What Are The Signs And Symptoms Of Colon Cancer

Colon Cancer (CRC) | Introduction

• Colorectal carcinoma/cancer (CRC)
• Cancer involving the large intestine and/or rectum
  • Tumor/growth may affect right colon, lest colon, or rectum
  • Malignant growth arises from polyp

Epidemiology

• 3^rd-4^th most common type of cancer
• Approximately 5% of cases are attributed to two genetic causes
• Most common cause of large bowel obstruction in adults
• Mean age of onset is 70 years of age

Colon Cancer (CRC) | Fisk Factors

• Older Age
  • >50 years old
• Family history of CRC
  • First-degree family members under age of 60
• History of Inflammatory Bowel Disease
• Ulcerative colitis

• Dietary History
  • Low fiber, processed meats

• Smoking
• Alcohol consumption
• Increased BMI
• Genetic conditions
  • Familial adenomatous polyposis
  • Lynch syndrome
  • Peutz-Jeghers syndrome
  • Gardner syndrome
  • Turcot syndrome

Colon Cancer (CRC) | Pathophysiology

• Colon cancer arises from colonic polyps (adenomas: adenomatous polyps)

• Adenocarcinomas represent majority of cases
  • Endoluminal adenocarcinomas
  • 98% are adenocarcinomas

Other tumor types

• Kaposi’s sarcoma
  • More likely to occur in HIV-positive/AIDS patients
  • Caused by an infection with human herpesvirus-8 (HHV-8)
• Carcinoid tumors
  • Neuroendocrine tumor
  • May excrete vary large amounts of serotonin
• Lymphomas

Colon Cancer (CRC) | Metastasis

Variety of patterns of spread of the cancer

01- Direct invasion/extension

• Grows within bowel, then may spread through bowel wall and invade into other abdominal structures/organs

02- Hematogenous spread

• Via gastrointestinal veins to the portal circulation
  • Liver metastases are the most common
• Via lumbar and vertebral arteries
  • May affect lungs, brain

03- Lymphatic system

• Regional spread

Colon Cancer (CRC) | Signs & Symptoms

• May be asymptomatic
• Abdominal pain
• Stool changes
  • Caliber
  • Frequency
• Bowel habit changes
  • Alternating constipation and diarrhea
• Weight loss
• Melena and/or hematochezia
  • Iron-deficiency anemia

Colon Cancer (CRC) | Other Clinical Features

Signs and symptoms of large bowel obstruction

• Nausea & vomiting
• Constipation
• Obstipation

Rectal Cancer

• Rectal “fullness”, mass
• Tenesmus
• Sensation of incomplete evacuation

Colon Cancer (CRC) | Screening

• Fecal occult blood testing (FOBT)
  • Also known as stool guaiac test
• Prone to false positives

• Fecal immunochemical test (FIT)
  • Preferred over FOBT
• Digital rectal exam (DRE)

Screening should begin at age of 50
Exceptions: Family history of CRC, begin screening at 40; if earlier diagnosis, start screening 10 years before age of onset

Colon Cancer (CRC) | Diagnosis

• Flexible sigmoidoscopy
  • Can diagnose approximately ¾ of cases
  • Requires FOBT/FIT
• Colonoscopy (& Biopsy)
  • Most sensitive and specifics
• Every 10 years, unless abnormalities are found

• Barium enema
  • “Apple core” lesion

• Carcinoembryonic antigen (CEA)
  • Can be used to prognostic purposes (>5 ng/mL)
  • Important to measure prior to treatment and during follow-up to assess for recurrence
• CT Scan

Colon Cancer (CRC) | Staging

TNM System of staging (“Tumor, Node, Metastasis”)

Stage 1
T: 1,2 Nodes: 0 Metastasis: 0

Stage 2
T: 3,4 Nodes: 0 Metastasis: 0

Stage 3
T: X Nodes: + Metastasis: 0

Stage 4
T: X Nodes: X Metastasis: 1

T1 – Invasion into submucosa
T2 – Invasion into muscularis propria
T3 – Invasion into muscularis propria and into serosa
T4 – Invasion into adjacent structures or organs

N0 – No regional node involvement
N1 – Metastasis in 1-3 regional nodes
N2 – Metastasis in 4 or regional nodes

M0 – No distant metastases
M0 – Distant metastases

Colon Cancer (CRC) | Treatment & Follow-Up

Non-cancerous polyps

• Polypectomy (colonoscopy)

Surgical resection of cancerous bowel

• Colectomy with primary anastomosis

Rectal Cancers

• Higher recurrence rate
• Resection

Adjuvant therapy in addition to surgery depends on stage of cancer

• Most often for patients with stage 3
• 5-Fluorouracil (5-FU)
• Capecitabine with oxaliplatin
• FOLFOX

Palliative if distant spread
For those who have recurrence, 90% will occur within 3 years of surgery
CEA measurement – levels that increase after treatment indicate recurrence