The Summary
- A new report shows that cancer cases are shifting from men to women in the United States and from older to younger adults.
- For the first time, cancer rates in women ages 50 to 64 have surpassed those in men, the report found.
- The reasons for the trend aren’t known — doctors raised factors such as alcohol consumption, lack of exercise and diets high in ultra-processed foods as some potential factors.
Men in 1992 had a 1.6 higher risk than women of being diagnosed with cancer. But as of 2021, the risk was almost equal, according to a report published Thursday by the American Cancer Society.
The report highlights that the cancer burden is shifting from men to women in the United States — narrowing the gap between the sexes — as well as from older to younger adults.
For the first time, cancer rates in women ages 50 to 64 have surpassed those in men, the report found. Women under age 50 also had an 82% higher cancer rate in 2021 than men the same age, compared with a 51% higher rate in 2002. The trend may be in part because of rising rates of breast and thyroid cancer in younger women, along with declining rates of melanoma, non‐Hodgkin lymphoma and prostate cancer in men under 50 over the roughly 20-year period.
“Here’s the bottom line: We’ve got more cancers overall, particularly those in younger people, and particularly those in women,” said Dr. Arif Kamal, chief patient officer at the American Cancer Society.
“Ten years ago, men were 50% more likely to get cancer than today,” he said. “Today, it’s almost close to even, and that’s a combination of two things: less cancers in men but, importantly, more cancers in women.”
The report also found that although cases of lung cancer declined overall from 2012 to 2021, the decrease was slower in women — most likely because women were slower to take up heavy smoking and slower to quit, said Dr. William Dahut, chief scientific officer for the American Cancer Society.
“For the first time, if you’re a woman under the age of 65 you have a greater chance of developing lung cancer than a man,” Dahut said on a call with reporters.
Overall, the report predicts that 2,041,910 cancer cases will be diagnosed this year, slightly more than last year’s prediction.
More cancer cases doesn’t mean more deaths, however: The mortality rate from cancer fell 34% from 1991 to 2022, the report says. It attributes the positive news to earlier detection of some cancers, better treatment options and decreases in smoking.
Dr. Neil Iyengar, an oncologist at Memorial Sloan Kettering Cancer Center, said part of the reason is immunotherapy treatments — an approach that uses a person’s immune system to fight disease. Genetic sequencing has also helped doctors better match patients with the appropriate treatments, he said. And new antibody drugs have helped increase the effectiveness of chemo while reducing side effects.
As for why the cancer burden has shifted more to women and younger people, it’s difficult to pinpoint one particular cause, said Dr. Jennifer Litton, vice president of clinical research at MD Anderson Cancer Center in Houston.
“If anyone says, ‘I know it’s because of X, Y or Z,’ it’s really hard to tease that out from this big swath of data,” said Litton, who wasn’t involved in the report.
Several doctors suggested the trend might have to do with lifestyle factors such as alcohol consumption, lack of exercise and diets high in ultra-processed foods, all of which increase cancer risk.
“Ten years ago, we thought that cancer was the product of either bad genetics or bad luck. And now we know that about half of cancers are the product of lifestyle,” Kamal said. “There are 13 different cancers associated with being overweight. There are seven different cancers associated with alcohol intake.”
Iyengar said obesity “is now the major cancer risk factor of our time.” According to the American Cancer Society, excess body weight causes about twice as many cancer cases in women as in men. Younger women in particular have recorded a rise in endometrial cancer, which is strongly linked to obesity.
“Obesity-related cancers are showing up more in people now who are 40s and 50s versus their parents who are 60s and 70s,” Kamal said. “We know that, generationally, people who are in their 60s and 70s grew up being a bit more active, grew up not eating ultra-processed foods as much.”
Another potential explanation, doctors said, could be exposure to cancer-causing substances in the environment, such as radon and air pollution. Radon — a radioactive gas found in some homes, particularly in the Midwest — is the leading cause of lung cancer in people who have never smoked.
“Probably what we’re seeing here is the shift in environmental exposures is catching up with the cancer statistics,” Iyengar said.
Doctors emphasized that lots can be done to prevent new cancer cases, however.
“The average person knows the importance of healthy eating and active lifestyle to reduce heart disease, diabetes, kidney disease and high blood pressure. Now we really need to be talking about the clear connection between those behaviors and cancer,” Kamal said.
