Lymphatic mapping and sentinel node identification as related to the primary sites of lymph node metastasis in early stage ovarian cancer

OBJECTIVE: We evaluated the primary sites of lymph node (LN) metastasis in patients during the early stage of ovarian cancer. METHODS: Study 1: patients with clinical stage I and II common epithelial ovarian carcinoma (n = 150) underwent systematic retroperitoneal LN dissection of the pelvic and paraaortic areas. The relationship between the incidence and location of LN metastasis and clinical and histological characteristics was examined. Study 2: we studied 11 women with endometrial or fallopian tube tumors. At laparotomy, activated charcoal solution was injected into the unilateral cortex of the ovary. Ten minutes later, the retroperitoneal spaces were opened and charcoal uptake within the pelvic lymph node (PLN) and paraaortic node (PAN) as far as the level of renal vein was examined. RESULTS: Study 1: The incidence of LN metastasis by stage was 6.5% (8/123) in stage I and 40.7% (11/27) in stage II. Among 19 patients with LN metastasis, 14 had only PAN, 2 had only pelvic LN, and 3 had both PAN and PLN metastases. Metastasis was limited to the ipsilateral side in 12 (63%) patients, but was bilateral in 5 (26%) and contralateral to the neoplastic ovary in 2 (11%). Positive peritoneal cytology was significantly (P < 0.05) correlated with lymph node metastasis. Study 2: Lymphatic channels along the ovarian vessels were identified in all injected ovaries. Charcoal was deposited in the LN of all patients. The locations of these nodes included PAN in all patients, common iliac node in three, and external iliac node in one. CONCLUSION: PAN is the primary site of LN metastasis in ovarian cancer. Bilateral PAN dissections are necessary to determine the extent of tumors even in stage I ovarian carcinoma.