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Grading and Staging of Tumors


Grading is the level of cellular differentiation (microscopic). It is done to obtain a microscopic picture of tumors. Tumors may be:

  1. Low grade –well differentiated, having nucleus cytoplasmic ratio slightly disturbed, loss of polarity less and less dysplasia.
  2. High grade.

1.      Tissue architecture

    • Regular glands
    • Irregular
    • Distorted
    • Scattered cells

2.      Nuclear atypia (disturbance of nuclear morphology)

    • N:C ratio
    • Hyperchromatism
    • Pleomorphic nuclei
    • Nucleoli prominence

3.      Number of mitosis

  • Number slightly increased in hyperplasia
  • Number is much more increased in tumors, along with abnormal mitosis

Actually for determination of grading, high power (40x) lens is selected and number of mitosis is counted:

  1. If each field has 5-10 mitosis, it is termed low grade (well differentiated)
  2. If each field has more than 10, we call it  moderately differentiated
  3. If each field has more than 20, we label poorly differentiated
Clinical significance

Grading is done for malignant tumors only.

If it is a low grade malignant tumor, there is better prognosis

Although grading is important for prognosis, but is less helpful, as biological behavior of tumor depends on many other features.

G1 G2 G3 G4
Well differentiated Moderately differentiated Poorly differentiated Undifferentiated
Tumor cells dispersed in well formed glands Slightly irregular Glands tumor cells are dispersed Scattered cells in glands
Tissue architecture is not disturbed N:C ratio disturbed Distorted structure Cannot appreciate differentiation
Slightly disturbed nuclear morphology

  1. Hyperchromatic
  2. Nucleoli prominent


  1. Hyperchromatic
  2. Nucleoli prominent
  3. Hyperchromatic
  4. Prominent nucleoli
High grade nuclear atypia
Number of mitosis is counted Increased mitosis Increased mitosis Increased mitosis

Spread of cancer within patient (clinically based) is known as staging of tumors.

Staging systems
  1. UICC –Union International Cancer Center
  2. AJC –American Joint Committee
TMN –Classification

T (tumor) –size of primary tumor

N (nodal spread)–extent of spread to regional lymph node

M (metastasis)–presence/absence of blood borne distant metastasis

Clinical Significance

Staging has greater clinical value than grading:

1. Used for decision of treatment
2. Prognosis of cancer (if no nodal involvement or metastasis, there is better prognosis)
3. Helpful in selection of therapy

  • If there is no nodal spread or metastasis, we go for surgical therapy only.
  • If nodal spread and metastasis is present, chemotherapy and radiotherapy is applied as well.

4. Response to treatment

After chemotherapy, again person is scanned, if spread is absent, person is responding well.

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