cancer risk.
“Cancer-based screening guidelines are designed for folks at average risk, including the ones in American Cancer Society,” Dahut said. “But many of the cancers in folks under the age of 50 are in people that have either a strong family history or have a known inherited genetic risk factor for cancer. Particularly, we’re talking about colorectal cancer.”
If possible, you should learn about your family history and consider learning about your own cancer genetics, he said. You can talk to your doctor to learn if you’re eligible for genetic testing, which can alert you to any mutations that put you at heightened cancer risk.
“You may discover that you’ve inherited a gene or a family of genes that puts you at higher cancer risk, and if that’s the case, your screening for cancer should be done very differently,” said Dahut, who added that known exposures like smoking or an HPV infection also put you at higher risk and are important to assess.
Additionally, make sure you have a good health care team. With cancer becoming more common in younger folks, every doctor should take your symptoms seriously.
If you notice persistent concerning symptoms, like rectal bleeding (in the case of colorectal cancer), breast pain (in the case of breast cancer) or abnormal vaginal bleeding (in the case of endometrial cancer), you need to advocate for yourself and talk to a doctor, Dahut said.
“If you’re told by a health provider you’re too young to have a problem, you need to see somebody else,” he said.
It’s also crucial that you take care of your overall health.
While many cancer risk factors are beyond our power to change, we can take proactive steps to manage our health.
“We can’t control some of the exposures that we’ve had in our early life, and we can, hopefully, make it better for future generations by... keeping the environment as clean as possible, by collectively advocating for good, healthy diets for kids, for doing everything we can to send public health messages to lower childhood obesity and obesity throughout the life course,” said Schapira.
This also includes exercise. Official guidelines from the Department of Health and Human Services say adults should get at least 150 minutes of moderate exercise, or 75 minutes of vigorous exercise, per week.
Kids ages 6 to 17 should do an hour of physical activity daily, according to the guidelines. The guidance for children 3 to 5 is a little more loose, but movement and movement-based play are encouraged.
“I think what we all can do is do what we can to strengthen the preventative health messages of ‘healthy diet, healthy environment, getting sleep,’” Schapira said.
This study raises some real concerns.
“The fact that... this will translate into, or is already translating into, more cancers, is certainly cause for concern,” said Schapira.
While the risk of cancer in the Gen X and millennial age groups is still relatively low, the increasing rates are worrisome, Dahut said. “If we’re seeing an increased risk in people in their 30s and 40s, as they age into the time when cancer is more common, this will just only accelerate that number and potentially can reverse some of the gains we’ve had in decreases in cancer mortality.”
It’s worth noting that there are some positives associated with this study, too. “In some cases, we actually see that we’ve been successful in lowering cancer incidence, for instance, with HPV vaccination,” Schapira said. “So that is a win.”
Additionally, Dahut noted that the overall risk of cancer in younger populations remains low.
But being aware of the trends in cancer diagnoses, and of your own risk, can only help you protect your future health.