Cancer Treatment - How to kill the tumor and not the patient

The title sounds a bit hard-core, but it's the truth.

Our last discussion was about how and why we get tumors. Some of these tumors become what we would refer to as cancer. Once a particular tumor has been identified and we know what we are dealing with, we can then begin discussing treatment.

The words radiation or chemotherapy often begin to evoke visceral reactions from owners. Most people have been exposed to the idea of chemotherapy or radiation because of a family member or friend who has battled cancer. Some chemotherapy and radiation options are pretty rough on the body. Some patients get very sick. But not everything that counts as chemo or radiation is hard on the body at all It really depends on the specific protocol.

In my opinion, it's all about QUALITY of life. Some would see it differently and say that QUANTITY is the more important half of the equation. I disagree. Quantity is nothing without quality. The sticking point becomes defining the point at which quality and quantity intersect at an acceptable point for YOU and YOUR PET.

By example, I am currently treating my own dog for stage 4-b lymphoma. That's about as bad as it gets. We decided to start chemotherapy because many of the initial drugs I was going to use in her treatment were fairly benign and it was worth a shot. Surprisingly, she's responded very well to her chemo and hasn't had any bad days because of it.

Until now.

I made the decision to go ahead and give her the doxorubicin. That is the one most likely to make her 'feel bad' for a few days. My decision to use that drug was based on the fact that a few days of nasty were worth the few weeks or months of happy. That was my take on it. Others would argue that the cost and misery of a few days is not an acceptable price to pay for a few weeks or months.

The take-home point is that the decision to treat and the decision how to treat is not something that can be made for you. Your doctor should give you options and you should consider the total picture and make an informed decision. For some, the answer is an easy. Hopefully you enjoy the support of a caring oncologist or primary care veterinarian and you will be an active part in the decision making process.

Staging the tumor:
Staging is something done when we are dealing with a malignancy (cancer). The goal of staging is to evaluate how 'badly' the tumor is behaving so that we can determine what therapy is required. It is necessary to help direct types of therapy in most cancers.

How we stage a tumor depends on tumor type. Some tumors tend to metastasize to the lungs first. Others met to a regional lymph node first. In the case of lymphoma we have to determine if the tumor is in the spleen, liver, or thymus and if it is in lymph nodes. Different locations have different prognoses because. Believe it or not - the same tumor found in two different places could behave dramatically differently.

Surgery:
If we are able to physically remove the tumor then we often take this as our first course of action. After all, why would we poison the entire body if we can cure the cancer by physically removing it from the body. There are many tumors where this is the ONLY treatment recommended.

Other times, our goal is to de-bulk the tumor. We know we won't get the entire tumor. We know there will be microscopic tumor left behind. But if we get all of the visible tumor, it makes the microscopic much easier to heal.

Because there is often microscopic invasion of the tumor in surrounding tissues, the amount of tissue to remove is sometimes impressively large. As an example, mast cell tumors require margins of approximately 3cm in every direction. By the time you account for the shape required to close the defect, a patient with a 1/2" mass may end up with a 6 inch incision.

Just like with real estate, it can all be about location, location, location. That same mast cell tumor on the foot simply can't be removed. There's not enough foot left to close the wound. So there are times that tumor location may dictate amputation of a particular body part (toe, ear, etc). Amputation doesn't have to be a bad word. Life without a toe isn't a bad idea if the only other option is death.

Radiation:
Radiation therapy means that energy in the form of radiation (gamma rays, x-rays) is poured into the tumor in hopes of causing such severe damage to the tumor cells that they die off. Unfortunately, normal tissues always get caught in the crossfire. There are some great new technologies that allow for the very precise delivery of radiation to a very tiny area and help minimize the amount of collateral radiation damage. Local reactions like burns (mild or severe) are the usual side-effects. When talking about the skin, that's not so bad. But if you are trying to irradiate a tumor in the pelvic canal, you end up burning the colon a bit, and the colon does not handle this very well. Again - Location, location, location.

Some tumors are particularly sensitive to radiation and die off quickly and easily. Some are very resistant and radiation doesn't really work. Radiation is usually applied to a very specific and focused location, but there are times where it is appropriate to irradiate an entire limb or an entire body. Whole-body radiation is something usually reserved for killing off the bone marrow in leukemia patients prior to marrow transplantation.

Chemotherapy - The 'other' Big C:
The goal of chemotherapy is to poison the body JUST ENOUGH that the tumor cells die but the patient does not. Chemotherapy is generally administered to the entire body. This is good if you have tumor around the entire body, but it also means that you are exposing all the normal cells in the body to the drug.

Nearly all chemo drugs target fast growing cells. This makes sense because the tumors are usually growing quickly. However, there are lots of cells in the body that have to grow quickly. Bone marrow, cells lining the intestines, and hair follicles are the major players. Not all drugs cause the same problems. For instance - vincristine is one of the drugs in lymphoma treatment. It is VERY well tolerated and is pretty uncommon to cause any issues. Doxorubicin, on the other hand, is quite likely to cause pretty severe gastrointestinal problems. In some dogs, it will cause balding.

The moral of the story is that you should not let the name chemotherapy scare you away all together. Some drugs are fairly simple and may provide excellent responses with nearly NO side effects. Others may be tolerated well in one patient but horribly in another. You simply have to weigh all the variables - patient, prognosis, finances, transportation, side-effects.

This posting does not even begin to cover everything. My hope was to at least cover the big picture. Like I say - I'm happy to entertain questions about specific tumors, drugs, or topics anytime. Just e-mail me!

AMH