ATLANTA — Lymphadenectomy improved survival in women with stage I, grade 3 through stage IV endometrioid uterine cancers in an analysis of more than 39,000 patients.
Although several studies have shown an association between lymphadenectomy and improved survival, questions remain about lymphadenectomy and staging, and whether there is a benefit for patients with stage I disease, said Dr. Nita Karnik Lee at the annual meeting of the American Society of Clinical Oncology.
The findings of the current study suggest lymphadenectomy performed during surgical staging is beneficial for women with stage I, grade 3 or higher endometrioid uterine cancers, Dr. Lee said.
The analysis focused on data from the U.S. National Cancer Institute's Surveillance Epidemiology and End Results (SEER) program during 1988–2001, including that from 12 registries. The data showed that of 39,396 women with endometrioid uterine cancers, 12,333 (31%) underwent surgical staging and lymphadenectomy. The remaining patients underwent hysterectomy and bilateral salpingo-oophorectomy without lymphadenectomy.
Overall 5-year disease-specific survival was 93% for stage I patients, 85% for stage II patients, 69% for stage III patients, and 38% for stage IV patients.
In the lymphadenectomy group, compared with the group without lymphadenectomy, 5-year disease-specific survival was 96% vs. 97% for those with stage I disease, 90% vs. 82% for those with stage II disease, 73% vs. 61% for stage III disease, and 52% vs. 28% for those with stage IV disease, said Dr. Lee, a clinical instructor at Stanford (Calif.) University Medical Center.
The differences were significant for those with stages II-IV disease, as well as for the subgroup of stage I patients with grade 3 disease. In this subgroup, 5-year disease-specific survival was 90% for those with lymphadenectomy vs. 85% in those without.
Also, in patients with deep myometrial invasion (stage IC, grade 3), there was a trend toward improved survival. The 5-year disease-specific survival was 82% in the lymphadenectomy group and 77% in the nonlymphadenectomy group; this difference was not statistically significant.
The proportion of patients with stage I disease was significantly higher in the group without lymphadenectomy (84% vs. 73%). In addition, there were about 20% more patients in the group without lymphadenectomy that had grade 1 disease. Perhaps consistent with these findings was the fact that this group received less radiation overall, compared with the lymphadenectomy group, she said.
On multivariate analysis, nonwhite race, advanced stage, advanced grade, and advanced age were prognostic factors associated with poorer survival. Year of diagnosis and presence of lymphadenectomy were independent prognostic factors associated with improved survival.
During a formal discussion of this study, Dr. Thomas Herzog of Columbia University, New York, noted that although it addresses the important question of the effect of lymphadenectomy on survival, the study is limited in a number of ways, including lack of randomization. Further, lymph node dissection was the only variable considered, minorities were underrepresented in the database, and the analysis fails to establish the role of lymph node dissection in all stage I cases, he added.
He said the methodological limits failed to answer critical questions, such as whether there is a threshold node count, whether there is value of lymphadenectomy in stage I patients, and whether the effect seen is a therapeutic or diagnostic effect, such as stage migration.
Nonetheless, the findings are consistent with guidelines released earlier this year regarding the role of lymphadenectomy in endometrioid uterine cancers, and they appear to help boost the level of evidence in support of these guidelines, he said.