Nothing strikes fear into the heart of clients the way cancer does. Even bringing a distant, slim prospect of cancer tends to halt all other pathways of thought. When we look at the human data, it’s no wonder that we’re so afraid.
As of August 12, 2012, the us has approximately 314,145,701 people. In 2012, about 1.6 million new cancer cases are expected to be diagnosed. While the percentage doesn’t seem to be high at all, the personal experiences of those who have dealt with cancer make the case for just how insidious the disease can be.
Cancer is, at its simplest explanation, an abnormal growth of a cell. The DNA – genetic instructions – inside a cell is altered somehow, causing the cell to do things it shouldn’t do. These cells, or groups of cells, may overproduce or underproduce things they’re supposed to make. They also differ from normal cells by displaying different surface proteins.
When we’re talking about cancer, we do need to be careful about which terms we use, so I’ll try to clarify a little.
Neoplasia: “new growth” This is a general term for abnormal cell division that results in a population of abnormal cells. Neoplasia usually results in a tumor. Tumors are also called masses. Some types of neoplasia don’t form a discrete tumor. Any cell type has the potential to undergo the changes that lead to neoplasia. Tumors can happen -anywhere- in the body.
Benign: A mass that does not show aggressive/destructive behavior, and that is unlikely to spread. These tumors do not cause harm to the person or animal.
Malignant: A mass that shows aggressive/destructive behavior, that may spread, and cause great harm to the person or animal. Malignant essentially means cancerous.
So, to review. Any tumor is a neoplasm, or new growth. Some tumors are not harmful, and are called benign. Some tumors are extremely harmful, and are called malignant or cancerous.
All of this terminology matters because when we’re dealing with a tumor, how we treat it depends greatly upon whether it’s benign or malignant. Benign masses of certain types can be left alone and monitored. Cancerous/malignant masses require some kind of treatment, whether it’s surgical removal, radiation, chemotherapy, or some combination of those things.
So why is cancer such a terrible and deadly disease? First, because neoplastic cells can also trick our immune system into thinking that they are normal cells and shouldn’t be destroyed. Our own defenses fail and allow the neoplastic cells to multiply into a mass. Secondly, because this disease originates in the body, it’s very difficult to kill the neoplasm without also damaging or killing the body. Chemotherapy is a perfect example of this. Chemotherapy drugs are designed to kill neoplastic cells. However, some normal cell types are also damaged. Hair follicle cells, for example, can be harmed, which is why human chemo patients can lose their hair. Radiation treatments can kill neoplastic cells, but it also damages tissue around the target area. When treating cancer, we walk a fine line by poisoning the body just enough to kill the tumor, but not enough to kill the patient.
We know exactly what tumor cells do in the body to evade being destroyed by the immune system. We also know that certain types of cancer will release certain chemical signals into the body that we can detect. Our ability to get images of the body in unique ways (MRI, CT sacn, PET scan, Nuclear Imaging, ultrasound, etc.) has also aided us in diagnosing neoplasms early. We still struggle with this in humans and veterinary patients. There are SO MANY types of neoplasia, in so many areas, that we simply can’t screen everything continuously. Despite our best efforts, neoplasms arise.
The conversation with clients about cancer occurs when we’ve found a mass. Most of the time, a simple examination with the naked eye is not enough to tell whether a mass is malignant or benign. Our hands and eyes are not a microscope, so we have a hard time telling whether a mass is truly dangerous. We need to send in a sample of the neoplastic cells for a pathologist to look at. In many cases, this microscopic examination allows us to state with more confidence that a mass is benign or malignant.
Clients frequently ask if there is a blood test for cancer. There are tests out there, but they currently aren’t sensitive nor specific enough for us to know whether they are helpful or not. It’s difficult to screen before a mass is found. And once it has been, it’s far more beneficial to simply send a piece or needle sample of the mass to the pathologist for examination under the microscope. A quick review of opinions from veterinary oncologists indicated that the few widely-known blood tests for cancer are not yet “ready for prime time.” The technology is good, but it’s just not refined enough for us to make or break a case on the results.
The take-home message here is that neoplasia is, in all of its forms, complex and difficult to manage. It requires a lot of investigation to diagnose. It requires extensive, sometimes dangerous, methods of treatment. Our best defense is to be proactive about having pets examined every 6-12 months, and for owners to examine their pets frequently at home for lumps, bumps, and changes. Needle or biopsy samples need to be taken and reviewed or sent to a pathologist for review. Treatment should be instituted as quickly as possible in order to have better outcomes. Just as some people survive cancer, so do some pets. Their chances are far better when we are vigilant.
Please ask questions in the comments! This is a diverse and complex topic that we could spend days and days on. Let me know what you think, or what you’re curious about. Thanks for reading!