Colorectal Cancer: Symptoms, Diagnosis, and Prevention

Posted on Jan 7, 2025 in Medicine & Health

Colorectal Cancer: Impact

Colorectal cancer affects 40% of men and 30% of women in Europe. Other countries also have a significant incidence. Within Europe, Germany has the highest incidence rate at 70.8%, while Spain’s rate is 45.8%. The mortality rate for colorectal cancer is dropping compared to other cancers, such as prostate and lung cancer.

Risk Factors

  • General: Age over 40 and family history.
  • Genetic:
    • Familial adenomatous polyposis (FAP)
    • Gardner syndrome
    • Lynch syndrome I (familial)
    • Lynch syndrome II (colon and extracolonic, e.g., ovary)
  • Pre-existing conditions:
    • Inflammatory bowel disease
    • Previous colorectal cancer
    • Neoplastic colonic polyps

Primary Prevention

  • Maintain a healthy lifestyle.
  • Follow a balanced diet: excessive red meat intake increases risk.
  • Avoid smoking and excessive alcohol consumption.
  • Adopt the Mediterranean diet to reduce risk.
  • Engage in moderate exercise.

Colorectal Cancer Prevention

While no specific diet has definitively proven to prevent cancer, the following may be helpful:

  • A low-fat, high-fiber diet
  • Calcium supplements
  • Aspirin or NSAIDs (consult with a doctor)

Preventive Measures

Starting at age 50, fecal occult blood tests can reduce mortality by 30-35%, potentially saving 3,600 lives annually. Early detection can lead to a cure in 90% of cases. It can take many years for a colon polyp to develop into cancer.

  • Sigmoidoscopy every five years
  • Colonoscopy every 10 years

Prognostic Factors (Post-Surgery)

  • Stage
  • Invasion of blood vessels/nodes
  • Number of local lymph nodes affected
  • Tumor penetration or perforation of the intestinal wall

Prognostic Factors (Rectal Cancer)

Unfavorable factors:

  • Tumor invasion or adherence to other pelvic parts or adjacent tissues
  • Deeply ulcerated tumors
  • Tumors involving more than 6 cm of the rectal wall (total length 15 cm)

Prognostic Factors (Colon Cancer)

Unfavorable factors:

  • Obstruction of the large intestine or rectum
  • Affected pelvic/abdominal ganglia
  • Invasion of veins and lymph vessels of the intestine
  • Poorly differentiated tumor cells
  • Abnormal chromosomal pattern in tumor cells
  • High blood levels of CEA after surgery
  • Abnormal DNA in tumor cells

Metastasis Frequency

Liver 38-60%, abdominal lymph nodes 39%, lung 38%, peritoneum 28%, ovary 18%, adrenal glands 14%, brain 8%.

Diagnosis

Screening (Medium Risk)

  • Age over 50 without known risk factors
  • Annual proctosigmoidoscopy and fecal occult blood test
  • One of the following:
    • Sigmoidoscopy every 5 years
    • Double-contrast barium enema every 5-10 years
    • Colonoscopy every 10 years

Screening (High Risk)

  • Age 40 with first-degree relatives who have colorectal cancer or adenomatous polyps
  • Same diagnostic options as for medium-risk patients

Symptomatology and Progression

Early Stage

  • No symptoms
  • Abdominal pain
  • Flatulence
  • Minimal changes in bowel movements
  • Rectal bleeding
  • Anemia

Advanced Stages (Left Colon)

  • Constipation or diarrhea
  • Abdominal pain and cramping
  • Symptoms of obstruction (nausea/vomiting)

Advanced Stages (Right Colon)

  • Vague abdominal soreness
  • Anemia
  • Weakness
  • Weight loss

Late Stages (Rectum)

  • Changes in bowel movements
  • Incomplete defecation
  • Sudden need to urinate
  • Bleeding
  • Tenesmus

TNM Staging

Primary Tumor (T)

  • TX: Primary tumor cannot be assessed
  • T0: No evidence of primary tumor
  • Tis: Carcinoma in situ: intraepithelial or tumor invades the lamina propria
  • T1: Tumor invades submucosa
  • T2: Tumor invades muscularis propria
  • T3: Tumor invades through the muscularis propria into the subserosa or into non-peritonealized pericolic or perirectal tissues
  • T4: Tumor directly invades other organs or structures and/or perforates visceral peritoneum

Regional Lymph Nodes (N)

  • NX: Regional lymph nodes cannot be assessed
  • N0: No regional lymph node metastasis
  • N1: Metastasis in 1-3 regional lymph nodes
  • N2: Metastasis in 4 or more regional lymph nodes

Distant Metastasis (M)

  • MX: Distant metastasis cannot be assessed
  • M0: No distant metastasis
  • M1: Distant metastasis