Mediastinal cancer is a malignant neoplasm of various morphologies located in the median parts of the thoracic cavity. The progression of mediastinal space cancer is accompanied by chest pain, shortness of breath, dysphonia, cough, dysphagia, and the development of Gorner and superior vena cava syndromes. Chest x-ray, computer and magnetic resonance imaging, mediastinoscopy or videothoracoscopy with biopsy helps to diagnose mediastinal cancer. Surgical treatment of mediastinal cancer can be radical or palliative (in order to decompress neighboring organs). In most cases, radiation therapy is also used.
ICD 10
C38.1 C38.2 C38.3
Meaning
The collective concept of “mediastinal cancer” includes various volumetric malignancies originating in the mediastinal space. Among all mediastinal tumors, malignant neoplasms of various histological structures account for 20-40%. Mediastinal cancer is most often represented by lymphoma (reticulosarcoma, diffuse and nodular lymphosarcoma), Hodgkin’s disease; malignant thymoma, angiosarcoma, neuroblastoma, dysgerminoma, chondrosarcoma and osteoblastoclastoma are less common. In addition, metastases of primary cancer of various localization, sarcomas, melanomas can be detected in the mediastinum. Malignant tumors of the mediastinum are found mainly in young and middle-aged people (20-40 years), with equal frequency in men and women. Specialists in the field of oncology and oncopulmonology are engaged in the treatment of mediastinal cancer.
Causes of mediastinal cancer
The true causes of the development of primary mediastinal cancer remain unclear. Oncologists suggest that the leading role in the etiology of malignant neoplasms of mediastinal localization belongs to ionizing radiation, contact with carcinogenic substances in everyday life, agriculture and production, viral agents (Epstein-Barr virus, HIV infection). The risk of non-Hodgkin’s lymphomas of the mediastinum is higher in people who have received radiation therapy for other oncological processes, as well as in patients with autoimmune diseases.
Some tumors initially develop as malignant (for example, lymphomas and sarcomas); others initially arise as benign, but under the influence of adverse factors they undergo malignancy (for example, thymomas, teratomas, etc.); others are metastatic in nature. Metastatic mediastinal cancer can be an “echo” of lung cancer, thyroid cancer, esophageal or stomach cancer, breast cancer, colorectal cancer, nephroblastoma, melanoma, hemorrhagic Kaposi’s sarcoma in AIDS. Metastasis from primary foci occurs by contact propagation, by lymphogenic or hematogenic pathway. Detection of metastatic mediastinal cancer is an unfavorable prognostic sign.
Classification
Thus, depending on its origin, mediastinal cancer is divided into primary (initially develops from mediastinal organs) and secondary (metastatic cancer of other localizations).
According to the histogenetic classification, primary malignant neoplasms of the mediastinum are divided into tumors originating from their own mediastinal tissues, tissues dystopized (displaced) into the thoracic cavity during embryogenesis, and tumors of the thymus gland:
Malignant tumors developing from their own mediastinal tissues include:
- neurogenic tumors (neurogenic sarcoma, neuroblastoma)
- mesenchymal tumors: from connective (fibrosarcoma), fatty (liposarcoma), muscular (leiomyosarcoma), lymphoreticular (lymphoma, lymphosarcoma), vascular (angiosarcoma) tissue.
Among the dysembriogenetic neoplasms of the mediastinum originating from dystopian tissues, there may be:
- tumors from thyroid tissue (malignant intra-thoracic goiter)
- tumors from multipotent cells (malignant teratoma – teratocarcinoma)
- chorionepithelioma, seminoma (dysgerminoma), etc.
Malignant thymomas (thymus cancer) are prone to infiltrative growth, early and extensive metastasis.
Mediastinal cancer can be classified by localization. So, in the upper mediastinum, lymphomas, thymomas, mediastinal goiter are detected from malignant tumors. In the anterior mediastinum, in addition to tim and lymphomas, mesenchymal tumors and teratomas are also found. The middle mediastinum is affected by lymphomas, the posterior mediastinum is a favorite place of localization of malignant neurogenic tumors.
Symptoms of mediastinal cancer
During mediastinal cancer, an asymptomatic period and a period of obvious clinical manifestations are distinguished. The duration of the asymptomatic stage depends on the location of the tumor, its size, histological type, growth rate, and relationships with other mediastinal structures. The symptoms of all mediastinal tumors are quite similar, but malignant neoplasms are characterized by rapid progression of symptoms. The clinical picture of any mediastinal tumor consists of general manifestations inherent in oncopathology, signs of compression or germination of mediastinal organs and specific symptoms characterizing different types of neoplasms.
