Over the last few years, there has been much work in attempting to improve canine cancer treatment.
One strategy has been to use lower, continuous doses of oral chemotherapy drugs. The goal in this is to lessen chemotherapy toxicity, reduce trips to the oncologist for IV injections (the medications are pills), and hopefully gaining life span and life quality gains.
This is approach is called metronomic chemotherapy. Here, lower doses of drugs such as cyclophosphamide and piroxicam have been used with some success. Initial trials show promise with cancers such as hemangiosarcoma and soft tissue sarcomas.
One of the ways this treatment works is by acting on an enzyme found in higher levels in some cancers, called COX-2. This enzyme is “turned on” during inflammation. When this enzyme is activated, cancerous cells are able to suppress the immune system and create new blood vessels to feed tumors (angiogenesis).
Many think of metronomic chemotherapy as an attack against angiogenesis.
Perhaps most importantly however, when COX-2 is active, cancer cells are able to avoid apoptosis. Apoptosis is a naturally occurring process which is coded for in normal body cell genes. When these cells become pre-cancerous, damaged, old or infected, the apoptosis genes create what is called “cell suicide”. Apoptosis is the name for this genetically programmed cell suicide directed towards clearing out unwanted cells.
Cox-2 has been found in a variety of dog cancers, such as transitional cell carcinoma, some mammary carcinomas, prostate carcinoma, squamous cell carcinoma, and carcinomas of the nasal and intestinal lining.
One of the common metronomic chemotherapy drugs is piroxicam. This drug is able to help block the effects of the COX-2 enzyme.
There are plant-derived substances that are capable of having similar effects on COX-2. These include luteolin, apigenin, and curcumin (among others). It was for this reason that these constituents were included in the Apocaps formulation.
Metronomic chemotherapy, and the use of substances that fight COX-2, are still in their early stages, and has not yet had large scale studies completed to assess its effectiveness on a wide variety of cancers. However, oncologists are using these promising strategies today for canine cancers.
Best,
Dr D
One of th
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