대 한 방 사 선 의 학 회 지 1993; 29 ( 1) : 118~ 1 25

Journal of Korean Radiological Society, January, 1993

CT Evaluation of Colon Carcinoma:Emphasis on Distant

Lymph N ode Invasion and Liver Metastases

Kyung Il Chung, M.D. , Kyoung Sik Cho, M.D. , Moon-Gyu Lee, M.D. , Seung Yeon Bael‘’ M.D. , Yong Ho Auh , M.D. , Jin Cheon Kim* , M.D.

Departmeηt 01 Diagnostic Radiology Asaη M edical Center, U:ηiversity 01 Ulsαη College 01 Mediciηe

- Abstract-

Even thou gh the value of computed tomography (CT) used to detect the colon carcinoma with minimal

invasion is limited , its usefulness in the evaluation of the extent of disease such as hepatic metastasis or dis­

tant lymph node invasion has been emphasized. To examine the role of CT in the evaluation of colon car­

cinoma , CT scans obtained during the past 2 years in 56 patients with surgically proven colon carcinoma

were reviewed and the findings correlated with pathologic results. The sensitivity and accuracy of CT for

peric이ic fat infiltration were 86 , 58 and 80% respectively. Those of regional node were 60 , 83 and 75%

and distant node 67 , 100 and 95 %. Liver metastases showed sensitivity, specificity and accuracy of 83 , 98 , 96% and peritoneal metastases 67 , 94 and 89% respectively.

CT detected local invasion with fair degree of accuracy but the true value of CT lie in the detection of

distant invasions such as liver and distant lymph node metastases thereby leading to preclusion of unnecessary

procedures and implementation of appropria te procedures.

Index Words: Colon Carcinoma

Liver , metastases

Lymph Node, metastases

INTRODUCTION

Almost two decades have passed since CT was

first introduced . Since then , it has been used to

d etect and to stage many tumors including col­

on carcinoma , recently joined by MR imaging, endoscopic sonography , and monoclonal an­

tibody imaging . Many conflicting reports on the

effectiven ess of the various m e thods has been

published in the literature largely due to

*울산대학교 의과대학 일반외과학교실

prem ature conclusions (1). Although the above

m ethods help to detect colon carcinoma , none

has the capacity to show full picture of colon

cancer. Accurate evaluation of colon carcinoma

requires both high sensitiv ity and specificity fo r

the presence oflocal , regional , and distant tumor

spreads. The precise role of these modalities are

still b eing debated (2) .

Nevertheless , the importan ce of an in-depth

analysis of the effectiven ess of these technologies

is emphasized by the fact that colon cancer is one

* Departmeηt 01 Geηeral 5;μrgery， Asan Medical Center, University 01 Ulsan College 01 Medicine 이 논문은 1992년 4월 28일 접수하여 1992년 11월 20일에 채택되었음.

Received April 28, Accepted November 20, 1992

- 118 -

of the most common cancer of this age and the

prognosis of patients with this neoplasm largely depend on the extent of tumor at the time of diagnosis (1 ,2)

Colon carcinoma is diagnosed on the basis of a clinical examination , endoscopy , and a dou­ble contrast barium enema study. The correct therapeutic choice requires knowledge of the

stage of the tumor obtained by endoscopy , ultra­sound , CT, or MR imaging.

CT is the most commonly used method for staging of colon cancer in spite of the debate on its accuracy. Accuracy of CT staging of primary colon carcinoma ranges between 47% to 64 % .

The major errors were caused by inability to detect pericolic extension and lymph nodes in­volvement (3-6). On the basis of these reports , preoperative local staging of colonic carcinoma

is clinical1y useless , and therefore it is not recom­mended (3 ,4).

Despite the current general lack of enthusiasm

for preoperative imaging of patients with colon

carcinoma, knowledge of extent of tumor spread before surgery could have a significant impact on therapy, such as preoperative and/or in­traoperative radiation therapy to control local

tumor spread or to make previously inoperative lesions resectable (7). Resection of liver metastasis and biopsy of suspected lesions may be facilitated with accurate preoperative imag­

ing. Appropriate nonsurgical therapy could be initiated sooner, and noneffective surgical pro­cedures could be avoided (2).

The aim of this study is to document CT role

in evaluation of colon carcinoma by attempting to prove the usefulness of CT in detection of dis­tant lymph nodes and liver metastases.

MATERIALS AND METHODS

CT scans were performed on 56 patients with

colon carcinoma prior to surgery and the diagnosis was confirmed subsequently by ex­ploratory laparotomy and pathological evalua-

Kyung 11 Chung, et al : CT Evaluation of Colon Carcinoma

tion of the resected specimen. Patients were given 700ml of 4.6% barium

sulfate (E-Z-Cat;E-Z-EM, Westberry) per or,al1y one hour before the CT examination. IV bolus

injection of 100ml of 68 % meglumine ioglicate (Rayvist 300;Schering, Germany) and 300ml of 1.5% barium sulfate per rectally were introduced prior to the examination.

