BONY CONTENTIONS
Multimodality approaches to bone-tumor management, and other options to amputation
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A bone tumor is an abnormal growth of cells within the bone that may be benign or malignant. While bone tumors are relatively uncommon, they could be a significant clinical finding due to the possibility of malignancy and a capacity for rapid growth and wide metastases. Fortunately, benign growths are more common than malignant ones, do not spread, and are rarely life-threatening. Primary bone cancer is rare (less than one percent of all malignant tumors), and is more often seen among people younger than 40 years old. Osteosarcoma is the most common type, developing in new tissue of growing bones. Another type, chondrosarcoma, arises from cartilage, while Ewing's sarcoma occurs in immature nerve tissues of bone marrow. Said Dr. Silverio Barba, a specialist in orthopedics and oncology at the University of Santo Tomas Hospital-Benavides Cancer Institute and the Veterans Memorial Medical Center-Department of Orthopedics: "[Among those] more than 40 years old,
mas common ang metastatic. Sources of metastatic bone tumor are the breast, lungs, kidneys, thyroid, and prostate. In patients less than 10 years old, [you can have] osteosarcoma, the leukemias, and neuroblastoma.
Pero sa 20 to 40 year-olds, chondrosarcoma ang common primary malignancy."
Genetics, radiation
Although bone tumor etiologies remain largely unknown, radiation exposure and heredity may put a person at increased risk. Children who may have had radiation therapy for other conditions, as well as those with hereditary retinoblastoma (a malignancy of the eye), are at higher risk for developing osteosarcoma. However, Barba pointed out that radiation therapy has now improved-low-dose radiation has become possible-this risk is no longer that significant.
Still, he added: "In most tumors, unknown
pa rin talaga ang etiology." Pain is the most common presenting symptom of bone cancer along with the presence of soft-tissue mass, although most benign tumors tend to be asymptomatic. However, symptoms may vary depending on
location and size. For example, those that can be found in or near joints may cause swelling
or tenderness. Advanced tumor activity may also herald pain in benign tumors, especially
with impending bone fracture. Barba said that benign-bone-tumor activity can be latent, active, or aggressive: "Usually, the latent and active phases can be asymptomatic, but when they become
aggressive, [patients] may also experience pain," he explained. "Malignancy-related
pain is more pronounced at night, even without any activity. Benign pain is the one usually relieved by nonsteroidal antiinflammatorydrugs (NSAIDs) and other pain medications." Since bone tumors have a tendency to enlarge and become highly aggressive, they are recommended for monitoring at threeto six-month intervals even for benign growths. Malignant tumors are usually hard with neovascularization, while benign lesions tend to be cystic. As a simplified rule of thumb, it is most probably benign if it is superficial (above the fascia) and small (less than five centimeters). If the tumor is deep and more than five centimeters, it is most probably malignant.
Tumor diagnosis
As a screening tool, diagnostic X-rays can show the location, size, and shape of a bone tumor. Said Barba: "With X-rays, you can have an idea if the tumor is aggressive.
Pag ang border ng lesion at 'yung normal bone hindi ma-delineate, you're probably dealing with a malignant bone tumor.
Pag sclerotic o maputi ang X-ray, most probably benign 'yung lesion." If based on the X-rays the tumor appears to be malignant, special imaging tests such as magnetic resonance imaging, bone scan, or an angiogram may be recommended to determine the status of the tumor or whether there is an extension into the surrounding soft tissues. This will also be important
in surgical planning. Computer tomography of the chest may also be needed to rule out metastasis to the lungs, a common occurrence in malignant bone tumors. Bone-forming tumors like osteosarcoma may also have elevated alkaline-phosphatase levels, which may signify active bone formation. A new modality, positron-emission tomography (PET) will show faster glucose utilization among malignant tumors than a benign or infectious process. But while a tissue biopsy from the bone tumor is still needed to determine the actual presence of cancer, not all tumors may require this particular procedure. "If you are convinced that it's a benign bone cyst, then there is no urgent need for biopsy," advised Barba. "You can just observe it, because they [benign tumors] usually regress when the child grows."
Multimodality options
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The multimodality approach to cancer management ensures that the patient is provided the best possible treatment options from a host of oncology specialists (surgical/medical oncologists, radiologists) as well as proper nursing care and even a network of support groups. Treatment options depend on type, size, location, and stage of the tumor, as well as the patient's age and health status. Surgery is often the primary treatment, but adjuvant chemotherapy and radiation treatment allow for better prognostic chances and wider surgical options. Said Barba: "Hindi na lang puro surgery
ngayon, may chemo and/or radiation therapy na. Kung malignant bone tumor, [the treatment] depends on the type of tumor. Like osteosarcoma for example, kailangan muna ng adjuvant chemotherapy." Patients already find it tough to deal with the fact that they have cancer. Facing the possibility of amputation could be doubly devastating. To them, surgical amputation could be no different from physical maiming. But because of advances in chemotherapy and radiotherapy, the ability to perform limb salvage has become an important development. Said Barba: "Nire-resect lang ang tumors with normal tissues and wide margins, then reconstruct the limb by using prosthesis, bone, or a combination of bone and implants. The bone can be from the patient or allograft from other patients. The bottom line is, it's possible now not to amputate." Still, amputation of a limb is sometimes necessary. The main criterion for limb-salvage surgery is to match the presurgical functioning of the patient. However, should surgery require removal of the nerves, and preoperative function not necessarily returned, amputation might still be a plausible option. "Now, with the advent of new chemotherapeutic agents and radiation therapy, there is greater potential for cure of certain bone tumors, depending on the stage and type," said Barba. "For example, stage-one osteosarcoma has a 60- to 80-percent 10-year survival rate after chemotherapy and surgery. With metastases, though, survival is affected. But now, even metastatic tumors in the lung can be removed through metastasectomy, which improves the survival rate."
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