Discussion
This study was powered to determine the impact of LND on survival for IR
and HIR EC, and it concluded that there were no differences observed
between patients in whom LND were performed and those in whom LND were
not performed with respect to 5-year Kaplan-Meier estimates of OS, and
DFS were statistically insignificant. Additional analysis, particularly
for IR and HIR EC groups was performed to determine whether these
estimates will converge or continue to diverge. Our results were in line
with the previously published two RCTs 2,3. These RCTs
revealed that LND in EC had only a diagnostic role to guide the adjuvant
treatments such as radiotherapy and chemotherapy without providing a
survival benefit.
These RCTs concluded that the routine systematic pelvic LND cannot be
performed for therapeutic purposes in primary surgery for early-stage EC
patients 2,3. The main critique of RCTs was the
presence of high percentage of EC patients with either low-risk or
advanced disease. Nevertheless, the administration rates of adjuvant
treatments are similar among LND and no LND groups. Our study diverges
from many studies with investigating IR and HIR EC groups by excluding
the remaining subgroups of EC. Besides, the present study had an equal
proportion of administering adjuvant treatments among LND and no LND
groups.
Moreover, to conduct a stratified analysis, we investigate the impact of
lymph node count on survival. Our results revealed that the count of
pelvic lymph nodes were not predictors of IR and HIR EC outcomes.
Contrary to our findings, Lutman et al. showed that pelvic lymph node
count was found to be a prognostic factor in high grade EC patients.
Further analysis revealed a total of 12 or more pelvic lymph nodes was a
predictor for survival in early staged HIR EC patients13. The putative therapeutic benefit of increasing the
number of dissected lymph nodes may be attributed to accurate stage
assignment and subsequent use of adjuvant therapies in node-negative EC14. The reason for the inconsistency of previous
results with our study might be the high proportion of utilizing
adjuvant treatments in the no LND group than its expected15,16
There were limited number of studies particularly focusing on
postoperatively assessed IR EC patients. Coronado et al. found that LND
has no any survival benefit in IR EC without increasing in perioperative
morbidity or mortality 17. Moreover, L. Bougherara et
al. also reported that survival benefit was not improved in IR EC
patients by performing lymphadenectomy without excluding the nodal
positive patients 11. Our results are consistent with
these two studies by showing LND in IR EC patients has no benefit on
survival. However, the SEPAL study concluded that performing complete
LND has a survival benefit for EC patients at intermediate risk that is
corresponding to IR and HIR according to ESMO-ESGO-ESTRO classification18.
Contrary to our findings, some retrospective studies showed a
therapeutic role of an adequate LND in HIR EC patients9,13,19. The main suggestions for the benefits of
survival were the suggested that the adequate LND might provide survival
benefit by the removing of occult lymph node metastases. While the
present study was not designed to evaluate for the presence of occult
metastases, the removal of possible occult metastases does not appear to
be clinically useful for IR and HIR EC. The inconsistency of our results
might be explained with the risk of LN involvement in IR and HIR EC
appears lower than some relevant previous studies19,20, with a rate of 10.3%. But larger-scale
prospective studies are needed to evaluate the oncologic safety of
omitting LND in HIR EC.
Some studies considered that the patients with no LND were more likely
to have nodal recurrence than the patients with LND in IR and HIR EC18-20, but our results did not support this finding.
Regarding HIR EC patients, a recent French national retrospective study
showed that unstaged patients had more nodal recurrence than surgically
staged patients 19. However, a recently performed a
retrospective matched pair study, which included 178 diagnosed of IR EC,
showed the number and the site of recurrence was similar in LND and no
LND groups 17.
The limitation of the present study are the retrospective design and the
lack of evaluating the risks of LND. Without illuminating the morbidity
of LND, there were no difference observed in OS and DFS between IR and
HIR EC patients with LND-induced complications and no LND. The results
of the present study were similar with many published studies including
two RCTs in highly stratified EC risk groups with lymph node counts.
Considering the systematic nodal staging is associated with higher
morbidity 21, with this regard, we believe that the
use of sentinel lymph node procedure might be better for minimizing the
possible post-operative morbidities in this selected patient groups.