Imagine being 47 years old and suddenly confronting a cancer diagnosis. This was the reality for many individuals, myself included, who found themselves facing the unexpected challenge of early-onset cancer. I was diagnosed with endometrial stromal sarcoma at the age of 47. I do have a strong family history of cancer on my paternal side but none occurred before 50 year old. Traditionally, cancer has been perceived as a disease affecting older adults, aged 50 and above. However, recent data have shed light on a concerning trend – a significant increase in the incidence of cancer among individuals younger than 50 years old, collectively termed early-onset cancer.
Adding to the gravity of this issue, I recently encountered a patient with breast cancer who shared a similar narrative. Her own battle with breast cancer commenced in her late 60s, following her daughter’s diagnosis at the tender age of 27. This poignant encounter underscored the urgency of understanding and addressing the global epidemic of cancer among younger people, encompassing its risk factors, prognosis, and implications for public health.
From a publication in JAMA in 2023, a cohort study of 562 145 people with early-onset cancer in the US from 2010 to 2019, the incidence rates of early-onset cancers increased substantially over the study period. Gastrointestinal cancers had the fastest-growing incidence rates among all early-onset cancers.
Understanding Early-Onset Cancer:
Early-onset cancer refers to the diagnosis of cancer in individuals under the age of 50. While historically considered uncommon in younger age groups, the recent epidemiological data have revealed a troubling rise in the incidence of various cancers among this demographic. Breast cancer, colorectal cancer, endometrial cancer, and others have all demonstrated an upward trajectory in diagnoses among younger individuals.
Risk Factors:
Several factors contribute to the escalating prevalence of early-onset cancer:
- Genetic Predisposition: Family history remains a significant determinant, with inherited genetic mutations predisposing individuals to certain cancers at a younger age. Notably, hereditary cancer syndromes such as BRCA mutations in breast cancer substantially elevate the risk of early-onset cancer.
- Lifestyle and Environmental Factors: Unhealthy lifestyle choices, including poor diet, sedentary habits, tobacco use, and excessive alcohol consumption, have been implicated in augmenting the risk of cancer at a younger age. Additionally, environmental factors such as pollution and exposure to carcinogens can exacerbate the likelihood of developing early-onset cancer.
- Delayed Childbearing: A societal trend towards delayed childbirth may inadvertently heighten the risk of certain cancers, particularly breast and endometrial cancer, due to prolonged exposure to oestrogen without the protective effects of pregnancy and breastfeeding.
- Obesity: The global epidemic of obesity is closely intertwined with an increased susceptibility to various cancers, including those affecting younger individuals. Obesity fosters chronic inflammation and hormonal imbalances, creating a conducive milieu for cancer initiation and progression.
Obesity
The global obesity rate has been steadily increasing over the past few decades. According to the World Health Organisation (WHO), in 2016, more than 1.9 billion adults aged 18 years and older were overweight, and of these, over 650 million were obese. Additionally, in 2016, 39% of adults aged 18 years and over were overweight, and 13% were obese worldwide. So it is important to elaborate more on how obesity can cause cancer, as it is after all a modifiable risk factor.
Obesity is a complex and multifaceted condition that can significantly impact various aspects of health, including cancer risk. These are a detailed exploration of how obesity may influence the risk of cancer:
- Chronic Inflammation: Obesity is characterised by a state of chronic inflammation, wherein adipose (fat) tissue releases pro-inflammatory molecules known as cytokines. This persistent inflammation creates an environment conducive to cancer development and progression. Chronic inflammation can promote DNA damage, cell proliferation, and the formation of blood vessels to support tumour growth.
- Hormonal Imbalance: Adipose tissue is not merely a passive energy reservoir but an active endocrine organ capable of secreting hormones and other signalling molecules. In obesity, there is often dysregulation of hormones such as insulin, insulin-like growth factor 1 (IGF-1), and oestrogen. Elevated levels of insulin and IGF-1 can stimulate cell growth and inhibit apoptosis (programmed cell death), promoting tumour formation and progression. Additionally, excess adipose tissue can lead to increased production of oestrogen, which is associated with an elevated risk of hormone-related cancers such as breast and endometrial cancer.
- Insulin Resistance: Obesity is closely linked to insulin resistance, a condition in which cells become less responsive to the effects of insulin. In response, the pancreas produces more insulin to maintain normal blood sugar levels. High insulin levels not only promote cell growth but also influence the insulin/IGF-1 signalling pathway, which plays a crucial role in cancer development and progression.
