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Featuring Demian Dressler, DVM and Sue Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

Why Rescue Chemotherapy Is Not As Good

Updated: October 1st, 2018

Cancer cells are really quite amazing, but not in a good way.

They have these little pumps in their outer wall (the cell membrane).  They go by a couple of different names, but the easiest one to remember is MDR.

MDR stands for Multi-Drug Resistance.

The reason these pumps are so amazingly bad is that they are able to save cancer cells from chemo drugs.  How does this work?

The MDR-1 pump is built into cells naturally.  Its normal function is to get the bad stuff out of cells, kind of like a little hallway out to the trash can.

The bad stuff gets literally pumped out of the cell, dumped outside of it, and the interior of the cell is now free of harmful substances.

Now, if we look at cancer cells, these MDR-1 pumps are really beefed up.  They work overtime.  They are very busy shuttling bad stuff out of the cancer cell to allow the cancer cell to live.

How does this relate to chemo?

Well, chemo drugs are essentially toxins to cancer cells (and to a certain extent also to healthy body cells..but that is a different topic).  Anyway, the cancer cells would really like it if the chemo drugs would get out.

When we administer a first-line chemo treatment, a good number of the cancer cells actually die off.  Some are left.  And the ones that are left either have actively eluded chemo, or have changed to be able to elude chemo.

So the cells left are even more robust.

This is not good for us.

We attack these new cells with the second round of chemo, using different drugs.  This is called a rescue protocol.

The problem is that the success rates are often significantly lower than that seen with the first chemo round since the remaining cancer cells are resistant.

Most commonly they have very active MDR-1 pumps.

As it turns out, there are substances that are able to paralyze cancer cells’ MDR pumps.  These substances are called chemosensitizers.  They have been shown to be able to effect higher kill rates with chemo drugs.

It was this information that prompted me to create the Apocaps formula for my patients.

When you think about the potential in chemosensitization, it is massive.  More effective chemo.  Or less chemo drugs with the same effect, minimizing side effects related to the chemo itself.

This is one of the reasons why oncologists don’t like it very much when vets in private practice start a dog with lymphosarcoma or something on prednisolone.  It tends to make the chemo less effective for this reason.

If you would like to read more about how to integrate different approaches to cancer care, check out The Dog Cancer Survival Guide.


Dr D

Leave a Comment

  1. Kathy on November 27, 2010 at 1:28 pm

    Happy Thanksgiving to you and all your family members including the fury ones!!


  2. Kathy on November 24, 2010 at 3:48 pm

    Dear Dr. Dressler,

    So glad to know you are working on international fulfillment on Apocaps. That’s great news!!

    I read your Survival Guide book and blog posts over and over again…. numerous times by now. It has helped me and my dog a lot on this cancer fighting journey. I have a couple of questions on Apocaps:

    In your practice, do you use Apocaps all the way along with chemotherapy in most cases? If so, once chemo is finished, do you still keep the cancer patients on Apocaps and Arte (alternating every 5 days)? Do you use different dosages while they are on and when they are off chemo?

    In several posts you emphasized the importance of doing blood test to monitor other organs’ functions. How often do you suggest we should let our dog get a blood biochemistry (profile) test? My dog’s oncologist always does CBC test, but not blood profile. I try to request for one every 1~2 months.

    Again, thanks for sharing all these great information with us. I have the book (I assume it’s 1st edition… purchased back in June of 2009). Is there a lot of new information in the new 2nd edition?

    Best regards,

    • DemianDressler on December 8, 2010 at 8:12 pm

      Dear Kathy,
      yes, the separate component in the Apocaps formula seem to have chemosensitizing effects. And yes, I keep going until at least two years out, or continually if the guardian wishes. The dose changes can be found on the FAQ on concerning NDSAID drugs and corticosteroid drugs. As to the blood tests, this varies on a case by case basis. There is no harm in checking, so prompt your oncologist, as you have been!!
      The second edition will have a very expanded section on conventional care, as well as new information in several areas of the “outside the box” areas (which as you know are my special interest)!
      Dr D

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