Incidence of colorectal cancer following adenomatous polyps of the large intestine

A Multicenter Study of Colorectal Adenomas Rationale, Objectives, Methods and Characteristics of the Study Cohort

Background and Aims

The Multicenter Study of Colorectal Adenomas (SMAC) is a retrospective-prospective cohort study involving four Gastrointestinal Endoscopy Units in Italy. The main aim of the study is to evaluate the relationship between clinical and pathologic information at index colonoscopy and subsequent incidence of adenoma and colorectal carcinoma. We report the rationale, objectives and methods of the study, including patient characteristics at initial presentation.

Methods

All patients were consecutively identified from the endoscopy registries of the four Centres from January 1, 1985 to December 31, 1992. Inclusion criteria were: age 18-69 years, endoscopy performed with adequate toilette at least up to the rectosigmoid junction, and removal of all detectable polyps. Exclusion criteria were: familial adenomatous polyposis, inflammatory bowel diseases, adenocarcinoma in adenoma with infiltrated margins, previous invasive cancer at any site, colon resection and geographic inaccessibility.

Results

Out of 20,071 patients who underwent endoscopy at the four Centres, 11,959 fulfilled the eligibility criteria (5,892 males and 6,067 females, mean age = 51.1 ± 11.6 years). The main reasons for exclusion were age (n = 4,020) and previous or present colorectal cancer (n = 2,389). Symptoms were the most common reason for referral (72.3%), while post-polypectomy follow-up and positive fecal occult blood accounted for most of the remaining cases. A pancolonoscopy was performed in 3,088 patients (25.8%), while a left-sided endoscopy was performed in 7,887 (66%). A total number of 4,810 polyps were removed from 2,699 patients (2,994 adenomas, 1,580 hyperplastic polyps and 236 polyps lost after resection). A significant association (p < 0.001) between age and the endoscopic findings was observed. The subjects without polyps (n = 9,198) had the lowest age (mean = 49.9; 95%CL = 49.6 - 50.1) followed by the patients with hyperplastic polyps (n = 661; mean age = 52.3; 95%CL = 51.5-53.1), and the patients with adenomas (n = 1,732; mean age = 56.2; 95%CL = 55.8 - 56.6), and the patients with hyperplastic polyps and adenomas (n = 306; mean age = 57.2; 95%CL = 56.3 - 58.2). Polyps were diagnosed more frequently in males than in females (28.6% versus 17.0%; p < 0.0001).

Conclusion

This study provides some insights in the natural history of colorectal cancer and stresses the need to develop adequate strategies in the follow-up of subjects after either positive or negative colonoscopy.

Gelatinases A and B expression in human colorectal cancer in upper Egypt: a clinicopathological study

AIM

Prognosis of colorectal carcinoma depends on many factors, such as age and sex of patient; location; multiplicity; local extent and size of tumor, bowel obstruction, or perforation; as well as tumor microscopic type and grade; vascular and perineural invasion; and nodal and distant metastasis. The matrix metalloproteinases (MMPs) are a family of proteolytic enzymes strongly implicated in tumor invasion and metastasis, hence in tumor prognosis. The purpose of this study was to assess the role of MMP-2 and MMP-9 expression in colorectal tumorigenesis, invasion, and metastasis, hence their prognostic values.

METHOD

Immunohistochemical analysis of MMP-2 and MMP-9 in colorectal cancer cells, an immunohistochemical score based on the intensity of immunoreactivity and proportion of immunoreactive cells that established for each MMP, and correlation of this expression with the established prognostic factors.

RESULTS

MMP-2 was expressed in 81.8% (strong expression in 40%) of cases, and MMP-9 was expressed in 72% (strong expression in 35%) of cases.

CONCLUSIONS

MMP-2 and MMP-9 are widely expressed in colorectal carcinoma, suggesting significant diagnostic and prognostic values in these tumors. Increased levels of MMP-2 and MMP-9 protein expression in colorectal carcinoma tissues as compared to normal tissues suggest their association with colorectal tumor invasion and metastasis and that they could be targets for intervention and therapy in colorectal carcinoma.

History of negative colorectal endoscopy and risk of rectosigmoid neoplasms at screening flexible sigmoidoscopy

BACKGROUND AND AIMS

Screening sigmoidoscopy can reduce incidence of colorectal cancer and mortality. The optimal re-screening interval has not yet been defined. This study is aimed at estimating the risk of distal advanced adenomas (diameter >/=10 mm, villous component >20%, high-grade dysplasia) and cancer at screening flexible sigmoidoscopy in subjects aged 55-64 years who reported pre-screening negative colorectal endoscopy.

PATIENTS

Eight thousands two hundred two subjects aged 55-64 years who underwent screening flexible sigmoidoscopy within the SCORE trial in Italy and who were able to report their previous history of colorectal endoscopy.

