Flexible sigmoidoscopy may be the most practical response to a steep rise in young onset colorectal cancers, Australian clinicians say.
With new figures showing rates of colon cancer rising as much as 9% annually in the under 30s, early diagnosis may be best achieved by immediate investigation with flexible sigmoidoscopy rather than waiting for colonoscopy, Queensland researchers suggest.
In their study of colonoscopy findings in 224 young patients under the age of 35 in 2017-2018 they found that 1% (two patients) had colorectal cancer. Both had been symptomatic (rectal bleeding and anaemia), and had stage IIIb disease, findings which concurred with other studies of young onset colorectal cancer.
The location of the cancers in the recto-sigmoid colon was also in agreement with other larger studies of young onset colorectal cancers that found almost 90% of young patients had left-sided colon or rectal cancer and 66% had advanced disease, the study authors noted
With evidence showing most young patients with colorectal cancer are symptomatic at the time of diagnosis, the delays in diagnosis may be due to low suspicion of malignant disease in this age group, the authors concluded.
“The overall increased rate of malignancy warrants early investigation for young patients presenting with any warning symptoms and our findings should promote increased awareness and the insistent search of symptoms in otherwise young, low-risk patients,” said study investigator Dr Rebecca Olivo, of the Department of Surgery, Caboolture Hospital.
“Given that increased age tends to correlate with more proximal colorectal cancers, offering flexible sigmoidoscopy to symptomatic patients rather than awaiting colonoscopy may result in earlier diagnosis,” she added.
“Provided the institution and variable wait times for colonoscopy, offering flexible sigmoidoscopy in a clinical setting may confer significant benefit in younger patients,” the authors concluded.
Two other studies published this week show steep rises in incidence of colorectal cancer among young people.
A study of 144 million people aged 20–49 years from 20 European countries showed colorectal cancer incidence increased by 7.9% per year among people aged 20–29 years from 2004 to 2016, with rates of colon cancer increasing by 9.3% annually in this age group.
Published in Gut, the study showed colorectal cancer incidence increased by 4.9% per year in the 30–39 years age group and by 1.6% per year in the 40–49 years age groups, respectively.
A separate study in Lancet Gastroenterology and Hepatology showed that in the 10-year period up until 2014, the incidence of colon cancer in people aged 0-49 years increased significantly each year in Australia and New Zealand (by 2.9%), Denmark (3.1%) and the UK (1.8%).
Significant increases in the incidence of rectal cancer each year were also noted in this age group in Australia (2.6%), Canada (3.4%) and the UK (1.4%).