FIGO Staging of Endometrial Adenocarcinoma: A Critical Review and Proposal potx

International Journal of Gynecological Pathology
28:1–9, Lippincott Williams & Wilkins, Baltimore
r 2008 International Society of Gynecological Pathologists
Review Article
FIGO Staging of Endometrial Adenocarcinoma:
A Critical Review and Proposal
Richard J. Zaino, M.D.
Summary: The optimal staging of tumors would reflect their biology and patterns of
spread, permit accurate prognostication, and facilitate therapeutic decision-making. The
last revision of the International Federation of Obstetricians and Gynecologists (FIGO)
staging of uterine corpus tumors was in 1988, and it represented the transition from a
clinical to a surgico-pathologic system. With 20 years of experience, we can now review
the accuracy, reproducibility, and utility of this system. Pathologists are in a unique
position to study each of these characteristics, comment on their ability to apply the
criteria in daily practice, and offer suggestions to further improve the FIGO system.
This paper selectively reviews some of the more problematic aspects of the current
FIGO system, including the following: the distinction of tumors confined to the
endometrium from those which are superficially myoinvasive; the method and utility of
histologic grading of endometrial adenocarcinoma; the utility and reproducibility of the
diagnosis of cervical epithelial and stromal invasion; the striking heterogeneity within
and among stage III A, B, and C tumors and their differing prognostic significance. It
concludes with recommendations for changes in a future revision of the FIGO staging
of endometrial carcinoma. Key Words: Endometrium—Carcinoma—FIGO—Stage.
In 19 88, the International Federation of Obstetri-
cians and Gynecologists (FIGO) made significant
changes to the staging scheme for cancers of the
uterine corpus (1), replacing the clinically based 1970
classification (2,3) with a surgico-pathologic system
(Tables 1, 2). This occurred in part because of a
change during the previous decade in the clinical
management of endometrial carcinoma, with surgery

replacing radiation therapy as the primary therapeu-
tic modality. This newer staging system represented
a dramatic improvement, as the older system was
inaccurate and neither highly predictive nor highly
reproducible. Two examples of the improvement in
prognostication and accuracy follow. Wolfson et al.
(4) retrospectively compared the prognostic signifi-
cance of surgical staging with clinical staging. The
5-year survival rate by clinical stage was as follows:
stage I—87%, stage II—86%, stage III—0%, and
stage IV—0%. Only 5% of women had stage III or
IV disease. In contrast, the 5-year survival rate by
surgical stage demonstrated far better discrimination,
as follows: stage I—91%, stage II—86%, stage III—
58%, and stage IV—0%. The clinicall y defined stage
was retrospectively reassigned after examination of
the surgical specimen in 25% of the cases, and 16%
of the women were found to actually have stage III or
IV disease. Creasman et al. (5) examined the accuracy
of the designa tion of clinical stage II endometrial
adenocarcinoma using data from a large Gynecologic
Oncology Group (GOG) protocol. In the FIGO
system of 1970, clinical stage II disease had been
defined as spread of carcinoma to the cervix based
upon the results of pelvi c examination of the cervix or
fractional curettage. Of 148 women found to have
stage II carcinoma clinically, as previously defined,
1
DOI: 10.1097/PGP.0b013e3181846c6d
From the Department of Pathology, M.S. Hershey Medical

Center, Penn State University, Hershey, Pennsylvania.
Address correspondence and reprint requests to Richard J.
Zaino, MD, Department of Pathology, M.S. Hershey Medical
Center, Penn State University, Hershey, PA 17033. E-mail:

only 66 actually had tumor present in the cervix in the
hysterectomy specimen. Thirty-one of these women
also had clinically occult extrauterine disease. Con-
sequently, only 35 (24%) of those assigned as clinical
stage II disease actually had a carcinoma that had
spread to the cervix alone.
The transition from clinical staging to surgico-
pathologic staging of tumors of the uterine corpus
thus represented a significant advance in prognos-
tication and determination of need for additional
therapy. The use of a surgico-pathologic system also
provides an opportunity and an obligation for
pathologists to become integral in the assessment
and further refinement of the staging system, as it is
only with meticulous examination of the surgically
derived tissue that accurate assignment of stage is
possible. It is the purpose of this paper to selectively
review some of the less reproducible and more
challenging or contentious aspects of the current
staging system, and to provide some suggestions for
consideration when the staging is next under revision.
STAGE I (TUMORS CONFINED TO
THE UTERINE CORPUS)
Although it is usually not difficult to determine
when a tumor is confined to the uterine corpus

