Impact of obesity on the oncological and surgical outcomes of thigh soft tissue sarcoma

Background. Malignant soft tissue tumors are a heterogeneous group with variable prognosis and with a tendency to recurrence and distant spread, mainly to the lungs. Also, obesity is a known risk factor for many diseases and cancers and is currently a global problem. While the thigh is one of the main fat deposition areas, it is one of the commonest sites for the incidence of soft tissue sarcoma. We tried to illustrate the impact of obesity on the outcomes of thigh soft tissue sarcoma patients. Material and Methods. We retrospectively recruited data of extremity sarcomas treated at our hospital from January 2008 to January 2020. The epidemiological and clinical data of all the included patients was analyzed, then the surgical and oncological outcomes between obese and non-obese patients were compared (defining obesity as BMI more than 30). We hypothesized that fat deposition in the thigh in obese patients may delay the diagnosis of soft tissue sarcoma, lead to the discovery of the masses at a larger size and stage, and hence may affect the disease-free survival and the overall survival. Results. Obese patients had significantly larger size tumors (median: 14.7 vs 9.9 cm) and as such significantly higher T stage. Another significant finding was that the mean diameter of liposarcoma tumours was 15.1 cm, while that of non-liposarcomas was 11.3 cm (p-value=0.023). Also, although they did not have a higher prevalence of distant metastasis at initial diagnosis, their metastasis tends to be isolated in the lung. Postoperative complications occurred more frequently in obese patients in comparison to nonobese patients (p-value=0.025). Neither overall nor disease-free survivals were different among both groups, although obese patients tend to have shorter DFS. Conclusion. Obesity added complexity to the diagnosis and treatment of extremity sarcoma, but seems not to affect survival.