What tests can tell me about osteosarcoma

Now, due to the social environment, the incidence of osteosarcoma is constantly increasing. There are many examination and treatment methods for osteosarcoma in clinical medicine. If we are unfortunately diagnosed with osteosarcoma, we need to go to a regular hospital for a detailed examination and diagnosis in time. Let me introduce to you what examinations can be done to know if you have osteosarcoma?

All patients suspected of osteosarcoma should undergo diagnostic examinations including: physical examination, imaging examination of the primary lesion (plain X-ray, local MRI and/or enhanced CT scan), bone scan, chest imaging examination (chest CT is the preferred imaging examination method for lung metastasis), laboratory examination (blood routine, lactate dehydrogenase, alkaline phosphatase), and then biopsy to obtain histological diagnosis. Finally, the staging diagnosis of osteosarcoma is completed. If conditions permit, PET-CT can be considered for auxiliary staging of the tumor and efficacy evaluation.

1. Clinical manifestations

The history of osteosarcoma is usually 1 to 3 months. Local pain is an early symptom, which may occur before the appearance of a lump. It is intermittent at first, and gradually turns into continuous severe pain, especially at night. The tumor near the bone end near the joint is large, with varying hardness, tenderness, high local temperature, dilated veins, and sometimes palpable pulsation. There may be pathological fractures.

2. Imaging manifestations

X-rays show bone cortical destruction and irregular new bone. In long tubular bones, it often occurs in the metaphysis. CT can show the bone shape and the internal process of the tumor. After enhancement, it can show the blood supply of the tumor, the relationship between the tumor and the blood vessels, and the range in the bone and soft tissue. MRI can clearly show the soft tissue and is very useful for preoperative planning. It can show the extent of tumor invasion in soft tissue and the extent of invasion in the bone marrow cavity, and find skip lesions. The accuracy of the tumor range determined by CT or MRI has been confirmed by surgical resection specimens, so CT or MRI is a necessary means of imaging examination for osteosarcoma. CT can better show the boundaries of cortical destruction and three-dimensional anatomy. Compared with CT, MRI has more advantages in showing tumor soft tissue invasion, and can accurately show the relationship between the tumor and adjacent muscles, subcutaneous fat, joints, and major neurovascular bundles. In addition, MRI can well show the medullary cavity conditions at the distal and proximal ends of the lesion, and find out whether there is skip metastasis. In some cases, digital subtraction angiography (DSA) can also be selected to clarify the relationship between blood vessels and tumors.

3. Laboratory examination

Laboratory tests such as lactate dehydrogenase and alkaline phosphatase are related to the diagnosis and prognosis of osteosarcoma and should be performed before patients receive neoadjuvant chemotherapy. Blood routine and liver and kidney function should be monitored during chemotherapy. It should be noted that these laboratory tests should be reviewed regularly during treatment and follow-up.

4. Pathological examination

The histological manifestations meet the definition of osteosarcoma, which is a highly malignant tumor originating in the medullary cavity, and the tumor cells can produce bone-like tissue. This definition explains two issues: first, the tumor originates in the medullary cavity and is a highly malignant tumor; second, the tumor cells can produce bone-like tissue, regardless of the amount.

When the clinical and imaging manifestations of the lesion suggest a typical osteosarcoma, a puncture biopsy is often used to confirm the diagnosis. A biopsy must be performed before surgical treatment. Generally speaking, failure to follow the appropriate biopsy procedure may lead to adverse treatment outcomes. The selection of the biopsy site is very important for subsequent limb-salvage surgery. The puncture point must be located at the incision line of the final surgery so that the puncture tract can be removed during the final surgery. Therefore, it is recommended that the biopsy be performed by the final surgeon or his assistant in the hospital where the surgical treatment is planned.

During the biopsy, be careful to avoid fractures. Core needle biopsy is recommended. Open biopsy can be performed if puncture biopsy fails. Excisional biopsy should be avoided as much as possible. Frozen biopsy is not recommended. Fine needle biopsy is also used as a routine biopsy diagnostic method in some bone tumor centers, but it requires the cooperation of experienced pathologists. Biopsy should try to obtain as much tissue as possible so that the pathology department can perform routine pathological examinations. Molecular biological analysis can also be performed on fresh specimens.