(stage I), the stage is subdivided into those which
are confined to the endometrium (stage IA), those
which invade the inner-half of the myometrium (stage
IB), and those which invade the outer-half of the
myometrium but do not extend to the uterine serosa
(stage 1C). In contrast to tissues such as the colon,
where a muscularis mucosa clearly separat es the
mucosa from the submucosa, the interface of the
endometrium and myometrium is often vague and
irregular. Irregular and often sinuous interdigitations
of the endometr ium with the myometrium are the
rule rather than the exception (Fig. 1). This archi-
tectural complexity is compounded by the fact that
invasive well-differentiated endometrial aden ocarci-
nomas often do not display incomplete glands,
individual cell permeation, or a desmoplastic host
response. The neoplastic glands of tumors actually
confined to the endometrium often over-run and
replace the endometrial stroma in these interdigita-
tions (Figs. 2A, B), and consequently the assessment
of superficial myometrial invasion is problematic (6).
Anecdotal reports suggest that most pathologists
prefer to overestimate rather than underestimate the
depth of invasion; so superficial invasion is probably
frequently overdiagnosed. This impression is sup-
ported by the observation that the most recent FIGO
data indicates almost identical 5-year survival data
for women with stage IA (91%) and stage IB (90%)
tumors (7).
TABLE 1. The International Federation of Obstetricians

and Gynecologists 1971 staging system for tumors of the
uterine corpus (3)
Stage Characteristics
0 Carcinoma in situ
I The carcinoma is confined to the corpus
Ia The length of the uterine cavity is 8 cm or less
Ib The length of the uterine cavity is more than 8 cm
Stage I cases should be subgrouped with regard to the
histologic grade of the adenocarcinoma
II The carcinoma has involved the corpus and the cervix
III The carcinoma has extended outside of the uterus but
not outside of the true pelvis
IV The carcinoma has extended outside of the true pelvis or
has involved the mucosa of the bladder or rectum
TABLE 2. The International Federation of Obstetricians
and Gynecologists 1988 staging system for tumors of the
uterine corpus (1)
Stage Characteristics
IA G123 Invasion confined to the endometrium
IB G123 Invasion confined to the inner half of myometrium
IC G123 Invasion to outer half of myometrium
IIA Endocervical glandular involvement only
IIB Cervical stromal invasion
IIIA Tumor invades uterine serosa, adnexa, and/or
positive peritoneal cytology
IIIB Vaginal metastasis
IIIC Metastasis to pelvic or paraortic lymph nodes
IVA Tumor invasion of bladder and/or bowel mucosa
IVB Distant metastasis including intra-abdominal or
inguinal node metastases

FIGURE 1. Secretory phase endometrium. Irregular and often
sinuous interdigitations of the endometrium with the myometrium
are very common in both normal and neoplastic specimens.
2 R.J. ZAINO
Int J Gynecol Pathol, Vol. 28, No. 1, January 2009
The distinction of inner-half invasion from outer-
half invasion is usually straightforward, and both the
probability of recurrence and likelihood of death
from tumor are markedly increased for women with
deeply invasive tumors. However, there are 3 situa-
tions in which the determination of maximal invasion
may be difficult. In the first situation, lymphatic
invasion may be most easily recognized and promi-
nent in the myometrium deep to the invasive front of
the carcinoma. The lymphatic channels containing
masses of neoplastic cells may be found in the outer-
half of the myometrium whereas the rest of the
neoplasm is confined to the inner-half of the uterus.
In such cases, I believe it is most appropriate to
classify the tumor as a stage IB (inner-half myoinva-
sive) tumor and simply note the presence of
lymphatic invasion, which represents a separate poor
prognostic factor. In the second case, for a highly
exophytic tumor, the location of the endometrial
myometrial interface may be obscured by the
presence of smooth muscle fibers that extend upward
into the endometrium. No rules have been proposed
for determination of the depth of invasion in this
situation, but Ali et al (6) have offered a few useful
suggestions. In such cases, I have arbitrarily esti-

