Topical baking soda applications may be helpful and ozone insufflation and application to the cancer area may be quite helpful.

If you can get your hands on some oleander leaves (and flowers if the plants are in bloom) which have not been exposed to pesticides, you can make a homemade oleander extract and condense it way down to where it is a syrupy consistency and then mix it with iodine, colloidal silver and a bit of DMSO, possibly in a carrier such as ozonated olive oil or vitamin E cream (with no added chemicals) and apply it topically a few times daily.

See:

The Recipe for Oleander Soup Part 1

The Recipe for Oleander Soup Part 2 - Tips and Advice

Caution:  Raw oleander is toxic, so don't mess around with the instructions on handling and preparation.  Properly prepared oleander extract is quite safe when used as described.

Two other suggestions: add a couple of teaspoons of colloidal silver to your dogs drinking water each day and also get some inositol/IP6, which has had very good success against canine cancers.

You may also wish to take a look at this:

An Anti-Cancer Protocol for Dogs