Appendix cancer is one of the rarest types of cancers, with cases generally limited to older adults, if ever, in cancer clinics.
But a new study in the journal Annals of Internal Medicine has found that the number of appendix cancer cases has increased dramatically — specifically in people born after the 1970s.
While the number of people getting appendix cancer is still very low — just a few people per million get the disease per year — the incidence has at least tripled, or even quadrupled, in younger generations, compared with those born in the 1940s.
What's concerning health experts is that appendix cancer is part of a trend of rising rates of cancers in young adults.
Colorectal, testicular, breast, ovarian, pancreas cancers are among many types of cancers rising in the same age group.
It's in every region of the world, too. A study in the journal The Lancet found that early-onset colorectal cancer incidence rates were rising in 27 of the 50 countries and territories that researchers examined.
The major health challenge for the future is that young people may carry this enhanced cancer risk with them into older age, potentially hampering significant progress in treating cancers over the past decades.
"This shift has left many experts puzzled and searching for answers," wrote Justin Stebbing, a biomedical scientist at Anglia Ruskin University, UK, in the Conversation.
What is causing the rising cancer rates among young adults?
The short answer is that researchers do not know what is causing more young people to develop cancer today than fifty years ago.
While they understand that certain risk factors may influence such diseases, they don't fully understand how or whether they directly cause cancer.
Smoking, obesity and diet are all well-established risk factors, but how they impact the disease is not well-known.
Scientists have ruled out genetic factors, as they say this would not explain why it is happening in any particular age group. Their best guess now is that people in born in the 1990s were exposed to chemicals and other environmental factors that were not around before then.
For example, some studies say exposure to microplastics and "forever chemicals" in the environment may cause more cancers.
Other studies link a rise in early-onset cancers with changes in the gut microbiome, perhaps caused by dietary changes, or increased antibiotic use.
And some studies link the so-called "Western diet" and rising obesity rates with early-onset cancers. The Western diet is characterized by a high intake of ultra-processed foods and sugar, while lacking fruit, vegetables, and fiber.
However, until now, such studies have only ever provided correlative links — they may be an associated risk or contributing factor, but not the cause of cancers, especially in young people.
How to reduce your risk of getting cancer
The best advice is to focus on prevention and awareness. Medical experts advise lifestyle changes to reduce exposure to things that could cause cancer in young people.
"Maintaining a healthy weight, eating a balanced diet rich in fruit, vegetables and whole grains, and staying physically active are all steps that can lower the risk of many types of cancer," wrote Stebbing.
Cancer Research UK — just one of many national bodies in the world — has these tips on how to reduce the risks of getting cancer:
Have a healthy balanced diet rich in fresh and unprocessed foods
Enjoy the sun safely with sunscreen — known as "slip slop slap" in Australia
