Regional Estimates of Colorectal Cancer Burden in Italy

Cancer Chemotherapy via Natural Bioactive Compounds

BACKGROUND

Cancer-induced mortality is increasingly prevalent globally which skyrocketed the necessity to discover new/novel safe and effective anticancer drugs. Cancer is characterized by the continuous multiplication of cells in the human which is unable to control. Scientific research is drawing its attention towards naturally-derived bioactive compounds as they have fewer side effects compared to the current synthetic drugs used for chemotherapy.

OBJECTIVE

Drugs isolated from natural sources and their role in the manipulation of epigenetic markers in cancer are discussed briefly in this review article.

METHODS

With advancing medicinal plant biotechnology and microbiology in the past century, several anticancer phytomedicines were developed. Modern pharmacopeia contains at least 25% herbal-based remedy including clinically used anticancer drugs. These drugs mainly include the podophyllotoxin derivatives vinca alkaloids, curcumin, mistletoe plant extracts, taxanes, camptothecin, combretastatin, and others including colchicine, artesunate, homoharringtonine, ellipticine, roscovitine, maytanasin, tapsigargin,andbruceantin.

RESULTS

Compounds (psammaplin, didemnin, dolastin, ecteinascidin,and halichondrin) isolated from marine sources and animals such as microalgae, cyanobacteria, heterotrophic bacteria, invertebrates. They have been evaluated for their anticancer activity on cells and experimental animal models and used chemotherapy.Drug induced manipulation of epigenetic markers plays an important role in the treatment of cancer.

CONCLUSION

The development of a new drug from isolated bioactive compounds of plant sources has been a feasible way to lower the toxicity and increase their effectiveness against cancer. Potential anticancer therapeutic leads obtained from various ethnomedicinal plants, foods, marine, and microorganisms are showing effective yet realistically safe pharmacological activity. This review will highlight important plant-based bioactive compounds like curcumin, stilbenes, terpenes, other polyphenolic phyto-compounds, and structurally related families that are used to prevent/ ameliorate cancer. However, a contribution from all possible fields of science is still a prerequisite for discovering safe and effective anticancer drugs.

Italian Cancer Burden by Broad Geographical Area

Aims and background

Cancer burden estimates in Italian regions are available for the period 1970-2010 as a result of the project “I TUMORI IN ITALIA” connected with EUROCHIP, the European project on cancer control. The Italian health-care system is organized at a regional level, so regional estimates of cancer indicators are useful to identify priorities for cancer plans. We compared cancer site-specific epidemiological estimates by 3 macro-areas (obtained by grouping regions) to suggest priorities for Italian cancer control plans, both at national and regional levels.

Methods

Mortality and incidence estimates for all cancers combined and for stomach, colorectal, lung, breast and prostate cancers were downloaded from the website www.tumori.net and aggregated in broad age classes (0-54, 55-74 and 75-84 years) and macro-areas (northern, central and southern Italy).

Results

Historically, Southern Italy had a lower cancer risk than the Center and North. After 2000 this epidemiological picture disappeared and the incidence and mortality rates in the Center are reaching those of the North. Also the weight of various cancer sites on all cancers has changed in Italy in the last decades. Lung cancer is still the most frequent cancer in the male population in the South, while in the Center-North it has been surpassed by prostate cancer and colorectal cancer. The lung cancer weight on all cancer deaths is increasing in women. Prostate cancer has become the most frequent male cancer in the Center-North in the age class 55-84. Breast cancer is the most frequent cancer in the female population and its incidence rates in the North are higher than those in the Center-South for all age classes. Colorectal cancer incidence rates have dramatically increased in men and colorectal cancer is nowadays the second cancer diagnosed in women in all age classes and macro-areas.

Discussion

From the epidemiological data here presented we derived the following suggestions and observations for cancer control plans: a) tobacco prevention should focus on the male population in the South, and on female populations in the country as a whole; b) prevention concerning diet and physical activity (risk factors for colorectal cancer) should be considered mainly for men at a national level; c) the coverage of breast cancer screening programs should be increased in the Center-South; d) colorectal cancer screening should be promoted at a national level; e) PSA testing (that is not actually included among the screening programs recommended) for prostate cancer is probably more widespread in the Center-North, resulting in an increased incidence without any evident decline in mortality as yet.

Cancer Prevalence Estimates in Italy from 1970 to 2010

Aims and background

The growing number of cancer survivors in Italy is expected to continue to increase as a consequence of population aging and survival improvements, but few estimates are currently available, particularly on the national and regional scale. The purpose of this work is to present detailed and updated prevalence estimates in Italy over the period 1970-2010 by cancer site (all cancers combined, stomach, colon and rectum, lung, breast and prostate) and gender.

