This study was conducted to determine whether tumor-associated macrophages (TAMs) correlate with clinicopathological features in endometrioid adenocarcinoma.

76 cases of endometrioid adenocarcinoma treated initially by hysterectomy with pelvic lymphadenectomy were retrospectively retrieved, and their histological features were evaluated. Immunohistochemical staining for CD68, CD34, and Ki-67 was performed on paraffin-embedded sections. TAMs were counted in two areas: in the invasive margin (margin TAMs) and in the tumor (intratumor TAMs).

Margin TAMs were significantly associated with FIGO stage (P=0.033), histological grade (P=0.008), myometrial invasion (P=0.0001), pelvic lymph node metastasis (P=0.027), and vascular space invasion (P=0.0001). Intratumor TAMs were significantly associated with intratumor Ki-67 (P=0.006) and microvessel density (P=0.020). Patients with high margin TAMs (≥20) had significantly worse progression-free survival (PS) and overall survival (OS) than those with low margin TAMs (<20) (log rank test, P=0.0031 and P=0.0085, respectively). On multivariate analysis, high margin TAMs were significantly associated with vascular space invasion (P=0.013; HR, 6.05; 95% confidence interval [CI], 1.468–24.938) and myometrial invasion (P=0.041; HR, 4.03; 95% CI, 1.06–14.71). Vascular space invasion was only associated with PFS.

Although on univariate analysis TAMs are associated with other poor prognosticators, on a multivariate analysis, TAMs appear only to be associated with MI and VI. TAMs may play a significant role in the biology of tumor progression of endometrial adenocarcinoma, but do not appear to be independent prognostic indicators of patient's survival.