Detection of Micrometastases in Cervical Cancer With a System That Evaluates Both Sentinel and Nonsentinel Lymph Nodes

Abstract

The aim is to reevaluate the accuracy of our sentinel lymph node (SLN) detection procedure and the use of SLN examination for detecting cervical cancer micrometastases. Patients affected by cervical cancer who underwent radical hysterectomy and total pelvic lymphadenectomy at Tohoku University Hospital from 2001 to 2003 were enrolled in this study. Patients in whom lymph node metastases were detected by routine histological examination or in whom no SLNs could be detected were excluded. Paraffin-embedded tissue blocks were cut into 3-microm thick slides at 200-microm intervals for both SLNs and non-SLNs. All lymph nodes were evaluated with step-serial sectioning and immunohistochemistry with an anticytokeratin antibody. One of the 10 patients had micrometastases, and 1 patient had isolated tumor cells (ITCs) in their SLNs. Thus, 2 (6%) of the 31 SLNs detected by our method had cancer cells. In contrast, none of the 309 non-SLNs obtained from 10 patients had micrometastases. The SLN micrometastases were detected in the right external iliac basin. The ITCs were detected in the left external iliac basin. The patient with micrometastases did not have vascular invasion but experienced recurrence. The case with ITCs had vascular invasion; however, she received adjuvant chemoradiotherapy and had no recurrence after 4 years. Our study suggests that only SLNs will contain micrometastases or ITCs, and non-SLNs will not. The SLNs detected by our method are probably real given the large total number of nodes evaluated. How micrometastases affect prognosis and the best way to detect them are areas of further study.