In the past 40 years, the treatment of bone and soft tissue tumors accounts for a small proportion in the whole orthopedic field, but its progress is very significant. In China, primary bone and soft tissue tumors account for about 2%–3% of the whole body tumors, and 1/3 of them are malignant bone tumors. With the introduction of chemotherapy, the improvement of surgical techniques, and the advocacy of comprehensive treatment and standardized treatment, the diagnosis and treatment level and strategy of bone and soft tissue tumors have developed significantly. Especially, the introduction of neoadjuvant chemotherapy has significantly improved the survival rate of patients with primary highly malignant bone tumors. Advances in surgical techniques have even led to higher patient satisfaction with the overall treatment outcome. In addition, the search for new targets for systemic therapy has been a focus of attention in recent years. Attempts to identify tumor markers associated with prognosis are also part of the effort. In the case of benign tumors, the focus is on the progressive reduction of the negative factors associated with therapeutic interventions over time. For soft tissue tumors, orthopedics, surgical oncology, and general surgery are now operating individually, lacking uniform norms and with variable clinical outcomes, and the establishment of a diagnostic and treatment center is imminent.
In general, insisting on standardized and comprehensive treatment of tumors, multidisciplinary collaboration and multicenter clinical research is always an important driving factor for the development of this discipline. The establishment of a bone and soft tissue tumor diagnosis and treatment center is the direction of development.
Current status of bone tumor diagnosis and treatment
(I) Benign bone tumors
The diagnosis of benign bone tumors is very important, and most patients do not need surgical intervention, but most physicians are not aware of this, and over-treatment is a common situation nowadays, especially in primary hospitals. On the other hand minimally invasive treatment methods, especially the application of navigation, have opened another new chapter for the treatment of benign bone tumors.
Benign bone tumors are often found incidentally on radiographs with no obvious clinical symptoms, and some of them are found after the development of pathological fractures.
Most endogenous chondrosarcomas of long tubular bones have no clinical symptoms and are found incidentally. Sometimes it is difficult to differentiate between “endogenous chondrosarcoma” and “highly differentiated chondrosarcoma”. Treatment of endochondroma of long tubular bone can be closely monitored clinically or by extended curettage. Long-term follow-up is essential.
Non-ossifying vascular tumors are often benign bone diseases that are found incidentally without clinical symptoms. Most patients do not require surgery, but patients with combined pathologic fractures may be treated surgically, and surgery should be performed to avoid pathologic fractures if the lesion extends beyond 50% of the invaded bone cross-section or if the lesion is >150 px in length.
Fibrodysplasia is a relatively common benign bone tumor characterized by decreased bone strength and increased toughness, resulting in bone overgrowth, multiple fractures, and various deformities accompanied by weight-bearing stress. Surgical treatment of fibrodysplasia is not aimed at removing the lesion, but rather at avoiding deformity, correcting the deformity, and maintaining or restoring the biological line of force. In the absence of severe deformities, too active surgical treatment is not advocated. The progression of the disease begins to cease after the bone has matured.
Bone cysts are more active in the early stages and the recurrence rate of scraping and implantation is very high in immature children. Minimally invasive treatments, such as needle penetration and intra-lesional hormonal injections, have proven to be effective and some patients can be cured by these methods, but sometimes multiple treatments are required. If minimally invasive treatment is not effective or in older patients, they can be treated by scraping the bone graft.
With osteoid osteoma, pain is the typical clinical symptom. Since the lesion itself is small (often less than 1.125 px), complete removal of the nest can cure this condition, and therefore many minimally invasive treatment methods have emerged. Computer-guided precise localization and lesion removal is a recommended approach.
Overall, the treatment of benign bone tumors and tumor-like disorders is based on accurate diagnosis, the timing of surgical intervention is very important, and overtreatment is the biggest existing problem that deserves attention.
