Trial Summary

Project Title

Prophylactic Antibiotic Regimens in Tumor Surgery (PARITY): A Multi-Center Randomized Controlled Study Comparing Alternative Post-operative Antibiotic Regimens in Patients Undergoing Tumor Resections with Endoprosthetic Reconstruction of the Lower Extremity.


Limb salvage surgery is the standard of care in the management of sarcoma of the long-bones. Advances in chemotherapeutic regimens and imaging techniques allow for wide resection and functional reconstruction in 95% of patients. The most common type of long-bone reconstruction involves the use of a tumor prosthesis, or endoprostheses. Due to the complexity and length of surgical resection and reconstruction, as well as the immunocompromised nature of patients treated with chemotherapy, the risk for infection remains high. Deep infection following endoprosthetic reconstruction is a devastating complication that requires staged revision surgery and long-term intravenous antibiotics. The risk for recurrent infection remains high, as does the risk for ultimate amputation. However, the most effective antibiotic regimen in preventing postoperative deep infections remains controversial, and the current state of practice varies widely, particularly with respect to antibiotic duration. Moreover, patients’ quality of life and function following infection are dramatically impacted, as are health care costs. Strategies to optimize prevention of infection and quality of life, while mitigating health care costs are needed.


The objective of this study is to determine whether long term (5 days) postoperative antibiotics will decrease the rate of infection following lower extremity tumor surgery, when compared to short term (24 hours) postoperative antibiotics.


We hypothesize that long-term antibiotics will result in lower rates of deep postoperative infection (primary outcome) and less antibiotic related complications (secondary outcome) at 12 months compared with short-term antibiotics.

Study Design

This study is a multi-center, blinded, randomized controlled trial, using a parallel two-arm design to investigate whether long term postoperative antibiotic regimens (5 days) will decrease the rate of infection among patients being surgically treated for a lower extremity bone tumor, when compared to short term postoperative antibiotics (24 hours). An international sample of 600 patients will be randomized using a computerized randomization system that allows random variable block sizes to one of two treatment arms (24 hours or 5 days). The randomization is stratified by: 1) center and 2) location of tumor (femur vs. tibia). The patients will be followed for 1 year after surgery. We will assess infection rates within 12 months after initial surgery across both study arms. Patients, surgeons, outcome adjudicators and data analysts will be blinded. We will measure function and quality of life preoperatively, and at 3 months, 6 months, and 1 year postoperatively.

Potential Impact of Study

This study represents a major international effort to resolve the incongruities around the use of prophylactic antibiotics in musculoskeletal tumor surgery. This trial will not only change current practice in surgical orthopaedic oncology, but will establish a collaborative network of surgeons to conduct research and set a benchmark for the conduct of future trials.