Trends in Colorectal Cancer: A UK Perspective

Colorectal Cancer (CRC) is a type of cancer that affects the colon or rectum. It is one of the most common cancers globally, with over 1.9 million cases reported in 2020. CRC is also a leading cause of death related to cancer, resulting in about 935,000 deaths in the same year. In the UK, around 42,900 new cases of CRC were diagnosed yearly between 2016 and 2018, making it the fourth most common cancer in the country.

#How Colorectal Cancer Develops

Most cases of CRC develop over time, usually following a pattern known as the adenoma-carcinoma sequence. This process can take around 10 to 15 years. Various factors may increase a person's risk of developing CRC, such as age, family history, certain inherited conditions, inflammatory bowel diseases, a sedentary lifestyle, unhealthy eating habits, heavy drinking, and smoking.

#Age and Gender Factors

Risk increases with age, with around 90% of cases occurring in individuals aged 50 or older. There has been a noticeable rise in CRC diagnoses among people under 50 in recent years. Men are more likely to develop CRC than women, possibly due to greater exposure to environmental risks and lower rates of Screening. Women may have some protection due to the effects of estrogen.

#Prevention and Screening

Given the risk factors, there are ways to help prevent CRC. This includes primary prevention, which focuses on stopping the disease from starting, and secondary prevention, which aims for early detection. Early detection can greatly improve Survival Rates. In the UK, the National Health Service (NHS) has a screening program for bowel cancer that began in 2006. This program invites those aged 60 to 74, and now also 50 and older, to get screened every two years. Studies have shown that screening can lead to better survival rates; for those diagnosed through screening, the five-year survival rate is 81.9%, compared to just 53% for those diagnosed without it.

#Recent Trends in Colorectal Cancer

Recent data shows that while overall cases of CRC have risen, there is a decline in incidence among certain age groups. Specifically, there is an increase in cases among younger people (under 50) and older adults (over 75). Additionally, CRC mortality in the UK has decreased between 2000 and 2017. However, the UK still has poor survival rates compared to other European nations.

To fully understand how CRC is changing over time, researchers need to examine trends in incidence, Prevalence, and survival rates. This is essential for developing effective screening and prevention strategies. There is still a gap in understanding how these trends vary across different population groups in the UK. The aim of this study is to better describe the burden and trends of CRC from 2000 to 2021.

#Study Design and Methods

A population cohort study was conducted using primary care data from two main databases in the UK. The first database is called CPRD GOLD, while the second one is CPRD Aurum. These databases contain various personal health information collected by the NHS, including patient demographics and medical history. The study focused on patients aged 18 and older, and it tracked individuals from the beginning of January 2000 until the end of 2021 or earlier, depending on their health outcomes.

To identify cases of CRC, specific medical codes were used to ensure that only primary cancer events were counted, excluding benign cancers and unrelated conditions. The study also looked at survival rates, which were calculated from the date of diagnosis until the date of death or the end of the study period.

#Patient Characteristics

The study found over 24 million eligible individuals in the CPRD Aurum database and over 11 million in CPRD GOLD. Among patients diagnosed with CRC, there was a higher prevalence of men (about 56%), with a median age of 72 at diagnosis. The most common age group among diagnosed patients was 70-79 years.

#Incidence Rates

From 2000 to 2021, the overall crude incidence rate of CRC was 61.5 per 100,000 person-years in CPRD GOLD, slightly lower at 56.6 in CPRD Aurum. Men had higher incidence rates compared to women (69.3 vs. 54.0 per 100,000). Over time, the annual incidence rates increased for both sexes, with men consistently having higher rates. The incidence peaked around 2011 before declining and then rising again in 2021, likely due to delays in diagnosis caused by the COVID-19 pandemic.

Younger age groups, such as those aged 18 to 29, had the lowest incidence rates, while the highest rates were found in those aged 80 to 89. The data from both databases indicated that CRC Incidences in individuals aged 30 to 59 increased annually, and there were also significant increases in the oldest age groups.

#Prevalence of Colorectal Cancer

In terms of prevalence, approximately 0.46% of the population had CRC in 2021 according to CPRD GOLD, with similar results in previous years. Prevalence was higher in men than in women and consistently increased throughout the study period, reflecting the trends noticed in incidence rates.

Prevalence varied with age, being highest in those 80 years and older. For younger age groups, the rates increased but showed a slight decline towards the end of the observation period.

#Survival Rates

The study reported on the survival of patients diagnosed with CRC. In CPRD GOLD, nearly 49% of patients died during the follow-up, while in CPRD Aurum, the number was slightly higher. Patients had a median survival time of about 5.4 years, with females tending to survive longer than males.

When broken down by age, median survival decreased as age increased. Younger patients, particularly those aged 18 to 49, had better short-term survival rates compared to those over 90. In general, one-year survival rates were high for younger people but fell significantly for older age groups.

Furthermore, there was slight improvement in survival rates over time for certain age groups, particularly those aged 60 to 69. This could be linked to the impact of screening programs introduced in the UK.

#Conclusion

This study highlights significant trends in CRC incidence, prevalence, and survival in the UK. While the overall incidence has decreased, particularly in adults aged 60-79, there is cause for concern with the rising incidence among younger adults. Screening programs play a crucial role in improving survival rates, but more work is needed to address CRC in younger populations. Understanding the biology and risk factors associated with young-onset CRC is essential for future prevention and management efforts.

Despite some improvements in treatments, survival rates still vary significantly based on age and gender, emphasizing the need for ongoing research and tailored approaches to CRC management.