Radiation Oncology Part 1 - Treatment

Almost as daunting as the initial diagnosis of Cancer is the leap into the intimidating realm of the treatment itself. This article will focus on the radiation experience specifically. The information contained in this article was gathered from the author's coursework as well as the Oncology Nursing Society, or ONS (full sources are noted at the end of the article).

Radiation treatment can be used to eradicate a specific cancer tumor or it can be used in palliative care. For instance, in terminal or end-stage patients where cancer has spread to their bones, radiation treatment is often used to kill off some of the cancer in order to lessen the pain felt by the patient.

The first step in understanding your radiation treatment is getting to know the individuals responsible for your medical care and sense of well-being.

Radiation Oncology Team Members:

This team consists of physicians, nurses and technicians who work both in the forefront and behind the scenes to give you the best and most accurate treatment and follow-up care possible.

The radiation oncologist is the physician responsible for prescribing the treatment, monitoring the patient's medical status during treatment, managing treatment side effects and evaluating patient outcomes.

The radiation oncology nurse is a registered nurse responsible for patient assessment and education, monitoring the treatment course and related side effects, developing interventions to manage side effects and promoting self-care skills.

The registered radiation therapist is responsible for assisting the technical planning of treatment during the simulation and for delivering the daily prescribed dose of radiation.

The medical physicist and dosimetrist work with the physician to establish the most suitable direction and size of the radiation beams. They also calculate the time necessary for each radiation treatment and ensure that the radiation is being properly delivered.

The mold-room technician creates customized immobilization devices for the patients. This equipment is essential for maintaining patient position during daily treatments and for promoting patient comfort and safety. These devices ensure that the patient's position does not change and that the target area is precisely treated each day.

A social worker will help coordinate care throughout the treatment course and beyond, including services such as daily transportation to and from the treatment center if needed.

A nutritionist will consult with patients who are at-risk for malnutrition or who already have evidence of malnutrition, such as low income patients, patients with a generally poor diet, patients who experienced anorexia from previous chemotherapy treatments or patients experiencing anorexia from the nausea produced from the radiation itself. It's very important for patients to have a proper and balanced diet during treatment. (ONS 2006)

A Radiation Treatment Walk-through

At the patient's and family's initial meeting with the radiation oncologist and radiation nurse, the patient's presenting diagnosis, past medical history, operative and pathology reports, and X-ray, CT Scan, PET Scan, etc. reports and films are reviewed. A complete physical examination is performed. Sometimes the patient meets with a multidisciplinary team in a clinic session, where the medical oncologist, the radiation oncologist, and the oncologic surgeon together examine the patient and the relevant history, pathology, and films and develop the treatment plan.

After reviewing the information, the radiation oncologist outlines and discusses the plan of care, which normally includes the goals of treatment, the number of days or weeks of therapy, and the anticipated short and long term side effects.

The radiation oncology nurse will complete a nursing assessment, which includes vital signs, medical allergies, current medications, baseline weight and pertinent family and psychosocial history.

The nurse provides patient and family teaching about all aspects of the proposed treatment, including the simulation process, the daily treatment schedule, general and site-specific treatment side effects, and self-care measures.

Immobilization Devices

Examples of immobilization devices include casts or alpha cradles, which maintain the patient's body position during treatment, plastic masks and bite blocks to maintain the head's position, arm boards, belly boards and tapes for securing positions. Immobilization is critical so that the radiation is directly targeted to the tumor to minimize exposure to normal tissues. (Itano & Taoka 2005)

Radiation Therapy Treatment Planning

Pretreatment studies, such as x-rays and CT scans, may be required to identify the tumor's location, type, and size. Simulation is the initial part of the treatment planning process. Depending upon the complexity of the treatment plan, it may last from 15 minutes to one-and-one-half hours. (Itano & Taoka 2005)

The simulator machine does not administer radiation but rather mimics the physical characteristics of the treatment machine, providing a "mock up."

The patient is gowned and draped to expose the treatment area and lies on a hard, narrow couch similar to an x-ray table. X-rays are taken by fluoroscope to isolate the tumor and to identify normal tissues that will be included in the radiation field.

Computerized simulation is becoming the standard technique. The CT simulator uses a computer to plan the exact dose delivery to the tumor and normal tissues in the radiation path. Virtual simulation software is widely available. CT simulation is highly definitive and is especially useful to define tumors that are located in anatomically deep regions such as prostate, brain, and head and neck tumors. (Itano & Taoka 2005)

Custom-made lead blocks are constructed and placed on a tray under the treatment machine to protect vital normal tissues from the path of radiation.

The treatment area includes the tumor itself plus adjacent areas of potential disease, such as local and regional lymph nodes. The area to be treated is outlined with a semi-permanent marker that gradually washes off. Tattoos, which are tiny, permanent black or blue dots, are placed with a fine needle at the edges of the treatment area to ensure accurate daily replication of the treatment field.

Radiation Treatment

The daily treatment routine requires that the patient lie on a hard, open x-ray table, known as a treatment couch, in the same position as for treatment planning. A machine known as a linear accelerator (LINAC) is used to administer external radiation.

Treatment Steps

The radiation therapist positions the patient safely and comfortably on the treatment couch. Once the patient's comfort is assured, the therapist leaves the room and administers the radiation treatment from the control center bordering the treatment room. The patient is reassured that he or she can be seen and heard on video and audio cameras should a problem arise during the brief treatment period.

The LINAC can only be turned on for less than ten minutes. (Itano & Taoka 2005) Frequent position checks of patients are done, and the patient is unable to feel or sense the radiation beam. The patient will see tiny beams of laser lights, which ensure position, and may hear the faint humming sound of the machine when it is turned on.

Radiation Treatment Course

Treatment recommendations are determined by the tumor size, location, side effects, and maximum tolerated dose. A treatment course may consist of external beam alone, internal radiation alone (such as the brachytherapy, or radioactive pellets, used internally for prostate cancer), or a combination of external and internal radiation.

The total dose is divided into fractions that are given daily and prescribed by the radiation oncologist. In general, treatments are administered daily, five days a week. The course of treatment may be as short as one fraction for palliative therapy or up to seven weeks for a curative treatment.

The total dose and schedule depends on the goal of treatment (cure, control, palliation) and the type and location of the tumor because different organs tolerate different amounts of radiation. (Itano & Taoka 2005)

Coming soon: Radiation Oncology Part 2 - Side Effects of Radiation Treatment.

Sources:

Oncology Nursing Society (2006) The Cancer Basics Course
Joanne Itano & Karen N. Taoka (2005) Core Curriculum for Oncology Nursing; 4^th edition. Missouri: Saunders.