The epidemic of colon cancer among young people is increasingly becoming the focus of research and alarm — but there is another form of the deadly disease that is rising even faster. 

Researchers from Vanderbilt University say appendiceal cancer, also known as appendix cancer, which killed actor Adan Canto at 42, is now surging among people under 50 years old.

A new study found Millennials (people 29 to 44) have the highest risk of developing the cancer, with rates among those in their 30s now up to seven times higher than they were in the 1940s — and much greater than the five other age groups included in the research. 

Despite the surge, the cancer remains extremely rare, the researchers said, with only around 3,000 cases diagnosed every year in the US.

It is not clear how many people die from the disease, but officials say if it is caught early between 67 and 97 percent of patients live longer than five years.

But appendiceal cancer is concerning because it is often dismissed in the early stages for other, more benign conditions, such as food poisoning or bowel problems.

It’s not clear what might be causing the cancer to become more common, but researchers said this could be linked to a new ‘environmental exposure’ that older generations weren’t exposed to.

Adan Canto, pictured above in 2016 participating in a triathlon in Malibu, California, died from the cancer at the age of 42 following a private battle with the disease

In the study, published in The Annals of Internal Medicine, researchers analyzed data from the SEER database — which collects data on cancer cases in the US.  

They extracted data on 4,858 patients diagnosed with appendiceal cancer between 1975 and 2019, and split them into birth cohorts.

Incidence rates by group were adjusted to account for age differences.

Rates per 100,000 people were then compared to those for people born between 1941 and 1950, who represented the mid-point of the birth cohorts.

Overall, they found Millennials — those born between 1981 and 1996 had an up to seven-fold increased risk of being diagnosed with the cancer compared to the Silent Generation, or those born between 1928 and 1945.

Those in Generation X, born between 1965 and 1980, had an up to two-fold higher risk of developing the cancer.

And Baby Boomers, those born between 1946 and 1964, had an up to 118 percent higher risk of suffering from the disease.

At the other end of the scale, people in the Greatest Generation – born between 1901 to 1927 – had an up to 80 percent lower risk of suffering from the disease when they were alive.

Researchers wrote in the report: ‘A birth cohort effect corresponds to population shifts in environmental exposures that may increase risk for generations now entering mid-adulthood.

‘The trends observed in our study may, in part, be explained by a burgeoning recognition over this past decade that appendiceal cancers are a biologically-distinct malignancy from colon adenocarcinomas.

‘Well established risk factors of colon and rectal cancer, including early-life experiences, environmental exposures, anthropometric and lifestyle factors (for example, obesity, diet, alcohol, and tobacco), as well as the interaction between these factors and genetic features may also contribute to appendiceal cancer.’  

Rebecca Hind before cancer, September 2015 at work in the Ogwen Valley, The Outward Bound Trust

The appendix is a small pouch located on the side of the colon. Its exact function isn’t known but researchers say it may help the immune system.

In cancer in this organ, cells start to divide uncontrollably — with early symptoms such as bloating and abdominal pain often dismissed as digestive complications.

In many cases, it is only when doctors remove the appendix suspecting appendicitis, or inflammation of the appendix, that the cancer is diagnosed.

If it is caught in the early stages, patients have a 67 to 97 percent likelihood of surviving more than five years. But for those whose cancer is not caught until it has spread, survival rates tend to be lower. 

Patients who have suffered from the cancer also include 39-year-old Rebecca Hind, from Cumbria, UK, who was diagnosed at the age of 33 years.

She started suffering from severe stomach pain after a Christmas party at work in 2018, which she initially put down to food poisoning.

But when they persisted for eight weeks, she went to doctors — who diagnosed the cancer.

Hind has now had surgeries to remove 13 of her organs, more than eight grueling rounds of chemotherapy and medically-induced menopause to beat the cancer.

The above graph showed the appendiceal cancer rate by birth cohort and age rate. The researchers said it shows that appendiceal cancer is becoming more common

The above graphic shows the symptoms of appendiceal, or appendix, cancer. Doctors are detecting a mysterious rise in cases of the disease

The uptick in appendix cancer, although from a very low base, appears to be faster than that for colon cancer — with cases rising 71 percent among 30 to 34-year-olds over the two decades to 2020.

Among adults aged 20 to 39 years old, estimates suggest cases have risen by two percent per year on average.

In Europe, data shows between 2005 and 2016, colon cancer cases rose by eight percent per year among those aged 20 to 29 years old.

In those aged 30 to 39 years old, cases rose by five percent per year overall. And among those aged 40 to 49 years, they rose by two percent per year on average.