SCIENTIFIC PAPERS

Endoscopy Versus Double-Contrast Barium Enema in the Evaluation of Patients With Symptoms Suggestive of Colorectal Carcinoma

Mary Jane Warden, MD, Nicholas J, Petre l , MD, FACS, Lemuel Herrera, MD, F A C S , and Amold Mit te lman, MD,

Buffalo, New York

The annual incidence of colorectal cancer in the United States for 1986 is estimated to be 140,000 cases, second only to lung cancer as the leading cause of carcinoma-related deaths [1]. Survival rates of patients with adenocarcinoma of the colon and rectum vary with the stage of disease at diagno- sis. Although the overall 5 year survival rate of all patients with colorectal malignancy is 40 percent, the survival rate of patients with early lesions is over 90 percent [2,3]. Screening programs to detect color- ectal lesions early in their natural history, and thus contribute to improving survival rates, have been developed [4-7]; however, in the present cost-con- scious medical climate, screening examinations must be both sensitive and cost-effective. This re- port describes our experience in comparing the neg- ative findings of the 65 cm flexible sigmoidoscope, with those on double-contrast barium enema and colonoscopy in the screening of patients with symp- toms characteristic of colorectal cancer.

M a t e r i a l a n d M e t h o d s

At Roswell Park Memorial Institute, patients with pos- itive findings on a stool guaiac test, hematochezia, a change in bowel habits, or a family history of colorectal carcinoma were referred from the screening clinic to the colorectal clinic for further investigation. All patients underwent a thorough history and physical examination

From the Department of Surgical Onoology, Roswell Park Memorial Insti- tute, Buffalo, New York.

Requests for reprints should be addressed to Nicholas J. Petrelli, MD, Department of Surgical Oncology, Roswell Park Memorial Institute, 666 Elm Street, Buffalo, New York 14263.

followed by sigmoidoscopy with the Pentax 65 cm flexible scope. Patients with normal findings on flexible sigmoi- doscopic examination underwent a double-contrast bari- um enema. If an abnormality was found by barium enema, the patient subsequently underwent colonoscopy. Pa- tients found to have adenomatous polyps on flexible sig- moidoscopy were referred for colonoscopy and will be the subject of a future report.

There were 276 patients referred from the screening clinic to the colorectal clinic who form the basis of this study. There were 105 men and 171 women. All patients underwent examination with the 65 cm flexible sigmoido- scope. The median distance from the anal verge examined by the flexible scope was 55 cm. The patients were pre- pared for the sigmoidoscopic exam with one to two Fleet | enemas 1 hour before endoscopy. The endoscopy was performed in the left lateral decubitus position by a surgi- cal fellow under the supervision of a staff surgeon fully trained in endoscopy.

R e s u l t s

The findings on flexible sigmoidoscopic and dou- ble-contrast barium enema examinations were in agreement in 258 patients. In 178 of these examina- tions, findings of both flexible sigmoidoscopy and barium enema were completely negative. In the re- maining 80 cases, both flexible endoscopy and bari- um enema revealed minor positive findings such as diverticulosis.

In an additional 18 patients, negative findings on flexible sigmoidoscopy were followed by positive findings on barium enema (Figure 1). Five of the barium examinations were interpreted as showing

224 The American Journal of Surgery

Endoscopy Versus Barium Enema

polyps in the colon or rectum, three reported de- scending colon polyps, three reported filling defects in the cecum, one a filling defect in the sigmoid, and one a narrowing in the ascending colon. Colonos- copy discovered no abnormalities in all 13 of these patients; therefore, the barium enema findings were considered false-positive (72 percent).

The remaining five patients were found to have significant findings on barium enema after normal findings on flexible sigmoidoscopy (Table I). One patient had a defect in the cecum on barium enema. On colonoscopy, a cecal polyp 3 mm by 5 mm was discovered together with a transverse colon polyp 2 by 3 mm in size. A second barium enema demon- strated a polyp in the ascending colon, and colonos- copy confirmed two adenomatous polyps in the as- cending colon. The third barium enema revealed a polyp in the transverse colon, and colonoscopy yielded an adenomatous polyp in the transverse colon and one in the cecum. A polyp in the splenic flexure noted on barium enema in the fourth patient was not found on colonoscopy. However, an adeno- matous polyp 8 cm from the anal verge, missed on both flexible sigmoidoscopy as well as barium ene- ma, was found. In the fifth patient, a polyp 50 cm within the descending colon found on barium enema was confirmed on coionoscopy and contained a fo- cus of carcinoma in situ. This patient had a redun- daut sigmoid colon, and it is possible that the flexi- ble scope was unable to reach the polyp. It is noteworthy that all polyps found on colonoscopy were less than 1 cm in diameter.

In this subset of 18 patients with positive findings on barium enema after no abnormalities were found on flexible sigmoidoscopy, 5 (28 percent) were found to be significant, 4 with adenomatous polyps and 1 with a carcinoma in situ. Also, in four of these five patients colonoscopy found additional polyps that were not seen on barium enema. Therefore, 5 of 276 patients (1.8 percent) had abnormalities found on barium enema after none were discovered by flexible sigmoidoscopy, 1.4 percent harbored pre- malignant polyps, and 0.4 percent had an unsus- pected colonic carcinoma in situ.

