Gut: first published as 10.1136/gut.27.10.1181 on 1 October 1986. Downloaded from Gut, 1986, 27, 1181 -1185 Cholecystectomy and adenomatous polyps of the large bowel KATHRYN J LLAMAS, LEILA G TORLACH, M WARD, AND C BAIN From the Department of Gastroenterology, Royal Brisbane Hospital and Department ofSocial and Preventive Medicine, University of Queensland, Queensland, Australia SUMMARY Seventy two patients (39 women) with colonic adenomas were compared with 72 adenoma free controls (39 women) to investigate the possible association between previous cholecystectomy and the subsequent development of adenomas. Data were gathered retrospectively from medical records. Overall there was no significant association between colonic adenomas and previous cholecystectomy. When women are considered separately, however, eight cases and no controls had undergone cholecystectomy (odds ratiooolower 95% confidence limits 1*7, p>001). No association between previous cholecystectomy and large bowel adenomas was found in men. Four of nine (44-4%) women with right sided colonic adenomas had undergone previous cholecystectomy compared with only three of 23 (13%) women with left sided adenomas. Several recent studies'-6 have investigated the rela- detected on colonoscopy, and who had no evidence tionship between colonic cancer and previous of present or past large bowel cancer. The control cholecystectomy. Most have indicated an increased group consisted of 72 men and women, in whom risk for women of developing right sided colonic colonoscopy was normal, individually matched for http://gut.bmj.com/ cancer after cholecystectomy,l 2 4 5 but at least one age (±5 years) and sex. study has shown a stronger association with rectal The controls were selected consecutively from a cancer,3 and some investigators have been unable colonoscopic diagnostic listing as having had a to confirm any relationship.6 normal colonoscopy, with no past history of adeno- As colonic adenomatous polyps are generally ma, colonic cancer, or other disease of the large thought to be precursors of colonic carcinoma,79 bowel. the purpose of this study was to determine whether The proportions of patients excluded, because on October 1, 2021 by guest. Protected copyright. there was any association between the presence of their charts were unavailable or contained insuffi- such lesions and previous cholecystectomy. cient data to determine cholecystectomy status, were comparable in the two groups (22 8% adeno- Methods ma patients and 29.4% controls). Data were obtained by retrospective review of PATIENTS medical records and colonoscopy reports of adeno- The study population consisted of patients who ma and control patients, and were recorded on underwent diagnostic colonoscopy during the years standard forms. Cholecystectomy status was deter- 1980 to 1982 in the Royal Brisbane Hospital, mined by review of the past history and clinical Department of Gastroenterology. There were 72 examination sections of the medical records, as well cases (39 women) for whom a matched control could as the surgeon's operation reports. Other gastroin- be found. The patients were aged 30-85 years, in testinal surgery, as well as the presence or absence whom one or more colonic or rectal polyps were of gall stones was also recorded. Histological type, size, number, and site of adenomas were noted from pathology and colonoscopy reports. Standard case Addrcss for correspondence: M Ward, Department of Gastroenterology, control analyses (matched or unmatched as Royal Brisbane Hospital. Herston. Queensland 40)29. Australia. appropriate) were carried out using computation of Received for publication 6 February 1986. odds ratio, 95% confidence limits and exact tests. " 1181 Gut: first published as 10.1136/gut.27.10.1181 on 1 October 1986. Downloaded from 1182 Llamas, Torlach, Ward, and Bain Results adenomas were less than 11 mm in diameter, eleven (15.3%) were between 11 and 30 mm and two The average age at colonoscopy of adenoma (2 8%) were greater than 30 mm. No measurements patients was 57-3 years, and ofcontrols was 55 *6 years. were available in 15 (20.8%). Histological information was available in 54-2% of The matched pair analysis of cholecystectomy cases, the majority of adenomas being tubular or status is shown in Table 3. Overall, the proportion tubulovillous (Table 1). Thirty eight (52.8%) of the of adenoma patients having had a previous cholecys- patients had only a single adenoma, 32 (44.4%) had tectomy was 11-1% (8/72) compared with 2-8% between two and six adenomas, and two had more (2/72) for controls. When the sexes are considered than six. The distribution of adenomas in the colon separately, however, some interesting differences is shown in Table 2. Forty four (61.1%) of the emerge. Very few men had a history of cholecystec- tomy, and the 95% confidence interval for the odds Table 1 Histological classification ratio is, in consequence wide (0.0-5-3). On the other hand, none of the 39 women controls had a history Histological type Patienits (%) Patietnts (ni) of cholecystectomy compared with eight of 39 women with adenomas (lower 95% confidence Villous adenoma 1-4 1 bound 1-7 (p<0.01); matched analysis). The aver- Tubulovillous adenoma 18 1 13 and Tubular adenoma 34 7 25 age time interval between cholecystectomy No histology available 45 8 33 colonoscopic diagnosis of adenomas in women was 4*5 years, range 7 months to 11 years. Total 100 0 72 Patients with adenomas in the caecum, ascending colon, hepatic flexure and/or transverse colon were classed as 'right sided adenoma patients', while Table 2 Distribution of adenomas in colon those with adenomas in the splenic flexure, descend- ing colon, sigmoid colon and/or rectum were classed Site Patients (%) Patients (n) as 'left sided adenoma patients'. The distribution in regard to cholecystectomy status in female patients Caecum 9-7 7 Ascending colon 2-8 2 is shown in Table 4. Of women with right sided Hepatic flexure 0.0 0 adenomas, 44% had undergone cholecystectomy, in Transverse colon 13 9 10 contrast with only 12% of those with left sided lesions Splenic flexure 2 8 2 (odds ratio 6-13, 95% confidence limit 0-7-53-1, http://gut.bmj.com/ Descending colon 11-1 8 Sigmoid colon 66-7 48 p=0-11). Patients with adenomas on both sides of Rectum 23-6 17 the colon were excluded from this analysis. There were no associations of polyps with a NB: Percentage total exceeds 10)0% because some patients had variety of types of previous gastrointestinal surgery adenomas in several sites. Table 3 History of cholecystectomy in adenoma and control patients (matched analysis) on October 1, 2021 by guest. Protected copyright. Adenoma Patients 95% Confidence limits Positive Negative Total for odds ratio 1. Men Controls Positive 0 2 2 Negative 0 31 31 Total 0 33 33 2. Women Controls Positive 0 0 0 Negative 8 31 39 Total 8 31 39 3. Men and women Controls Positive 0 2 2 Negative 8 62 70 (0(8-38.7) Total 8 64 72 Note: 'Positive' and 'negative' refer to history of cholecystectomy. Gut: first published as 10.1136/gut.27.10.1181 on 1 October 1986. Downloaded from Cholecystectomy and colonic adenomas 1183 Table 4 Distribution of adenomas in female patients faecal specimens from subjects living in countries with a high incidence of colonic cancer.'3 In a case Previous cholecvstectomv control study,'9 faecal concentrations of secondary bile salts were higher in patients with colon cancer Group Yes No Total and in patients with adenomatous polyps of the Right sided adenomas 4 5 9 colon, than in patients with other digestive diseases Left sided adenomas 3 23 26 and in normal controls; and laboratory studies20 21 have shown that the secondary bile acids, lithocholic Totals 7 28 35* acid, and deoxycholic acid, act as cocarcinogens in induced colonic cancer in animals. *Four female patients with adenomas both sides are excluded from experimentally this Tahle. Although the bile salt/bacterial theory of mechan- ism of development of colonic cancer and adenomas is an attractive one, there are several other explana- (including appendicectomy, hernia repair, vago- tions for the apparent association between previous tomy, and surgery for inflammatory bowel disease). cholecystectomy and development of colonic adeno- mas. Gall bladder disease itself, and not cholecys- Discussion tectomy per se, could lead to increased risk of cholecystectomy and of colonic adenomas and can- The results of this study suggest that cholecystec- cer. A recent study has examined the relationship tomy increases subsequent risk of developing adeno- between cholecystectomy, silent cholelithiasis and mas of the large bowel in women, a finding which is colonic adenomas. Mannes et a122 compared the congruent with increasing evidence of an association prevalence of adenomatous polyps detected at between previous cholecystectomy and the develop- colonoscopy in 333 patients who had previously ment of large bowel cancer. 1-5 The data also suggest undergone cholecystectomy with an asymptomatic a tendency for adenomas to occur on the right side group of 406 patients shown by ultrasonography to of the colon after cholecystectomy in women paral- have gall stones in the gall bladder. There were no leling a similar right sided preponderance found for differences between these groups except among colon cancer after cholecystectomy.5 Vernick et a14 those aged 6-8(0 years. Patients who had undergone argue that the right side of the colon is most likely to a cholecystectomy more than 10 years ago had be affected by the potential carcinogenic effect of significantly more adenomas (38 5%) (and cancers) bile salt metabolites. than either those having had their cholecystectomy http://gut.bmj.com/ The lack of any apparent association between less than 10 years ago (218%) or a matched cholecystectomy and the development of adenomas cholelithiasis group (23-7%).