Precise Radiation for Bone Cancer
Bone cancer is relatively rare in the United States. Only primary bone cancer requires surgery. However, bone cancer is often secondary, metastasized from cancers in other areas of the body. Radiation therapy is the primary form of treatment for secondary bone cancer.
If radiation therapy is warranted, cutting-edge therapies such as Intensity Modulated Radiation Therapy (IMRT) and Image-Guided Radiation Therapy (IGRT) enable physicians to deliver higher and ultra precise doses of radiation to previously unreachable tumors while sparing nearby healthy tissue. For this reason, IMRT/IGRT may be effective in some bone cancers for which radiation therapy previously was not an option.
What Is Bone Cancer?
Bone cancer occurs when there are abnormalities in the cells that make up the bones. Abnormal cells can form benign tumors (which are not cancerous), or malignant tumors (which are cancerous). The tumors can be primary, meaning they began directly in the bone, or secondary, meaning they began somewhere else and spread (metastasized) to the bone.
Primary bone cancers are sarcomas (cancerous tissue) that develop in the bones, and include:
- Osteosarcoma – the most common form, which starts in the bone itself.
- Chondrosarcoma, which starts in the cartilage cells.
- Ewing’s family of tumors, which usually start in the bone, but can start in other tissues and organs.
Most bone cancers are secondary cancers that started elsewhere in the body and then spread to the bone. This is called “metastatic” cancer and often happens to people with advanced breast, prostate and lung cancer.
Other “bone” cancers start in the soft tissue inside the bone called the marrow. These include multiple myeloma, certain lymphomas and all leukemias.
Who Gets Bone Cancer?
Primary bone cancers make up a very small percentage of all cancers. According to the American Cancer Society, there were approximately 2400 new cases of bone and joint cancer in 2008.
Osteosarcoma and Ewing’s sarcoma usually occur in children and adolescents. Chondrosarcoma occurs more often in adults.
How Do I Know If I Have Bone Cancer?
Unlike some other cancers, there are no tests that can detect bone cancer early. The best thing to do is report symptoms to your doctor. The most common symptom is bone pain, which is not constant at first, but becomes constant as the cancer grows. Other symptoms include swelling, tenderness, difficulty with normal movement, fatigue and weight loss. Symptoms can appear in other areas of the body if the cancer has spread.
There are several tests physicians can use to further the diagnostic process and look for tumors. These include x-ray, CT, MRI, Radionuclide bone scan or PET scan. As with other cancers, the only way to know for sure is with a biopsy—a procedure in which a sample of the tumor is sent to the lab to be examined under a microscope. With a needle biopsy, a needle is used to remove a small amount of fluid and tissue from the suspect area. With a surgical biopsy, the doctor cuts through the skin to extract a small piece of the tumor.
What Are My Treatment Options?
Physicians use the results of diagnostic tests to determine the site of the cancer and to stage it—or tell how far it has spread. This helps determine the outlook for recovery and the best course of treatment. There have been great advancements in the treatment of bone cancer over the last three decades. Historically the only treatment available was cutting off the limb (amputation). Today, this is rarely necessary. Still, patients should work together with their physician to choose among several treatment options that may be used alone or in combination, and understand the risks and benefits of each.
In order to cure bone cancer it must be completely removed—even from areas where it has spread—so surgery is the primary treatment. The goal is to remove all of the cancer as well as some of the surrounding tissue so that it can be examined for any traces of cancer cells. Adjunct therapies may be necessary in cases where the tumor cannot be completely removed surgically.
Limb-Salvage Surgery While it requires special expertise on the part of the surgeon, “limb-salvage” surgery leaves the patient with as much of the working limb as possible. Removed bone is replaced with bone grafts from donors, or rods made of metal or other material. Problems with this approach can include infection and grafts or support rods that become loose or broken. Patients may also need additional surgery or amputation.
Amputation For arms and legs, full amputation may be necessary to remove all of the cancer, but in most cases this is not necessary.
In this procedure, the tumor is cut from the bone, leaving behind a hole. Curretage is often followed by cryosurgery, a therapy in which liquid nitrogen is poured into the hole to freeze and kill any remaining cancer cells. The hole is then filled with bone grafts or surgical bone cement called PMMA. The heat given off by PMMA as it cures also helps kill any remaining cancer cells.
Chemotherapy (also called “chemo”) employs oral or injected drugs to kill cancer cells. These drugs enter the bloodstream and travel throughout the body, making the treatment useful for cancers that have spread to distant organs. Except for Ewing sarcoma and osteosarcoma, chemotherapy is seldom used for bone cancer unless it has spread.
Because chemo kills some normal cells in addition to malignant ones, it can cause side effects that vary depending on the type of drug used. These include, but are not limited to, fatigue, nausea, vomiting, loss of appetite, hair loss, mouth sores, changes in menstrual cycle and infertility. It can also cause low white blood cell and platelet counts resulting in higher risk of infection and easy bruising/bleeding. Most side effects cease once treatment stops. Chemotherapy is typically given in cycles with rest periods in-between.
Radiation therapy uses various forms of radiation to kill or shrink cancer cells. It is not as widely used as a primary treatment for bone cancer as bone cancers are not easily killed by this method. Instead, radiation is helpful as an adjunct therapy to shrink tumors before surgery or to destroy remaining cancer cells when tumors cannot be completely removed by surgery. It is also helpful in controlling symptoms such as pain and swelling when surgery is not an option. Side effects are usually limited to irritation around the radiation site, although many patients also report fatigue.
