The number of young adults with bowel cancer is rising at an alarming rate in England, according to a study led by researchers from the University of Bristol, Bristol, UK, which included over 56,000 patients with diagnosed bowel cancer.
In the study, ‘Demographic trends in the incidence of young‐onset colorectal cancer: a population‐based study’, published in the in the British Journal of Surgery, researchers used NHS data from over four decades to chart the trend of bowel cancer in young adults in England. The target population comprised all adults in England between the ages of 20 and 49 years who were diagnosed to have colorectal cancer in the study period 1974 to 2015.
They carefully analysed the demographic changes in the incidence of colon cancer among adults under the age of 50 years and reported that the most persistent upward trend in incidence was seen in the group aged 20 to 29 years, with the earlier increase in women. The next rise is seen about ten years later, in the 30-39 age group. This is a dismal finding because the outcome of young bowel cancer is typically poorer, due to the presentation of the disease at a more advanced stage.
The increased incidence could be due to the simultaneous rise in obesity rates among young adults. No apparent difference in the incidence of bowel cancer was seen between people with diverse social and economic
The rise in the incidence of bowel cancer in this segment is shown to be due mainly to a more significant number of cancers occurring in the lowest part of the large bowel - the sigmoid colon or the rectum. However, proximal tumours also showed an increase in incidence in the age groups 20-29 years and 30-39 years.
The researchers did not find any link with male or female sex, or with the socioeconomic position of the individual. In other parts of the UK, specifically in Scotland, lower socioeconomic status is associated with a higher risk of bowel cancer.
However, the incidence varied strikingly with geographic location. Specifically, the incidence was observed to rise most rapidly in the southern part of England, at over 10% a year in the South West. One possible reason is the increased affluence in this region, coupled with better diagnostic facilities and a higher rate of case detection due to the greater access to health care.
“Age has always been a major risk factor for bowel cancer, with the majority of cases being diagnosed in patients over 60 and therefore bowel cancer screening has focused on older age groups,” said co-author, Dr Adam Chambers. “However, this study shows that over the past 30 years, there has been an exponential increase in the incidence of bowel cancer among adults under 50.”
The study findings are in agreement with other research carried out in Europe and the US in the recent past, which indicates a rapid rise in the incidence of this cancer in young adults. The chief contribution of this study is its insight into the features that characterize the target population.
While it is not recommended that the age of screening for bowel cancer be dropped, due mainly to the cost of screening, the researchers do indicate the need for more research.
“It is likely that the increased risk in the youngest cohorts will be carried forward as they age, which will place a significant burden on future healthcare resources,” the authors wrote. “The role of environmental factors, such as diet, obesity, physical exercise, and the gut microbiota, in the development of young‐onset colorectal cancer, is incompletely understood and requires further research.”
“Bowel cancer is becoming increasingly common in younger adults,” added co-author, Dr David Messenger. “Future research needs to focus on understanding why this trend is occurring and how it might be reversed, potentially through the development of cost-effective testing strategies that detect tumours at an earlier stage or polyps before they become cancerous.”
To access this paper, please click here