INVESTIGATIONS

SANJUKTA SAHA10.03.2017

Malda Medical College

SCREENING AND CONFIRMATION OF DIAGNOSIS

DETECTION OF METASTASIS AND SPREAD

PROGNOSIS

Preliminary Investigations

Digital Rectal Examination

Laboratory studies:

• Complete Blood Count, Hematocrit, PCV, ESR - Anemia

• Liver Function Test

• Renal function test

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Fecal Occult Blood Test

• Simple, Non invasive.

• Detects peroxidase in hemoglobin

• Not specific for location of bleeding in the GIT

• Types:

Guaiac based FOBT

Immunochemical based FOBT

• False positive results- diet containing red meat

• Combined with flexible Sigmoidoscopy

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COLONOSCOPY

• Investigation of choice

• Bowel preparation and sedation required

• Picks up primary cancer

• Can detect synchronous polyps and multiple carcinomas

• Detects small polyp (<1cm)

• Uses: THERAPEUTIC DIAGNOSTIC

PolypectomyControl BleedingStricture dilatation

Biopsy

• Risk of Perforation

• Contraindications:

Suspected Colonic perforation

Toxic megacolon

Fulminant Colitis

Severe IBD with ulceration

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RADIOLOGY

DOUBLE CONTRAST BARIUM ENEMA

• Constant irregular filling defect

• False positive – 1-2%

• False negative 7-9%

• Detects polyps > 1 cm

• More accurate in proximal colon

• Disadvantage : Misinterpret polyp for diverticular disease

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CT Colonography

• Virtual Colonoscopy• Noninvasive technique that visualizes the entire

colon• Categorization of Lesions:

C0 : Study inadequateC1 : Study NormalC2 : Indeterminate (Polyp 6-9mm, <3 in no.)C3 : >10 mm or >3 in 6-9 mmC4 : Colonic mass with luminal narrowing or

extra-colonic extension

• Risk of perforation

• Disadvantage over conventional colonoscopy:

Radiation exposure

Intersystem variability

Biopsy cannot be taken

CT colonography shows a largepolypoid adenocarcinoma in thececum adjacent to the ileocecal valve.

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METASTASIS AND SPREAD

1. ULTRASONOGRAPHY SPREAD TO LIVER (>1.5 cm)PERITONEUM, LYMPH NODES, RETROVESICAL SECONDARIES

2. CT SCANCT Angiography

• ASSESS LOCAL SPREAD, INVASION,EXTENT, STAGE, LYMPH NODE INVOLVEMENT

• LIVER METASTASIS• LUNG METASTASIS

3. FNAC SUPRACLAVICULAR LYMPH NODES

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Ultrasound scan through the right lobe of the liver showing large hyperechoic metastasis from colon cancer.

Ultrasound scan of a large cecalcarcinoma showing concentric thickening of the hypoechoic bowel wall by the tumor.

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Contrast-enhanced CT showing liver metastases. Several low-density metastases from the colon primary tumor involve both lobes of the liver.

CT scan in patient with rectal carcinoma and liver metastases, showing pulmonary metastasis in right lower lobe.

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Surveillance

• CT Surveillance of Chest, Abdomen, Pelvis

• Frequent clinical evaluation

• CEA testing

• Follow-up colonoscopy

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Prognosis - CEA

• Tumor marker discovered by Gold and Freedman

• Surface glycoprotein produced by colonic epithelium

• t ½ = 10 days

• Normal level <2.5ng/ml

• >5ng/ml is significant

• Low sensitivity

MALIGNANT BENIGN

COLORECTAL CARCINOMAPANCREATIC CARCINOMAGASTRIC CARCINOMALUNG CARCINOMABREAST CARCINOMA

PANCREATITISHEPATITISOBSTRUCTIVE JAUNDICEBPH

IMPORTANCE OF CEA AS A PROGNOSTIC MARKER

1. Pre operative level > 7.5 ng/dl – Poor prognosis

2. Post operative fall not adequate – metastasis or incomplete resection

3. During follow up, increased CEA – recurrence or secondaries

4. Rapid increase in CEA levels – metastasis

5. For follow up, post-op CEA levels checked 3 monthly for first 2 years even if pre op level was normal

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TNM Staging

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