While women await surgery for type I endometrial cancer, depot medroxyprogesterone acetate reduces tumor glandular cellularity

Abstract

Background: Multiple population-level studies have demonstrated an adverse effect of long wait times to surgery on survival for women with endometrial cancer. Other retrospective and nonrandomized prospective studies have shown that preoperative administration of depot medroxyprogesterone acetate decreases tumor glandular cellularity, which may be a surrogate marker for clinically meaningful tumor response.

Objective: We sought to determine whether preoperative injection with depot medroxyprogesterone acetate decreases tumor glandular cellularity when compared to placebo injection in women awaiting hysterectomy for endometrial intraepithelial neoplasia or type I endometrial cancer, and to determine whether depot medroxyprogesterone acetate injection affects quality of life while waiting for surgery.

Study design: This was a double-blind, randomized controlled trial of 400-mg depot medroxyprogesterone acetate injection or 0.9% saline injection at the preoperative visit. Patients with recent use of progesterone analogs were excluded. A sample size of 76 patients (38 per arm) was calculated to detect a 20% difference in decreased glandular cellularity between arms. Pathologic characteristics including the primary outcome, tumor glandular cellularity, from patients' diagnostic biopsies were reviewed by 2 dedicated gynecologic pathologists and compared to posttreatment hysterectomy specimens. On the night prior to surgery, patients completed the Functional Assessment of Cancer Therapy-Endometrial Survey (Version 4) to report quality of life while waiting for surgery. In comparing characteristics between the intervention and control groups, t tests were used for continuous variables, and χ² or Fisher exact tests were used where appropriate for categorical data.

Results: From March 2015 through March 2016, 148 women were screened and 76 patients were enrolled. In all, 38 patients were randomized to and received depot medroxyprogesterone acetate injection and 38 were randomized to and received placebo injection. Demographics were similar between groups. Patients who received depot medroxyprogesterone acetate injection experienced a larger decrease in tumor glandular cellularity (mean change -64 [-31.8%] vs -14 [-5.5%] cells per quarter high-powered field in depot medroxyprogesterone acetate vs placebo groups, P = .002). This effect was most pronounced in women waiting ≥3 weeks for surgery. Several additional histologic and immunohistochemical markers of tumor differentiation and decreased cell proliferation were more pronounced in the depot medroxyprogesterone acetate group than in the placebo group. There were no significant differences in quality of life between groups on the Functional Assessment of Cancer Therapy-Endometrial Survey. Only 5.3% of patients who were approached declined to participate due to concerns regarding an intramuscular injection.

Conclusion: Administration of depot medroxyprogesterone acetate prior to surgery for type I endometrial cancers caused greater tumor effect than placebo injection. Injection of depot medroxyprogesterone acetate was acceptable to and well tolerated by patients. Depot medroxyprogesterone acetate may represent a meaningful bridge to surgery in women who can expect long wait times.

Keywords: endometrial cancer; progesterone analogs; wait time to surgery.