**5. Staging**

Osteosarcoma is considered a systemic disease. Tumor cells are present in the circulating blood and tumor micro-metastases are possible in the lungs. Approximately 10–20% of osteosarcoma patients are metastatic at the time of diagnosis [15].

It is a three-grade system generally used in determining tumor grade. Grade 1 represents low grade. There is a well-differentiated tumor. Grade 2 represents middle grade, there is a moderately differentiated tumor. Grade 3 represents high grade, there is an undifferentiated tumor. If the tumor grade is low, the tumor is resistant to chemotherapy and radiotherapy [2, 7].

#### **Figure 2.**

*MRI images involving the right femur distal and joint; a) coronal T1 sequence, b) coronal T2 - STIR image, c) axial T2 sequence and d) T1 + contrast image. In the images, the distal third of the right femur has an extension to the superior part of the inner femoral condyle and the midline distal of the femur, and has a satellite nodular structure of approximately 5.5 mm in the epiphyseal line, especially in the T1A series, the heterogeneous hyperintense signal in the T2A series, infiltrating bone marrow fat 12.5 there is a mass lesion of x4cm. Especially when T2 sequence was examined, it was determined that the mass showed extra cortical and extra osseous spread in the inner part, periosteal reaction and accompanying a soft tissue mass in the intramuscular localization with an intramuscular localization of approximately 84x48mm with a heterogeneous necrotic contrast in the soft tissue. Low-intensity, especially peripherally wavy rim-style contrast enhancement was noted in post-contrast series.*

Osteosarcoma most often metastasizes to the lungs. This is followed by bone metastases. Contrast-enhanced thin-section CT of the lung is the gold standard in detecting the presence of metastasis in the lung. Skip metastases in the same bone and distant bone metastases can be detected by Whole-Body Bone Scintigraphy. PET-CT is valuable in showing all body metastases and evaluating the chemotherapy response after treatment. Also useful for detecting nucleus [7, 8, 11].

**91**

*Current Therapeutic Approaches for Osteosarcoma DOI: http://dx.doi.org/10.5772/intechopen.98434*

In the past, patients with osteosarcoma were tried to be treated with amputation, but patients were lost due to micro-metastatic disease and lung metastases. With the discovery that chemotherapy can eliminate micro-metastases (1970's), limb-sparing surgeries came to the fore [16]. The application of neoadjuvant chemotherapy and limb-sparing surgeries became standard in the 1980s. This paved the way for the development of limb salvage procedures that can achieve limb with better functional and cosmetic results. With the advances in treatment, studies on long-term functional and cosmetic extremity acquisition methods have

With the development of induction and adjuvant chemotherapy protocols and advances in surgical techniques and radiological staging studies, approximately 90–95% of patients are now treated with limb-sparing methods instead of amputation. In limb-sparing surgery, reconstruction is applied in necessary patients in addition to tumor resection. And after all these advances, the chance of long-term survival and cure rate of these patients increased to 60–80% in localized (non-

In classical osteosarcoma, the general treatment plan is preoperative (neoadjuvant) chemotherapy, extremity conserving surgery if possible, and postoperative chemotherapy regimen based on the extent of tumor necrosis. In surgical treatment, the tumor is resected with wide margins. Amputation is performed for patients who cannot undergo limb-sparing surgery [18]. Osteosarcoma is a radiore-

The high-dose methotrexate with leucovorin rescue (HDMTX), doxorubicin and cisplatin (MAP) trio is the basis of standard systemic chemotherapy and is administered for approximately 30 weeks [16]. In a newly diagnosed osteosarcoma patient, 2 cycles of neoadjuvant chemotherapy (2 MAP cycles for approximately 10 weeks)

After the HDMTX infusion administered for 2 weeks, a 1-week break is taken, then doxorubicin and cisplatin are administered for 2 days. And a 2-week break is given for bone marrow recovery. And the cycle repeats. Then, surgical treatment is

Histological response value evaluated during surgical treatment is a strong prognostic factor. High tumor necrosis rate has better clinical outcomes after

The results of surgery alone are very poor in osteosarcoma treatment. And with

Local control can be achieved through limb salvage surgery or ablative surgery (**Figure 3**). There is no significant difference between amputation and wide resection in local surgery in terms of recurrence and survival rates. Metastasectomy

In recent years, many studies have been conducted on reconstruction after tumor resection with wide margins in local treatment and reconstruction options have been diversified. Custom-made or modular tumor resection prostheses are one of them. In addition, osteoarticular allografts and composite allografts are other options. With the advances in microsurgery, vascular fibula and myo-cutaneous flaps have also become an alternative for reconstruction. Another option is the method of recovered bone (reconstruction of the bone with the tumor tissue covered by removing the tumor, autoclaving or irradiating it or treating the bone

After the HDMTX infusion administered for 2 weeks, a 1-week break is given, then doxorubicin and cisplatin are administered for 2 days. And a 2-week break is

sistant tumor and radiotherapy does not have therapeutic properties.

chemotherapy alone, only about 10% of the patients responded [21].

**6. Treatment management**

increased.

metastatic) diseases [17].

are applied first.

applied [19].

neoadjuvant chemotherapy [20].

with liquid nitrogen) [11, 22].

should be considered in lung metastases [14].
