Colorectal cancer (cancer of the colon or rectum, or bowel cancer) is the fourth most common cancer in the UK, with over 41,000 new cases diagnosed each year according to Cancer Research UK's bowel cancer statistics. Risk factors include increasing age, genetics and family history (particularly syndromes such as familial adenomatous polyposis and Lynch syndrome), inflammatory bowel disease and other dietary and lifestyle factors. Survival rates have improved over time, with almost 60% of people diagnosed with colorectal cancer surviving for at least 5 years. Survival is linked to disease stage at presentation, with better survival the earlier the disease is detected and treated.
People with Lynch syndrome have an increased risk of colorectal cancer, with lifetime risk estimated to be between around 50% to 80% (see Lynch Syndrome in Gene Reviews). The main strategy to prevent colorectal cancer in people with Lynch syndrome has been regular screening with colonoscopy and polypectomy. Aspirin has been suggested as another potential prevention strategy for colorectal cancer.
Diagnosis and staging of colorectal cancer are well established with histology and appropriate imaging, and are not covered by this guideline.
Management of colorectal cancer has advanced over time with new treatment methods and strategies being trialled and used. Management of local disease differs depending on the site of the cancer. The standard practice for colon cancer is to offer surgery for those who are fit for it. Recent trials have studied the effectiveness of preoperative systemic anti-cancer therapy for colon cancer to improve survival. Treatment for rectal cancer is more complex. There is variation in current practice in the treatment for early rectal cancer, use of preoperative (chemo)radiotherapy, surgical technique for rectal cancer surgery, and treatment for locally advanced or recurrent rectal cancer. This guideline addresses all these issues. Until now, the standard duration of adjuvant systemic therapy for colorectal cancer has been 6 months, which has been recently challenged by suggestion of a shorter duration in order to lower toxicity caused by the treatment.
Metastatic colorectal cancer commonly affects the liver, lungs or peritoneum. Treatment for metastatic colorectal cancer depends on, for example, the site and number of the metastases and if the metastases are amenable to local treatment. In addition, the role of molecular biomarkers in predicting effectiveness of systemic anti-cancer therapy has been discussed increasingly in recent years.
People who have been treated for colorectal cancer may have long-term side effects of their treatments. For example, low anterior resection syndrome can have major impact on quality of life and daily living, and it affects around 40% of those who have undergone sphincter-preserving surgery for rectal cancer. It is important that the treatment options, their implications and potential consequences are discussed together with the person with colorectal cancer in order to enable shared decision making.