Major Finding: Women with node-negative cervical cancer who had more than 30 lymph nodes removed were 37% less likely to die, compared with those who had fewer than 10 nodes removed.
Data Source: Retrospective study of more than 5,500 women in the SEER database.
Disclosures: Dr. Shah had no financial conflicts to disclose. Dr. Gold has received grants and research support from Ikonisys Inc., and he has served on the advisory board of Hologic Inc.
SAN FRANCISCO — Extensive lymphadenectomy improves survival for node-negative cervical cancer patients, based on a review of data from more than 5,500 women with stage IA2-IIA cervical cancer.
Overall, the greatest benefit was seen in women who had more than 30 nodes removed, but this was seen only in node-negative patients, Dr. Monjri Shah reported.
“Likely this represents a removal of the micrometastases, or [means that clinicians] are identifying women and triaging them to a proper adjuvant treatment group,” she said in an interview.
Lymph node status is “the most important prognostic factor that influences treatment planning,” noted Dr. Shah of Columbia University in New York. “While the diagnostic benefit of lymphadenectomy is well established, the potential therapeutic benefit remains unknown,” she told attendees, explaining why the investigators undertook the study.
Dr. Shah and colleagues reviewed data from the National Cancer Institute's SEER (Surveillance, Epidemiology, and End Results) database on 873 node-positive patients and 4,648 node-negative patients who were diagnosed with stage IA2-IIA cervical cancer between 1998 and 2005. The researchers created separate models for node-positive and node-negative patients.
Among the node-positive patients, 131 (15%) had 10 or fewer nodes removed, 320 (37%) had 11-20 nodes removed, 236 (27%) had 21-30 nodes removed, and 186 (21%) had more than 30 nodes removed.
Among the node-negative patients, 762 (16%) had 10 or fewer nodes removed, 1,709 (37%) had 11-20 nodes removed, 1,251 (27%) had 21-30 nodes removed, and 926 (20%) had more than 30 nodes removed.
Significant predictors for a more extensive lymphadenectomy included age older than 40 years, white race, earlier year of diagnosis (1988-1993), and stage IB-IIA disease. Factors that predicted cancer-specific survival included age younger than 40 years, white race, later year of diagnosis (2000-2005), squamous histology, small tumor size, stage IA2, and the number of lymph nodes removed.
Overall, patients who had more than 30 nodes removed were 29% less likely to die than those who had 10 or fewer nodes removed. Extensive lymphadenectomy had no significant effect on survival for women with positive nodes. But among node-negative women, those with more than 30 nodes removed were 37% less likely to die than those who had fewer than 10 nodes removed.
The morbidity of lymphadenectomy should be weighed against the possible survival advantage, Dr. Shah advised.
The results were surprising in that women with positive nodes had no survival advantage with an extensive lymphadenectomy, but those with pathologically negative nodes did, she added in an interview. “Given that this is a retrospective analysis of the SEER database, we certainly need more information regarding comorbidities and factors that may have influenced patient and physician preferences for treatment,” said Dr. Shah.
Prospective, observational studies are needed to determine whether the results are an effect of extensive lymphadenectomy, and to determine how many lymph nodes constitute an adequate lymphadenectomy, as has been done in other types of cancers, she added.
Lymph node positivity is an important predictor of survival in cervical cancer, said study discussant Dr. Michael Gold of the University of Oklahoma in Oklahoma City.
In early-stage disease, lymph node positivity is among the most common criteria for adjuvant chemoradiation, said Dr. Gold. In theory, more-thorough lymphadenectomy in early-stage patients should allow clinicians to detect more occult metastatic disease, as has been shown with other cancers, including cancers of the colon, rectum, breast, lung, skin, and endometrium. Given the potential survival advantage that is seen with more thorough lymphadenectomy, more research is needed to make evidence-based recommendations.
In an interesting retrospective evaluation of the SEER database, investigators noted superior survival within the subgroup of individuals with node-negative cervical cancer who had the largest number of lymph nodes (more than 30) removed at the time of surgery, compared with those from whom fewer than 10 nodes were removed.
These provocative findings represent another example of the age-old debate as to whether the favorable outcome results from the elimination of “micrometastatic” cancer in these individuals who undergo extensive lymph node surgery, or whether the procedure has simply more carefully defined a population with “true” lymph node-negative disease.