mated the depth of invasion based on the thickness of
the myometrium in a portion of the fundus not
affected by the neoplasm. In the third situation,
carcinoma is found confined to foci of adenomyosis
in the deep myometrium. Several studies have
demonstrated that this should not be considered a
form of deep myoinvasion, as the outcome for these
women is no worse than for those in whom tumor is
absent from the adenomyosis (8,9).
HISTOLOGIC GRADE (GRADES 1, 2, AND 3)
Stage I endometrial carcinomas are further sub-
divided by histologic grade, reflecting the prognostic
importance of tumor differentiation, particularly in
early stage disease. Although assignment of histologic
grade is not particularly problematic currently, this
largely reflects the significant clarification regarding
histologic grading provided by pathologists during
the past 2 decades. In the early 1980s, the pathology
committee of the GOG arbitrarily defined an
architecturally based grading system for endometrial
adenocarcinomas, using the percentage of the surface
area in which there is glandular arrangement of the
neoplasm (10). Grade I tumors are those in which less
than 5% of the neoplasm is arranged as solid growth;
grade 2 tumors are those in which 5% to 50% of the
neoplasm is arranged in solid sheets; and grade 3
tumors are those in which greater than 50% of the
neoplasm form solid masses. Foci of squamous
differentiation are not included in the assessment.
This system was later found to effectively discrimi-

nate survival probab ility for women with clinically
stage I and II endometrioid endometrial adenocarci-
nomas, with 5-year survivals of 93% for women with
grade 1 tumors, 85% for grade 2 tumors, and 69%
for grade 3 tumors (11). Interestingly, it was later
found useful not only in stratifying the overall
survival for women with surgical stage I disease, with
5-year survival rates of 92%, 88%, and 75%,
respectively, but also for those with metastatic (stage
III) disease, with rates of 70%, 63%, and 40%.
FIGURE 2. Interface of endometrial carcinoma with myometrium.
At low magnification (A), bundles of smooth muscle separate
neoplastic glands from one another. At higher magnification (B),
it is more evident that this simply represents the interdigitations
of the basalis endometrium with myometrium, and a benign
endometrial gland is present in the middle of the field at the same
depth as the neoplastic glands.
3FIGO STAGING OF ENDOMETRIAL ADENOCARCINOMA
Int J Gynecol Pathol, Vol. 28, No. 1, January 2009
FIGO adopted this general schema for the 1988
system, but added the 3 provisos that follows: 1)
notable nuclear atypia, inappropriate for the archi-
tectural grade, raises the grade of a grade 1 or grade 2
tumor by 1; 2) in serous, clear cell and squamous cell
carcinoma, nuclear grading takes precedence; and 3)
adenocarcinomas with squamous differentiation are
graded according to the nuclear grade of the
glandular component (1). Notable nuclear atypi a
was not precisely defined. The first and third of these
provisos were subsequently addressed in studies by

the GOG. Of 715 women with endometrioid adeno-
carcinomas, with or without squamous differentia-
tion, Zaino et al. (12) found that upgrading was
prognostically justified only for those tumors in
which the majority of the neoplasm was composed
of cells with large, pleomorphic nuclei, coarse
chromatin, and large irregular nucleoli (Fig. 3). A
lesser degree of nuclear atypia or severe but only focal
nuclear atypia was not associated with a significantly
diminished probability of survival. With respect to
endometrioid adenocarcinomas with squamous dif-
ferentiation, the architectural differentiation of the
gland-forming portion of the tumors provided better
prognostic information than the nuclear grade of the
glandular or squamous component (12). Although
grading is prognostically important for endometrioid
adenocarcinoma an d its subtypes, it has not been
found to be useful for serous, clear cell, or pure
squamous carcinomas. Tumors of these cell types are
associated with an aggressive behavior that does
not seem to be influenced by architectural or nuclear
features that have been studied to date. Conse-
quently, by convention, serous and clear cell carci-
nomas of the endometrium are considered to be grade 3.
Multiple prognostically useful alternative grading
systems have been proposed during the past decade,
based on either a 2-tiered or a 3-tiered division
according to architectural grade, nuclear grade, or a
combination of both (13–16). All of the systems
display moderate to good reproducibility in limited

