"Cancer Before Age 49" Increases by 80% Over 30 Years: Revealing Why Younger Cancer Patients Are On the Rise Globally
Mutsuko Ohnishi, MD, Internal medicine physician in Boston, USA
Researchers from Harvard University reported in September last year that the number of new cancer patients aged 14 to 49 has increased by 80% over the past 30 years. This finding was published in a British medical journal. Why is there a sudden surge in cancer patients among the younger population? Dr. Mutsuko Onishi, an internal medicine physician based in Boston, USA, provides an explanation.
American Researchers Predict Cancer Incidence Rates
On June 10, an article by researchers at the National Cancer Institute (NCI), including Dr. Philip Rosenberg, was published in the American Medical Association Journal. They predicted that Generation X (born between 1965 and 1980) will experience higher cancer incidence rates in their 60s compared to the Baby Boomer generation (born 1946-1964). They concluded that "cancer incidence rates in the US are likely to remain unacceptably high for decades to come" (1).
Dr. Rosenberg, who identifies himself as part of the Baby Boomer generation, wanted to check whether his generation was more fortunate than his parents' - the Greatest Generation (born 1908-1927) and the Silent Generation (born 1928-1945), and whether his children's generations, the Millennials (born 1981-1996) and Generation Z (born 1997-2012), are even more so (2).
Researchers used data from 3.8 million people diagnosed with various types of "invasive" cancers (20 types for women, 18 types for men) across the US from 1992 to 2018 to compare cancer incidence rates between the X generation and the Baby Boomers.
Generation X is More Prone to Cancer Than Their Parents
Compared to the Baby Boomer generation, Generation X women are predicted to see increases in thyroid, kidney, rectal, uterine, colon, pancreatic, ovarian cancers, as well as non-Hodgkin's lymphoma and leukemia.
For Generation X men, increases are predicted in thyroid, kidney, rectal, colon, and prostate cancers.
The increase in cancer incidence rates is more pronounced in Generation X than in the Silent and Baby Boomer generations, across all racial and ethnic groups except for Asian or Pacific Islander men.
The largest increases were observed in Hispanic women at 35%, followed by Asian or Pacific Islander women at 20%, Caucasian women at 15%, and African American women at 6%. Increases for Hispanic men were 14%, and 12% each for Caucasian and African American men.
However, there is a silver lining: Generation X women have seen a decrease in lung and cervical cancers compared to the Baby Boomer generation, and Generation X men have seen decreases in lung, liver, gallbladder cancers, and non-Hodgkin's lymphoma.
This makes sense as the anti-smoking campaigns over the last 50 years have been some of the most successful public health campaigns, reducing lung cancer rates. Additionally, public health measures like the Human Papillomavirus (HPV) vaccine have helped decrease cervical cancer rates. However, when all cancers are combined, the numbers of increased cancer types outnumber those that have decreased.
A Healthy Lifestyle Is an 'Unattainable Privilege'
Researchers conclude their discussion by stating that the American Cancer Society (ACS), the Centers for Disease Control and Prevention (CDC), and the World Health Organization (WHO) advocate for a series of preventive actions to reduce cancer risk.
These include reducing tobacco and alcohol use, increasing physical activity, improving dietary habits, and promoting breastfeeding. However, due to income disparities, lack of insurance, food swamps and deserts, architectural environment deficiencies, and other factors, it is challenging for everyone to lead a healthy and active lifestyle.
These findings indicate that a healthy lifestyle, for many people in the US, is not so much a basic right as it is a privilege that is difficult to achieve. The extent to which lifestyle disparities explain the rise in cancer incidence rates among generations and the decrease in average life expectancy in other studies remains unclear, necessitating further research.
Recently, there has been an increase in 'early-onset cancer' worldwide, meaning cancers diagnosed between the ages of 14 and 49.
Cancer Before Age 50 Has Increased by About 80% Over the Last 30 Years
Last year, researchers from Zhejiang University School of Medicine, Harvard University, and the University of Edinburgh reported that the number of new cancer patients under the age of 50 worldwide has increased by about 80% over the past 30 years (1990-2019). This analysis was based on the 2019 Global Burden of Disease study data, examining changes in cancer incidence and mortality rates among people aged 14 to 49 across 204 countries. In 2019, over one million people under 50 died from cancer, an increase of about 28% since 1990 (3).
Researchers predict that by 2030, the number of new cases of early-onset cancer and associated deaths will increase by 31% and 21%, respectively, with the most cases occurring in people in their 40s. In 2019, the cancers that caused the most deaths and subsequent deterioration in health status were breast cancer, followed by tracheal, bronchial, lung, colon, and stomach cancers.
Breast Cancer Is Increasing Among Japanese Women
Data from the National Cancer Center's Cancer Information Service (4)(5) indicate that early-onset cancer, especially breast cancer, is increasing among women in Japan.
Among women aged 35 to 49, the incidence rate of breast cancer per 100,000 population is higher in Japanese women than in American women (Chart 2).
In the US, the incidence rate of young-onset cancers is also increasing. According to a report in the American Medical Association Journal from 2010 to 2019, gastrointestinal cancers are increasing the fastest.
Colorectal cancer, for instance, ranked fourth among adults under 50 in 1998 but is now the leading cause of cancer death in men and the second-leading cause in women after breast cancer. Additionally, patients are increasingly middle-aged rather than elderly (6)(7).
The Relationship Between Young-Onset Cancer and Accelerated Aging
Researchers are striving to understand the reasons behind this. In April this year, researchers at the Washington University School of Medicine pointed out at the American Cancer Society meeting that the increased cancer risk in young adults is related to accelerated aging (8).
To investigate this link, the research team used data from about 150,000 people registered in the UK Biobank, a large-scale biomedical database that includes information on 500,000 residents of the UK.
Biological age refers to a person's physical state relative to their chronological age. Researchers analyzed nine biomarkers in the blood (albumin, alkaline phosphatase, creatinine, C-reactive protein, blood sugar, mean corpuscular volume (MCV), red cell distribution width (RDW), white blood cell count, and lymphocyte ratio) to calculate participants' biological ages.
They found that people born after 1965 had a biological age 17% higher than those born between 1950 and 1954.
The team then examined the connection between accelerated aging and the likelihood of developing early-onset cancer (diagnosed under the age of 55). The results showed that the earlier the body ages, the higher the incidence of early-onset lung, gastrointestinal, and endometrial cancers. Additionally, the risk for late-onset gastrointestinal and endometrial cancers also increased.
What Can Be Done Now to Prevent Cancer
Factors influencing biological age include diet, activity level, and smoking habits. Additionally, genetics is another factor that can affect biological age. Even people who lead a healthy lifestyle can be diagnosed with early-onset cancer, possibly due to genetic factors.
While early detection and better treatment have improved survival rates for most cancers, cancer prevention remains a significant challenge. One thing that can be done starting today is to improve a sedentary, ultra-processed food-dependent lifestyle.
For example, replace car travel with walking, and use stairs instead of escalators or elevators. Also, swap instant noodles and diet drinks for homemade ramen made with plenty of vegetables, low-fat meats, and seafood, and replace them with tea or water.
These small changes can add up to help prevent aging and cancer. Do not forget regular screenings.
References
*This article is a translation of Japanese MRIC published on Jan 9, 2024
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