The results from the Lymphadenectomy in Ovarian Neoplasms (LION) trial, published in the New England Journal of Medicine, which compared systematic pelvic and paraaortic lymphadenectomy with no lymphadenectomy in some women with advanced ovarian cancer, showed no benefits associated with lymphadenectomy. In fact, this procedure actually appeared to increase risks for these patients.1

The results were applicable to patients with advanced ovarian cancer undergoing primary cytoreductive surgery with disease that had been completely resected intraabdominally and with macroscopically normal lymph nodes.

Most women with ovarian cancer have metastatic disease at the time of diagnosis. The standard of care for the treatment of these women involves surgical removal of all visual, intraabdominal evidence of the primary tumor.  Since the likelihood of micrometastatic disease spread to pelvic and aortic lymph nodes is relatively high, the question of whether to also routinely perform lymphadenectomy during primary surgery has been debated. Nevertheless, conflicting results have been obtained regarding the risks and benefits of lymphadenectomy in the setting of normally appearing lymph nodes.

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In addressing this question, the LION study was carefully designed to remove many potential confounding factors that had been identified in previous studies evaluating lymphadenectomy in this setting.1,2 For example, all participating centers had to meet surgical quality standards before being allowed to enroll patients. In addition, only women who had undergone complete intraperitoneal cytoreduction were included, and randomization was conducted only following a determination of complete cytoreduction.

Furthermore, an assessment of potential lymph node involvement was performed visually in the same manner for all patients, and no women with lymph node involvement on visual inspection were included in the study. The primary end point of the trial was overall survival (OS), with secondary study end points including progression-free survival (PFS) and safety.

A total of 647 women with International Federation of Gynecology and Obstetrics (FIGO) stage IIB to IV epithelial ovarian cancer were randomly assigned in a 1:1 ratio to 1 of the 2 study arms from December 2006 to January 2012. No significant differences were observed in either median OS (69.5 months vs 65.5 months for patients not undergoing or undergoing lymphadenectomy, respectively; hazard ratio [HR]=1.06; 95% confidence interval [CI], 0.83-1.34; P =.65) or median PFS (25.5 months in both groups; HR=1.11; 95% CI, 0.92-1.34; P =.29) when the 2 study arms were compared. Notably, serious postoperative complications (P =.01) and 60-day mortality following surgery (P =.049) were significantly higher in the group undergoing lymphadenectomy.

In commenting on the results of the LION trial, authors of an accompanying editorial wrote that “the procedures required to achieve complete cytoreduction already have attendant risks, and eliminating ineffective techniques such as systematic lymphadenectomy is prudent to improve patients’ overall recovery.”

References[

  1. Harter P, Sehouli J, Lorusso D, et al. A randomized trial of lymphadenectomy in patients with advanced ovarian neoplasms. N Engl J Med. 2019;380:822-832.
  2. Eisenhauer ELChi DS. Ovarian cancer surgery – heed this LION’s roar. N Engl J Med. 2019;380:871-873.