(P 489) SIMULTANEOUS VERSUS DELAYED FLAP RECONSTRUCTION FOLLOWING SOFT TISSUE SARCOMA RESECTION

Objective: The morbidity associated with soft tissue sarcomas (STS) treatment is significant considering the preferred surgical option is a limb sparing wide local excision. Accordingly, there are well-documented complications associated with wound healing in this population. To abate these complications, nuanced reconstruction methods including the use of muscle flaps may be utilized as a means to protect the surgical site and promote wound healing. Though, reconstruction methods are not without cost given they are associated with longer hospital stays and may necessitate multiple surgeries in the form of a planned reconstruction following completion of the original procedure. This retrospective study serves to compare surgical and oncologic outcomes between patients receiving simultaneous or delayed flap reconstruction following STS resection.

Methods: 37 patients who underwent flap reconstruction following resection of a primary STS at a tertiary referral center for musculoskeletal tumors from 2019 to 2022 were retrospectively evaluated. Patients who received primary wound closure but subsequently required reconstruction due to complications were excluded (n=3). Of the 34 remaining patients, 24 (71%) received simultaneous reconstruction during the index surgery and 10 (29%) underwent planned delayed reconstruction. Preoperative patient specific metrics, tumor characteristics, surgical, and patient outcomes were collected and are organized in Table 1. The greatest dimension upon radiographic and pathologic measurement was the recorded size. For patients who received delayed reconstruction, the intraoperative and surgical hospitalization metrics for both surgeries were summed and used for data analysis. Significance of differences in means was determined using independent T-tests. Significance of differences between frequencies was determined using chi-square or Fisher’s exact tests.

Results: Mean time between resection and planned reconstruction for those undergoing delayed reconstruction was 9.7 ± 2.7 days. Mean follow-up was 15.91 ± 10 and 17.17 ± 14 months in the simultaneous and delayed cohorts, respectively. Age, sex, BMI, ASA class, tumor grades, presence of metastases at time of surgery, EBL, and OR time were similar amongst both groups (P-values=0.328, 0.575,0.919, 0.069, 0.914, 0.162, 0.184, 0.409). More patients (P-value=0.021) in the simultaneous reconstruction group received chemotherapy in the neoadjuvant setting than did the delayed group. There were no statistical differences between other neoadjuvant or adjuvant therapies, including radiation. Hospital length of stay (HLOS) and complications during operative hospitalization were similar amongst both groups (P-values=0.555, 0.760). Though surgical margins were more often negative in the delayed group (P-value=0.043), the rate of unplanned positive surgical margins was no different between groups (P-value=0.328). The overall postoperative complication, reoperation, and 90-day unplanned readmission rates were equivalent in both groups (P-values=0.935, 0.336, 0.857). The disease specific survival rate at last follow-up was similar in both groups (P-value=0.328) (Table 1).

Conclusion: This retrospective chart review study evaluated surgical and oncologic outcomes for patients undergoing simultaneous or delayed flap reconstruction following STS resection. These data indicate the populations were similar regarding their demographic and comorbid characteristics. It is important to note that more patients in the simultaneous coverage group were receiving chemotherapy and 2 patients had metastases prior to resection, possibly indicating a worse burden of disease amongst that group. Surgical outcomes, complications, readmissions, reoperations, unplanned positive resection margin and disease specific survival were equivalent in both groups suggesting either method can be utilized safely. Patients with planned positive margins had unresectable disease with intraoperative brachytherapy (1) or metastatic disease (2). Each patient undergoing treatment of STS was managed by a multidisciplinary team, and surgical decision making was performed based on patient and tumor characteristics. The advantage of simultaneous reconstruction is that it can be accomplished during a single surgery and anesthetic episode. Alternatively, a critical feature that favors a delayed reconstruction is the ability to assure positive margins prior to final closure. This is valuable in the setting of certain histologic tumor types, such high-grade myxofibrosarcoma, or if the tumor is adjacent to a critical structure and obtaining a negative margin is less certain. In conclusion, this study finds that either simultaneous or delayed flap reconstruction following STS resection can be appropriately implemented in the setting of shared decision making based on a patient’s specific goals of care, tumor characteristics, histology, and tumor location. Future research will focus on mitigating limitations of this study such as improving sample sizes, collecting patient reported outcome data, increasing follow-up length and performing propensity matching to decrease error due to confounders.