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Ovarian tumors of low malignant potential (LMP) comprise 15% of all epithelial ovarian neoplasms.1 Approximately 3,000 women in the US are diagnosed annually.2 Histological criteria for making the diagnosis include nuclear atypia, stratification of the epithelium, formation of microscopic papillary projections, and the absence of stromal invasion. Overall, LMP tumors have a low recurrence rate (7%) and excellent 10-year survival rate (95%).3,4 Surgical staging for LMP tumors apparently confined to the ovary involves cytological washings, random peritoneal biopsies, omentectomy or generous omental biopsy, and retroperitoneal lymph node sampling.5 Appendectomy is also commonly performed, especially for mucinous tumors. Staging biopsies will upstage 24–47% of women and 4–27% will have retroperitoneal lymph node metastases.6–8
Advanced stage appears to be a prognostic factor for decreased survival.4,9 However, few upstaged patients will receive adjuvant therapy because it has not been shown to improve clinical outcome.10,11 In a previous report of 93 women with ovarian LMP tumors, survival and recurrence rates were not significantly different between those who were staged and those who were unstaged.3 However, a recent survey of gynecological oncologists revealed that 97% advocate surgical staging.5 Our group performed a multicenter study to compare the outcome of surgically staged patients with LMP tumors with that of those who were not staged.12
Routine Surgical Staging
Routine pelvic and para-aortic lymph node dissection is not necessary in the majority of women with ovarian LMP tumors. In our study, only 1% of 832 submitted pelvic nodes had metastases and all 314 para-aortic nodes were negative. Pelvic nodal metastases upstaged only two (2%) of 118 patients undergoing lymph node dissection.12 Winters et al. have also recently challenged the utility of nodal sampling after observing nodal metastases in just three (6%) of 48 surgically staged ovarian LMP tumors.3 Camatte et al. reported nodal metastases in eight (19%) of 42 LMP patients undergoing lymphadenectomy. They noted a markedly increased frequency of metastases in the presence of enlarged nodes. All eight patients also had grossly evident invasive or noninvasive peritoneal implants. Importantly, none of the patients with early-stage disease— without gross peritoneal implants—had nodal involvement discovered by routine lymphadenectomy.13
In a meta-analysis of 97 studies including 4,129 patients, lymph node involvement in ovarian LMP tumors was associated with a 98% survival rate at 6.5 years.14 Nodal dissection may be indicated if invasive ovarian cancer cannot be ruled out or if nodes are palpably enlarged. However, complete surgical staging with pelvic and paraaortic lymph node dissection is not routinely performed in the majority of LMP tumors.7