With the patient in the supine position , scans

were obtained from the xyphoid process to sym­physis pubis using 5mm thickness and 5mm gap on a GE 9800 (GE Medical Systems , Milwaukee) or Picker 1200 (Picker lnternational Inc , Cleveland) scanner.

The CT images were evaluated without the knowledge of surgical or pathological findings , taking into account the morphology of the tumor , penc이ic infiltration , invasion of adjacent organs and lymph nodes , and metastases to distant organs such as liver and distant lymph nodes

The site of the primary tumor, mesentery , and

retroperitoneum were evaluated for tumor in­volvement along with the presence of ascites. Lymph nodes >10mm in diameter were con­sidered positive involvement.

RESULTS

The locations of the colon cancer (Table 1) were 6 cases involving cecum, 14 cases ascending colon , 3 hepatic fl exure , 9 transverse colon , 2 descending colon , and 22 sigmoid colon dis-

Table 1. Location of Colon Carcinoma

Location No

Mu

m

뼈

C A

6

% 3 9

2

있 -%

Hepatic flexure Transverse Descending Sigmoid

Total

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Journal of Korean Radiological Society 1993; 29 (1) 1 18~ 125

Table 2. Cases o[ Pathologic Stages*

Stage No

A/B l B2 C1 C2 D

Total 56

* Modified Dukes Classification

regarding rectal cancer. 8 cases showed obstruc­

tion which included 2 cases of intussusseption and cancer perforation was noted in 4 cases . U s­

ing the Astler Coller version (8) of Dukes

Classification modified by Turnbull (9) of Col­

on Carcinoma (Table 2) there were 5 cases of

stage A or B1 , 15 cases ofB2 , 4 ofC1 , 15 ofC2 , and 17 cases of stage D with the correct stage

shown in 31 cases (55 %). The CT results for

detecting pericolic infùtration are shown in Table

3. Pericolic infiltration was detected in 38 cases

and it showed the sensitivity , specificity , and ac­

curacy of86 ,58 , and 80 % respectively. Among

the five false positive cases , two had intussuscep­

tion and one h ad synchronous tumor. All of these

apparently did not have pericolic infiltration as

they appeared to have in CT. Among the six false

negative cases , lesion could not be identified in one case and three cases had either liver or

peritoneal metastases without definite sign of

penc이ic infiltration . There were 20 cases with

regional lymph node involvement and CT de­

tected 12 of them resulting in the sensitivity and

accuracy of 60 % and 75% (Table 4) (Fig. 1).

Nine cases of distant lymph nodes involvement

included 3 cases of paraaortic (Fig. 2) , 1 each

of rectal shelf, iliac bifurcation, middle colic

artery , and retroperitoneal lymph nodes . One

of the paraortic nodes (Fig. 3) and lymph nodes

at iliac bifurcation and middle colic artery did

not show up in CT. There were n o false positive

cases giving the specificity and accuracy of 100 %

and 95 % for the distant lymph nodes . Overall

ζJ r이) AT

CJ

껴/

1

1

1

Fig. 1. 73 year old female patient with sigmoid adenocarcinoma. Perico\ic fat and lymph node in­filtrations shown on CT but pathology proved negative lymph node involvement

Table 3. CT results in Determining Perico\ic In­filtration

Pericolic Infiltration(n = 56)

No . of true positives No. of true negative No. of false positives No. o[ fal se negatives % Sensitivity % Specificity % Accuracy

% 7 5 6

% %

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Table 4. CT results in Determining Metastatic Lym­phadenopathy

Regional Distant Nodes(n = 20)Nodes(n = 9)

No. of true positives 12 6 No . of true negative 30 47 No. of false positives 6 0 No. of fal se negatives 8 3 % Sensitivity 60 67 % Specificity 83 100

% Accuracy 75 95

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Kyung 11 Chung, et al : CT Evaluation of Colon Carcinoma

a b

c d

Fig. 2. 35 year old male patient with sigmoid mass. CT revealed cardiophrenic and pa raortic lymph node enlargem ent (a ,b). Eight months after the resection of the lesion and implementation of chemotheraphy , follow-up CT showed complete resolution of the lymph node involovement (c,d)

a b

Fig. 3. 48 year old male pa tient with ascending colon mass and pericolic fat infiltration on CT (a). Three months after tumor rescction , follow-up CT revealed extensive retroperitoneal node inva sion (b)

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Journal of Korean Radiological Society 1993; 29 ( 1) : 1 18~ 125

a b

c d

Fig.4. 47 year old male patient with ascending colonic lesion and a focalliver metastasis on CT (a ,b). Dur­ing the resection of the main lesion , porthocath was inserted for chemotheraphy of the hepatic lesion (c). 2 month follow-up CT showed resolution of the metastatic lesion (d).

