Qué es el osteosarcoma y cuáles son sus síntomas principales

Author: Han Xiuxin, Tianjin Medical University Cancer Hospital.

Title: What is Osteosarcoma and What Are Its Main Symptoms.

One. Understanding the 'king of bone cancer in adolescents' - Osteosarcoma.

When we hear the word 'cancer,' we often first think of lung cancer, breast cancer, thyroid cancer, stomach cancer, among others. However, there is also a highly malignant tumor in the skeletal system that particularly affects children and adolescents, known as the 'king of bone cancer in the young,' which is osteosarcoma. Understanding its characteristics and achieving early detection, timely diagnosis, and prompt treatment are key to conquering this 'king of bone cancer'.

What is osteosarcoma?

Osteosarcoma, as its name implies, is a malignant tumor that originates in the bony tissue itself and is capable of producing immature bone tissue. It is more common in adolescents aged 10 to 20 years, with an annual incidence of approximately 2-3 cases per million people. Although it represents a relatively low proportion of all malignant tumors in humans (around 0.2%), it constitutes 11.7% of primary bone tumors, being the most common primary malignant tumor in children and adolescents.

Three. Clinical characteristics of osteosarcoma.

The most characteristic feature of osteosarcoma is local pain and swelling. Initially, the pain may be intermittent, but it gradually worsens, becoming intense and continuous, especially noticeable at night. This pain is often confused with growing pains, which can lead to a delay in diagnosis. Tumors typically appear in areas of active growth, such as the distal end of the femur (near the knee), the proximal part of the tibia, and the proximal part of the humerus. High-risk populations: in addition to adolescents, individuals with genetic predisposition syndromes (such as Li-Fraumeni syndrome, characterized by mutations in the TP53 gene, or with a history of retinoblastoma) are at greater risk of developing this disease. Furthermore, it is also a relatively common secondary malignant bone tumor following radiotherapy.

Four. Prevention and detection of osteosarcoma: the key is to be alert to early signs.

Currently, there are no specific prevention measures or detection methods for osteosarcoma. Therefore, it is crucial to be vigilant and recognize early symptoms. If you or your child exhibit any of the following signs, it is essential to seek medical attention immediately: persistent and progressive bone pain of unknown cause, especially if it occurs at night; the appearance of a painless or painful lump near the joints at the ends of bones, with possible local temperature increase and, in some cases, visible veins; recurrent pain or swelling in the same area that does not improve with rest and is not related to exercise injuries; upon presenting any of these symptoms, one should go as soon as possible to a specialized center for the treatment of bone tumors. The doctor will conduct a detailed inquiry, a physical examination, and, in combination with imaging studies (such as X-rays, CT scans, or MRIs), will be able to make a preliminary assessment.

Five, diagnosis and treatment of osteosarcoma: integrated therapy is the key tool.

The diagnosis and treatment of osteosarcoma is a systematic process that emphasizes 'integrated treatment,' meaning multi-disciplinary team collaboration.

5.1 Accurate diagnosis.

Imaging examinations: these include X-rays, contrast-enhanced computed tomography (CT), and contrast-enhanced magnetic resonance imaging (MRI) of the affected area, used to assess the extent of the tumor and its relationship with surrounding vessels and nerves. Chest CT is necessary, as the lungs are the most common site of metastasis for Ewing sarcoma. Whole-body bone scans or PET/CT help detect lesions in other areas.

Pathological biopsy: this is the 'gold standard' for diagnosis. Generally, image-guided needle biopsy is preferred to obtain tissues for pathological analysis. The design of the biopsy trajectory is crucial, as it must ensure that the needle path can be removed during subsequent surgery to prevent tumor dissemination.

5.2 Comprehensive treatment.

The treatment of osteosarcoma has evolved from simple amputation in the past to an integrated approach that combines neoadjuvant chemotherapy, surgery, and adjuvant chemotherapy, significantly increasing cure rates and limb conservation.

Chemotherapy: it is the basis of treatment. It is generally administered prior to surgery (neoadjuvant chemotherapy) with the aim of reducing the tumor, eliminating possible micrometastases, and creating better conditions for limb-sparing surgery. Additionally, it allows for evaluating the tumor's sensitivity to medications. Commonly used chemotherapy drugs include doxorubicin, cisplatin, high-dose methotrexate, and ifosfamide, among others. After surgery, adjuvant chemotherapy continues based on treatment effectiveness (assessed through tumor necrosis rates).

Surgery: The goal is complete tumor removal. Nowadays, approximately 90%-95% of patients with osteosarcoma in the limbs can undergo limb-sparing treatment, which involves reconstructing limb function after tumor removal, using artificial prostheses, allografted bones, or reimplantation of inactive bones. Amputation is only considered when the tumor invades important blood vessels or nerves, when chemotherapy is ineffective, or when safe surgical margins cannot be obtained for secure limb conservation. In cases of tumors in special locations such as the pelvis or spine, the surgical challenges are greater, but thanks to technologies like 3D printing and computer navigation, precise removals and reconstructions are also possible.

Radiotherapy: Osteosarcoma is not sensitive to conventional radiotherapy. However, in cases where complete surgical removal is not possible or in those with positive margins, especially in tumors located in the pelvis or spine, radiotherapy can be an important adjunct treatment. Precision radiotherapy techniques, such as proton/carbon therapy, have shown certain advantages.

Targeted therapy and immunotherapy: For recurrent or refractory osteosarcomas, targeted drugs (such as anlotinib, regorafenib, apatinib, among others) offer new options for patients. Immunological therapies, such as immune checkpoint inhibitors, are also being explored and could provide hope for some patients.

Treatment and prognosis: The prognosis is related to several factors, including whether the tumor had metastasized at the time of diagnosis, the tumor's response to chemotherapy, and whether surgery can achieve safe surgical margins, among others.

Six. Rehabilitation and follow-up of osteosarcoma: a bridge to normal life.

The completion of treatment does not mean the end of the process, as systematic follow-up care is key to ensuring long-term quality of life. Functional rehabilitation: postoperative recovery should occur in stages. In the early stage, the focus is on promoting wound healing and preventing complications; in the intermediate stage, the goal is to gradually regain joint mobility and muscle strength; in the later stage, the aim is to further improve physical capacity, with the ultimate goal of reintegrating the patient into normal life and learning. For patients who have undergone surgery in the lower limbs, gait training and balance training are particularly important. Regular follow-up: after treatment, it is crucial to adhere strictly to the follow-up plan, which generally consists of examinations every three months for the first two years, every four months in the third year, and then extending the interval. Follow-up includes physical examinations, imaging studies of the surgical area (ultrasound, MRI/CT), and a chest CT, aiming to detect local recurrences or metastases early.

Seven, psychological support therapy.

The diagnosis of osteosarcoma represents a significant psychological challenge, especially for adolescent patients and their families. Positive psychological interventions and social support are essential to help patients build confidence, effectively complete treatment, and reintegrate into society.

In summary, although osteosarcoma has a high degree of malignancy, it is not an untreatable disease. In the face of this, we need scientific knowledge: to be alert to any painful bone mass of unknown origin and seek medical attention as soon as possible; to trust a multidisciplinary team specialized in bone tumors to receive integrated and appropriate treatment; and to emphasize systematic rehabilitation and long-term follow-up after treatment. Through collaboration between doctors and patients, it is entirely possible to conquer this 'king of bone cancer in adolescents' and restart a beautiful life.