Osteosarcoma

Diagnosis

Diagnosis of osteosarcoma can be made through the following techniques:

• Medical history and physical examination: Patients may experience the symptoms of osteosarcoma for a considerable period, generally for weeks or months, before the patients seek consultation from the orthopedics. During the consultation, the patients undergo a comprehensive evaluation of signs and symptoms to determine the cause. Sometimes the patients also have to undergo complete body evaluation to find symptoms in the organs other than bones to determine the spread of the disease.
• Blood tests: No blood test is sufficient to diagnose osteosarcoma. However, blood tests assist in determining the overall health of various body organs, including bones. The patients may undergo tests to detect the levels of biochemical markers, such as lactate dehydrogenase and alkaline phosphatase. The patients may have elevated alkaline phosphatase levels due to increased activity of osteoblasts, which may be possible because of osteosarcoma. Very high alkaline phosphatase levels indicate a very high tumor burden, possibly lowering the chances of favorable outcomes. Evaluation of tumor biomarkers may also be evaluated during the treatment.
• X-rays: Once the patients are suspected of having bone mass, tumor, or osteosarcoma, they are advised to undergo a radiographic examination. The results of the radiographic examination may reveal bone destruction. The other characteristic features of the radiographic results in osteosarcoma are cloud-like lesions and osteoid matrix calcification due to the tumor.
• Magnetic resonance imaging: It is a preferred imaging modality in diagnosing osteosarcoma. The technique further characterizes the presence of lesions identified during radiographic examination. MRI also assists in detecting the spread of tumors inside and outside the bone. The radiologists generally involve one joint above and below the affected bone to avoid skipping the lesions. MRI also provides valuable information about the spread of the tumor to surrounding soft tissues, neurovascular bundles, and joint involvement.
• Computed tomography scan: CT scan is not used once the tumor is detected through the radiographic examination and MRI scan. The CT may assist in disease staging and planning the surgery. However, in patients with lytic lesions, a CT scan may be used as the radiographic examination, and MRI may not be able to detect this type of lesion. Further, a CT scan is the preferred imaging modality for evaluating the chest for metastatic osteosarcoma.
• PET scan: PET scan detects the spread of osteosarcoma in various body parts. The technique specifically detects metabolically active lesions. Once the suspicious mass is detected during the preliminary imaging methods, the patients may undergo a PET scan to determine the extent of tumor lesions and to identify subtle lesions. The patients may also expect a PET scan to diagnose cancer recurrence.
• Bone scan: Bone scan is the method to detect bony metastasis. The technique involves using radionucleotide, which is injected into the vessels and accumulated in the abnormal areas of the bone.
• Biopsy: The biopsy is a procedure that involves obtaining samples of the affected bone and sending them to the laboratory to detect the presence of cancer cells. There are several types of biopsy for osteosarcoma. These are:
• Core needle biopsy: Core needle biopsy involves using a thin, hollow needle to remove the bone tissue as a cylinder. The procedure is performed under the action of local anesthesia. If the tumor is deep inside the bone, ultrasound (ultrasound-guided biopsy) or CT scan (CT-guided biopsy) may assist in the biopsy.
• Surgical biopsy: In cases where the tumor sample is not obtained through core needle biopsy, the patients may have to undergo surgery to obtain the sample. The procedure is done under anesthesia. The skin is cut, and the sample is removed by exposing the affected bone.