Methods

Prevalence was derived with the MIAMOD statistical method, using cancer-specific mortality and relative survival as input data. Survival data from the Italian cancer registries were modeled to derive a national estimate for each cancer site and sex. To estimate prevalence trends, survival was assumed to improve in the future with the same rate observed in the period 1978-1994. A double scenario for survival - increasing or stationary - was considered to decompose the prevalence growth from 1995 to 2005 by its determinants: demographic changes, incidence and survival dynamics. The prevalence estimates were also decomposed by disease duration (2, 5 and 10 years) and by age (0-44, 45-59, 60-74 and 75-99).

Results

The proportion of cancer survivors in 2010 is expected to be about 4% in women and 3% in men, about twice the values attained in 1990. The highest dynamics was observed for prostate cancer, with a three-fold increase just in the 1995-2005 period (from 212 to 623 per 100,000), whereas in absolute terms breast cancer presented the highest levels (1,700 per 100,000 in 2010). The overall number of cancer prevalent cases is expected to rise by about 48% in the decennium 1995-2005 (from 1,152,000 to 1,709,000), and this growth is mainly attributable to incidence dynamics (+21%), then to survival improvements (+14%) and population aging (13%). In 2005, the 2-year prevalent cases were estimated to be 20% of all cancer survivors, 21% between 2 and 5 years from the diagnosis, 23% between 5 and 10 years, with 36% surviving for more than 10 years. Prevalence proportion was very high in the elderly (12.6% for 75-84 years and 8% for 60-74 years).

Conclusions

Updated prevalence data with appropriate coverage of the national territory are essential to define priorities in health care management and to develop cancer control programs. Prevalence by disease duration and by age should be the basis for planning research on the quality of life of cancer survivors, as long as cancer continues to become an even more chronic disease.

Methodology for Estimation of Cancer Incidence, Survival and Prevalence in Italian Regions

Background

The Italian health care system is based on a regional responsibility and organization. Incidence, survival and prevalence of cancer patients were estimated for major cancer sites by single regions in Italy within a collaborative project “I TUMORI IN ITALIA” aimed at providing epidemiological information in a web site, www.tumori.net , for health operators, health programmers, epidemiologists and the general public. The aim of this paper is to present the methodology used to derive regional estimates of cancer burden indicators in Italy for major cancer sites.

Methods

Estimates require a complex methodology to be used. We present herein the methodology to provide regional estimates that involves a combined use of multiple methods to model and extrapolate patient survival to derive incidence and prevalence estimates and future projections.

Results

Regional patient survival estimates in Italy are presented and discussed. Cancer survival has greatly improved over the years and differences between northern-central and southern regions have persisted. The fraction of patients cured from cancer is today over 50% for young men and women aged 15-44 and declines to 15%-25% at older ages (75-99).

Discussion

We integrated different methods to derive estimates of cancer burden in Italy, at a regional level, in order to take advantage of all information available and to obtain the most reliable estimates. The value of producing regional estimates of cancer burden indicators was motivated by the lack of such information systematically on the Italian national territory.

Estimated and Observed Cancer Incidence in Italy: A Validation Study

Aims and background

The study aimed to validate model-based incidence estimates by means of observed incidence rates provided by Italian cancer registries, for five major cancer sites (stomach, colon and rectum, lung, breast and prostate cancers) and for all cancers together.

Methods

Recent incidence rates observed by Italian population-based cancer registries were extracted from the data base of the Italian Association of Cancer Registries. Regional estimates of incidence rates for the same cancers were obtained by the MIAMOD method. Observed and estimated crude incidence rates and incidence trends were compared for the period of diagnosis 1985-2000. Eight Italian cancer registries and seven regions were selected for the analysis since they had incidence data available during the entire selected period.

Results and conclusions

An excellent agreement between estimated and observed crude incidence rates was found for all single cancer sites, regarding absolute incidence levels and time trends. A partial exception was breast, where empirical data showed a sudden increase in the last three years of observation, perhaps due to organized screenings in some Italian regions, and not captured by statistical models. Substantial underestimation of model-based incidence rates was found for all cancers combined, where the difference tended to increase with calendar year, up to a maximum of 20% in recent years. The greatest part of the discrepancy can be attributed to multiple cancers, which were included in cancer registries statistics but were not accounted for in MIAMOD estimates.

