By Dr Fatima Hoosain: surgeon with a special interest in breast and thyroid cancer 

The trend is unmistakable: younger people are being diagnosed with cancer more frequently. Over the past three decades, global research has revealed a concerning surge in early-onset colon and breast cancers, with very little data available on what is driving this disturbing trend.

Let’s look at the numbers

Early-onset cancers refer to malignancies diagnosed in individuals under the age of 50. According to a presentation by Irit Ben-Aharon, Md, PhD, at the European Society for Medical Oncology (ESMO) Annual Meeting 2024, the incidence of all early-onset cancers has increased by 79.1% since the 1990s. 

This is supported by an article published in Medscape in April 2024. They say ‘breast cancer cases in young Canadian women, especially women in their 20s, have risen by as much as 45.5% in recent years. Study findings, which were published on April 25 2024 in the Canadian Association of Radiologists Journal also highlighted an increase in cases among women in their 30s and 40s by as much as 12.5% and 9.1%, respectively.’ 

In an American Cancer Society research piece published in December 2024, colon cancer was specified as ‘one of 17 different types of cancer rising for Gen X and millennials’.

In South Africa, the last available data from the National Cancer Registry is from 2019, so there is a dearth of data as to whether we, too, are experiencing increased rates of breast and colon cancer. In my practice, we have experienced a 30% increase in the number of patients under the age of 40 who have been diagnosed with breast cancer. Only 10% of these patients carry a genetic mutation. All the patients were diagnosed after feeling a mass in their breast, for which they then sought medical help. 

There are multiple concerning issues related to this, one of which is the issue of diagnostic delay, as these women are not in the age group where screening is recommended, and the second is the risk of false reassuranc,e as benign pathology is far more common in this age group. 

These patients tend to have aggressive cancers that have a rapid growth pattern. They also tend to be resilient and cope with the rigours of treatment well.

What are the causes?

The rising incidence of cancers among the younger population is currently poorly understood. This is largely due to a lack of longitudinal data tracking health outcomes from childhood to adulthood for the affected generations. While pinpointing a single cause is therefore challenging, there is a long-established link between healthy habits and reduced cancer risk.  For that reason, researchers are actively exploring the potential impact of nutrition and physical activity on early-onset cancer development. 

We know, for example, that lifestyle and environmental factors have undergone a significant change over the generations. The mid-20^th century marked a particularly notable shift in diet, food and exercise habits as well as environmental conditions, including a more pronounced emphasis on productivity in the workplace. So, while well-known habits like smoking and binge drinking should be avoided, and the obesity epidemic needs attention, it is also important to acknowledge the impact of today’s work environment on our health. Finding a balance between work and rest is as essential as good nutrition and lifestyle choices to mitigate the physical effects of stress. 

Globally, breast cancer is the cancer that accounts for between 14-and 30% of all cancers in women.  Unfortunately, the survival rates for women 35 and under are worse when compared to those in older women. This is due to multiple factors, including a lack of screening and therefore later cancer diagnoses, which means that cancers diagnosed in this age group tend to be more aggressive or faster growing. There is also more often a genetic predisposition that results in the development of the cancer at such a young age. 

The importance of early detection 

But it’s not all bad news. The good news is that this increased early-onset cancer diagnosis has sparked global research efforts, with breast cancer being one of the most extensively studied. 

As with all cancers, early detection remains the most important measure to take. Those with a family history can now have genetic testing from the age of 16, enabling doctors to adjust and tailor their screening appropriately. 

While there is not yet a call for earlier screenings, we are advising people to start with mammographic screening by the age of 40 and colon screening from the age of 45. 

Here’s what you can do

By combining healthy lifestyle choices, genetic testing, and timely screenings, you can significantly reduce your risk of early-onset cancer. Furthermore, I believe the international oncological community should investigate historical trends to better understand the underlying causes of these alarming statistics. 

This research will enable us to develop more effective screening protocols. For now, prioritising early screening and taking proactive care of one’s body remain crucial prevention strategies, regardless of age.

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Dr Fatima Hoosain is a specialist surgeon in a super-specialist breast and thyroid health centre.

The views and opinions expressed in this opinion piece are those of the author, who is not employed by Health-e News. Health-e News is committed to presenting diverse perspectives to enrich public discourse on health-related issues.