Incidence of Ewing's Sarcoma in Different Age Groups, Their Associated Features, and Its Correlation With Primary Care Interval.

Introduction Primary care interval is the time duration from a patient's first presentation to the final diagnosis. Ewing's sarcoma is a rare small round blue cell bone tumor originating from neuroectoderm and undifferentiated neuroepithelial cells, having an annual incidence of approximately one case per million in the United States. In this study, we analyzed the age pattern among patients diagnosed with Ewing's sarcoma undergoing management, along with associated features including involved site, regional lymphadenopathy, and distant metastasis at the time of presentation and their correlation with the primary care interval. Methods This is a cross-sectional study carried out at the Oncology department of a Tertiary Care Government Hospital in Karachi, Pakistan. The duration of our study was from January 2020 to December 2020. During this period, all patients with proven diagnosis of Ewing's sarcoma between ages 10 years and 65 years were included in the study. All the participants of the study were divided into groups, based on the age and site of the tumor. Results A total of 895 cases of bone cancer were reported. Among these, 147 cases (16.4%) had Ewing's sarcoma. Of these patients, 88 were male (60%) while 59 (40%) were female. The mean age of patients was 18.9 ± 3.2 years. Ewing's sarcoma most commonly occurred during 15 to 20 years of age. The most common region involved was lower limb (n=76, 52%) followed by upper limb (n=63, 43%) followed by pelvis (n=8, 5.4%). Conclusion The peak time for the occurrence of Ewing's sarcoma is from 15 years to 20 years of age. Regional painful swelling is the most common presenting feature in our study population. Factors causing a prolonged primary care interval include early age of onset, non-specific clinical presentation, and insufficient knowledge of the primary care physician, which results in poor prognosis. Hence, it is important to consider Ewing's sarcoma as a differential on the first presentation especially in the high-risk age group.