Colorectal Cancer from Detection to Treatment
What is Colorectal Cancer?
Colorectal cancer is a cancer that begins in the colon or rectum, parts of the large intestine.
It usually starts as a polyp - a small growth inside the colon - which can become cancerous over time.
Colorectal cancer is a cancer that begins in the colon or rectum, parts of the large intestine.
It usually starts as a polyp - a small growth inside the colon - which can become cancerous over time.
1. Initial Detection / Screening
Routine screening
Colonoscopy
Fecal Immunochemical Test
Guaiac-based Fecal Occult Blood Test
Stool DNA test
Flexible sigmoidoscopy
CT colonography
Symptoms leading to detection
Blood in stool
Unexplained anemia
Abdominal pain
Change in bowel habits
Weight loss
Routine screening
Colonoscopy
Fecal Immunochemical Test
Guaiac-based Fecal Occult Blood Test
Stool DNA test
Flexible sigmoidoscopy
CT colonography
Symptoms leading to detection
Blood in stool
Unexplained anemia
Abdominal pain
Change in bowel habits
Weight loss
2. Diagnostic Testing
Colonoscopy with biopsy
direct visualization and tissue sampling.
Pathology
Cancer type
Grade
Molecular/Genetic Testing
• Microsatellite instability or mismatch repair deficiency
• KRAS, NRAS, BRAF mutations → important for targeted therapy
• HER2 amplification, NTRK fusions
Colonoscopy with biopsy
direct visualization and tissue sampling.
Pathology
Cancer type
Grade
Molecular/Genetic Testing
• Microsatellite instability or mismatch repair deficiency
• KRAS, NRAS, BRAF mutations → important for targeted therapy
• HER2 amplification, NTRK fusions
3. Staging
Imaging
CT scan
MRI
PET-CT
Blood test
Carcinoembryonic antigen
Staging system
Stage 0 - carcinoma in situ.
Stage I–III - localized/lymph node spread.
Stage IV - distant metastasis.
Imaging
CT scan
MRI
PET-CT
Blood test
Carcinoembryonic antigen
Staging system
Stage 0 - carcinoma in situ.
Stage I–III - localized/lymph node spread.
Stage IV - distant metastasis.
4. Treatment Options
➛ Surgery
Polypectomy
removal of precancerous polyps during colonoscopy.
Colectomy
removal of part of the colon containing cancer, plus nearby lymph nodes.
Low anterior resection
for rectal cancers, preserves sphincter.
Abdominoperineal resection
for low rectal cancers, may require permanent colostomy.
Liver/lung metastasectomy
if metastasis is limited and resectable.
➛ Radiation Therapy
• More common for rectal cancer than colon cancer.
• Given before surgery (neoadjuvant) to shrink tumors, or after surgery to reduce recurrence.
➛ Systemic Therapy
Chemotherapy
FOLFOX (5-FU, leucovorin, oxaliplatin).
FOLFIRI (5-FU, leucovorin, irinotecan).
CapeOX (capecitabine + oxaliplatin).
Targeted therapy
EGFR inhibitors
VEGF inhibitors
Immunotherapy
Checkpoint inhibitors
➛ Surgery
Polypectomy
removal of precancerous polyps during colonoscopy.
Colectomy
removal of part of the colon containing cancer, plus nearby lymph nodes.
Low anterior resection
for rectal cancers, preserves sphincter.
Abdominoperineal resection
for low rectal cancers, may require permanent colostomy.
Liver/lung metastasectomy
if metastasis is limited and resectable.
➛ Radiation Therapy
• More common for rectal cancer than colon cancer.
• Given before surgery (neoadjuvant) to shrink tumors, or after surgery to reduce recurrence.
➛ Systemic Therapy
Chemotherapy
FOLFOX (5-FU, leucovorin, oxaliplatin).
FOLFIRI (5-FU, leucovorin, irinotecan).
CapeOX (capecitabine + oxaliplatin).
Targeted therapy
EGFR inhibitors
VEGF inhibitors
Immunotherapy
Checkpoint inhibitors
5. Palliative & Supportive Care
For Stage IV or unresectable disease → focus on extending survival and quality of life.
Options:
Systemic therapy
Palliative radiation
Stent placement for bowel obstruction
Pain management.
For Stage IV or unresectable disease → focus on extending survival and quality of life.
Options:
Systemic therapy
Palliative radiation
Stent placement for bowel obstruction
Pain management.
6. Follow-Up and Survivorship
Colonoscopy:
1 year after treatment, then every 3–5 years depending on findings.
CEA blood test:
every 3–6 months for 2 years, then every 6 months up to 5 years.
CT scans:
every 6–12 months (for higher stage patients).
Colonoscopy:
1 year after treatment, then every 3–5 years depending on findings.
CEA blood test:
every 3–6 months for 2 years, then every 6 months up to 5 years.
CT scans:
every 6–12 months (for higher stage patients).
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