Preparing for Treatment

Treatment for bone cancer can be determined after proper diagnosis and staging.

Genetic Testing

In preparation for treatment, you might have genetic testing or counseling, as certain genetic changes such as a TP53 aberration may affect your prognosis.

The TP53 gene codes for a protein called tumor protein p53, or p53. This protein acts as a tumor suppressor, which means that it regulates cell division by keeping cells from growing and dividing too fast or in an uncontrolled way.

Some mutations in this gene can reduce its function in a manner that’s the equivalent of taking the foot off the brakes of cell division—a process that can favor malignancy. People who have p53 mutations may be at risk for cancers other than bone cancers, as well.

Additional Consultations

You might meet with other specialists before you begin your cancer treatment. For example, young people may seek procedures for the preservation of fertility. This may entail sperm or egg banking.

Because the treatment of bone cancer may produce side effects and toxicities, your healthcare providers will want to gauge your health with certain baseline tests.

Pre-treatment tests may include an echocardiogram, which shows heart function; audiology testing, which measures hearing; and blood tests that show how well your liver, kidneys, and bone marrow are functioning—since some chemotherapies have toxicity profiles that may damage these areas.

Treating Osteosarcoma

There are several types of bone cancer, and your precise type guides your treatment.

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Localized Osteosarcoma

In the case of localized osteosarcoma, there is no detectable spread of cancer to other areas of the body. Localized osteosarcoma only affects the bone in which it developed and the tissues next to the bone, such as muscle and tendon. In young adults, most localized osteosarcomas occur around the knee.

The current standard treatment for localized osteosarcoma involves multiple steps:

First, treatment with chemotherapy that will shrink cancer (referred to as neoadjuvant chemotherapy)Surgery to take out the primary diseaseAdjuvant chemotherapy, ideally in a clinical trial when one is available.

Adjuvant chemotherapy is done in addition to surgery. Even though the surgery is done to remove detectable areas of cancer, there may be microscopic remnants of cancer left behind. That is where the adjuvant chemotherapy comes in—to kill any remnant cancer cells.

Chemotherapy

Methotrexate, doxorubicin, and cisplatin (MAP) chemotherapy may be used for first-line treatment.

Standard MAP therapy includes a doxorubicin dose that can put people at risk for long-term heart toxicity, and an agent called dexrazoxane may be used to help protect the heart. A common regimen is two 5-week cycles of neoadjuvant MAP therapy, which can facilitate limb salvage (saving the limb).

Surgery

Limb salvage is a surgical procedure that replaces a cancerous bone and reconstructs a functional limb with either a metal implant, a bone graft from another person (allograft), or a combination bone graft and metal implant (allo-prosthetic composite).

During surgery, your surgeon will remove all of the cancer from your limb if possible. Then reconstruction with an artificial device (endoprostheses) may be performed.

In some cases, when a portion of a limb is removed, the remaining limb below the involved portion is rotated and reattached (rotationplasty).

Radiation Therapy

When osteosarcoma occurs in the skull, ribs, spine, or certain other areas, surgery might not be an option. When the disease would be extremely challenging to remove surgically or when the margins of the surgery are positive for cancer, radiation therapy has been shown to improve outcomes. Higher total radiation doses or larger daily doses (called hypofractionation) may improve control of the cancer.

Stereotactic radiosurgery involves the use of radiation therapy to deliver precisely targeted radiation in fewer high-dose treatments than traditional therapy. This can help preserve healthy tissue.

Response to Therapy

The response or shrinkage of the tumor (tumor necrosis) after neoadjuvant chemotherapy can help anticipate prognosis.

Recently, the European and American Osteosarcoma Study (EURAMOS) group completed a large study that failed to demonstrate improved outcomes with modified treatment based on tumor necrosis, and so continuing MAP adjuvant chemotherapy regardless of tumor necrosis has been recommended.

Treating Metastatic Osteosarcoma

Most people who have osteosarcoma are first diagnosed when the cancer is localized and hasn’t spread. However, up to 30% have cancer that has already metastasized (spread), at the time of diagnosis. This spread occurs most commonly in the lungs.

Known as “equivocal pulmonary lesions,” suspicious lung spots are actually quite common in current high-resolution scans, according to Reed and colleagues.

