Shining a Light on Colorectal Cancer: An Interview with Professor Pedro Pimentel Nunes, Gastroenterology and Clinical Research Medical Director, Unilabs Portugal Skip to main content


01 March 2024

Shining a Light on Colorectal Cancer: An Interview with Professor Pedro Pimentel Nunes, Gastroenterology and Clinical Research Medical Director, Unilabs Portugal

March marks an important month in the medical calendar: Colorectal Cancer Awareness Month. 

Colorectal cancer, a malignancy affecting the colon or rectum, is the third most common cancer worldwide. While the disease predominantly affects individuals over the age of 50, recent trends show a concerning rise in cases among younger adults. Lifestyle factors, genetic predisposition, and family history play significant roles in its development.

At Unilabs, we stand at the forefront of diagnostics, dedicated to empowering individuals and healthcare professionals in the fight against colorectal cancer. We interviewed Professor Pedro Pimentel Nunes, Gastroenterology and Clinical Research Medical Director, Unilabs Portugal to shed light on this condition.

What are the key risk factors associated with colorectal cancer, and how do they contribute to its development?

Colorectal cancer (CRC), much like many other cancers, is influenced by a variety of risk factors, some of which are modifiable while others are not. For instance, age stands out as a significant risk factor, with the majority of CRC cases diagnosed in individuals over the age of 50. However, in the last decade, we have observed an increase in incidence among younger age groups, particularly between 40 and 50 years old. Genetics also plays a crucial role, with 5% of CRC cases linked to hereditary syndromes such as familial adenomatous polyposis (FAP) or Lynch syndrome (hereditary nonpolyposis colorectal cancer), while as many as 30% may arise in individuals with a family history of CRC. Additionally, diet and lifestyle factors contribute significantly to risk. A diet high in red and processed meats, low in fiber, fruits, and vegetables, and high in saturated fats has been associated with an elevated risk of CRC. Furthermore, a sedentary lifestyle, obesity, smoking, and heavy alcohol consumption have all been correlated with increased rates of CRC. Many of these risk factors function by facilitating the accumulation of genetic mutations and environmental exposures over time, which can predispose individuals to the formation of colon polyps. Over time, these polyps may progress into cancer. Indeed, individuals with a history of colorectal polyps face an elevated risk of developing CRC in the future.

Could you explain the role of early detection in improving outcomes for patients with colorectal cancer?

Early detection plays a pivotal role in improving outcomes for patients with CRC, similar to many other cancers. What sets CRC apart is the availability of highly effective tools for early detection and prompt treatment. When CRC is identified early, it often remains localised to the colon or rectum, without spreading to distant sites. Consequently, patients benefit from a broader array of treatment options, including minimally invasive endoscopic resection. Early-stage CRC is more amenable to successful treatment with less aggressive interventions, resulting in improved outcomes and heightened chances of survival. Notably, early detection not only enhances the likelihood of treating existing CRC but also aids in averting cancer progression. By detecting precancerous lesions (polyps) through screening tests like colonoscopy, these lesions can be promptly removed (via polypectomy) before evolving into invasive cancer. This proactive approach can effectively thwart the development of CRC, thus alleviating the overall disease burden. Ultimately, early detection translates into reduced reliance on debilitating treatments such as aggressive surgeries and colostomies, chemotherapy, and radiotherapy. It culminates in improved survival rates and an quality of life for our patients.

What screening methods are available for colorectal cancer, and how do they differ in terms of effectiveness and patient experience?

Several screening methods are available for colorectal cancer, each differing in effectiveness and patient experience. Stool-based tests, including the Fecal Occult Blood Test (FOBT), Fecal Immunochemical Test (FIT), and stool DNA test, are non-invasive options that do not require bowel preparation. FOBT detects blood in the stool using a chemical reaction, while FIT, using antibodies, is more sensitive and specific, increasingly replacing FOBT in many screening programmes. Conversely, the stool DNA test targets DNA mutations associated with colorectal cancer, offering heightened specificity at a higher cost. CT colonography, or virtual colonoscopy, is a non-invasive imaging technique using CT scans to generate detailed colon images. While less invasive than traditional colonoscopy and without sedation requirements, it requires bowel preparation. However, positive findings on stool tests or abnormalities detected via virtual colonoscopy necessitate further assessment with colonoscopy. Despite its invasiveness and associated risks (although generally safe), colonoscopy is my preferred screening method and considered the gold standard for CRC detection due to its unparalleled efficacy. It enables simultaneous biopsy collection and polyp removal, potentially preventing cancer development. While sigmoidoscopy (a limited version of colonoscopy focusing on the distal colon) was once considered a valid screening method, its inability to detect proximal colon lesions warrants its abandonment, in my opinion. At the end, the choice of screening depends on patient preferences, risk factors, and resource availability. While colonoscopy is most effective, its invasiveness may limit its suitability for some patients. Non-invasive tests offer convenience and may be favored by some individuals, despite potential limitations in detecting abnormalities. Regardless of the chosen method, any positive screening result should prompt further evaluation, typically involving colonoscopy, to confirm diagnosis and guide treatment.

In your opinion, what are some of the most promising advancements in colorectal cancer detection and treatment?

There have been several promising advancements in CRC detection and treatment in recent years. As a gastroenterologist, my primary focus is on preventing and detecting lesions early. In this area, the use of artificial intelligence (AI) during colonoscopy has been a significant breakthrough. AI helps detect more lesions (reducing missed detections) and categorise them as non-neoplastic or neoplastic, guiding appropriate intervention. Liquid biopsies are another major area of research. They involve analysising blood samples for circulating tumour cells, circulating tumour DNA (ctDNA), or other CRC biomarkers. These tests offer a non-invasive way to detect cancer early, monitor treatment response, and identify recurrence. In treating more advanced lesions, developments in minimally invasive surgical techniques, immunotherapy, targeted therapies, and biological therapies offer new and revolutionary options for our patients. Coupled with progress in molecular research, these advancements pave the way for the era of precision medicine. This approach involves tailoring treatment to each patient’s cancer characteristics, optimising treatment efficacy while minimising side effects. Continued research and innovation in these areas have the potential to further transform CRC detection and treatment in the future.

What advice would you offer to individuals who may be concerned about their risk of colorectal cancer?

Maintain a healthy lifestyle and diet, avoid smoking, engage in regular exercise, know your family history, and most importantly, undergo regular CRC screening. Look out for symptoms such as changes in bowel habits, rectal bleeding, abdominal discomfort or pain, unexplained weight loss, or fatigue. However, note that symptoms often only manifest with advanced lesions. Early-stage lesions are typically asymptomatic, making screening the most effective preventive measure against CRC. If you have a family history of CRC, consider scheduling a colonoscopy at age 40 or 10 years earlier than the age of diagnosis in your family. Even without a family history, I strongly recommend screening at age 40-45, ideally with a colonoscopy. Remember, early detection and prevention are pivotal in reducing the burden of CRC. By being proactive about managing your risk and prioritising your health, you can decrease the likelihood of developing CRC or catch it early when treatment is most effective.

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