(ii) Malignant bone tumors
Osteosarcoma is the most common primary malignant bone tumor, and its 5-year survival rate has increased from less than 20% 35 years ago to more than 60% today, thanks to the introduction of chemotherapy (including adjuvant and neoadjuvant chemotherapy). However, a plateau in survival rates for patients with osteosarcoma has emerged in the last decade, and new drugs and technologies have made it difficult to make further breakthroughs in this regard. 2013 NCCN bone tumor guidelines were updated on advances in second-line treatment of osteosarcoma, and new treatment recommendations were added for metastatic osteosarcoma, which is present in approximately 10-20% of patients at diagnosis and is event-free at 2 years. The survival rate was 21% and the 2-year overall survival rate was 55%; the number of metastases and whether all lesions could be completely resected constituted independent prognostic factors. In terms of second-line drug selection, polyene-paclitaxel, gemcitabine, cyclophosphamide, etoposide, topotecan, isocyclophosphamide, and carboplatin are available. A phase II clinical study in Italy showed a 4-month progression-free survival rate of 46%, a median disease-free survival time of 4 months, a clinical benefit rate (6-month disease-free progression) of 29%, and partial remission and disease stabilization rates of 8% and 34%, respectively, after sorafenib application. For the treatment of progressive osteosarcoma, preoperative chemotherapy followed by extensive resection of the primary tumor is recommended for cases with resectable metastases. Treatment modalities for metastases include chemotherapy and surgical resection, and for cases with unresectable metastases, chemotherapy or radiation therapy to the primary lesion is recommended, followed by evaluation of the primary lesion to select the appropriate modality for local control.
As a common primary malignancy of bone, histologic grading of chondrosarcoma remains the best indicator of patient prognosis. Treatment of low-grade chondral lesions can still be of interest and remains controversial. Mohler et al. reported a 4.3% recurrence rate with curettage and cryotherapy in the treatment of low-grade chondrosarcoma of the limb and concluded that curettage and cryotherapy is a reasonable alternative therapy for low-grade chondral lesions compared to extensive resection.
Patients with malignant tumors of the limb usually opt for limb-preserving surgery rather than amputation. For highly malignant sarcomas, preoperative chemotherapy with surgical excision of the invading bone and a 50px safety zone around it is the usual treatment. Navigation techniques for precise resection of tumors in complex sites are also gradually being developed, such as the application of navigation techniques for peri-acetabular tumor resection and reconstruction, sacral tumor resection, and joint preservation for limb tumors. On the other hand, reconstruction methods for bone defects include artificial prosthesis, allograft bone, autologous bone, fibula with vascular tip and bone handling.
Artificial prosthesis replacement includes femoral, tibial and humeral joint prosthesis replacement. Knee artificial prosthesis replacement is the most common, and wear, loosening and infection are the main complications. The upper tibial prosthesis often fails due to inadequate soft tissue coverage or necrosis, and the gastrocnemius flap is the best means of preventing deep infection after upper tibial prosthesis reconstruction. Lengthenable prostheses, for pediatric applications, can be adjusted in length periodically. Composite reconstruction with prosthetic allograft bone, which increases the length of the diaphysis to improve prosthetic stability and provide a muscle attachment surface, is sometimes advocated and has also been more widely used. Autologous bone inactivation is also in use, but carries the risk of recurrence and late fracture. Allogeneic bone is still in use, but problems such as immune resorption rejection, low healing power or fracture during postoperative chemotherapy, and atrophy of articular cartilage have not been resolved. Transplanted vascularized fibula is viable, resistant to infection, and has the ability to grow and repair, but it is prone to fracture due to the incomplete shape of the donor and requires long-term protection. Bone transfer is done by threading the needle according to the bone lengthening method, and fixed with a bone lengthening frame to lengthen at a certain speed until it heals with the osteotomy segment after transfer. It is easy to operate, less complications and biological reconstruction can be applied for a long time, but it takes longer time and has nail tract infection. It is suitable for reconstruction of bone defects after resection of large tibial segments.
In recent years, surgical resection techniques for spinal tumors have made great progress, and total spine resection has been widely used in the resection of various spinal tumors. However, there is still disagreement on the indications for total spine resection and the concept of complete resection of spinal tumors. Total spine surgery can completely remove tumor lesions, which is directly related to patient’s prognosis, so it is obviously important to study this technique vigorously, but the complications are very high, so the operator needs to master the indications and cannot promote and apply it blindly.
In addition, the surgical treatment of pelvic tumor has been a difficult point in bone tumor specialty, because of the complex anatomical structure of malignant pelvic tumor and the lack of natural barrier, it is very difficult to resect and reconstruct. There is no unified understanding on whether and how to reconstruct the pelvis after resection, especially for pelvic tumors involving sacrum.
In general, the treatment of bone tumors has been progressing, especially in the field of surgery, but there is no significant breakthrough in oncological control. In the end, bone tumor is an oncology discipline, which needs to emphasize tumor control over functional reconstruction and to improve the oncological prognosis of patients.