Comments In the present study, we compared the use of the

65 cm flexible sigmoidoscope and double-contrast barium enema in the screening of patients with symptoms suggestive of colorectal cancer.

The benefit gained in screening for colorectal can- cer is due to the prevalence of the disease in the population and the improved chance for cure if di- agnosed early in the natural history of the disease. Colorectal adenomatous polyps are known to be precursors of the development of adenocarcinoma. Thus, a program which detects and eliminates these premalignant lesions should improve the survival

18 Patients j ~

e ~ ~ ~ 13 Pati 5 Patients (28%)

False-positive BE True-positive BE via colonoscopy via colonoscopy (Table I)

Figure 1. Patients with negative findings on 65 cm flexible endoscopy with abnormalities found on barium enema. BE = barium enema.

TABLE I Patients with True-Positive Findings on Barium Enema (BE) and on Colonoscopy

Patient No. Findings on BE Findings on Colonoscopy

1 Defect in cecum Cecal polyp; transverse polyp

2 Ascending polyp 2 ascending polyps 3 Transverse polyp Transverse polyp; cecal

polyp 4 Splenic flexure polyp Rectal polyp; no splenic

flexure polyp 5 Descending polyp Descending polyp (carcinoma

in situ)

rate of colorectal carcinoma. According to Gilbert- sen [8], in a group of patients in whom adenomas were removed by endoscopic polypectomy, the actu- al incidence of rectosigmoid carcinoma was only 15 percent of the expected incidence. Although there is agreement that screening for colorectal carcinoma can improve survival rates, there is no agreement on the best methods of accomplishing that screening. For example, the problems associated with the fecal occult blood test have been reviewed b y Simon [9] previously.

In the present study, findings 0nbar ium enema and flexible sigmoidoscopic examination were in agreement in 93 percent of cases. Of the 18 patients in whom there were major discrepancies between barium enema findings and flexible sigmoidoscopy findings, 13 (72 percent) were confirmed to be false- pos!tive barium studies by colonoscopy. Of greater significance is the fact that of the 276 patients re- ferred for workup of colorectal malignancy, only 1.8 percent of patients had significant findings beyond the reach of the 65 cm flexible sigmoidoscope after an unremarkable examination, whereas 1 pat ient had a colonic carcinoma in situ. This becomes im- portant when the cost-benefit ratio of screening for colorectal cancer is taken into account. Although colonoscopy is the definitive examination to rule ou t a colonic tumor, this is not practical as a screening tool, and a less expensive and time-consuming pro- cedure that does not significantly diminish sensitiv- ity must be employed. Flexible sigmoidoscopy ap- pears to fulfill these requirements.

Volume 155, February 1988 225

Warden et al

Summary Two hundred seventy-six patients with positive

findings on a stool guaiac test, hematochezia, a Change in bowel habits, or a family history of color- ectal carcinoma were referred to the colorectal clinic for further investigation. There were 105 men and 171 women. All patients underwent examination with the 65 cm flexible sigmoidoscope. Patients with no abnormalities on endoscopy underwent a double-contrast barium enema. If the barium ene- ma revealed a polyp or other suspicious pathologic process, the patient was referred for colonoscopy. In 258 patients, findings of barium enema and flexible sigmoidoscopy were in agreement. The findings in 178 of these examinations were completely nega- tive, and in the remaining 80 cases flexible endosco- py and barium enema revealed diverticulosis. In an additional 18 patients, negative findings on flexible sigmoidoscopy were followed by positive findings on barium enema. Thirteen of these 18 patients (72 percent) had negative findings oncolonoscopies and therefore had false-positive findings on barium ene- ma. In the remaining five patients (28 percent), an unsuspected colonic carcinoma or premalignant polyp was discovered on barium enema and docu-

mented by colonoscopy. Also, in four of these five patients, colonoscopy found additional polyps that were not seen on barium enema.

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3. Evans J, Vana J, Aronoff B, et al. Management and survival of carcinoma of the colon: results of a national survey by the American College of Surgeons. Ann Surg 1978; 188: 716- 21,

4. Cummings M, Michalek A, MetUin C, Mittelman A. Screening for colorectal cancer using the Hemoccult II stool guaiac slide test. Cancer 1984; 53: 10: 2201-5.

5. Greegor D: A progress report: detection of colorectal cancer using guaiac slides. CA 1972; 22: 360-3.

6. Miller S, Knight A. The early detection of colorectal cancer. Cancer i977; 40: 945-9.

7. Gilbertsen V, McHugh R, Schuman L, et al. The earlier detec- tion of Colorectal cancers: a preliminary report of the results of the occult blood study. Cancer 1980; 45: 2899- 901.

8. Gilbertsen VA. Proctosigmoidoscopy and polypectomy in re- ducing the incidence of recta! cancer. Cancer 1974; 34: 936-59.

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226 The American Journal of Surgery