of Regional Lymph Nodes in
Stage I and II Colorectal Cancer:
With and Without Recurrence
Juan C. Paramo, MD*
Mark Landeros, MD*
Christopher I. Wilson, MD†
Amadeo Cabral, MD*
Robert J. Poppiti, MD†
Thomas W. Mesko, MD, FACS*
*Department of Surgery, and
†Department of Pathology
Miami Beach, FL
KEY WORDS: colorectal cancer, immunohistochemistry,
lymph nodes, recurrence
Background and Objectives: The implications of up-staging
patients with stage I or II colorectal cancer based on the presence
of nodal micrometastases are controversial. Therefore, a case-control
study was performed to evaluate possible differences in the immunohistochemistry
results of patients with recurrent versus nonrecurrent stage I or
Methods: All cases of stage I and II colorectal cancer
from 1980 through 1998 were reviewed. The study group included all
cases of documented recurrence. A control group of patients without
recurrence was included in the study for comparison. All patients
had negative lymph nodes on initial hematoxylin and eosin examination.
Deeper sections from the tissue blocks were made at 5 different levels
and stained with low-molecular-weight cytokeratin (CAM
Results: The study group included 7 patients and 120
lymph nodes. The control group included 14 patients and 157 nodes.
Immunohistochemistry stains showed micrometastases in 6% of nodes
in the recurrence group and in 17% in the control (P = 0.01). Overall,
57% of the patients with recurrence and 36% of the patients without
recurrence were up-staged based on the immunohistochemistry stains
(P = 0.3).
Conclusions: Immunohistochemical stains do not determine
which patients with stage I or II colorectal cancer will experience
recurrence, and the presence of micrometastases according to immunohistochemical
stains does not imply a worse prognosis.
Recent technological advances have improved the detection
of malignant disease at the cellular level. Among these evolving techniques,
immunohistochemistry (IH) has become a very sensitive method for detecting
malignant cells. IH has been applied diversely, especially in the
study of sentinel lymph nodes in melanoma and breast cancer patients.
However, the use of IH stains in colorectal cancer has produced uncertain
results. In an attempt to further clarify this issue, we performed
the present study, which summarizes our experience with IH evaluation
in patients with stage I or II colorectal carcinoma.
MATERIALS AND METHODS
We reviewed all cases of colorectal carcinoma listed
in the tumor registry at our institution from January 1980 through
December 1998. Patients whose cancer was staged as I or II per the
American Joint Committee on Cancer Staging System1 were selected.
A case-control study was performed as follows: the study group consisted
of all patients with documented recurrent disease. The control group
was made up of randomly selected patients from the tumor registry
database who had colorectal cancer but who
did not have evidence of recurrence. No patients in either group had
Once the groups were established, the paraffin tissue
blocks containing all mesenteric lymph nodes from the surgical specimens
were reviewed. Lymph nodes had been identified by gross dissection
and all had been reported as negative for malignancy on initial hematoxylin
and eosin (H&E) examination. Deeper sections were made from the
tissue blocks at 5 different levels and stained with low-molecular-weight
cytokeratin (CAM 5.2; Becton Dickinson, San
Jose, CA). Positive
micrometastasic involvement of a lymph node was defined as the presence
of at least one cell composed of a clearly defined nucleus surrounded
by positive IH staining of the cytoplasm.
In every case, the age, gender,
site of the tumor, stage (I or II), total number of dissected mesenteric
nodes, number of positive nodes, and total length of follow-up were
documented. In the study group, the time interval until recurrence
was recorded. The overall mortality was calculated for both groups,
and statistical analysis was performed using a 2-sample t test for
ordinal variables. A Fisher exact test and z test with Yates correction
for continuity were used for nominal variables. A P value of less
than 0.05 was considered statistically significant.
A total of 458 patients with stage I or II colorectal
carcinoma were reviewed. There were 20 patients with documented recurrence.
Of these 20 patients, paraffin blocks were available for 7 patients,
which formed the study group. A total of 14 patients were selected
as the control group. Characteristics of both groups are summarized
in Table 1.
The study group consisted of 6 women and one man, aged
31 to 85 years old (average, 65 years). Tumors were located in the
right colon in one case, left colon in 2 cases, sigmoid colon in 3
cases, and rectum in one case. All cases were stage II. Average tumor
size was 4.3 cm (range 1.5 to 10 cm). A total of 120 regional lymph
nodes were studied using IH, with an average of 17 nodes per patient
(range 4 to 57 nodes). Seven nodes (6%) were positive according to
IH (Figure 1). Overall, 4 (57%) of the patients in this group had
evidence of malignant nodal involvement according to the IH stains
Average time until
recurrence was 14 months (range, 2 to 33 months), and mean follow-up
time was 30 months (range, 2 to 67 months) in the study group. Patients
with evidence of micrometastases were followed up on average for 17
months. Only one patient (14%) in this group died, at 14 months postoperatively
due to recurrent disease.
The control group consisted of 14 patients, 7 men and
7 women. Five tumors were located in the right colon, one in the left
colon, 6 in the sigmoid colon and 2 in the rectum. Three cases were
stage I, and 11 cases were stage II. Average age was 73 years (range,
56 to 86 years). Mean tumor size was 4.5 cm (range, 2.5 to 10 cm)
in this group. A total of 157 nodes underwent IH staining, with an
average of 11 nodes per patient (range, 2 to 23 nodes). Twenty-six
nodes (17%) were positive according to IH. Overall, 5 (36%) of the
patients in this control group had evidence of micrometastases using
IH staining (Table 2).
