NEW YORK (CBSNewYork) – There are some troubling colon cancer statistics out Thursday from the American Cancer Society.

Colon and rectal cancer cases are on the rise in young adults, and doctors are not sure why.

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Colorectal cancer is the second most common cause of cancer death in the United States, CBS2’s Dr. Max Gomez reported.

Thanks to better screening – mostly colonoscopies – the incidence in people 65 and older has been dropping rapidly. But those improvements have been somewhat offset by increases in those younger than age 50.

At 47-year-old, Sandy Kyrkostas was diagnosed with stage 4 colon cancer that had spread to his liver.

“When they tell you and your wife when you have two young children ‘get your life in order,’ that’s a scary, that’s a scary point,” he said.

With no family history and symptoms that started only weeks before his diagnosis, cases like his are on the rise.

The American Cancer Society says colorectal cancer among people under 50 has shot up 51% since 1994.

The reasons for the increase are unclear.

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“There are multiple hypotheses floating around as to what it is, whether it has to do with diet, exercise, antibiotic use. There are multiple theories, but no one has really found the Holy Grail as to what’s actually causing this increase in young people,” said Dr. Michael Buckstein of the Mount Sinai Health System.

That’s why the American Cancer Society issued new guidelines two years ago recommending people start colorectal screening at age 45 instead of 50, to bring screening benefits to that younger population that’s increasingly at risk.

Even with the lower age, some young people will not be screened and will develop colorectal cancer. So you have to be aware of your body’s signals.

“Every person should be a little bit more aware, him or herself, to see a doctor if something doesn’t feel quite right with their bowel movements. If they’re seeing blood or black in their stool,” Dr. Buckstein said.

And the same goes for doctors who dismiss who may dismiss some symptoms because the patient is young.

“Primary care providers should be more aware that what they might be seeing, what they think is perhaps hemorrhoids, is in fact an early stage cancer,” Dr. Buckstein said.

Another troubling consequence of the young trend in colorectal cancer is that because doctors and patients may both not take symptoms seriously, young people are presenting with more advanced stage cancer.

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And that’s really tragic, because colorectal cancer is usually curable if found at an early stage.