- Altered Adipokine Secretion: Adipose tissue secretes a variety of bioactive molecules called adipokines, which regulate processes such as inflammation, metabolism, and cell growth. In obesity, there is an imbalance in adipokine secretion, with increased production of pro-inflammatory adipokines such as tumor necrosis factor-alpha (TNF-α) and decreased secretion of anti-inflammatory adipokines such as adiponectin. This dysregulated adipokine profile contributes to the chronic inflammatory state associated with obesity and can promote cancer initiation and progression.
- Dyslipidemia: Obesity is often accompanied by dyslipidemia, characterised by elevated levels of triglycerides and low-density lipoprotein (LDL) cholesterol, and reduced levels of high-density lipoprotein (HDL) cholesterol. Dyslipidemia can promote tumour growth and metastasis through various mechanisms, including alterations in cell signalling pathways, enhanced angiogenesis, and modulation of the tumour microenvironment.
- Immune Dysfunction: Obesity can impair immune function, leading to a state of immunosuppression that facilitates tumour evasion and growth. Adipose tissue produces factors that suppress immune cell function, such as adipokines, cytokines, and chemokines. Additionally, obesity is associated with the accumulation of immune cells with pro-inflammatory properties, further exacerbating the chronic inflammatory state and promoting tumour progression.
Overall, obesity exerts a profound influence on cancer risk through its effects on inflammation, hormonal balance, insulin resistance, adipokine secretion, dyslipidemia, and immune function. Addressing obesity through lifestyle modifications such as dietary changes, regular physical activity, and weight management strategies is crucial for reducing the risk of obesity-related cancers and improving overall health outcomes.
Prognosis and Challenges:
Early-onset cancer presents distinct challenges compared to cancer occurring in older adults:
- Delayed Diagnosis: Both patients and healthcare providers may overlook cancer symptoms in younger individuals, harbouring the misconception that cancer primarily afflicts older adults. Consequently, diagnosis and treatment initiation may be delayed, potentially compromising prognosis and survival outcomes.
- Aggressive Disease Presentation: Early-onset cancer may manifest as aggressive disease subtypes, necessitating more intensive treatment modalities. The impact of cancer treatment on fertility, reproductive health, and quality of life is particularly poignant for younger patients.
- Psychosocial Impact: A cancer diagnosis at a younger age can engender profound psychosocial ramifications, affecting relationships, career trajectories, and mental well-being. Financial burdens associated with cancer treatment and long-term survivorship may exacerbate the distress experienced by younger patients and their families.
Addressing the Epidemic:
Mitigating the burgeoning burden of early-onset cancer necessitates a comprehensive approach:
- Public Awareness and Education: Heightened awareness regarding the risk factors and symptoms of early-onset cancer among both healthcare professionals and the general populace is imperative for timely detection and intervention.
- Genetic Screening and Counselling: Routine genetic screening and counselling for individuals with a familial predisposition to cancer can facilitate the identification of high-risk individuals and enable the implementation of proactive measures, such as enhanced surveillance and risk-reduction strategies.
- Lifestyle Modification: Promoting healthy lifestyle behaviours, encompassing a balanced diet, regular physical activity, smoking cessation, and moderation of alcohol consumption, is pivotal in mitigating the risk of early-onset cancer.
- Access to Quality Healthcare: Ensuring equitable access to timely diagnosis, specialised treatment modalities, and comprehensive supportive care services is paramount for optimising outcomes and addressing the unique needs of younger cancer patients.
Conclusion:
The escalating prevalence of early-onset cancer constitutes a formidable public health challenge with far-reaching ramifications. By understanding the underlying risk factors, enhancing early detection efforts, and providing holistic support to affected individuals, we can strive towards reducing the burden of cancer among younger populations and fostering improved outcomes for future generations.
References:
- Keegan, T. H., et al. (2019). Future of cancer incidence in the United States: Burdens upon an aging, changing nation. Journal of Clinical Oncology, 37(15), 1285–1291.
- Bray, F., et al. (2018). Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA: A Cancer Journal for Clinicians, 68(6), 394–424.
- National Cancer Institute. (2021). Cancer in Young Adults. Retrieved from https://www.cancer.gov/types/aya.
- Patterns in Cancer Incidence Among People Younger Than 50 Years in the US, 2010 to 2019. JAMA, 2023;6(8)