The average follow-up interval
in the control group was 39 months (range, 16 to 79). Mean follow-up
time in patients with micrometastases was 42 months. Two patients
(14%) in this group died, at 16 and 79 months, respectively, due to
medical reasons not related to their colon cancer.
Comparison of the
results from the 2 groups showed no statistically significant differences
with regards to age (P = 0.2), mean tumor size (P > 0.5), average
number of nodes per patient (P = 0.5), percentage of patients with
micrometastases (P = 0.3) or average follow-up time (P = 0.5). There
was a statistically significant difference with regards to the percentage
of positive nodes, which was higher in the control group (P = 0.01).
Colorectal cancer is the most common cancer of the gastrointestinal
tract, with a worldwide population-adjusted incidence of approximately
45 to 50 cases per 100,000.2 Early recognition
of this disease is critical for successful therapy. However, even
after an adequate surgical resection, the cancer recurs in 10% to
40% of patients. Therefore, identifying patients at risk continues
to be a challenge.3,4
Risk factors associated with increased incidence of
recurrence include the site of origin of the carcinoma, the depth
of penetration of the tumor into the intestinal wall, degree of differentiation
of the carcinoma, presence and number of lymph nodes with metastasic
disease, vascular invasion, and overall stage.2,4–7
Previous studies have demonstrated the benefits of adjuvant
therapy in advanced colon cancer, with the use of chemotherapy in
stage III carcinomas considered the standard of care.2 There are no
established guidelines for systemic therapy for stage II colon carcinoma,
although several clinical trials including subsets of these patients
are ongoing. Stage II rectal cancer patients receive adjuvant chemoradiation
use of IH has had a wide acceptance because of its various diagnostic
applications. IH is a sensitive technique that is used as a complementary
diagnostic modality. Because IH is a more sensitive technique, micrometastases
can be found with IH in nodes determined to be negative by H&E.
However, IH is more expensive and may not be cost-effective for widespread
use. In colorectal carcinoma, some studies have shown important benefits
of performing IH in mesenteric nodes while other experts believe that
it should not be used routinely.
The prognostic implications of micrometastasic nodal
involvement are debatable. Previous reports have shown that between
25% and 54% of patients with stage I or II colorectal cancer can have
evidence of micrometastases on IH only.8–11 Some studies have shown
IH results to be a prognostic factor,10 although others have shown contradictory results.9 In our
study, the rate of micrometastasic involvement shown by IH was 57%
in patients with recurrence and 36% in patients without recurrence
(P = 0.3). These results suggest that positive IH cells in previously
negative H&E lymph nodes may not be of clinical significance.
Other studies have shown that even though occult tumor cells might
increase the risk for local recurrence, they do not influence the
patients’ prognosis.12 Our study confirms
the limited benefit of IH as a predictor of tumor recurrence.
However, if the presence of nodal micrometastases implies
up-staging of stage I or II colon cancer to stage III, IH results
would have therapeutic implications because adjuvant chemotherapy
would then be indicated.2,13 In cases of rectal cancer, up-staging
stage I tumors would likewise indicate adjuvant therapy.14 Therefore,
these issues would suggest justification for the use of IH staining.
Some studies, however, show that overall survival and outcomes are
not altered by the presence of micrometastases.8,10,15–17
Our study corroborates this finding because the evidence of nodal
micrometastases in the group without recurrent disease was not statistically
different from that in the group with recurrent disease.
The lack of clinical significance of IH micrometastases
may have 2 possible explanations. First, not all cytokeratin-positive
cells are tumor cells; they may be mesothelial cells. Second, even
if they are tumor cells, clinically significant metastases may need
more than just their presence in the lymph node to develop. That is,
some other unknown factors may be responsible for initiating and sustaining
the growth of these cells.
Another issue is the routine use of serial sectioning
as a method to increase the detection of lymph node metastases. In
breast cancer, using step and serial sectioning with H&E staining
alone identified “occult” metastases in 22% of patients.18 Another
study concluded that although lymph node micrometastases may be more
easily detected using IH, careful screening of H&E-stained sections
by a pathologist appeared to be equally sensitive.19 Although we did
not perform H&E staining on the serial sections in our study,
we believe that IH detected metastases that would likely not be found
on H&E, because several metastases were single cells or groups
of only a few cells (Figure 1).
The immunohistochemical study of regional lymph nodes
in patients with colorectal cancer did not provide prognostic or therapeutic
implications. Immunohistochemical stains did not determine which patients
with stage I or II colorectal cancer will experience recurrence. This
needs to be further elucidated with larger studies.
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Table 1. Characteristics of patients with and without
(recurrence) (no recurrence)
Age 65 years 73 years 0.2 (NS)
(31–85 years) (56–86 years)
Male:Female 1:6 7:7 NA
size 4.3 cm 4.5 cm > 0.5 (NS)
(1.5–10 cm) (2.5–10 cm)
time 30 mo 39 mo
(2–67 mo) (16–79 mo)
Figure 1. Mesenteric
lymph node with evidence of micrometastases after immunohistochemical
staining is seen. Notice the single darker tumor cell that had been
undetected on initial hematoxylin and eosin examination.
Table 2. Lymph nodes results in patients with and
(recurrence) (no recurrence)
lymph nodes 120 157 NA
nodes 17 11 0.5 (NS)
per patient (4–57) (2–23)
nodes by IH 7 26
with 4 5 0.3 (NS)
positive nodes by IH (57%) (36%)