Colorectal adenomas and food. A prospective study of change in volume and total mass of adenomas in man

Natural history of diminutive and small colorectal polyps: a systematic literature review

BACKGROUND AND AIMS

Diminutive (1-5 mm) and small (6-9 mm) polyps comprise 90% of detected lesions during colonoscopy and rarely contain advanced histology or colorectal cancer (CRC). Routine removal of these lesions results in a significant burden to colonoscopy programs. At the same time, the risk for progression of these polyps to CRC is unclear. We performed a systematic review to explore the natural history of diminutive and small colorectal polyps.

METHODS

We searched MEDLINE and EMBASE for studies investigating the natural history of colorectal polyps. Studies were considered eligible when they assessed patients with 1- to 9-mm polyps that were not treated with polypectomy and that underwent follow-up. We excluded studies in patients with inflammatory bowel disease, polyposis syndromes, and previously diagnosed CRC. We independently extracted study characteristics and evaluated CRC and advanced adenoma (size ≥ 10 mm, containing high-grade dysplasia or villous features) as outcome parameters.

RESULTS

Of 8775 retrieved studies, 9 studies with 721 patients were included that prospectively evaluated the evolution of 1- to 9-mm polyps. In 7 studies the average duration of observation was 2 to 3 years. There was only 1 study in which 1 small polyp might have progressed to cancer. Of 1034 adenomas sized 1 to 9 mm in those studies, 6% progressed to advanced adenomas over time.

CONCLUSIONS

Based on this systematic review, it appears that some 1- to 9-mm adenomas progress to advanced adenomas within 2 to 3 years. No information on long-term CRC transition rates was found. Defining the biologic significance of these polyps is needed to balance between benefits and harm of polypectomy. (PROSPERO database registration number: CRD42016036577.).

Association between diverticulosis and colonic neoplastic lesions in individuals with a positive faecal immunochemical test

BACKGROUND

The association between diverticulosis and colonic neoplastic lesions has been suggested, but data in literature are conflicting. This study aimed to investigate such a relationship in patients participating in a colorectal cancer screening program who underwent high-quality colonoscopy.

METHODS

Data from consecutive individuals 50-75 years of age with a positive faecal immunological test were considered. Diverticulosis was categorised as present or absent. The prevalence of neoplastic lesions (adenoma, advanced adenoma, and cancer) between individuals with and those without diverticula was compared. A multivariate analysis was performed.

RESULTS

Overall, data from 970 consecutive individuals were evaluated, and diverticulosis was detected in 354 (36.5%) cases. At least one adenoma was detected in 490 (50.5%) people, at least one advanced adenoma in 264 (27.2%), multiple adenoma in 71 (7.3%), whilst a cancer was diagnosed in 48 (4.9%) cases. At univariate analysis, the adenoma detection rate in patients with diverticula was significantly higher than in controls (55.9% vs 47.4%; p = 0.011). At multivariate analysis, presence of diverticulosis was an independent risk factor for both adenoma detection rate (OR = 1.58; 95% CI = 1.14-2.18; p = 0.006) and advanced adenoma (OR = 1.57; 95% CI = 1.10-2.24; p = 0.013), but not for colorectal cancer.

CONCLUSIONS

In a colorectal screening setting, the adenoma detection rate was significantly higher in individuals with diverticulosis than in controls.

Fruit and vegetable intake and prevalence of colorectal adenoma in a cancer screening trial

BACKGROUND

Research on the association between fruit and vegetable intake and risk of colorectal adenoma is inconclusive.

OBJECTIVE

We studied whether intake of fruit, vegetables, or their subgroups is associated with a lower risk of prevalent colorectal adenoma.

DESIGN

In men and women (aged 55-74 y) who were screened for colorectal cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) (1993-2001), we compared 3,057 cases with at least one prevalent histologically verified adenoma of the distal large bowel with 29,413 control subjects. Using a food-frequency questionnaire, we quantified intake of fruit and vegetables in the 12 mo before screening as energy-adjusted pyramid servings/d (ps/d). Adjusted odds ratios (ORs) and 95% CIs were estimated by logistic regression.

RESULTS

Risk of distal adenoma was significantly lower among subjects in high (approximately 5.7 ps/d) versus low (approximately 1.2 ps/d) quintiles of total fruit intake (OR: 0.75; 95% CI: 0.66, 0.86, P for trend <0.001), which was not completely explained by dietary folate or fiber intake. Inverse associations between adenoma and total fruit intake were observed regardless of adenoma histopathology and multiplicity. However, the protective effect was seen only for colon and not rectal adenoma. Total vegetable intake was not significantly associated with reduced risk of adenoma. ORs for colorectal adenoma among persons with high versus low intakes of deep-yellow vegetables, dark-green vegetables, and onions and garlic were significantly related to lower risk of adenoma, although the P for trend for dark-green vegetables was not significant.

CONCLUSION

Diets rich in fruit and deep-yellow vegetables, dark-green vegetables, and onions and garlic are modestly associated with reduced risk of colorectal adenoma, a precursor of colorectal cancer.

