A patient has a tumor that contains 10¹⁰ cancer cells.Treatment includes two consecutive courses of an antineoplastic regimen,and each course kills 99% of the existing cells.Assuming that the tumor did not have time to grow between the two courses,how many tumor cells are left?

Question

Quizplus · Accepted Answer

If 99% of cells are killed in one course of therapy,that means that 1% remain (1% of 10¹⁰ = 0.01× 10¹⁰ or 10⁸).If the remaining 10⁸ cells were subjected to another course of therapy and 99% were killed again,1% of these would remain (1% of 10⁸ = 0.01× 10⁸ or 10⁶).That means 1 million cells remain! A major problem with treating neoplastic cells is that the cell growth is exponential.A large cell load must be present before diagnosis is made.Mixing several chemotherapeutic agents can increase the chance of killing more cells because they work by different mechanisms and have different adverse reactions.

A Patient Has a Tumor That Contains 10¹⁰ Cancer Cells