External-Beam Radiation Therapy Much like a traditional x-ray, radiation beams are focused on the affected area from outside the body. This outpatient treatment is typically administered five days a week for a defined number of weeks, depending on the size, location and type of cancer and the goals of treatment. This allows enough radiation to get into the body to kill the cancer while giving healthy cells time each day to recover. Radiation treatment takes only minutes and is usually painless, but it can ultimately cause damage to nearby, healthy tissue.
IMRT/IGRT are rapidly replacing traditional external-beam radiation therapy for treating certain cancers. These methods deliver higher radiation doses more precisely to cancerous tumors while avoiding healthy tissue. With IMRT/IGRT, physicians may be able to treat some bone cancers for which radiation therapy previously was not an option. They can also potentially shorten the duration of therapy. Like traditional radiation, IMRT/IGRT for bone cancer is used in conjunction with, or following another primary treatment, typically surgery.
Your Bone Cancer Treatment Partner
At Lonestar Radiation Oncology, we offer patients a variety of treatment options, from traditional radiation to cutting-edge therapies such as IMRT/IGRT that may not be widely available in other treatment centers. Regardless of the treatment path, we pride ourselves on providing each patient with the best outpatient experience in the most comfortable atmosphere. Treating bone cancer can be a complicated process, so our personal Cancer Navigators help guide each patient through their journey.
IMRT & IGRT: Fighting Bone Cancer with Precision
Quick and painless, external-beam radiation has long been used to destroy cancer cells. The latest methods—Intensity Modulated Radiation Therapy (IMRT) and Image-Guided Radiation Therapy (IGRT)—provide the most advanced technology for fighting cancer. Used alone or together, these therapies allow higher doses of radiation to be delivered with greater precision and accuracy without destroying surrounding, healthy tissue. For instance, they may be used to treat a tumor surrounding the spinal cord with very little radiation reaching the cord itself. They may also help physicians treat difficult-to-reach bone tumors.
For patients, IMRT/IGRT means:
- more effective treatment focused on cancer cells
- less radiation exposure to normal tissue
- potentially fewer and milder side effects
- treatment for some tumors that couldn’t previously be treated by radiation
How IMRT Works
IMRT is a specialized radiation therapy that uses powerful treatment planning software to calculate precise beam angles, shapes and exposure times tailored to each tumor. The radiation beam can be broken up into many smaller beams and the intensity of each small beam can be adjusted individually. This may allow a higher dose of radiation to be delivered to the tumor with less risk to nearby healthy tissue, potentially decreasing the duration of treatment and increasing the chance of a cure.
How IGRT Works
Tumors can move during a course of treatment. IGRT combines imaging and treatment capabilities on a single machine. This way, tumors can be tracked between, as well as during, treatments, allowing radiation to be focused more precisely. Images captured before each radiation session are compared to previous sessions so that clinicians know the exact location of the tumor each time. IGRT software also accounts for breathing and motion during treatment, ensuring the radiation stays focused on the tumor.
External-Beam Radiation Therapy
Lonestar Radiation Oncology can also provide traditional radiation therapy to bone cancer patients. Like a regular x-ray, radiation beams are focused on the affected area from outside the body. It can be used alone, but for bone cancer, it is typically used in combination with other cancer therapies. External-beam radiation therapy has proven to be very successful in palliative care for cancer of the bone.
What to Expect During Treatment
The treatment process is similar for IMRT, IGRT and traditional external-beam radiation therapy.
First, we’ll schedule an appointment with a radiation oncologist. During this visit, we’ll perform a simulation of the treatment. You will be positioned on the treatment machine the same way you will be for actual treatment. The radiation oncologist will determine the need to use an immobilization device (such as a cast, mold or headrest) to keep you in the same position during treatment. Then, we’ll take a CT scan to precisely map your anatomy. Using information from the CT scan, the radiation therapist will mark the area(s) to be treated, either on your skin or on the immobilization device. Simulation sessions take 30 to 60 minutes and may be repeated at intervals throughout your course of treatment.
Next, your radiation oncologist and treatment team will design a treatment plan tailored to you. They will use information from the simulation session, anatomical maps obtained from the CT scan, previous medical tests and, in many cases, sophisticated treatment planning software.
For cancer in the bone, radiation therapy is typically administered 5 days per week. The number of weeks will vary widely and will be determined by your radiation oncologist. During each session, positioning takes from 5 to 15 minutes. Actual treatment time lasts about 10 minutes and is painless. The radiation is delivered using a machine called a “linear accelerator” which generates x-rays or photon radiation. The linear accelerator moves so that patients can lie comfortably without being re-positioned during treatment.
The treatment room is spacious, and you will not be completely enclosed by equipment. A radiation therapist will position you to ensure successful treatment then go to an adjoining control room. From there, he or she will monitor you closely during radiation treatment using video cameras. The therapist can hear you at all times, and the treatment can be immediately discontinued if you feel uncomfortable or ill. If IMRT/IGRT are employed, the therapist may move the machine or treatment table during treatment to best target the exact area of the tumor. Once each treatment is complete, you can return to your normal daily activities.
A follow up exam with your radiation oncologist will be scheduled about one month after your last treatment to discuss side effects. From there, your physicians will determine the proper course of ongoing treatment.