investigations. It is not clear whether any of the
alternative systems would significantly improve
the reproducibility, ease, or prognostic utility of the
current method.
STAGE II (CARC INOMAS THAT EXTEND
INTO THE UTERINE CERVIX)
Women with endometrial adenocarcinoma that
spread to the cervix have a diminished probability
of survival compared with women whose tumors are
confined to the uterine corpus, with FIGO results
from 2003 indicating a 75% 5-year overal l survival
compared with about 88% for stage I tumors (7).
However, tumors that spread to the cervix more often
display other poor prognostic features, such as high
grade, invasion of the outer-half of the myometrium,
and lymphatic invasion, than do tumors confined to
the corpus (17). In one study of 170 women with stage
II carcinoma, 58% had outer-half myoinvasion
(versus 44% for stage I), 42% had capillary/
lymphatic space involvement, and 72% were grade
2 or 3 (versus 60% for stage I [18]). It is unclear
whether involvement of the cervix is prognostically
significant after adjustment for other poor-risk
factors, but the effect of cervical spread in isolation
seems to be a weak factor, if present.
Stage II carcinomas are further divided into stage
IIA (Fig. 4A), which are those tumors in which
carcinoma is confined to the endocervical glands, and
stage IIB, which are those tumors in which carcinoma
involves the cervical stroma (Fig. 4B). FIGO has not

provided any guidelines regarding the histologic
definition or identification of carcinoma confined to
glands, and different authors have considered it to
represent surface epithelial involvement only, surface
and underlying gland involvement, or mucosal spread
(although no mucosa exists in the cervix) (8,19–22).
Some of these definitions imply either a Pagetoid
FIGURE 3. Grade 3 endometrioid adenocarcinoma. The majority
of this architectural grade 2 adenocarcinoma was composed of cells
with large, pleomorphic nuclei, coarse chromatin, and large
irregular nucleoli, justifying its upgrade to a International
Federation of Obstetricians and Gynecologists grade 3 endome-
trioid adenocarcinoma. Caution is justified, as many carcinomas
with extensive gland formation and high-grade nuclei actually
represent serous carcinoma.
4 R.J. ZAINO
Int J Gynecol Pathol, Vol. 28, No. 1, January 2009
spread of neoplastic cells within the basement
membrane of the epithelium from a contiguous
primary tumor, or implantation and replacement of
denuded epithelium after curettage. In practice, for
grade 1 endometrial tumors, it is often difficult to
determine whether the neoplastic glands in the cervix
represent preexisting or newly formed glands, parti-
cularly as a desmoplastic host response often is
absent in low-grade tumors. In contrast, higher-grade
tumors have solid masses of neoplasm that infiltrate
the stroma and often provoke a desmoplastic
response. Most tumors classified as stage IIA are
grade 1. Consequently, it is not surprising that

various studies have yielded conflicting data with
survival and recurrence rates for women with stage
IIB disease either worse or no different from those for
women with stage IIA disease (5,8,19–25). In most
studies, stage IIA disease is associated with the same
prognosis as stage I tumors. In summary, neither
the prognostic importance nor the reproducibility of
the diagnosis of stage II (and substages IIA and IIB)
tumors has been rigorously evaluated, but reprodu-
cibility seems to be poor and prognostic importance
weak.
STAGE IIIA (TUMOR INVADES UTE RINE
SEROSA, ADNEXA, OR POSITIVE
PERITONEAL CYTOLOGY)
Stage IIIA is extra ordinarily heterogenous, as it
includes those tumors that have not demonstrated
spread beyond the uterus , those tumors which are
present as isolated cells in peritoneal fluid but may
not be cap able of implantation, and those tumors
with definite metastasis to other pelvic organs.
Between 3% and 30% of women with clinical stage
I or II endometrial carcinoma are found to have
tumor cells in either ascitic fluid or in pelvic washing
cytology, but only about 5% to 10% of women with
no extrauterine metastases identified pathologically
have positive peritoneal cytology (26–35). Numerous
studies have produced conflicting results regarding
the significance of positive peritoneal fluid cytology
as a risk factor for tumor recurrence or survival in
women with clinical stage I or II carcinoma. In about

