[Diagnostic clinical algorithm for mediastinal tumors].

Objective: To optimize therapeutic and tactical algorithm in patients with mediastinal tumors.

Material And Methods: The study included 300 patients with mediastinal tumors examined and treated in the Thoracic Surgery Department of the Hertzen Moscow Cancer Research Center between 2008 and 2019. Patients were stratified into 2 groups. The diagnostic group consisted of 160 patients including 80 ones after 89 ultrasound-assisted transthoracic biopsies and 80 patients after open biopsy through parasternal mediastinotomy. The treatment group consisted of 140 patients who underwent 145 resections of mediastinal tumors. We analyzed the results of diagnosis and treatment in both groups, mistakes, risk factors of non-informative biopsies and complicated course of the postoperative period. Subsequently, a clinical algorithm was developed. Its effectiveness in 50 patients was compared with 90 patients who constituted the historical control group.

Results: The final histological diagnosis after transthoracic ultrasound-assisted biopsy of the mediastinum was established in 71 out of 89 cases (80%). Informative value of ultrasound-assisted biopsy for thymic tumors was 100%, for metastatic mediastinal lesions - 92%. Repeated ultrasound-assisted biopsies were performed in 7 (9%) patients that made it possible to establish the final diagnosis in 5 (71%) cases. In the parasternal mediastinotomy group, the final correct histological diagnosis was made in 79 out of 80 (99%) patients. Analyzing thoracoscopic approach and traditional sternotomy or thoracotomy, we found surgery time decrease from 187 (150-215) to 140 (122-165) min (<0.01), blood loss from 300 (200-350) to 50 (35-150) ml (<0.01), postoperative hospital-day from 12 (9-14.5) to 7 (6-8) days (<0.01). Mean dimension of tumor was 5 (4-6) cm in the thoracoscopy group and 7.5 (6-10) cm in the open surgery group (<0.01). Postoperative complications occurred in 19 (13%) patients, mortality rate was 2.8%. Multivariate analysis revealed superior vena cava syndrome (OR=5.1, 95% CI=1.246-21.343; =0.024) and invasion of the right pleural cavity (OR 4.2, 95% CI 1.12-7.69; =0.006) as the most significant predictors of postoperative complications. The proposed algorithms made it possible to reduce the incidence of non-informative biopsy from 12% to 0% (<0.05), misdiagnosis from 9% to 1% (<0.05), exploratory surgeries from 23% to 0% (<0.05).

Conclusion: The developed algorithm is valuable to avoid the errors and improve the results of diagnosis and treatment of patients with mediastinal tumors.