“How do chemotherapy and radiation differ?”

Chemotherapy causes systemic (multiple organ symptoms such as nausea, vomiting, diarrhea, hair loss, and low blood counts. Side effects from radiation therapy is more related to the area of treatment. For pancreas, patient may experience nausea, vomiting, loss of appetite or diarrhea, or may not feel anything if your doctor use IMRT technique.

The two therapies are quite different. Chemotherapy is given to impact disease in any location in the body (does not always get to the brain) so it is a systemic treatment with the hope of prolonging life. Radiation is focused on a single area, therefore local therapy, with the hope of improving symptoms. Therefore with the goal of improving pain control, preventing fracture and treating local complications of the cancer. Sometimes in pancreatic cancer a combination of chemotherapy and radiation will be used with the goal of shrinking the tumor enough to have a surgical procedure.

Chemotherapy goes into the bloodstream and kills cancer cells in the bloodstream and in the mass. It can make you lose your hair and feel ill. The radiation is a local therapy similar to the sun which kills tumor cells more locally.

Chemotherapy acts throughout your body (systemically) and can affect both your normal cells and the cancer cell through one of many mechanisms, often by interfering with cell division. Radiation therapy acts in one particular region where the beam is focused (locally) and creates cell damage to that region through generation of oxygen free radicals, which damages DNA. There is some evidence that radiation also can work secondarily throughout the body by stimulating the immune system to attack the cancer.

Dear Concerned Friend,

Radiation and chemotherapy are both utilized to kill cancer cells. However, they represent different modalities of treatment, with differential characteristics. While chemotherapy is systemic treatment, i.e., administered intravenously (via the blood stream) or orally (in tablet form), radiation therapy is delivered directly to the site of the cancer, thus rendering a more anatomically targeted/focal treatment. As a result, chemotherapy-induced side effects can be more diffuse (general), affecting other tissues not limited to the cancer site or its adjacent organs. Alternatively, the side effects of radiation are only associated with the cancer site and the organs in close proximity to the target/tumor. It is important to note that, while the route and mechanism of chemotherapy and radiation are different, they function synergistically, as they co-augment their ability to kill cancer cells.
I hope that this explanation lends more clarity to the subject in question.

Sincerely,

Dr. EB

Chemotherapy in general is a treatment that is administered through intravenous infusion of medications and sometimes oral medications. The effects of the treatment attack cancer throughout the body regardless of where it is located. Radiation on the other hand is a focused beam of radiation that only treats the tissues that are being targeted and does not treat the rest of the body.