Long-term oncological results of patients with primary and metastatic tumors of the musculoskeletal system who underwent arthroplasty

Introduction. Primary malignant tumors of the skeletal system mostly develop in young and middle-aged people. Morbidity in this age group amounts to between 75 and 80 % of overall morbidity. Due to low survival caused by patient death in the first 5 years mostly because of metastases of primary malignant tumors, the main focus of treatment was on prolongation of life, study and development of new methods of conservative therapy. Therefore, until the early 1970 amputation surgery was the generally accepted standard of surgical intervention. Positive oncological results required revision of the surgical concept of treatment in this patient group. This problem was solved through active development of oncological endoprosthesis started in the second half of the 1970s and led to shaping of orthopedic oncology into a separate oncological specialty. The study objective is to study long-term oncological results of treatment of patients with primary and metastatic tumors of the locomotor system after oncological endoprosthesis. Materials and methods. The study included 1292 patients with primary sarcomas of the bones, soft tissues and patients with metastatic and benign bone tumors who underwent 1200 bone resections/extirpations of varying scale with endoprosthetic replacement between January of 1992 and January of 2020. In the total group of patients who underwent endoprosthesis, the number of men and women was approximately the same: 677 (52.4 %) and 615 (47.6 %), respectively. At the time of surgery, age of the patients in the total group varied between 10 and 81 years. Mean patient age was 34.7 years. Most commonly, endoprosthetic replacement was performed in patients between the ages of 21 and 30 years (in 29 % of cases). Oncological endoprosthesic replacement was performed in 814 (67.8 %) patients with primary malignant tumors, 143 (11.9 %) patients with metastatic lesions in long bones, and 243 (20.3 %) patients with benign neoplasms. Mean follow-up period after endoprosthesis of different bone segments was 82.8 months (between 0 and 335.7 months). Results. In 27 years of observations, total frequency of recurrences after endoprosthesis for various tumor locations (type V complication per the International Society of Limb Salvage system (2013) (ISOLS 2013)) was 8.8 % (86/979); among them recurrence in the bone (type VA complication) was observed in 1.7 % (17/979) of cases, recurrence in the soft tissues (type VB complication) in 7.0 % (69/979) of cases. Primary endoprosthetic replacement due to recurrence after previous surgical treatment leads to 2.2-time increase in the risk of development of this complication. The obtained results show that repeat recurrence significantly increases the risk of recurrence in soft tissues and does not affect the risk of recurrence in the bone. The most recurrences developed in patients with non-differentiated pleomorphic sarcoma (15.4 % of cases), chondrosarcoma (15.0 % of cases) and parosteal osteosarcoma (14.3 % of cases). Frequency of recurrences in patients with giant cell bone tumors and aneurysmal bone cysts was 4.0 and 3.8 %, respectively. In cases of tumor recurrence after endoprosthesis, limb amputation was the most common treatment: 33.7 % (28/83) of cases. In this study, recurrence mostly developed after femur resection with knee joint endoprosthesis: in 45.8 % (38/83) of cases. Frequency of oncological complications in patients with bone sarcomas who underwent endoprosthetic replacement was 31.9 % (283/886). In the total patient group in 27 years of observations, in 25.3 % (224/886) of patients disease progression in the form of metastases was observed. Local tumor recurrence was accompanied by metastases in 6.7 % (59/886) of cases. Conclusion. Decreased risk of development of local recurrences depends on the effectiveness of complex approach to therapy in this disease group. Changes in surgical endoprosthesis techniques in tumors of varying differentiation levels allowed to achieve significant radicalness of treatment. Progression risk for bone sarcomas, level of response to specialized therapy and, as a result, patient’s prognosis depend on the presence of epigenetic, genetic, molecular and chromosomal abnormalities.