(P 305) THE INCIDENCE OF THROMBOEMBOLIC EVENTS DURING HOSPITALIZATIONS FOLLOWING SURGICAL RESECTION OF LOWER EXTREMITY SARCOMAS IN CHILDREN: UTILIZING THE PEDIATRIC HEALTH INFORMATION SYSTEM (PHIS) DATABASE

Objective: Venous thromboembolism (VTE) is a frequent occurrence during treatment for adults with sarcoma, and the British Orthopedic Oncology Society VTE Committee recommends consideration of mechanical and chemical VTE prophylaxis for adults undergoing orthopedic oncologic surgery, with special consideration for high-risk patients (pelvic or hip resections, prosthetic reconstruction, malignant diagnosis, presence of metastases, or surgical procedures longer than three hours). The incidence and underlying risk factors of postsurgical VTE in children and adolescents undergoing resection of sarcoma is unknown.

Methods: Using ICD-9 diagnostic and procedure codes, the Pediatric Health Information System (PHIS) database was queried for patients age 18 years and under, discharged from 2004-2015 with a diagnosis of lower extremity malignant neoplasm who had a tumor resection or amputation performed during the encounter. Malignant neoplasms of the pelvic bones and soft tissues were categorized as ‘Pelvis Tumors’, while malignant neoplasms of bone and soft tissues of the lower limbs were categorized as ‘Lower Limb Tumors”. Hospitalizations were evaluated for the occurrence of VTE (collectively defined as pulmonary embolism (PE) and deep venous thrombosis (DVT)). Demographic characteristics (age at admission, sex, race, and race/ethnicity) are reported as counts with percentages, and incidence of VTE in these subsets were also tabulated.

Results: There were 2400 patients identified. Of these, 19 experienced VTE (0.79%) during their surgical hospitalization encounter. By anatomic group, the rate of VTE was 1.4% (CI 0.5%-3.2%) for tumors in the Pelvis and 0.6% (CI 0.3%-1.0%) in Lower Limb Tumors. Categorizing by age, the incidence of VTE was 1.2% in patients aged zero to five, 0.3% in patients six to 13 and 1.2% in patients 14 to 18 years old. (Table 1). The extremely low rate of VTE occurrence precluded further analysis of risk factors.

Conclusion: In this PHIS analysis, post-surgical VTE during hospitalization following pelvic and lower extremity sarcoma resection was an uncommon event in children and adolescents. There appeared to be an increased incidence of postsurgical VTE in Pelvic Tumors when compared to Lower Limb Tumors, however the rarity of all events precluded formal statistical analysis. A more robust dataset would be required to determine if there are subsets of children and adolescents with sarcoma at higher risk of VTE that could benefit from thromboprophylaxis in the postoperative setting.