Cancer Treatment 101
Common modalities of treatment
Surgery:
has been the most common first step, historically.
To diagnose
To fix, by removal
To alleviate symptoms, e.g. bowel obstruction or bleeding.
But other modalities are gaining importance, and being used either before, after, or instead of surgery.
Radiation
is a controlled, targeted delivery of a small radiation dose in a daily treatment, to reach the desired dose. This can take a total of several weeks, but is usually a quick process on a daily basis. It is painless for the first several weeks, but as the treatment reaches it’s second half, it does cause fatigue and other local problems. This mainly depends on the body part that is being treated.
The target dose depends on the goal (cure vs. no cure) and the organ being radiated. Different organs have different doses of radiation they can tolerate. Also, the tissue has a lifetime memory of being radiated. If the cancer recurs in the same spot, radiating the same spot carries the risk of tissue breakdown in that spot and is usually not recommended. If the “radiation fields” don’t overlap, you can undergo radiation to the new spot.
Radiation does not travel through out the body; only the targeted part is affected.
Chemotherapy
has historically been the most maligned modality, but serves many useful functions: full disclosure- I am a Medical Oncologist, and chemotherapy is what I do.
Chemotherapy is a big tent that includes a vast array of drugs. These are mostly infused directly into the blood stream, mixed in a saline bag. This process takes up to several hours at a time, and sometimes takes several days. Nowadays, most of these treatments are given as an outpatient, and overnight treatment is delivered via a small portable pump.
Some chemotherapy drugs are now available by pill form. For this to be an effective way of delivering chemotherapy, the absorption has to be reliable, and the drug should not undergo degradation in the liver before it reaches the target tissue. That is why oral chemotherapy drugs have not been easy to develop. In addition, we have to depend on the patient to take the pills in the numbers and schedules prescribed.
Chemotherapy is given for various reasons.
-As a stand alone treatment, in cancers which are exquisitely sensitive to chemotherapy, e.g. lymphomas or leukemias
-After an operation, to increase the chances of cure
-As a pre-treatment, to shrink tumors, and make them more operable
-with radiation, as a helper or radiosensitizer
-After a recurrence, to slow down tumor growth, prolong life and alleviate discomfort
Other treatments:
-Hormone therapy, or hormone blockade, for specific cancer types
-New targeted agents, targeted towards specific receptors on cancer cells, or against proteins, which encourage cancer growth, or blood vessel formation, which feeds tumors. We will talk about these as we get into individual cancer treatments. This is a brand new area of drug development, which has exploded in the last 10 years.