Metronomic chemotherapy (MC) is the oral administration of anticancer drugs at low, minimally toxic
doses on a frequent or continuous schedule. This is commonly executed using a combination of
cyclophosphamide (cytoxan) and anti-inflammatories, however several other protocols have been
published, including chlorambucil, lomustine and palladia. It is often an attractive option for clients due
to its relatively low toxicity profile, moderate cost, and less intensive recheck schedule. In contrast to
more traditional chemotherapy administered at maximally tolerated doses (MTD), the anticipated
outcome with metronomic chemotherapy is disease stabilization or dormancy, therefore it is often
pursued as a maintenance therapy, following surgery and/or MTD chemotherapy.
lmmunoregulatory - In patients with cancer, immunosuppressive T regulatory (Treg) cells are recruited
by the tumor and present at high levels. This suppresses the anti-cancer immune responses and induces
tolerance, allowing tumors to evade the immune system. Metronomic cytoxan and chlorambucil have
been shown to reduce circulating Treg numbers in dogs with soft tissue sarcomas.