half of the reports, it is associated with increased
recurrence rates and decreased survival (28,32–34,
36–40), but in the other half, no difference was detected
(28–32,34,35,39,41–43). Positive peritoneal fluid
cytology is frequently associated with other high-risk
factors such as high histologic grade, deep myome-
trial invasi on, and extrauterine disease. The reported
5-year survival for those women with positive
cytology but with no extrauterine metastases varies
from about 80% to 90%, whereas the recurrence rate
is about 30%. In a somewhat dated but excellent
review of 17 studies and over 3,800 patients by
Milosevic and colleagues in 1992 (33), they identified
5 studies in which multivariate analyses had been
conducted that included grade and depth of invasion
in the models. In the 3 larger studies, a malignant
cytology was associated with a significant, indepen-
dent decrease in survival or increase in the rate of
recurrence, but its effect was less important than
histologic grade. In the 2 smaller studies, no such
effect was found. Recurrence in this group of patients
is typically as disseminated intraperitoneal carcino-
matosis. In about 5% of peritoneal fluid cytology
FIGURE 4. Cervical invasion by endometrial adenocarcinoma.
The distinction of cervical stromal invasion from endocervical
glandular involvement only can be difficult. Although in some
areas, one might consider that his tumor could simply be involving
the cervical glands (A), in an adjacent field the invasion of the
stroma is evident (B).
5FIGO STAGING OF ENDOMETRIAL ADENOCARCINOMA

Int J Gynecol Pathol, Vol. 28, No. 1, January 2009
specimens, atypical cells are present that may
represent either reactive mesothelial cells or low-
grade adenocarcinoma. In the absence of immuno-
histochemical stains that are absolut ely specific and
sensitive, it is likely that this group that is indefinite
for stage IIIA cancer cannot be reduced further.
Women whose tumor s have spread to the adnexa
have a diminished survival compared with those
women without ad nexal involvement. Once again,
most of these women also have other adverse features
such as high grade, lymphatic invasion, deep myo-
metrial invasion, and other sites of extrauterine
disease. Connell et al. (44) reported a 5-year
disease-free survival of 37% for those with adnexal
spread, but it was 71% for those withou t other
extrauterine involvement. The latter figure is close to
the mean disease-free survival of 79% taken from
a literature review for solitary adnexal involvement
(44). This data should be viewed with caution as
almost 5% of women with endometrial adenocarci-
noma are found to have carcinoma in the ovary, and
many of these patients are believed to have separate
primary tumors, for whom the prognosis is excellent
(45). Until better ways are routinely employed to
distinguish synchronous primary tumors from me-
tastases, the impact of isolated ovarian or tubal
metastases will remain obscure.
The third subgroup of stage IIIA consists of
women whose tumors have extended through the

myometrium to the uterine serosa. It was found in
about 7% of women treated by primary surgery,
of whom half had extrauterine spread, and overall
carries a poor prognosis, with a 5-year disease-free
survival of about 30% in one study (46). As an
isolated finding in the absence of known metastasis
(a relatively uncommon event), the survival in-
creased, but was still poor at 41% at 5 years (46).
Mariani and colleagues (47) found a better 5-year
survival rate, but 83% of the tumors recurred in
extra-abdominal sites in that period of time.
STAGE IIIB (TUMOR SPREAD
TO THE VAGINA)
Although vaginal recurrences of endometrial ade-
nocarcinomas are relatively common, less than 1%
of patients present with vaginal metastasis in the
absence of spread to lymph nodes or distant sites
(48). More specifically, only about 2% to 3% of
women with stage III tumors are stage IIIB. Such
tumors are biologically aggressive, with a reported
5-year survival of abo ut 25% and a median sur-
vival of only 1 to 2 years. As the patients typically
do not have contiguous spread from uterine corpus
to cervix to vagina, it is likely that the tumor re-
flects a lymphatic metastasis. The sites of recurrent
disease in this group of patients are quite variable,
and include pelvis, lymph nodes, abdomen, and
distant sites.
STAGE IIIC (TUMOR METASTASIS TO PELVIC
OR PARA-AORTIC LYMPH NODES)

