Cancer Chemotherapy Fact

Here’s some eye opening info… Cancer chemotherapy treatment is a type of drug therapy that usually involves a combination of drugs administered under a specific regimen.  A round of chemotherapy kills 99.9% of the cancer cells.

Isn’t that impressive? 99.9%!!!

So why aren’t people getting cured from cancer all the time?  Well, in a disseminated, metastatic cancer, there are about one trillion cancer cells.  That’s 10^12.  Or in other words 1,000,000,000,000 tumor cells.

• If you subtract 99.9% from 100%, we are left with 0.1%.
  • So what is 0.1% of a trillion?
    • 0.1%/100 = 0.001.
      • 0.001 x 1 trillion = 1 billion

So 0.1% of one trillion is ONE BILLION!  Even though the chemotherapy is killing 99.9% of the cancerous cells (and lots of the normal, rapidly growing human cells as well), we are still left with a billion cancerous cells! 🙁

So how come we’re able to get so close to 100% but we’re not hitting 100%?

A cell needs to be replicating or active in some way to be affected by a drug.  The cells that are not being affected by the chemotherapy are in the dormant phase.  Antibiotics work on the same principal as well.  If a bacteria is dormant or replicates very slowly, then the antibiotics can’t affect it.

And I’ll end this post with a relevant comic from XKCD…