The diagnostic role of lymph node dissection in early-stage
endometrial cancer
LND is used in the surgical staging of EC. The International Federation
of Gynaecology and Obstetrics (FIGO) classification system is the most
widely accepted method for EC staging. It was refined in 2009 based
on advancements in the literature (Table 2)(18).
Table 2 | This table was adapted by the authors from
Table 3 of The International Federation of Gynaecology and Obstetrics
(FIGO) classification system(19). EC = endometrial
cancer. *Either G1, G2 or G3.
A key diagnostic role of LND in EC is to guide adjuvant
treatment(20). The ASTEC study (A Study of the
Treatment of Endometrial Cancer) (2009) is one of two randomised
controlled studies in this field. Given the low node-positivity rate in
this study, a large number of patients would be required for adequate
power. However, this requirement was not fulfilled as out of 683
patients in the standard surgery group and 686 in the LND group, only 9
and 54 patients respectively, were node-positive. The ASTEC study
concluded that LND cannot be recommended in stage I EC unless it affects
adjuvant therapy(20). They therefore did not resolve
an important clinical question: do higher risk patients benefit from
LND?
A review by Todo et al(18) highlighted the importance
of stratifying patients by risk and not staging alone because within
each stage, different risk groups have different outcomes to treatments.
The ESMO-ESGO-ESTRO 2016 consensus recognises this importance. It does
so by incorporating other pathological prognostic features alongside
FIGO 2009 to identify patients at risk of LN metastasis or
recurrence(5). During diagnostic investigations,
clinical and aforementioned features are gathered and collated. This is
used to stratify patients into risk groups. The defining features and
management recommendations for early-stage EC based on ESMO-ESGO-ESTRO
2016 are summarised by risk group in Table 3.
The features that define “low-risk” are varied within the literature,
resulting in differences in how surgical management and adjuvant
therapies were tailored, as seen in this systematic
review(21). For the low-risk group, FIGO
2009(19) and National Comprehensive Cancer Network
(NCCN) 2016 identify tumour diameter as an important pathological
feature in addition to those in ESMO-ESGO-ESTRO 2016 (Table 3). A 2017
study also incorporated tumour size of less than 2cm into its risk
stratification system, however this was not found to be an independent
prognostic factor(12,22). Without a standardised
approach, this poses difficulty both in the clinical setting and when
comparing clinical trials.
Table 3 | Summary of ESMO-ESGO-ESTRO Consensus
Conference 2016 risk stratification system for early-stage endometrial
cancer. The figure was created by authors based on ESMO-ESGO-ESTRO
Consensus Conference 2016(5). Depth of myometrial
invasion: Stage IA = Superficial <50%; Stage IB = Deep ≥50%.
Cervical involvement: Stage II. EBRT = external beam radiation therapy.