Routes of lymphatic spread: A study of 112 consecutive patients with endometrial cancer

Objective. The goal of this work was to assess different patterns of lymphatic spread to pelvic and para-aortic lymph nodes (LNs) in endometrial cancer as a function of the location of tumor within the uterus. Methods. Between 1984 and 1999, 625 patients with endometrial cancer were managed with hysterectomy and node dissection at our institution. The present study includes the 112 (18%) patients who had positive pelvic and/or para-aortic LNs; 41 (37%) of them had cervical involvement. Results. The external iliac was the most commonly involved pelvic LN site both in patients with tumor limited to the corpus and in those with cervical invasion. Isolated pelvic LN metastases to a single site were more frequently observed in external iliac LNs and obturator LNs in patients with tumor confined to the uterine corpus, whereas they occurred more commonly in external iliac and common iliac LNs in patients with cervical involvement. Metastasis to the common iliac LNs was more frequent in patients with disease extension to the cervix. In fact, common iliac LNs were positive in 67% of patients with cervical invasion, compared with only 30% of those with tumor confined to the uterine corpus (P < 0.01). Para-aortic LN invasion was significantly associated with obturator LN status. In fact, para-aortic LNs were positive in 64% of patients with positive obturator LNs compared with 23% of patients with negative obturator LNs (P = 0.01). All patients with positive para-aortic LNs and tumor invading the cervix had positive common iliac LNs. By contrast, when tumor was limited to the corpus, common iliac LNs were involved in only 27% of patients with positive para-aortic LNs. Conclusion. External iliac LNs are the most commonly involved LNs in endometrial cancer. Compared with carcinomas limited to the uterine corpus, endometrial cancers invading the cervix spread more readily to the common iliac LNs. Furthermore, these data suggest that para-aortic LN metastases spread via a route shared by the common iliac LNs when tumor involves the cervix but spread predominantly via a route common to the obturator LNs (and/or external iliac LNs) when the primary tumor site is the corpus only.