Over the past several decades, cancer has become more common in those under the age of 50. Researchers at Brigham and Women’s Hospital found that early-onset malignancies, or those diagnosed before the age of 50, have significantly increased globally since 1990. These cancers include those of the breast, colon, oesophagus, kidney, liver, and pancreas. In attempt to understand why so many younger individuals are being diagnosed with cancer, scientists conducted in-depth analyses of the readily available data in the literature and online, including information on early life exposures that may have contributed to this trend.
The research’s findings were disseminated in Nature Reviews Clinical Oncology. “We noticed a phenomenon known as the birth cohort effect from our data. This result indicates that people who were born later in time (by a decade or more) have a higher risk of developing cancer in later life, most likely as a result of risk factors they were exposed to when they were younger “said Professor and physician-scientist Shuji Ogino, MD, PhD, of the Brigham’s Department of Pathology.
“We discovered that the risk is growing with each passing generation. For instance, the chance of developing cancer before the age of 50 was greater for those born in 1960 than in 1950, and we expect that this risk will rise with time.” Tomotaka Ugai, MD, PhD, the study’s senior author and an associate professor in the Department of Pathology, and his colleagues first examined global data on the incidence of 14 distinct cancer types in persons under the age of 50 between 2000 and 2012. The researchers then looked for studies that looked at general population trends for potential risk factors, such as early life exposures.
Finally, the researchers looked at the literature showing the differences between early-onset cancers identified before the age of 50 and later-onset cancers in terms of clinical and biological tumour features. The scientists conducted a thorough assessment and discovered that the early life exposome, which includes one’s nutrition, lifestyle, weight, exposure to the environment, and microbiota, has altered significantly over the past several decades. They thus put out the hypothesis that the westernised food and lifestyle may be a role in the rising rate of early-onset cancer. The authors noted that early diagnosis through cancer screening programmes is partially to blame for this rise in the incidence of some cancer forms.
They were unable to quantify the exact percentage of this rising incidence that could be simply due to screening and early identification. However, they pointed out that it is doubtful that a rise in the incidence of many of the 14 cancer types is the result of improved screening by itself.
Alcohol intake, sleep deprivation, smoking, obesity, and consuming highly processed foods were all potential risk factors for early-onset cancer. Surprisingly, researchers discovered that youngsters are receiving far less sleep now than they did decades ago, despite the fact that adult sleep length hasn’t changed significantly over the years. Since the 1950s, risk factors have considerably grown, including highly processed meals, sugary drinks, obesity, type 2 diabetes, sedentary lifestyles, and alcohol usage, which experts believe has been accompanied by changing microbiota.
“Eight of the 14 cancer types that were on the rise and that we looked at were associated with the digestive system. The microbes in our stomach are nourished by the food we eat, “Ugai explained. The microbiome’s makeup is directly impacted by diet, and over time, these changes may have an impact on illness risk and prognosis.
The lack of sufficient data from low- and middle-income nations to track trends in cancer incidence throughout the years is one of the study’s limitations. Ogino and Ugai intend to carry on this research in the future by gathering more information and working with other international research institutions to better track global trends. Additionally, they discussed the significance of undertaking long-term cohort studies with parental approval to include young children who may be monitored for decades.
Without these research, it’s challenging to determine what someone with cancer did years ago or as a youngster, according to Ugai. “We want to do more longitudinal cohort studies in the future as a result of this difficulty, in which we follow the same cohort of people throughout their lifetimes while gathering health information, maybe through electronic health records, and biospecimen at predetermined intervals. Considering the numerous cancer kinds that need to be examined, this is not only more cost-effective, but in my opinion it will also provide us with more precise insights into cancer risk for future generations.”