What is the primary role of chemotherapy in treating cancer in small animals?

The primary role of chemotherapy in treating cancer in small animals is to kill or inhibit the growth of cancer cells. Chemotherapy involves the use of drugs that specifically target rapidly dividing cells, which is a characteristic of many cancer cells. These drugs can disrupt the cell cycle, leading to cell death or preventing further proliferation of the tumor.

This method is particularly advantageous for systemic cancers, where the disease has spread beyond a localized area and is not amenable to surgical removal. Chemotherapy can also be employed after surgery to eliminate any remaining cancer cells, thereby reducing the risk of recurrence. Its effectiveness can vary based on the type of cancer, the individual animal's response, and various other factors such as the overall health and concurrent medical conditions of the patient.

While enhancing immune response and preventing infection are important aspects of overall cancer care and management, they are not the primary function of chemotherapy. Weight gain is not a goal in treating cancer and can actually be contrary to the intended outcomes of treatment, as weight loss often occurs due to the disease itself or as a side effect of the therapy. Thus, emphasizing the specific action of chemotherapy on cancer cells highlights its crucial role in the treatment of cancer in small animals.