CT gave sensitivity, specificity, and accuracy of Table 5. CT results in Determining Tissue/Organ 52 , 77 , and 66 % . M etastases

There were 6 cases of metastases to liver (Fig

4);two from the ascending, one from transverse , one descending, and two from sigmoid colon.

Although one case was incorrectly interpreted as

having a metastatic lesion while another was

undetected , CT showed high sensitivity , specificity , and accuracy of 83 % , 98 %, and 96 % (Table 5). Peritoneal seeding was correctly

detected by CT in 6 cases in which 2 had cancer

perforation and 2 others had malignant ascites .

Three cases were falsely interpreted as having

peritoneal seeding and 3 cases didn ’ t show (Fig.

5) with the result of sensitivity and accuracy of

Liver Peritoneum (n = 6) (n = 9)

No. of true positives 5 6 No. of true negative 49 44 No. of false positives 3 No. of false negatives 3 % Sensitivity 83 67 % Specificity 98 94 % Accuracy 96 89

m 4

Fig. 5. 59 year old male patient with ascending col­on mass and pericolic fat infiltration on CT which showed no evidence of peritoneal involvement but pathology proved otherwise.

67% and 89 %. CT detected metastatic lesions

in 20 cases and 13 of them were proven to be

true lesions which included ureter and stomach

m etastases in each case. There were 4 false

negative cases which included metastases to

uterus , bladder , stomach , and abdominal wall

in each case. Seven false positive cases include

2 cases to pancreas , and 1 each to seminal vesi ­

cle , lung, and gastrocolic ligamen t. Overall sen­

sitivity , specificity , accuracy of CT in

evaluationg distant metastases were 76 , 82 , and

80 % respectively.

DISCUSSION

According to the study by Kelvin (10) , liver

metastases are found in 15 % -20 % of patients at

the time of surgery and 29 % of patients with

disease-free liver at laparotomy develop liver

metastases within 2 years suggesting possible fre­

quency of liver metastases as close as 50 % . More

than half of the deaths after the surgery of col­

orectal carcinoma are secondary to hepatic

m etastases , and therefore detecting liver

metastases by CT before and after surgery is very

importan t. Freeney reported hepatic metastases

in 11 out of 103 patient (11 %) in his study which

Kyung 11 Chung, et al : CT Eva luation of Colon Carcinoma

gave sensitigity and specificity of 72.7 % and

98 .9% (4) . This series showed hepatic m etastases

in 6 out of 56 patients (11 %) giving sensitivity

and specificity of 83 % and 98 % . These results

are quite similar except for the higher sensitivi­

ty shown in this study . Most of the previous

studies reported accuracy rate of 76 % -96 %

which is quite comparable to the value of 96 % in this series (13-15)

In evaluating lymph node involvement , Zaun­

bauer (11) reported an accuracy of 100 % , Thompson (3) a sensitivity of 22 % and specificity of75% , and Balthazar (5) a sensitivity of73%

and a specificity of 58 % .

Regional lymph nodes were reported to be

recognizable in only 22 % -35 % by studies before

(10). Freeney also reported 7 true positive and

20 false negative lymph node (out of 80) involve­ment by colon carcinoma giving sensitivity , dnd

specificity of 25.9% and 96 % (4) .

On the contrary, this study showed correct CT

detection rate oflymph node involvement in 12

out of 56 patients with 60 % sensitivity and 83 %

specificity. These differences in value can part­

ly be explained b y different diagnostic criteria

used to detect lymph nodes in each study (e .g . ,>1. 5cm versus>1.0cm in our study) and

also due to this series not including rectal car-

Clnoma.

Contrary to the low values in detecting regionl

lymph nodes , this series showed sensitivity , specificity , and accuracy of 67 , 100 , and 95 %

in detecting distant lymph nodes by CT.

Although sen sitivity of 67 % is not highly

reflected by miss-reading of one paraaortic lymph

node, both high specificity and accuracy suggest

the usefulness of CT in evaluating extensive

diseases .

Previous studies recognized local extension of

tumor into or beyond the pericolic fat in

61 % -77 % (10) . In this series , pericolic fat in­

filtration was observed in 68 % (38 out of 56 pa­tients). Freeney reported sensitivity and

specifici ty of 61. 2 % and 80 .6 % (4) whereas this

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Journal of Korean Radiological Society 1993; 29 (1) : 1 18~ 125

study showed those of 86 % and 58 %. Low

specificity is due to the lack of spatial resolution

necessary for detecting minor degree of pericolic

infiltration by CT limiting its reliability in this

regard.

