Grading and Staging of Tumors

Grading

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.

Parameters

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.

 Classification

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 Hyperchromatic Nucleoli prominent	Hyperchromatic Nucleoli prominent Hyperchromatic Prominent nucleoli		High grade nuclear atypia
Number of mitosis is counted	Increased mitosis	Increased mitosis	Increased mitosis

Staging

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.