Cancer-understand the cause, diagnosis and treatment of cancer
Cancer is a disorder of cell growth (uncontrolled cell division) that results in purposeless abnormal tissue (tumor). Grow more than
Normal tissue, uncoordinated, persists after the cause disappears. There are many different types of cancer.
What causes cancer?
Cancer is essentially the result of non-fatal genetic damage to cells (DNA genome mutations). The causes of this mutation include radiation, chemicals, hormones, and infections. Certain damage to cellular DNA is a daily “wear and tear” event, but all mammals have many safeguards to prevent or repair such damage. However, this protection mechanism is not perfect. Some people even have defects in this defense, leading to higher-than-expected cancer incidence. Some defects in protection can be inherited, and in purebred dogs, this may lead to hereditary cancer. In other cases, this is excessive injury.
The mutated DNA disrupts normal cell growth regulation, causing uncontrolled and careless growth of “altered” cells that no longer follow the rules of coordinated cell activity.
Why does your pet get cancer?
All animals can get cancer. In many cases, this is an opportunity and unfortunate problem. The more divisions a cell undergoes, the more likely it is to mutate, so cancer is more common in cells that divide more frequently, after more divisions, just like in older animals. Pets live longer, and the frequency of cancer increases with age. In other cases, animals are exposed to factors that cause or promote cancer (carcinogens) in the environment. These include sunlight, some chemicals and some infections, and some animals are more likely to develop cancer (genetic susceptibility). Some breeds have more cancers than others, usually of a specific type. A few tumors require hormones to start growing or make them persist.
Can your pet catch cancer from another animal?
In most cases, the answer to these two questions is “No!” Animals can be infected by viruses or other microorganisms, some of which can cause cancer. Some people are infected from their mothers before or at birth, but they can also be infected through contact with other animals. Some can be spread by biting “carriers” such as fleas or ticks. For example, feline leukemia virus can cause cancer of the blood and lymphatic system in cats. The virus is sometimes transmitted from an infected queen to her kittens before birth, but it is more commonly acquired through close contact with infected cats, which spread the virus in saliva, urine, and feces. If your cat is infected, it will spread the infection to other cats.
How does cancer affect your pet?
The most obvious effect of most cancers is the enlargement of the mass, but most masses are not malignant masses. This mass may ulcer, bleed, or have physical effects (pressure, displacement, etc.) on surrounding tissues. Benign tumors only expand locally through smooth expansion, while malignant cancers may invade the area with antennae (ie “cancer crabs”). In fact, we use these differences in growth habits to help determine whether cancer is benign or malignant, and it spreads widely through the body. When cancer cells are separated from the original tumor, they are widely distributed in the body cavity (such as the pleural cavity or abdominal cavity) and when the cancer cells invade the blood. These cells may then be carried to distant tissues, where the cells stay and start a new tumor mass (metastasis). Weight loss due to the loss of body fat and muscle is common in malignant tumors, and unexplained weight loss may be
An important sign. A small number of clinical signs induced by tumors are not easily explained by the local or distant spread of the tumor. These are called paraneoplastic syndromes. Some syndromes are caused by abnormal hormones produced by cancer. (Hormones are internal secretions that enter the blood and stimulate the activity of other organs.) Examples of paraneoplastic signs and symptoms include hair loss, increased or decreased blood sugar, and increased blood calcium levels.
How is cancer diagnosed?
Cancer is usually suspected as a clinical symptom (such as lumps, loss of appetite and energy, weight loss, etc.). X-ray examination may help find internal tumors, including metastases. Blood tests can help find some tumors. In order to identify most tumor types, it is necessary to obtain a sample of the tumor itself. May require surgical invasiveness, such as needle aspiration, perforation biopsy, total resection, or exploratory surgery. In many cases, the simplest method is to aspirate (aspirate) tumor cells with a syringe and needle. It does not require general anesthesia or surgery. The microscopic examination of cells is called cytology. However, a more reliable examination requires the removal of tissue samples under anesthesia. The preparation and microscopic examination of the stained sections extracted from the resected tissues is called histopathology. This is done in a specialized laboratory, where the slides are checked by a veterinary pathologist. Histopathology report pass
It often includes text that indicates whether the tumor is “benign” (non-diffusive, locally grown) or “malignant” (can spread to other parts). Malignant tumors are usually represented by tumor names ending in “cancer” or “sarcoma”. These factors, coupled with the origin or type of the tumor, the grade of the tumor (the degree of similarity to normal cells), and the stage (the degree of spread) indicate the possible manifestations of the cancer. Veterinary pathologists usually increase the prognosis (what might happen). This may include predicting the possibility of local recurrence or metastasis (distant spread).
If it is not treated, can the cancer go away?
Cancer rarely disappears without treatment, but since its development is a multi-step process, it may stop at any stage. The body’s immune system can kill cancer cells through a mechanism that specifically targets tumor cells that are considered “foreign”. These mechanisms include immune system cells, such as cytotoxic lymphocytes and macrophages, and the production of antibodies.
Not all tumors are considered foreign, and even if they are foreign, the immune system rarely eliminates the cancer 100% effectively. For example, cancer loses its blood supply due to its own supply pressure and rarely causes tumor cell death, but the dead tissue may need to be surgically removed.
What treatment options are available?
The most common and effective treatment is surgical removal of the mass. For blocks that are too large or too large to be removed or in unreachable places, other treatments can be considered. These include drugs (chemotherapy), immunotherapy (specific or non-specific stimulation of the immune system) and radiation. New methods such as gene-based therapies are under development. Chemotherapy or radiotherapy is not suitable for all types of cancer and may have side effects. The targets of chemotherapeutic drugs are different between cancer cells and normal cells, but there are very small margins. It is inevitable that some normal cells will also be destroyed. There are many questions in cancer treatment decisions
Consider, your veterinarian will discuss these issues with you.
How do you know if the cancer has been cured permanently?
In many cases, the diagnosis and prognosis indicate that a complete cure is highly likely. Sadly, the diagnosis and prognosis of some cases indicate that surgical resection will only temporarily relieve the recurrence or spread of cancer. Some tumors have unpredictable behavior. Like humans, our understanding of cat and dog cancer is increasing. Survival rates are improving, many animals are still alive, and there are “cancer survivors”.
The strict medical term “cancer” is used for malignant tumors, but in general usage, it is often used as a broader term, including benign tumors and malignant tumors.