[Incidence and influencing factors of distal external iliac lymph node metastasis in early cervical cancer].

OBJECTIVE: The distal external iliac lymph nodes are located along the external iliac artery between the deep circumflex iliac vein and the inguinal canal. Our study aimed to investigate the incidence of metastasis in distal external iliac lymph nodes and its association with clinicopathological factors in patients with early stage cervical cancer, and to determine the role of distal external iliac lymph nodes dissection in the surgery. METHODS: Five hundred and twenty-four patients with early stage cervical cancer underwent radical hysterectomy and bilateral pelvic lymphadenectomy in the Shandong Province Cancer Hospital between June 1995 and December 2011, and their clinicopathological features were analyzed retrospectively. RESULTS: Of the 524 patients, 124 (23.7%) had pelvic lymph node metastasis. The metastasis rates were 16.2% (85 of 524 patients) in the obturator lymph nodes, 12.2% (64 of 524 patients) in the internal and external iliac lymph nodes, 2.9% (15 of 524 patients) in the common iliac lymph nodes, 2.1% (11 of 524 patients) in the distal external iliac lymph nodes, and 1.7% (9 of 524 patients) in the para-aortic nodes. The incidence of isolated positive distal external iliac lymph nodes was 0.2%. Univariate analysis showed that lymphovascular space invasion, pelvic lymph node metastases (excluding distal external iliac lymph nodes) were significantly associated with distal external iliac lymph node metastasis (P < 0.05). Logistic regression analysis showed that pelvic lymph node metastasis (excluding distal external iliac lymph nodes) was the independent risk factor for metastasis to distal external iliac lymph nodes. CONCLUSIONS: In early stage cervical cancer, distal external iliac lymph node metastasis is rare, especially in cases with stage IA or without pelvic lymph node metastasis. Less extensive pelvic lymphadenectomy may be considered in these patients in order to reduce operative complications and improve patients' quality of life. The deep circumflex iliac vein may be an appropriate landmark for the caudal limit of external iliac lymphadenectomy. However, if pelvic lymph node metastasis (excluding distal external iliac lymph nodes) is found by intraoperative rapid pathological diagnosis, systematic pelvic lymphadenectomy including removal of the distal external iliac lymph nodes should be performed in order to reduce the risk of distant metastasis.