Dietary Habits and Growth and Recurrence of Colorectal Adenomas: Results From a Three-Year Endoscopic Follow-Up Study

Diet has been associated with sporadic colorectal cancer (CRC) risk. The relationship to the growth rate of adenomas is largely unknown. Previous analyses of our cohort of polyp cases have shown 1) indicators of a healthy diet were inversely associated with adenoma occurrence, 2) diet was related to the fecal profile, 3) obesity was positively associated with adenoma growth, 4) familial predisposition of CRC was positively associated with adenoma growth, and 5) intervention with calcium and antioxidants was not associated with adenoma growth. The present aim was to study the effects of diet on growth and recurrence of adenomas. Data were collected from a 3-yr polyp growth and intervention study. Polyps larger than 9 mm were removed, whereas the remainder and newly discovered polyps smaller than 10 mm were left in situ for 3 yr. Diet was assessed by a 5-day dietary record by weighing (DR) and food-frequency questionnaire (FFQ). Weak inverse associations were found only between adenoma growth and fruits and berries (adjusted odds ratio, aOR = 0.3; 95% CI = 0.1-0.9) and carbohydrates (aOR = 0.1; 95% CI = 0.1-0.6; both only DR data) and between adenoma recurrence and vegetables (crude odds ratio, cOR = 0.4; 95% CI = 0.1-0.9; only FFQ data). Taken together, the present and previous findings from this cohort may indicate an early role for dietary factors in CRC development.

Lifestyle-related factors and colorectal polyps: preliminary results from a Norwegian follow-up and intervention study

Lifestyle-related variables are suggested to play a major role in the development of colorectal cancer (CRC). Within a 3-year follow-up and intervention study with calcium and antioxidants against growth and recurrence of colorectal polyps, supplementary studies were performed in which different aspects of lifestyle were examined. Instead of polypectomy at diagnosis, polyps <9 mm were left in situ in 116 polyp patients (50-76 years, 50% men). After 3 years, all polyps were removed and subjected to histology. Two different sets of control groups were included (all controls were age- and sex-matched and proven to be free of polyps). We applied two different methods in order to assess most exposure variables. Generally, in case-control studies, the validity of the study outcomes is high if they are similar regardless of choice of controls and methods, since bias due to these choices may affect the risk estimates. In contrast, the validity of the study outcomes is low if dependent upon these choices. Our preliminary data support the theory that different factors may be of importance in different stages of the neoplastive formation, and that lifestyle-related factors are likely to play a major role in CRC development.

Current diet and colorectal adenomas: a case-control study including different sets of traditionally chosen control groups

High intake of fat and a low intake of foods rich in antioxidants and fibre are suggested to be associated with risk of colorectal adenomas. Inconsistency may, however, be due to dietary assessment problems or differences in the identification of cases and controls. We have compared 87 adenoma cases aged 50-76 years with 35 healthy controls and 35 'hospital' controls. All the controls were matched for sex and age (+/-5 years) and proven to be free of polyps. Current habitual diet was measured by a 5-day dietary record by weighing. Regarding the intakes of vegetable fat, protein, cholesterol, vitamin A, total vitamin D, edible fats, coffee and fish and fish products, the outcomes of the analysis depended upon the source of controls. However, an increased adenoma risk compared with either set of controls related to a low consumption of vegetables, cereals, iron, vitamin C and fibre and a high intake of total fat was found. This is suggestive of substantial differences, since bias due to abdominal symptoms, the dietary records or an inappropriate choice of controls, would have affected the estimations. The findings give further strength to the role of these dietary factors in the formation of precancerous lesions in the large intestine.

Significance of serum iron and ferritin in patients with colorectal adenomas

BACKGROUND

Colorectal adenomas are often detected on mass screening, although detection rates with fecal occult blood tests are low. The relationship between colorectal adenomas and the resulting blood loss was examined indirectly, using serum iron and ferritin levels.

METHODS

Serum iron and ferritin concentrations were measured in 184 men with colorectal adenomas (> or = 1 cm in 92; < 1 cm in 92) and in 92 healthy male controls. Values in the three groups were compared. In the patients with adenomas > or = 1 cm, serum iron and ferritin levels were compared on the basis of the site, number, histology, and degree of dysplasia of the adenoma.

RESULTS

The mean serum iron level was significantly lower in patients with adenomas > or = 1 cm than in controls (P < 0.05), although this level did not differ significantly between those with adenomas < 1 cm and controls. The mean serum ferritin level also was significantly lower in patients with adenomas > or = 1 cm than in those with adenomas < 1 cm and controls (P < 0.05, P < 0.01, respectively), although this level did not differ between those with adenomas < 1 cm and controls. There was no difference in mean serum iron or ferritin levels on the basis of the site, number, histology, or degree of dysplasia of the adenoma.

CONCLUSIONS

We conclude that decreased serum iron and ferritin levels are related only to adenoma size and that adenomas > or = 1 cm may bleed steadily, resulting in iron deficiency. However, low dietary intake of iron and fiber may be one of the causes of low serum iron and ferritin.

Intervention studies in adenoma patients

There is considerable evidence that most colorectal carcinomas arise in preexisting adenomas. It also appears that there may be a considerable influence of diet in the genesis and growth of adenomas. This evidence is discussed and the current dietary intervention studies in humans are reviewed.