Comparison of Tumor Recurrence in Oncoplastic Pelvic Reconstruction with Vertical Rectus Abdominis Musculocutaneous (VRAM) versus Omental Flaps: Outcomes Following Ablative Abdominoperineal Resection (APR) and Pelvic Exenteration

BACKGROUND – Little is known about the impact of the type of soft-tissue reconstruction on local tumor recurrence in patients with pelvic malignancy undergoing abdominoperineal resection.  Therefore, the purpose of this study is to describe our experience and outcomes in oncoplastic pelvic reconstruction for patients who underwent either vertical rectus abdominis musculocutaneous (VRAM) or omental flap following abdominoperineal resection (APR) at a single tertiary care institution.

STUDY DESIGN/METHODS - All patients who underwent oncoplastic reconstruction following APR with either VRAM or omental flaps at the Mayo Clinic in Rochester, Minnesota from January 1992 – January 2017 were retrospectively reviewed. Patient demographics and relevant comorbidities (i.e. hypertension, diabetes mellitus, smoking status) were collected for all patients.  Additionally, chemotherapy and radiation therapy (neoadjuvant, intra-operative, or adjuvant) data were collected and analyzed. In addition, margin status at the time of oncologic resection was analyzed.  Flap-specific data were collected for each approach, including use of skin paddle and rationale for using one approach over the other (i.e. previous omentectomy or diverting colostomy).  Oncologic data collected includes cancer type, stage at time of APR, tumor recurrence within the flap and stage of tumor at time of recurrence. Statistical analysis was performed with SPSS Version 11.0 statistic software package (SPSS, Chicago, IL). Comparisons between groups were performed with analysis of non-parametric test. A value of P < 0.05 was considered statistically significant. Univariate and multivariate analyses were performed.

RESULTS – A total of 585 patients were identified who underwent pelvic soft-tissue reconstruction with either VRAM or omental pedicle flaps.  Of these, 297 (50.8%) underwent VRAM reconstruction (270, 90.90% with skin paddle) and 288 (49.2%) underwent omental flap reconstruction. All margins were negative at time of cancer ablation surgery. Specific complications and their respective rates of occurrence in each reconstructive approach included bowel obstruction [VRAM=0; Omentum=17(5.9%)], wound dehiscence [VRAM=31(10.4%); Omentum=26(9.0%)], and tumor recurrence within pedicle flap [VRAM=14(4.7%); Omentum=40(13.9%)]. Of the 31 cases (10.4%) of wound dehiscence in VRAM patients, 6 occurred in the abdomen and 25 occurred in the perineum at the skin paddle.  Chi-squared test comparing tumor recurrence between these two reconstructive approaches showed a significantly higher recurrence rate in omental flaps compared to VRAM flaps (p= 0.000127).

CONCLUSIONS – The results of this study suggest a significantly higher tumor recurrence rate in omental flap pelvic reconstruction compared to patients reconstructed with VRAM flaps. This knowledge has the potential to influence surgical planning and flap selection in oncoplastic pelvic reconstruction.