What we know about colon cancer
Colon cancer is one of the most studied tumors. Today we know a good deal about how to prevent it, how to detect it early and how to treat it.
We know the causes
• Adenoma-carcinoma sequence: 95% arise from benign polyps over 10-15 years
• Risk factors: A diet low in fiber, red/processed meat, obesity, physical inactivity
• Genetics: Hereditary syndromes (Lynch, FAP) in 5-10% of cases
See how to prevent colon cancer.
We know how to prevent it
• Population screening: Occult blood test + colonoscopy reduces mortality by 30-50%
• Polypectomy: Removing polyps prevents 76-90% of cancers
• Lifestyle: A diet high in fiber, exercise, a healthy weight, not smoking
We know its molecular biology
• Molecular pathways: Chromosomal instability, microsatellite instability (MSI), CpG island methylator phenotype (CIMP)
• Key mutations: APC, KRAS, TP53, BRAF
• Therapeutic implications: Personalized treatment according to the molecular profile
Increasingly effective treatments
• Surgery: Laparoscopic/robotic surgery with fast recovery
• Chemotherapy: Optimized regimens (FOLFOX, FOLFIRI)
• Targeted therapies: Anti-EGFR (cetuximab, panitumumab) in RAS wild-type tumors, anti-angiogenic drugs (bevacizumab)
• Immunotherapy: Pembrolizumab in MSI-H/dMMR tumors, with response rates higher than those of chemotherapy
Rising survival
• Overall 5-year survival: >65% (it was 50% thirty years ago)
• Stage I: >90%
• Stage III: 60-70% (vs 30-40% twenty years ago)
• Stage IV with resectable metastases: 30-50% at 5 years
Areas of active research
• Liquid biopsy: Circulating tumor DNA for early detection of recurrences
• Gut microbiome: Its role in carcinogenesis and in the response to immunotherapy
• Artificial intelligence: Polyp detection in colonoscopy, prediction of treatment response
Colon cancer? The prognosis has improved in recent decades (see survival results). At Quenet Torrent Institute we treat it with laparoscopic and robotic surgery. Contact us.
Frequently asked questions
The most common questions answered with concrete data.
How much has colon cancer survival improved in recent decades?
Overall 5-year survival is above 65%, compared with 50% thirty years ago. In stage I it is above 90%, in stage III it reaches 60-70% (compared with 30-40% twenty years ago) and in stage IV with resectable metastases it is between 30% and 50% at 5 years.
What is the main cause of colon cancer?
95% of colon cancers arise from benign adenomatous polyps through the adenoma-carcinoma sequence, a process that takes between 10 and 15 years. The most relevant modifiable risk factors are a diet low in fiber, eating red and processed meat, obesity and physical inactivity.
Which advances have improved colon cancer treatment?
The most relevant advances include laparoscopic and robotic surgery (which reduces complications and hospital stay), optimized chemotherapy regimens (FOLFOX, FOLFIRI), targeted therapies (anti-EGFR in RAS wild-type tumors, bevacizumab) and immunotherapy with pembrolizumab in MSI-H tumors.
What is microsatellite instability and why does it matter?
Microsatellite instability (MSI-H) is a molecular alteration present in 15-20% of colon cancers. MSI-H tumors respond well to immunotherapy with checkpoint inhibitors (pembrolizumab), with response rates much higher than conventional chemotherapy. That is why this status is determined before deciding on treatment.
What is RAS and BRAF mutation status?
Mutations in the RAS genes (KRAS, NRAS) are present in 50-60% of colorectal cancers. Tumors with mutated RAS do not respond to anti-EGFR antibodies (cetuximab, panitumumab), so determining mutation status before starting treatment is necessary to choose the right strategy.
What is the tumor marker CEA used for?
Carcinoembryonic antigen (CEA) is a tumor marker that is useful mainly in the postoperative follow-up of colon cancer. High levels before surgery can indicate more extensive disease. During follow-up, a rise can detect recurrences before they are visible on imaging tests.
What is liquid biopsy and what role does it play?
Liquid biopsy analyzes circulating tumor DNA in peripheral blood. It is an area of active research with growing use for the early detection of recurrences in colon cancer that has already been treated. It makes it possible to monitor the response to treatment and detect resistance before it is clinically evident.
How many colon cancer cases are hereditary?
5-10% of colorectal cancers are hereditary. The two main syndromes are Lynch syndrome (3-5% of cases, lifetime risk of 50-80%) and familial adenomatous polyposis (APC mutation, 100% risk if untreated). If you have several affected relatives or a diagnosis before the age of 50, ask about genetic counseling.
What impact does population screening have on mortality?
Screening programs reduce colon cancer mortality by between 30% and 50% in the population that actively takes part. They also reduce incidence by 20-30% by removing polyps, and more than 60% of cases detected through screening are at stage I-II, compared with 40% when diagnosed because of symptoms.
Does the gut microbiome play any role in colon cancer?
Current research suggests that the composition of the gut microbiome influences both carcinogenesis and the response to immunotherapy. Bacteria such as Fusobacterium nucleatum have been associated with a worse prognosis. Although it is still a developing field, the microbiome is one of the most active areas of research in colorectal oncology.
Does artificial intelligence improve colon cancer diagnosis?
Yes. Artificial intelligence systems applied to colonoscopy have been shown to increase the polyp detection rate, especially for small or flat polyps that can be missed. Algorithms are also being developed to predict the response to treatment and detect recurrences from CT or PET images.