About 10% of women with clinical stage I and II
endometrial carcinoma are found at the time of
surgico-pathologic staging to have metastasis to
pelvic and/or para-aortic lymph nodes (49–51). After
lymphadenectomy, radiation therapy is often directed
to the pelvis and nodal regions. The probability of
nodal spread is strongly related to risk factors,
including cell type, histologic grade, depth of
myometrial invasion, and lymphatic invasion (17).
There is a relatively predictable pattern of spread of
endometrial carcinoma to regional nodes, with the
pelvic nodes involved first, followed by ascent to
the para-aortic chain. About one-third to one-half of
women who have disease in the pelvic nodes also have
spread to the para-aortic lymph nodes (17,49,50).
Even this substage is quite heterogeneous. Mariani
and colleagues (52) reviewed 51 patients with stage
IIIC disease. Although the 5 years recurrence-free
survival was 68% for women who had lymph nodes
as the only site of extrauterine disease, it dropped to
25% for those whose tumors also involved uterine
serosa, adnexa, vagina, or peritoneal cytology (52).
Relapses in the former group were largely confined to
the node-bearing areas; whereas, the majority of the
latter group had recurrences in other areas. Similar
but even more dramatic differences in survival
between the 2 groups (93% versus 39%) were found
by McMeekin et al. (53), who also noted that the
depth of invasion in the uterus remained significant in
a multivariate analysis of survival. Women with

metastatic disease in the para-aortic lymph nodes
have a much worse prognosis than those with
spread only to the pelvic lymph node s, with 5-year
survivals of about 30% to 40% versus 70% to 80%
(50,51,54). Further risk stratification is found accord-
ing to the presence of residual nodal disease, divided
as occult, macroscopic resected, and macroscopic
residual (49).
6 R.J. ZAINO
Int J Gynecol Pathol, Vol. 28, No. 1, January 2009
GENERAL COMMENTS
AND A FEW NOTES
ON THERAPY
As one reviews the voluminous literature, it is evident
that the prognosis of endometrial adenocarcinoma is
related to a wide variety of features including those
intrinsic to the tumor (such as cell type and grade),
those related to its growth in the uterus (including the
depth of myometrial invasion and lymphatic inva-
sion), and those related to extrauterine spread. As
noted previously, some of the features of the tumor in
the uterus still affect the prognosis for women with
metastatic tumor, and no single characteristic seems
to represent an overwhelmingly dominant prognostic
factor. Thus, the prognosis, and sometimes therapeu-
tic decisions, for an individual patient often is based
on a constellation of features, rather than simply the
identification of the most advance d site of spread.
This set of observations complicates the creation of
an optimal staging system.

In the prior discussion, I have focused on prognostic
issues. I will follow with a series of brief and pro-
vocative generalizations about the current limitations
or controversies regarding therapy. Although 70%
to 80% of women with endometrial adenocarcinoma
are cured by surgery alone, disease beyond the uterus
remains a source of tremendous frustration, and stag-
ing systems should address the differences between
nodal disease, localized pelvic spread, peritoneal carci-
nomatosis, and extra-abdominal metastasis. Patients
with high-risk, localized cancers treated with adjuvant
radiation to the pelvis or abdomen have lower rates of
pelvic recurrence, but are at equal risk for later distant
failure and seem to have no survival benefit. Whole
abdominal radiation therapy is inferior to chemother-
apy for the treatment of women with maximally
debulked advanced endometrial adenocarcinoma.
Several studies have suggested that lymphadenectomy,
in itself, may result in improved survival for women
with metastasis to pelvic and para-aortic lymph nodes.
Targeted radiation therapy may be effective for the
treatment of localized vaginal recurrences, but neither
hormonal nor chemotherapy provides more than short
term and incomplete responses in most of the women
with distant or disseminated disease. In summary,
therapy for advanced or recurrent endometrial adeno-
carcinoma remains suboptimal, with mean survival
measured in months to a few years, for most situa-
tions. Further advances in treatment outcomes are
unlikely to result from conventional forms of hormo-

