Is colorectal cancer on the rise in young adults?

Is colorectal cancer the new health concern for Gen X, Millennials and even Gen Z? We sit down with DR RONNIE MATHEW, Medical Director at Colorectal Care Specialists, to find out his opinions on the rise of colorectal cancer in Singapore (and around the world) in young adults, plus symptoms to watch out for and what we can do to protect ourselves.

Have you seen more young people being diagnosed with colorectal cancer in Singapore or around the world? Who is most affected?

Yes, I have. Traditionally, colorectal cancer was mostly observed in adults over the age of 50. However, there is now a worrying rise in cases among those in their 20s to 50s – amongst Generation Z, Millennials and Generation X. This trend is seen globally and has become more evident over the last decade.

Indeed, there is now a new category for this called Early-Onset Colorectal Cancer (EOCRC). This has been concerning colorectal surgeons and oncologists worldwide. According to the American Cancer Society, colorectal cancer is now more common in younger adults than in the past. EOCRC accounts for approximately 10 to 15 percent of all cases. This proportion has been rising globally, including in Singapore.

It is typically diagnosed in individuals in their 30s to early 40s, though it can occur in even younger people. This age group is usually at greater risk of receiving a diagnosis at later stages, as colorectal cancer is often not considered in young patients until symptoms become severe.

Why do you think we’re increasingly seeing the disease in Singapore in young adults?

The exact cause of the sudden rise of this EOCRC in the last decade is not fully understood. Many of these young individuals who develop cancer may have no family history or traditional risk factors, making this trend especially concerning.

Traditional risk factors include lifestyle factors (for instance, a diet high in red or processed meat and low in fibre, a sedentary lifestyle, obesity, smoking and excess alcohol use), a family history of colorectal cancer or inherited syndromes (such as Lynch syndrome or hereditary non-polyposis colorectal cancer or familial adenomatous polyposis), inflammatory bowel disease (Crohn’s or ulcerative colitis, for example) and genetic mutations.

While this surge remains a perplexing medical mystery for clinicians, the suspected driving factors are likely poor diet, lifestyle and obesity. Changes to the microbiome (bacteria within the gut) may also play a role. Regarding family history or inflammatory bowel disease, there does not appear to be a correlating rise in statistics related to this.

What are the early signs of colorectal cancer young adults should watch out for?

The most important point to consider is that there are usually no signs or symptoms in the early stages of the disease. The passage (lumen) of the colon and rectum is relatively large. Hence, a small-sized cancer growth does not usually cause any symptoms unless it reaches a larger size. In fact, the most common stage of colorectal cancer presentation is stage III. That’s when cancer has spread beyond the colon walls into the surrounding lymph nodes. Just last week, I treated a young adult with a short period of symptoms over a couple of weeks and unfortunately, he was diagnosed with advanced stage IV colorectal cancer.

These symptoms, when they occur, include a change in bowel habits (diarrhoea, constipation, change in calibre of the stool), blood in stool, unexplained weight loss, abdominal discomfort and fatigue (due to low haemoglobin in your blood). Colorectal cancer symptoms are often overlooked or dismissed, leading to delayed diagnoses and more advanced stages of the disease. Symptoms in younger individuals may be subtle or mistaken for other conditions, such as gastroenteritis or irritable bowel syndrome.

Are treatment options or chances of recovery different for younger patients?

The fundamental principles of the management of colorectal cancer essentially remain the same, regardless of age. However, one advantage younger individuals have is that they are usually fit and healthy otherwise. Therefore, they can better withstand radical treatments when required and their recovery is generally quicker from these.

Nonetheless, it’s also important to note that many may overlook colorectal cancer symptoms until they become severe. For this reason, in young adults it’s often diagnosed at a more advanced stage, making it harder to treat. The prognosis for early-onset colorectal cancer can vary widely depending on the stage at diagnosis. Early detection and treatment are critical for improving outcomes. Some studies suggest young adults with colorectal cancer may experience worse survival rates, possibly due to later-stage diagnoses or more aggressive tumour biology.

We’ve always been told to start getting colonoscopies from our 50s onwards. Does that still apply today?

Early detection through screenings like colonoscopies is essential, as colorectal cancer is one of the few cancers that can often be prevented. Colonoscopy has consistently shown itself to be the standard amongst all investigations to diagnose and reduce or prevent the risk of the disease. The latter is because most colorectal cancers develop from polyps that slowly grow over time. These polyps can be found and removed at colonoscopy. This is before they have the chance to become cancerous. If the cancers are found at a very early stage, they are curable or have an extremely high chance of being curable.

I am a strong advocate of early national screening for colorectal cancer in Singapore, at least from the age of 45 years onwards or even 40 years for any country that has a statistic for cancer rise in their younger population. Indeed, some national colorectal societies, including in the USA, have revised the population screening age to start from 45 years. Other national colorectal societies are considering revising this similarly.

What advice would you give about lowering cancer risk? Are there any lifestyle changes that can help prevent colorectal cancer in young adults?

There are a few things young adults or even those who are older should consider:

• Maintain a balanced diet, have adequate fibre and reduce red meat, processed foods and high fructose corn syrup.
• Make healthy lifestyle changes. These can include being more active, avoiding smoking and reducing alcohol use.
• Avoid obesity.
• Seek a specialist when there are any worrying symptoms, as mentioned above.
• If you have a family history of colorectal cancer or genetic syndromes, start screening at age 40 or 10 years before the youngest cancer case in the family.
• Be aware that genetic counselling and testing for genetic mutations linked to CRC can help identify high-risk individuals who may benefit from earlier screening.

More about the doctor

Dr Ronnie Mathew is a Senior Consultant Surgeon with almost three decades of surgical experience. He has a sub-specialty interest in colorectal surgery and is a keen advocate for minimally invasive surgery, especially robotic surgery.

Colorectal Care Specialists (CRCS) is at #14-15 Mount Elizabeth Medical Centre, 3 Mount Elizabeth. 
6738 0328 | WhatsApp 9725 2381 | thecrcs.com

This article about colorectal cancer in Singapore first appeared in the April 2025 edition of Expat Living. You can purchase the latest issue or subscribe so you never miss a copy!

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