People who have nodules or equivocal lung spots on imaging have two treatment options:

Wedge resection: This is a surgical treatment that involves removing the suspected cancerous cells in the lung as well as a margin of surrounding healthy tissue. It is preferred to taking a biopsy sample through a needle, for instance, because it will confirm whether or not the lung spots are indeed cancer. It’s also the optimal therapy for cancer since it completely removes the tumor. Chemotherapy and observation: If a nodule doesn’t change in size after chemotherapy while the primary tumor shrinks, then the lung spot is less likely to be a tumor. Continued close monitoring after adjuvant chemotherapy is very important in these cases, though. In contrast, if a lung spot decreases in size or mineralizes (becomes more white or opaque on imaging) in response to the chemotherapy, then this is more indicative of cancer—and it may need to be surgically removed.

The optimal timing for the removal of metastases, such as lung spots, is not known. Reed and colleagues recommend proceeding with surgical removal of the lung metastases after four cycles of MAP chemotherapy (followed by two more cycles after surgery) or at the end of treatment.

Treating Relapsed Osteosarcoma of the Lung

Sometimes it is not always clear if a spot on the lung in imaging scans is an actual metastasis or some other finding. Recent expert recommendations state that taking some time to make sure suspicious spots are, indeed, cancer will not compromise the quality and goals of therapy.

Relapsed/refractory bone metastatic osteosarcoma is very challenging to treat and the prognosis is bleak. Clinical trial enrollment in these situations is often recommended.

Treating Ewing Sarcoma

The treatment for Ewing sarcoma typically involves taking out the primary tumor (via surgery and/or radiation) combined with chemotherapy that is designed to kill any remaining microscopic cancer sites.

Neoadjuvant chemotherapy may be given, followed by radiation, surgery, or both. Further chemotherapy is then given. Agents involved include ifosfamide and etoposide (IE) plus vincristine, doxorubicin, and cyclophosphamide (VDC) for younger people who have localized tumors. This schedule involving the administration of VDC-IE is now the standard of care in North America.

Treating Metastatic Ewing Sarcoma

About 25% of people diagnosed with Ewing sarcoma will have metastatic disease in the lungs at the time of diagnosis. Reed and colleagues recommend whole-lung radiotherapy after the completion of chemotherapy; and recommend that a biopsy before treatment is started should be considered, if feasible.

Clinical trial enrollment can be an option if you have metastatic sarcoma. Investigations are ongoing combining conventional chemotherapy with targeted drugs.

Treating Relapsed Ewing Sarcoma

As with relapsed osteosarcoma, recurrent Ewing sarcoma is, overall, associated with a very poor prognosis. Subsets within the overall group can be extremely important, however. For instance, Reed and colleagues note that although patients with an early relapse (within 2 years of the initial diagnosis) have less than a 10% chance of long-term survival, up to one-fourth of those with a later relapse may potentially be cured.

Sometimes, when the recurrence is not metastatic, a local therapy such as radiation or surgery can be administered in addition to chemotherapy. If you have metastatic or recurrent disease with better long-term prognoses, stereotactic body radiotherapy can be an option, as is the case in some instances with osteosarcoma.

One difference between the treatments of recurrent osteosarcoma versus Ewing sarcoma is that chemotherapy is generally recommended for all recurrent Ewing sarcoma, whereas surgical removal of the metastasis may be the only therapy used for metastatic osteosarcoma.

Treating Chondrosarcoma

Surgery to take out the cancer is required for any chance of a cure in the case of chondrosarcoma, and lung metastases that can be removed are also taken out.

There are different subtypes of chondrosarcoma. However, conventional chondrosarcoma does not respond to chemotherapy. Another type of chondrosarcoma that may be more sensitive to chemotherapy includes dedifferentiated chondrosarcoma.

Chondrocytes are the cells in your body that make cartilage, and chondrosarcomas tend to have a unique tumor environment, just as cartilage is somewhat of a unique tissue. It has been theorized that the reason chemotherapy doesn’t seem to work on chondrosarcoma is that something about the cartilaginous tumor prevents delivery of chemotherapy to the malignant cells.

If someone with chondrosarcoma develops metastases or the disease comes back in an area that cannot be surgically removed, it’s recommended that the tumor genetics be tested and clinical trials would be the main consideration at that point.

Surgery to remove all or part of the tumorRadiation therapyChemotherapyTargeted therapy, depending on the type and stage