RESULTS

Eight hundred eighty three of 8,202 subjects (10.8%) reported at least one prescreening negative endoscopy: among them, after 3-5 years, 6-10 years and >10 years intervals between last reported examination and screening endoscopy, the Absolute Risk of advanced adenomas was 1.5%, 0.9% and 0.9%; one cancer was detected (0.1%). Among the 7,319 subjects who did not report prescreening endoscopy the risks of advanced adenoma and cancer were 3.2% and 0.4%, respectively. Subjects with a previous colorectal examination had a 65% decreased risk of advanced adenomas (OR=0.35, 95%CI 0.18-0.66) and a 71% decreased risk of cancer (OR=0.29, 95%CI 0.04-1.12) as compared to those who did not. For subjects without family history of colorectal cancer the statistically significant decrease of the risk persisted up to ten years. The observed benefit seems not to apply to subjects with family history of colorectal cancer.

CONCLUSIONS

Our results are consistent with the hypothesis that the interval between screening sigmoidoscopies could be safely expanded beyond 5 years for subjects without specific risk factors for colorectal cancer.

Increased cumulative incidence of prostate malignancies in colorectal cancer patients

BACKGROUND

Identifying subjects at an increased risk of colorectal cancer (CRC) is of considerable importance in designing effective screening strategies. Malignancies that cosegregate with CRC provide important markers for higher-risk patients. CRC and prostate cancer share many similarities with regard to etiological factors. However, the previous reports on associations between these common malignancies are contradictory and confounded by a lack of rigorous controls.

AIM OF THE STUDY

The aim of this study was to further elucidate the relationship between CRC and prostate cancer.

METHODS

We performed a retrospective case-control study of subjects receiving medical care at the Omaha Veteran's Administration Medical Center between 1992 and 2002. Cases (patients with CRC) were obtained through the pathology records, whereas controls (patients with a negative colonoscopy during the same time period) were found through assessment of the endoscopy database. All subjects had the pathology database queried for other malignancies. The medical record also was assessed for confounding factors such as prostate cancer screening, radiation therapy status, and so on.

RESULTS

We identified 149 male patients with CRC cases and 186 controls (age-matched male patients with a negative colonoscopy). The 10-yr cumulative incidence of prostate cancer was 10.7% of the cases but only 3.8% of the controls (p = 0.016). There were no significant differences between cases and controls among 11 other primary malignancies evaluated. The association between CRC and prostate cancer was unrelated to characteristics such as location in the colon and differentiation. Furthermore, confounding factors including frequency of prostate cancer screening and radiation therapy status did not explain the cosegregation between CRC and prostate.

CONCLUSION

This preliminary report suggests that there is an association between CRC and prostate cancer. If replicated in other populations, this may have important implications for cancer screening strategies.

Colorectal cancer risk in adenoma patients: a nation-wide study

Colorectal cancer incidence after adenoma removal has been studied in selected populations of adenoma patients. Our study estimates the trend in colorectal cancer incidence after adenoma removal in actual clinical practice. From PALGA, a nationwide network and registry of histo- and cytopathology in the Netherlands, we extracted data of all patients diagnosed with colorectal adenomas between 1 January 1988 and 1 October 1998. The data were used to calculate population-based colorectal cancer incidence rates after adenoma removal. A total of 78,473 adenoma patients were followed for a mean of 4.5 years after the first adenoma removal. The colorectal cancer incidence ratio compared with the general population matched by age and gender was 38.4 (37.3-39.5) in the first year after adenoma removal and 1.5 (95% confidence interval (CI): 1.4-1.6) after Year 1. The incidence ratio decreased from 2.8 (2.5-3.1) in Year 2 to 0.9 (0.6-1.2) in Years 9-11. This time trend is the opposite of the upward time trend that was expected after adenoma removal. Adenoma patients in the Netherlands are at increased risk for colorectal cancer compared to the general population. The high cancer incidence in Years 1-5 after polypectomy can be explained by a colonoscopic sensitivity for cancer of approximately 90%.

Reduced incidence of colorectal adenoma among long-term users of nonsteroidal antiinflammatory drugs: a pooled analysis of published studies and a new population-based study

