Cancer Research Lab

Women with stage I non-clear cell ovarian cancer who undergo lymphadenectomy live longer than their counterparts who don’t go through the same procedure, according to analysis of data from the Surveillance, Epidemiology and End Results (SEER) Program.

Even though standard therapy for all cases of ovarian cancer is supposed to include lymphadenectomy, many of the 25% of cases diagnosed with early stage disease fail to undergo a complete staging procedure, Dr. John K. Chan and associates note in their report, published in the January issue of Obstetrics and Gynecology.

To assess the potential therapeutic benefits of lymph node dissection in these patients, Dr. Chan, from Stanford University School of Medicine, and associates in California examined the records of 6,686 women with stage I invasive ovarian cancer diagnosed between 1988 and 2001.

The investigators observed that only 42.8% of patients had a lymphadenectomy. When the procedure was performed, the median number of nodes resected was 9 (range 1-84).

Characteristics associated with significantly higher likelihood of undergoing a lymphadenectomy included age < 50 years, non-African race, residence in the western region of the US, having a clear-cell cancer, and diagnosis in the most recent time period (between 1998 and 2001) (p < 0.001 for each).

Overall, 5-year disease specific survival was 92.6% for those who underwent removal of lymph nodes versus 87.0% for the remainder (p < 0.001). Significant improvements in survival were noted for women age 50 or older, Caucasian women, and those with non-clear cell epithelial ovarian cancer. The authors note that women of other races experienced similar benefit, but the differences did not attain statistical significance.

The outcomes for other types of ovarian cancer - clear cell, sarcoma, germ cell and sex cord stromal tumors - were not affected significantly by lymphadenectomy.

Dr. Chan’s group suggests several ways that lymphadenectomy may help. It may be that patients receive more accurate staging and hence more appropriate adjuvant treatment.

Another possibility is that, even though metastatic lymph nodes were not observed, micrometastatic disease may have been removed. Or it may be that “the removal of resistant clones of cells and regions of poor blood supply” provides the survival benefit, “rather than a dramatic reduction in tumor volume.”

“Without the explicit ability to prove that an ovarian tumor is benign preoperatively or during surgery, consultation with a physician with advanced training in gynecologic cancer surgery should be considered,” Dr. Chan and his colleagues conclude, “because our data suggest that women with stage I non-clear cell epithelial ovarian cancers who underwent lymphadenectomy had a significant improvement in survival.”