Rate of Unexpected Malignancy at the Time of Hysterectomy Being Performed for a Benign Indication

Abstract

<h3>Study Objective</h3> Determine the proportion of patients undergoing hysterectomy for benign indications who have unexpected malignancy (UM) on postoperative pathology and characterize the nature of and factors associated with UMs. <h3>Design</h3> Retrospective review. <h3>Setting</h3> 7 Ontario, Canada hospitals (4 academic, 3 community). <h3>Patients or Participants</h3> Patients undergoing hysterectomy for a benign indication from July 2016-December 2019. Hysterectomies for invasive placentation, malignant, and premalignant indications were excluded. <h3>Interventions</h3> Primary outcome was rate of unexpected malignancy as defined by the number of patients with malignancy on final pathology divided by the number of hysterectomy cases in our cohort. <h3>Measurements and Main Results</h3> Data was extracted from health records and electronic medical records. Associations between UM status and perioperative variables were assessed using bivariate logistic regression. During the study period, 2779 hysterectomies were performed for benign indications. Rate of UM was 1.8% (51/2779), with one patient having two malignancies (total UMs = 52). The most common UM location was uterine (endometrial (27/52, 51.9%), sarcoma (13/52, 25%), gestational trophoblastic neoplasia (1/52, 1.9%)) followed by ovarian (6/52, 11.5%), fallopian tube (4/52, 7.6%) and appendiceal (1/52, 1.9%). Patients with UM were older (57.2 ± 11.4 years vs 52.8 ± 12.5 years, p = .015) and had more previous laparotomies (2 (1.25, 2.0) vs 1 (1.0, 1.0), p < .001). They also had a higher BMI (29.7 ± 7.2 kg/m² vs. 28.0 ± 5.9 kg/m², p=.049) and ASA class (<i>p</i> < .028). Regarding surgical factors, patients with UM had more adhesions (p= .001), transfusions (p= .020) and blood loss (p= .006) compared to those with benign pathology. <h3>Conclusion</h3> The rate of UM among women undergoing hysterectomy for benign indications was 1.8%. The most common types of malignancy were endometrial cancer and sarcoma. Several perioperative variables were associated with an increased chance of UM at the time of hysterectomy.