Resection of solitary hepatic metastases results

in 5-year survival rate of 42 %, and of multiple

metastases to a single lobe rate of 25 % (12). In

view of the poor prognosis of untreated hepatic

metastases , the usefulness of CT is emphasized

in detecting the colon carcinoma metastases to

liver.

With its ability to detect distant lymph nodes

and hepatic metastases with high degree of

specificity and accuracy, and also with its limita­

tion in the overall sensitivity and accuracy oflocal

staging of colon carcinoma, the true value of CT

lie in detecting distant metastatic lesions thereby

preduding unnecessary procedures or including

necessary procedures such as preoperative and/or

intraoperative radiation therapy to controllocal

tumor spread or to make previously inoperable

les ion resectable , and implantation of

chemotherapy devices.

REF'ERENCES

1. Theoni RF. Corectal Cancer: Cross-sectional lmaging for Staging of Prima ry Tumor and Detection of Local R ecurrence . AJR 1991; 156:909-915

2. Moss AA. lmaging of Colorectal Carcinoma. Radiology 1989 ;170 :308-310

3. Thompson W , Halvorsen R , FosterW, Roberts

L , Gibbons R . Preoperative and Postoperative CT Staging of Rectosigmoid Cancer. AJR 1986; 146: 703-710

4. Freeney PC , Marks WM , RyanJM , BolenJW.

Colorectal Carcinoma evaluation with CT:

preoperative staging and detection of postopera­tive recurrence. Radiology 1986;158:347-535

5 . Balthazar EJ , Megibow AJ , Hulnick DB , Naidich DP. Carcinoma ofthe Colon: Detection and Preoperative staging by CT. AJR 1988 ; 150: 301-306

6. Angelellei G , Macarini L , et al. Rectal Car­cinoma: CT Staging with Water as Contrast M edium. Radiology 1990;177:511-514

7. Theoni RF. CT Evaluation of Carcinoma of the

Colon and Rectum. CT of Gastrointestinal Tract. 1989 ;27 (4):731-741

8. Astler VB , Coller FA. The prognostic signifi­cance of direct extension of carcinoma of the col­on and rectum. Ann Surg 1954;1 39 :846-851

9. Turnbull RB J r. The no-touch isolation techni­que of resection. JAMA 1975 ;23 1:1181-1182

10. Kelvin FM , Maglinte DD. Colorectal Carci­noma: A Radiologic and Clinical Review. Radi­ology 1987;164:1-8

11. Zaubauer W , Haertel M , Fuchs WA , et al.

Computed tomography in carcinoma ofthe rec­tum . Gastrointest Radiol 19081;6:79-84

12. Adson MA, Van-Heerdon JA . Major hepatic resections for metastatic colore ctal cancer . Ann Surg 1980 ;191 :576-583

13. Alderson PO , Adams DF , Mc-Neil BJ , et al.

Computed tomography , ultrasound , and scin­tigraphy of the liver in patients with colon or breast carcinoma: a prospective comparison

R adiology 1983 ;149:225-230 14. KnopfDR , Torres WE , Fajman WJ , Sones PJ

Jr . Liver lesions: comparative accuracy of scin­tigraphy and computed tomography. AJR 1982; 138:623-627

15. Smith 매， Kemeny MM , Sugarbaker PH , et al.

A prospective study of hepatic imaging in the detection of metastatic disease. Ann Surg 1982 ; 195:486-491

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Kyung 11 Chung, et al : CT Eva luation of Colon Carcinoma

〈국문 요약〉

대장암의 전산화단층촬영소견 : 원격임파선과 간전이에 대한 고찰

울산대학교 의과대학 진단방사선과학교실， 일반외과학교실*

정 경 일 • 조 경 식 • 이 문 규 • 오 용 호 • 검 진 천*

대장암의 근접부위전이 평가에 대한 전산화단충촬영의 유용성은 그 한계가 제시되고 있고 대신 광범위전이에 대한

이의 이용도가 강조되고 있다. 대장암에 있어서 이와같은 전산화단층촬영의 유용성을 평가하기 위하여 지난 2년간

병리학적으로 대장암으로 판명되었던 56명의 환자들의 전산화단층촬영 소견을 분석하여 근위지방조직침범은 86, 58,

80%의 민감도， 특이도， 정확도를 보였으며 근위임파선침입 60, 83, 75%, 원위임파선전이 67, 100, 95%, 간전이

83, 98, 96%, 복막전이 67, 94, 89%등의 결과를 보였다. 전산화단층촬영은 본 연구에서 근위부침입 평가시 비교적

좋은 정확도를 보였으나 간이나 원위임파선전이 같은 원격광범위전이 평가시 이의 가치가 더 있는 것으로 판명되었

으며 이러한 소견은 환자의 적절한 치료유도에 기여할 것이다.

m

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