Objective: To determine whether pelvic lymph node count is associated with patterns of recurrence or survival in patients with FIGO stage I and II endometrial cancer.
Methods: Single institution retrospective study of 467 patients with FIGO stage I and II endometrial cancer treated with primary surgery including lymph node dissection. Analysis included pelvic lymph node count, histology, stage, age, race, BMI, year of surgery, depth of myometrial invasion, and adjuvant radiation. Kaplan-Meier life-tables were used to calculate survival; the Cox proportional hazards model was used to identify prognostic factors independently associated with survival.
Results: Mean pelvic lymph node count was 12.6 (SD +/- 8). Distant recurrence was associated with decreased pelvic lymph node count, high-risk histology, and postoperative pelvic radiation. Pelvic lymph node count was not associated with survival by univariate analysis, however, overall (OS) and progression-free (PFS) survival were significantly better with pelvic lymph node counts >or=12 among women with high-risk histology (P < 0.001), but not among women with low-risk histology. Multivariable Cox proportional hazards regression identified increasing age, non-Caucasian race, and high-risk histology as independent negative prognostic factors for both OS and PFI. Among patients with high-risk histology, pelvic lymph node count remained an independent prognostic factor for both overall (OS) and progression-free survival (PFS) in the model, with hazard ratios of 0.28 and 0.29, respectively, when >or=12 pelvic lymph nodes were identified. Pelvic lymph node count had no association with OS or PFS in women with low-risk histology.
Conclusion: Pelvic lymph node count >or=12 is an important prognostic variable in patients with FIGO stage I and II endometrial cancer who have high-risk histology. Most likely, the association of survival and lymph node count in this group is the result of improved staging among patients with higher pelvic lymph node counts.