Can cancer disappear without treatment?
Cancer rarely disappears without treatment but as development is a multi-step process, it may stop at any stage. The body’s immune system can kill cancer cells using mechanisms that specifically target tumor cells that are recognised as “foreign”. These mechanisms include immune system cells such as cytotoxic lymphocytes and macrophages and antibody production. Not all tumors are recognised as foreign and even when they are, the immune system is rarely 100% effective in eliminating the cancer. Rarely, loss of blood supply to a cancer, by pressure on its own supply for example, will result in tumor cell death but the dead tissue will probably need surgical removal.
What types of treatment are available?
The most common and often most effective treatment is surgical removal of the lump. For lumps that are too big or too numerous to be removed or that are in inaccessible locations, other treatments can be considered. These include drugs (chemotherapy), immunotherapy (specific or non-specific stimulation of the immune system), and radiation. New approaches such as gene-based therapies are under development. Chemotherapy or radiation are not suitable for all types of cancer and can have side effects. Chemotherapy drugs target differences between the cancer cells and normal cells, but there is a fine margin and inevitably some normal cells are also destroyed. There are many issues to be considered in the decisions on cancer treatment and your veterinarian will discuss these with you.
How do you know if the cancer is permanently cured?
In many cases, the diagnosis and prognosis indicate there can be a high likelihood of complete cure. Sadly, there are some cases where the diagnosis and prognosis indicate that surgical removal will only give transient relief and the cancer will recur or spread. There are a few tumors that are difficult to predict behaviorally. As in humans, our understanding of cancer in dogs and cats is increasing. Survival rates are improving and many animals are alive and well as “cancer survivors”.