From the Guidelines
The progression of colorectal cancer from initial development to stage four typically takes about 10 years, with some cases taking up to 20 years or more. This timeline is based on the average time it takes for adenomatous polyps to transform into cancer, as reported in a study published in the Journal of the American College of Radiology in 2018 1. The process usually begins with the formation of polyps, which are abnormal growths in the colon or rectum. These polyps can slowly transform into cancer over several years. Some key points to consider include:
- The rate of carcinoma and high-grade dysplasia is very low or low in subcentimeter adenomas, reported at 0.05% for diminutive polyps and 0.9% for 6- to 9-mm polyps 1.
- For larger adenomas measuring 10 to 20 mm, the rate begins to increase to 7.3% 1.
- Adenomas >25 mm have a 22.5% chance of containing invasive cancer or high-grade dysplasia 1.
- Polyps ≥10 mm have an 8% chance of progressing to invasive cancer at 10 years, which increases to 24% at 20 years 1. Regular screening through colonoscopies is crucial because it allows for detection and removal of precancerous polyps before they develop into cancer, effectively preventing the disease or catching it at an earlier, more treatable stage. The American Cancer Society recommends that tests that simultaneously screen for polyps and cancers should be preferred over tests that detect cancers only when resources permit 1.
From the Research
Colorectal Cancer Development Timeline
- The development of colorectal cancer from start to stage four can take around 7-10 years, as stated in the study 2.
- This prolonged development period can make early detection and diagnosis difficult, as the disease can be asymptomatic for a significant amount of time.
Disease Progression and Treatment
- Colorectal cancer can affect all parts of the colon and rectum, but it is more fatal with poor disease outcomes when it is right-sided, as mentioned in the study 2.
- The treatment of colorectal cancer has seen significant advancements, with notable approaches including surgery, chemotherapy, radiation therapy, and cryotherapy, as discussed in the studies 3, 2, and 4.
- Chemotherapy plays a crucial role in the management of colorectal cancer, especially in advanced stages, with various agents such as 5-fluorouracil, irinotecan, and oxaliplatin being used, as mentioned in the studies 3 and 2.
Targeted Therapy and Future Perspectives
- Targeted therapy has emerged as a new approach for the treatment of colorectal cancer, with agents blocking different critical pathways and immune checkpoints being developed, as discussed in the study 5.
- The use of monoclonal antibody therapies, such as bevacizumab and cetuximab, has been approved for the treatment of colorectal cancer, but challenges such as off-target effects and therapeutic failures still exist, as mentioned in the study 2.
- Future perspectives for the treatment of colorectal cancer include the development of novel delivery strategies, such as ligand-based targeting of CRC cells, and the investigation of new agents and combination therapies, as discussed in the studies 2 and 4.