The most common complaint of patients suffering from mediastinal cancer is a pain syndrome caused by compression or germination of nerve trunks. The pain is localized on the side of the lesion, often radiating into the shoulder, neck, the area between the shoulder blades, sometimes imitating angina pectoris. When a tumor conglomerate squeezes the upper thoracic nerve roots, Gorner’s syndrome occurs. With the interest of the recurrent laryngeal nerve, hoarseness of voice appears, with compression of the trachea and large bronchi – shortness of breath and cough, esophagus – difficulty swallowing food.
When a growing tumor squeezes large venous trunks, the syndrome of the superior vena cava, typical for mediastinal cancer, develops, characterized by shortness of breath, puffiness and cyanosis of the face, heaviness in the head, swelling of the neck veins. In some cases, mediastinal cancer reveals enlarged lymph nodes above the collarbone, the growth of a tumor of the chest wall, in children – swelling of the sternum. In the late stages of mediastinal cancer, weakness, sweating, fever, weight loss occur. Sometimes there are edema of the extremities, arthralgia and swelling of the joints, arrhythmias, hepatomegaly, ascites.
Specific symptoms of malignant lymphomas are night sweating and itching of the skin. With intra-thoracic goiter, symptoms of thyrotoxicosis occur. Episodes of spontaneous hypoglycemia are typical for mediastinal fibrosarcomas – a drop in blood glucose levels. Patients with malignant thymoma often develop myasthenia gravis syndrome, Cushing’s syndrome, hypogammaglobulinemia, anemia.
Diagnostics
Patients with a suspected diagnosis of mediastinal cancer are referred for consultation to a thoracic surgeon or oncologist. To establish an accurate morphological and topographic-anatomical diagnosis, the data of X-ray, tomographic, endovideosurgical studies, and biopsy results play a crucial role.
The mandatory list of X-ray examinations includes chest X-ray, esophageal X-ray with contrast, computed tomography. In most cases, the conducted examination allows to establish the localization of mediastinal cancer and the prevalence of the process, the interest of the organs of the thoracic cavity (lungs, diaphragm, aorta, chest wall). MRI helps to clarify the condition of soft tissues in the area of neoplasm, to identify tumor metastases in lymph nodes and lungs.
Endoscopic methods are widely used in the diagnosis of mediastinal cancer. Bronchoscopy allows you to exclude bronchogenic localization of the tumor, the germination of neoplasms into the trachea and large bronchi. In addition, a transbronchial biopsy of the formation can be performed during the study. In some cases, transthoracic biopsy is resorted to under ultrasound or X-ray control. If enlarged lymph nodes are detected in the subclavian region, a precalculated biopsy is indicated. If lymphoreticular tumors are suspected, a sternal puncture is performed with the study of a myelogram.
Highly informative diagnostic studies are videothoracoscopy and mediastinoscopy, which make it possible to verify the topography of the mediastinal tumor, to take material for morphological examination under the control of vision. Parasternal thoracotomy and mediastinotomy can also be used for revision and biopsy of the mediastinum. Mediastinal cancer must be differentiated from aortic aneurysm, sarcoidosis, echinococcosis, coelomic cyst of the pericardium, abdominal-mediastinal lipoma and other benign tumors of the mediastinum.
Treatment for mediastinal cancer
The tactics of mediastinal cancer treatment depends on the type of malignant tumor, its localization and prevalence. Some malignant tumors (reticulosarcoma) are sensitive to radiation treatment, others (lymphoma, lymphogranulomatosis) – to polychemotherapy, radiation, immunochemotherapy. In metastatic mediastinal cancer, palliative irradiation is performed in combination with chemotherapy or hormone therapy. Combination therapy is recognized as the most effective approach to the treatment of radiosensitive connective tissue tumors and teratoblastomas, where radical removal of mediastinal tumors is preceded by neoadjuvant radiation therapy. Radioresistant tumors (chondrosarcomas, fibrosarcomas, malignant schwannomas, leiomyosarcomas) in resectable cases are immediately subject to removal.
Resection of mediastinal tumors is often associated with technical difficulties, which are caused by intervention in the area of vital organs, large nerve trunks and major vessels. The extended removal of mediastinal cancer means the complete excision of the tumor together with the lymph nodes of the surrounding tissue, which is often supplemented by resection of the organs into which it germinates (pericardium, lungs, esophagus, nerves, vessels, etc.). When the neoplasm is localized in the posterior mediastinum, lateral or posterolateral thoracotomy is usually performed; in the anterior mediastinum – anterolateral thoracotomy or sternotomy.
In addition to radical excision of mediastinal cancer, palliative removal of the formation can be carried out in order to decompress the mediastinum. After complete or partial removal of the tumor, chemotherapy or radiation treatment is performed, taking into account the greatest sensitivity of the mediastinal neoplasm to one or another effect. The prognosis for mediastinal cancer varies depending on the type of tumor, but is generally unfavorable. In terms of survival, combined treatment with pre- and postoperative radiation therapy has advantages over surgical.