nal, radiation, or chemotherapy.
A SUMMARY OF PROBLEMS
AND SUGGESTIONS FOR
REFINEMENT IN THE FIGO
STAGING SYSTEM
1) Stage IA (tumors confined to the endometrium)
cannot reliably be distinguished from stage IB
(tumors invading the superficial myometrium)
microscopically in many cases;
2) Stage IIA and IIB are poorly defined pathologi-
cally and may not differ prognostically;
3) Stage II is probably not a statistically significant
independent prognosticator of survival;
4) Stage III disease is very heterogeneous;
5) Stage IIIA alone is heterogeneous; isolated posi-
tive pe ritoneal cytology alone is rare and probably
significant but with small survival effect (85%
5-year survival); isolated adnexal spread is more
significant (70% 5-year survival); uterine serosal
involvement carries a poor prognosis (30% 5-year
survival);
6) Stage IIIB (vaginal metastasis) is very rare and
has a prognosis similar to stage IV tumors (25%
5-year survival);
7) Stage IIIC is heterogeneous, and patients who
have nodal spread without other extrauterine
spread have a significantly better prognosis
(70%–90% 5-year survival) than those with both
nodal and other extranodal disease (25%–40%
5-year survival);

8) Among women with stage IIIC disease, the
prognosis for those with pelvic node metastasis
is significantly better (70%–80% 5-year survival)
than for those with positive para-aortic nodes
(30%–40% 5-year survival);
9) Among women with stage IIIC disease, the
survival rates vary according to whether the nodes
are grossly or microscopically positive (as assessed
by the operating surgeon), and whether the disease
can be completely resected.
Given the described problems in reproducibility,
accuracy, and predict ive value noted previously, and
to provoke further discussion, I would suggest that
consideration be given to a staging system as shown
in Table 3. If we are to make further improvements in
treatment and prognostication, it is time for pathol-
ogists, gyn ecologic oncologists, radiation oncologists,
and medical oncologists to engage in this conversa-
tion together. I look forward to the discussion that
may follow.
7FIGO STAGING OF ENDOMETRIAL ADENOCARCINOMA
Int J Gynecol Pathol, Vol. 28, No. 1, January 2009
Acknowledgments: The author thanks Drs Catherine
Abendroth and Timothy Leonard for their critical review
and Amanda Smith for her excellent assistance in the
preparation of this manuscript.
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TABLE 3. A proposal for a revised staging system for
tumors of the uterine corpus
Stage Characteristics
IA G123 Invasion to endometrium/inner-half of myometrium
IB G123 Invasion to outer-half of myometrium
IIA Positive peritoneal cytology
IIB Uterine serosa, adnexal, or other pelvic spread
IIIA1 Pelvic nodal metastasis only (microscopic)
IIIA2 Pelvic nodal metastasis only (gross* )
IIIB1 Para-aortic nodal (7pelvic nodal) metastasis only
(microscopic)
IIIB2 Para-aortic nodal (7pelvic nodal) metastasis only
(gross* )
IIIC Pelvic or para-aortic nodal metastasis with other
extrauterine spread
IVA Vaginal metastases, invasion of bladder or bowel
mucosa
IVB Distant metastasis including intraabdominal or
inguinal node metastases
* The assessment of gross involvement of lymph nodes by
metastatic tumor is made by the operating surgeon.
8 R.J. ZAINO

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9FIGO STAGING OF ENDOMETRIAL ADENOCARCINOMA
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