GI cancer

High rates of colorectal cancer in under 50s show need to lower screening age

Growing evidence for an increasing incidence of colorectal cancer in young people supports calls to lower the age of FOBT screening from 50 years to 45 years.

A Gold Coast study, published in the ANZ Journal of Surgery, reviewed 557 patients under the age of 50 years who received a colonoscopy during the five years 2013 to 2017.

Patients were referred mostly for PR bleeding (35.5%) or other GI symptoms (18.5%). A further 15.3% were scoped as part of high-risk surveillance.

The study found 21.5% of colonoscopies identified pathology – 1.9% had malignancy, 14.4% had tubular adenoma, 2.7% had tubulovillous adenoma and 5.7% had sessile serrated adenoma.

Of the patients diagnosed with colorectal cancer, all were symptomatic and had stage 3 (36.4%) or stage 4 (45.5%) disease. One patient was diagnosed with hereditary non-polyposis colorectal cancer.

The study, led by colorectal surgeon Dr Michael von Papen, said their findings suggested that red flag symptoms, such as PR bleeding, should not be ignored.

“In young patients some have advocated for a flexible sigmoidoscopy in the investigation of PR bleeding. It is argued that in young patients with no other risk factor, there is a low risk of proximal cancer, hence flexible sigmoidoscopy will have a low risk of missing significant lesions. It also offers a quicker and safer procedure that does not require complete bowel preparation.”

“However, in our study 36.4% of cancers were right sided. This is consistent with findings by Koh et al. and reinforces the importance of complete investigation with colonoscopy rather than flexible sigmoidoscopy.”

“All patients with symptoms or strong indication should be referred for specialist assessment for colonoscopy.”

They said their findings also contribute to the evidence for lowering the NBCSP screening age for CRC.

“Concerningly, patients in our study diagnosed with CRC had high stage disease at diagnosis,” they said.

“Delays in diagnosis could be due to a lack of available screening in younger populations and could be seen to support lowering of the screening age, or due to delays in proceeding to colonoscopy due to an impression that diagnosis is unlikely.”

The American Cancer Society lowered the age to begin average-risk screening from 50 to 45 years in its 2018 update of CRC screening guidelines.

Colorectal surgeon and Bowel Cancer Australia director Associate Professor Graham Newstead told the limbic that 1 in 10 new cases now occur in Australians under 50.

“A lower start-age for bowel cancer screening could be part of the solution, together with ways to reduce risk through diet and lifestyle changes, as well as improved symptom awareness among both patients and GPs.”

“It may be ambitious, but we should be able to increase screening participation rates for people over 50 and also begin to screen those aged 45-49.”

Gastroenterologist Dr Cameron Bell, a contributor to Clinical practice guidelines for the prevention, early detection and management of colorectal cancer, told the limbic that symptoms, especially PR bleeding and abdominal pain in younger people should not be dismissed as “just haemorrhoids”.

However lowering the screening age below 50 years was unjustifiable, he said.

Instead there should be more focus on improving NBCSP participation rates in 50-74 year olds which remain at a low 42%.

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