SSI Rates in Patients Undergoing Mastectomy Without Reconstruction- A Multicenter, Double-blinded RCT.

Overview

Breast cancer is the second most prevalent malignancy in the world and an important component of treatment warrants surgical procedures such as mastectomy. Surgical site infections after breast surgery may range from 1-26%, which is high for surgeries that are considered "clean procedures", as defined by the Centers for Disease Control and Prevention (CDC) wound classification system. Prophylactic antibiotics given before the surgical incision as per Joint Commissions SCIP (Surgical Care Improvement Project) guidelines, have been shown to decrease the rate of postoperative infections in a vast number of patients. There is however, no clear consensus due to lack of evidence on continuation (duration) of prophylactic antibiotics in patients undergoing mastectomy with indwelling drains, and thus antibiotic prescribing practices may vary among breast as well as reconstructive surgeons. In this trial all patients undergoing mastectomy without immediate reconstruction will receive a single prophylactic dose of preoperative antibiotic, and subsequently, the patients will be randomized to either continue the prophylactic antibiotics or receive a placebo for the duration of indwelling drains. The aim of this trial is to compare the difference in SSI rates between these two study arms as the main outcome. In addition, the factors associated with differing rates of SSI in the intervention and control group will also be identified.

Introduction: Worldwide, breast cancer comprises 10.4% of all cancer among women, making it the second most common cancer (after lung cancer) and the fifth most common cause of cancer related death. The management of patients as a matter of patient preference or as dictated by extent of disease often warrants a mastectomy. Reports of surgical site infections after breast surgery including mastectomy may range from 1-26%, which is high for surgeries that are considered "clean procedures". Despite a high rate of surgical site infections, there is no consensus on the continuation/duration of prophylactic antibiotics in patients undergoing mastectomy. Consequently, practices may vary among breast and reconstructive surgeons. Evidence regarding the risk of SSI with the use and duration of indwelling drains is also controversial. The length of prolonged, postoperative antibiotic may also vary by practitioners, some using a pre-defined regimen of about 2-7 days, and others continuing them until the drains are removed. Most guidelines recommend a single dose of pre-operative antibiotics and continuation after surgery has been discouraged. The use of common or more specific antibiotics for the duration of drains being in place is also controversial. The recommendation by recent national clinical guidelines is to use one dose of pre-procedural antibiotics for mastectomy patients with or without drains. The American Society of Breast Surgeons also does not recommend the continuation of post-surgical antibiotics in the absence of relevant indications. However, practices vary. Rationale: Since there is lack of evidence and significant surgeon practice variation despite guidelines developed by leading societies, we propose to study the difference in rates of surgical site infection (SSI) with or without continuation of prolonged post-operative, prophylactic antibiotics in all patients undergoing mastectomy without immediate reconstruction and with indwelling drains. Aim: In this trial all patients undergoing mastectomy without immediate reconstruction will receive a single prophylactic dose of preoperative antibiotic, and subsequently, the patients will be randomized to either continue the prophylactic antibiotics or receive a placebo for the duration of indwelling drains. The aim of this trial is to compare the difference in SSI rates between these two study arms as the main outcome. In addition, the factors associated with differing rates of SSI in the intervention and control group will also be identified. Significance: Through this study, the investigators will be able to identify the most effective prophylactic regimen to reduce rates of SSI among mastectomy patients with indwelling drains leading to evidence-based and informed decision making. Primary Objective: To determine rates of surgical site infection (SSI) in patients in two separate arms of this trial, in which all patients will receive the first prophylactic pre/perioperative antibiotic dose and then be randomized to: 1. Post-operative antibiotic prophylaxis continued for the duration of indwelling drains 2. Those who only receive a single dose of preoperative prophylactic antibiotic. Secondary Objective: To identify factors associated with differing rates of SSI in the intervention and control group Primary Outcome: Surgical site infection(SSI) rates at the mastectomy wound site or the drain(s) insertion site among patients. In this study SSI will be evaluated using the standard CDC criteria which are as follows: 1. purulent drainage from the incision or drain site; 2. organisms isolated from an aseptically obtained culture of fluid or tissue; 3. deliberate opening of the incision by a surgeon in patients having either tenderness, localized swelling, redness, or warmth; or 4. diagnosis of SSI by the surgeon or study wound assessor (trained research assistant) or 5. prescription of therapeutic antibiotics; 6. Patients clinically diagnosed and documented to have cellulitis.