[Lymphatic mapping and parametrial lymph nodes identification in patients with early stage cervical cancer]

To determine the presence, distribution, and metastasis incidence of parametrial lymph nodes (PLN) of patients with cervical cancer and to investigate the role of lymphatic mapping and topographic section in PLN identification.

Sixty patients with early stage (Ib-IIa) cervical cancer undergoing radical hysterectomy and pelvic lymphadenectomy were included in the study. Before surgery 4 ml methylene was injected into the cervix around the tumor. The blue-dyed lymph nodes were identified as sentinel lymph nodes (SLN) during operation. An immediate topographic section on uterine specimen was performed to separate the PLN from parametria for pathologic examination.

Ninety five PLN were presented in 38 (63%) of 60 specimens, with a mean size in diameter of (0.46 +/- 0.24) cm. Among the total PLN, 57 (60%) were located parallel to uterine artery through the entire broad ligament, and the other 38 (40%) were scattered in cardinal ligament, sacral ligament and vesicocervical ligament. After lymphatic mapping, 69 (73%) of PLN were dyed and identified as SLN. Parametrial metastasis was found in 12 (20%) patients, and parametrium was the only site containing positive nodes in 2 patients with parametrial metastasis. On routine pathologic evaluation, 17 PLN were found to be positive. Among the remaining 78 PLN, multilevel sectioning in conjunction with immunohistochemical analysis was carried out and 3 PLN containing micrometastases were identified.

The study shows that PLN are usually found in the parametria, and these nodes often contain metastatic diseases which are easily overlooked. Lymphatic mapping followed by meticulous topographic section is feasible in PLN identification in patients with cervical cancer.