Cell Cycle

Basic Concepts of Chemotherapy

Fractional Cell Kill Hypothesis: Each time the chemo does is repeated, the same proportion of cells not the same absolute number is killed.

3 Log Kill, 1 log re-groth principle- In a tumor of 10¹⁰ cells, A cycle of chemotherapy will result in 10³ (3 log kill) cells dying and 10⁷ cells remaining. Therefore, repeated cycles of are required to eradicate re-growing cells.

 

Objective of Chemotherapy:

Ø   A Cure may be sought with aggressive therapy for a prolonged period of time to eradicate all disease.

Ø   Palliative therapy is usually given when complete eradication of the tumor is considered unlikely. Here chemotherapy is given to decrease tumor size, control growth and reduced symptom.

Ø   Adjuvent chemotherapy is used after initial surgical or radiation therapy to eliminate any remaining disease or minimize recurrence

Ø    Neoadjuvent chemotherapy is given prior to definitive treatment (surgery or radiation) to reduce tumor burden.

Ø   Salvage chemotherapy used after recurrence of refractory tumor  after previous chemotherapy.