Prior to the 1970s, bone sarcomas were routinely treated with amputation, yet most patients still died from metastatic disease.1 The advent of the use of chemotherapy for bone sarcomas in the 1970s was shown to increase long-term survival,2–5 contributing in part to tremendous subsequent advances in the treatment of the most common bone sarcomas—osteosarcoma and Ewing sarcoma. Today, long-term disease-free survival rates of about 60% to 80% are observed for patients with Ewing sarcoma or osteosarcoma with no metastasis at presentation.6,7 In addition to the chemotherapy advances, modular metallic prosthetic limb reconstruction systems are now readily available, eliminating the need to wait for custom reconstructive hardware. Moreover, these systems can be used in combination with large bone allografts or vascularized bone flaps.
The majority of patients with bone sarcomas require multimodal treatment, primarily with surgery and chemotherapy. Patients with chondrosarcomas are the primary exception, as chondrosarcomas are generally treated with resection alone. Thus, management of most patients with bone sarcomas requires a multidisciplinary team that includes orthopedic, medical, and radiation oncologists as well as plastic and reconstructive surgeons, physical therapy specialists, pathologists, and radiologists with expertise in bone tumors.
Despite this broad need for multimodal therapy, surgical resection is fundamental to the management of virtually all bone sarcomas and is the primary focus of this article. The roles of chemotherapy and radiation therapy for bone sarcomas are detailed in the final two articles in this supplement.
INITIAL EVALUATION OF SUSPICIOUS BONE MASSES
History and physical examination
As noted in the preceding article in this supplement, most bone sarcomas (particularly osteosarcomas and Ewing sarcomas) occur in pediatric patients and young adults and develop in the extremities (especially the distal femur) or pelvis.
In terms of history, most patients with a bone sarcoma will report pain, but pain is not a good indicator of malignancy, as some patients with no pain or an improvement in pain have sarcomas while many patients with pain do not have malignancies.1
The other most common finding in patients with a bone sarcoma is an enlarging mass. The presence of a mass, as well as its location, depth, size, and overlying skin quality, can be determined on physical examination. An accurate neurovascular exam should be performed as well, although damage to neurovascular structures is a late finding in sarcoma patients.
Radiographs are important in any patient with prolonged unexplained bone pain and will almost always reveal an aggressive lesion in the patient with a bone sarcoma. Lengthy delays in the diagnosis of a bone sarcoma are nearly always explained by failure to obtain a radiograph.
Magnetic resonance imaging (MRI). Questions about whether a radiograph of a lesion is determinate or not are best resolved by MRI, which is the primary imaging method for evaluating bone lesions, their exact location, and their proximity to neurovascular structures. While “determinate” and “indeterminate” are most precisely used to refer to imaging studies of a lesion, these terms are often used in clinical parlance to refer to the lesions themselves. As such, “determinate lesions” by imaging are those that can be accurately judged malignant or benign with a high level of certainty. Determinate benign inactive lesions such as enchondromas and osteochondromas, if asymptomatic and without severe bony destruction, do not require a bone biopsy. “Indeterminate lesions” by imaging are those whose imaging findings are not clearly consistent with a single diagnosis, and nearly all of these lesions require a biopsy.
In general, any patient with a bone mass with indeterminate imaging results should be referred to an orthopedic oncologist.
When imaging findings are highly suggestive of bone sarcoma, efforts should be made to delineate how far the tumor extends and whether systemic disease is present. Bone sarcomas can metastasize to other bones, but their most common site for metastasis is the lung.
MRI of the lesion without gadolinium is indicated, and the entire bone is imaged to determine the extent of the external mass outside the bone and to look for medullary extension and skip lesions (eg, smaller foci of sarcoma occurring in the same bone or on the opposing side of a joint). The precision offered by MRI has dramatically increased surgeons’ ability to achieve negative margins during resection.
Radiography or computed tomography of the chest is required to accurately assess the lungs for metastasis. A nuclear medicine technetium scan can be obtained to look for other similar bone lesions (metachronous lesions) or metastatic bony disease.
Laboratory tests are not helpful in the staging of bone sarcomas.
Biopsy is the gold standard for diagnosis of bone sarcoma (Figure 1). The primary biopsy methods used are needle or open biopsy techniques, and Tru-cut needles or core bone biopsy needles are increasingly used. If the core needle biopsy is diagnostically inconclusive, an open biopsy can promptly be performed. Biopsies yielding specimens that are too small can result in inconclusive pathology reports. Regardless of the biopsy technique, hemostasis is of paramount importance, and patients are generally advised to not use the affected limb for at least several days after the procedure to reduce the risk of a cancer cell–laden hematoma.
If a needle biopsy is performed, 2 to 10 minutes of gentle pressure is applied to the site. In an open biopsy, electrocauterization is used extensively. Aggressive hemostasis is achieved, and if a drain is placed it should be in proximity to the incision site itself so that the drain site will be resected with the specimen at the time of definitive resection. Open biopsies are performed in the operating room with regional or general anesthesia. Incisions are made longitudinally and never transversely.
Ideally, the biopsy should be performed or supervised by a physician experienced with limb salvage for bone sarcomas. Otherwise there is risk for an inappropriate biopsy tract or approach, misinterpretation of the radiographic studies, misinterpretation of the pathology, or biopsy complications. These errors may lead to undertreatment or even unnecessary amputation.8,9