Chronic treatment with nonsteroidal antiinflammatory drugs (NSAIDs) has been associated with a reduced risk of colorectal cancer, but less information is available on the relationship between NSAIDs and colorectal adenoma. We carried out a population-based cohort study with nested case-control analysis to determine the association between the use of aspirin and individual NSAIDs and the risk of colorectal adenoma. The General Practice Research Database in the United Kingdom was the source population. We followed 943,903 persons who were 40-79 years of age and free of colorectal adenoma or other cancer at baseline, which varied between January 1994 and September 1997. There were 1,864 incident cases of colorectal adenoma, for an incidence rate of 6.8 per 10,000 person-years. Compared with non-users, long-term users (1 year and more) of nonaspirin NSAIDs had a 40% decreased risk of colorectal adenoma (relative risk = 0.6; 95% confidence interval = 0.4-0.9). Long-term NSAID use was still associated with a reduced risk 1 year after stopping NSAID treatment. Use of most individual NSAIDs conferred a reduced risk. The risk of developing colorectal adenoma was reduced in long-term users of aspirin at doses of 300 mg daily (relative risk = 0.6; 95% confidence interval = 0.4-1.0), but reduced risk was not evident with daily doses of 75 and 150 mg aspirin. These results add further support to the value of NSAIDs as a candidate for primary prevention of colorectal tumors.

Allergy and other selected diseases and risk of colorectal cancer

It has been reported that allergy and other diseases may be related to colorectal cancer risk. The aim of this study was to perform a systematic analysis using information about medical histories specifically to see if there was any relation between allergies or other medical conditions and colorectal cancer risk. A multicentric case-control study was conducted in six Italian areas between 1992 and 1996 on 1225 incident cases of colon cancer, 728 cases of rectal cancer and 4154 controls comparable with cases according to sex and age group, admitted for acute conditions to the same network of hospitals where cases had been identified. Unconditional logistic regression models including terms for sex, age, study centre, years of education, body mass index, physical activity, smoking, history of colorectal cancer in first-degree relatives and energy intake were used to estimate the odds ratios (OR) of colon and rectal cancer according to history of allergy and other selected diseases. The OR for history of allergy was 0.88 (95% confidence interval, CI, 0.67-1.14) for colon and 0.64 (95% CI, 0.44-0.92) for rectal cancer, and the inverse association was stronger when allergy was diagnosed at age 35 years or more, or less than 10 years before the cancer diagnosis. No clear pattern emerged in strata of age and sex. History of other selected diseases, including hypertension and cholelithiasis, was not related to colon or rectal cancer risk, though there was a moderate increase in the risk of colon cancer (OR = 1.18, 95% CI, 0.66-2.14) in patients with a history of intestinal polyps. This study lends support to the hypothesis that allergic individuals may be at a lower risk of developing colorectal cancer.

Pathologic features of initial adenomas as predictors for metachronous adenomas of the rectum

BACKGROUND

Colorectal cancer is the third most common cancer in the world, arising mostly from pre-existing adenomatous polyps (adenomas) of the large bowel. Patients with colorectal adenomas are at increased risk of colorectal cancer because of a high recurrence rate for adenomas. We followed a cohort of 1490 patients with rectal adenomas to determine whether recurrence might be related to pathologic characteristics of the initial adenomas.

METHODS

The patients were identified in Haining County, China, from 1977 through 1978 by means of examination with a 15-cm rigid sigmoidoscope. They were followed by endoscopic examination at years 2, 4, 6, 11, and 16 after their initial polypectomy. New adenomas in the rectum were identified in 280 patients in these follow-up examinations.

RESULTS

Statistically significant twofold to threefold elevated risks of metachronous (recurrent) adenomas were observed for patients who had more than two initial adenomas or whose most advanced initial adenoma was more than 1.0 cm in size, was of villous/tubulovillous type, or showed moderate to severe dysplasia. Much stronger associations were observed for advanced metachronous neoplasms, which are defined as cancers or adenomas with severe dysplasia, with multivariate adjusted relative risks (95% confidence interval) of 4.2 (1.8-9.9) for a large initial adenoma (>1.0 cm), 8.1 (4.2-15.6) for villous/tubulovillous architecture, and 14.4 (5.0-41.3) for severe dysplasia. In particular, patients who had a large (>1.0 cm) adenoma with severe dysplasia at baseline had a relative risk of 37 (7.8-174.7) of developing advanced metachronous neoplasms compared with patients who had small adenoma(s) with mild dysplasia.

CONCLUSIONS

The risk of metachronous adenomas is closely related to the pathology of initial adenomas, thus allowing identification of a high-risk group of adenoma patients for close surveillance after their initial polypectomy.

Habitual intake of fruits and vegetables amongst patients at increased risk of colorectal neoplasia

We assessed consumption of fruit and vegetables amongst patients with ulcerative colitis, colorectal polyps or previous carcinoma. The dietary intakes for 119 patients attending a gastroenterology clinic for colonoscopy were assessed using a questionnaire. A single age- and sex-matched control subject was recruited for each patient. The patients consumed 12.8% less energy than the controls (P < 0.02) and 28.9% less fruit and vegetables (P < 0.0001). Patients with neoplastic disease consumed 21% less fruit and vegetables than the controls (n = 60; P < 0.01). This group of patients at increased risk of colorectal cancer selected diets containing significantly less fruit and vegetables than symptomless controls.