Colorectal polypoid lesions and expression of vascular endothelial growth factor in a consecutive series of endoscopic and surgical patients

Colorectal cancer incidence in patients undergoing screening protocols is decreasing because of the higher rate of discovered preneoplastic colonic lesions; however, adenomatous polyps may not always be removable endoscopically and surgery may still be necessary. The aim of this study was to assess the vascular endothelial growth factor expression in the different steps of colorectal carcinogenesis to explore its potential role as a marker of malignancy in polypoid lesions. A total of 92 subjects with colonic adenoma or cancer who underwent screening colonoscopy or surgery were prospectively enrolled. Real-time reverse transcription polymerase chain reaction for VEGF-A messenger RNA expression and immunohistochemistry for VEGF-A were performed. Immunoassays for VEGF-A, VEGF-C, VEGFR-1, VEGFR-2, and VEGFR-3 were also performed. Non-parametric statistics, receiver operating characteristic curve analysis, and logistic multiple regression analysis were used. VEGF-A messenger RNA expression was higher in patients with high-grade dysplasia or colorectal cancer than in those with low-grade dysplasia adenomas (p = 0.01). At immunohistochemistry, VEGF-A expression was significantly higher in colorectal cancer patients compared to dysplastic adenomas (p < 0.001), and the accuracy of VEGF-A expression for prediction of malignancy was 91.7 (95% confidence interval = 78.7-97.9). VEGF-C protein expression was lower in colorectal cancer patients than in simple adenomas (p = 0.02). VEGF-A levels were directly correlated to polyp size (rho = 0.73, p = 0.0062). Multivariate analysis demonstrated that malignancy and polyp size were independent predictors of VEGF-A mucosal levels. This study demonstrated that the VEGF-A expression changes along the colorectal carcinogenesis pathway showing a neat step up at the passage from high-grade dysplasia to invasive cancer. This feature might potentially be useful to stratify colorectal polyps in different risks of progression classes. Moreover, the high level of VEGF-A expression predicted the presence of lymphovascular invasion with good accuracy.

Estimates of cancer burden in Trentino-Alto Adige

Aims and background

The Trentino-Alto Adige region is composed of two autonomous provinces (Trento and Bolzano), each with its own cancer registry. The registries' total coverage is 100% of the regional population. The main difference between the two provinces in terms of cancer epidemiology is related to the prostate cancer incidence and survival, with higher values in Bolzano. This paper provides an update until 2015 of the basic epidemiological indicators for seven major cancers for the entire region.

Methods

The indicators were estimated by means of the MIAMOD method, a statistical back-calculation approach to derive incidence and prevalence figures starting from mortality and relative survival data. Mortality data were provided by ISTAT for the period 1970—2002 while survival was modeled on the basis of published data from the Italian cancer registries.

Results

The estimates for 2012 show that breast cancer was the most common cancer in women and prostate cancer was most common in men. Incidence and mortality were decreasing for cervix cancer and stomach cancer in both genders during the whole study period. The lung cancer incidence and mortality were decreasing in men but increasing in women. The colorectal cancer incidence rose in both genders while the mortality was decreasing in women. The incidence of skin melanoma increased in both sexes, while the mortality remained very low. The breast cancer incidence was increasing up to 2015 while the mortality was declining since 1986. The prostate cancer incidence increased up to 2006, thereafter the rates stabilized while mortality started to decrease in the early 2000s. The highest mortality rates were estimated for lung cancer in men and breast cancer in women.

Conclusions

Lifestyle plays an important role in cancer trends, as does organized screening for early detection of cervix, breast and colorectal cancer. The provincial data on risk factor distribution and adherence to and coverage of organized screening are satisfactory and their optimization may allow additional benefits in terms of public health.

A combination of faecal tests for the detection of colon cancer: a new strategy for an appropriate selection of referrals to colonoscopy? A prospective multicentre Italian study

INTRODUCTION

Colonoscopy workload for endoscopy services in Western countries is increasing markedly because of the implementation of faecal occult blood-based mass screening programmes against colorectal cancer (CRC). We therefore explored the possibility of using a combination of faecal tests to prioritize the access to colonoscopy with criteria other than symptoms and/or time of referral.

AIMS AND METHODS

We tested a combination of faecal tests [immunochemical faecal occult blood test (i-FOBT), M2-PK, calprotectin] as markers for advanced neoplasia in a selected series of patients requiring colonoscopy for the suspicion of CRC. All the tests were performed in a 1-day stool sample of patients aged 50-80 years, without any dietary restriction, before colonoscopy.

RESULTS

A total of 280 patients' stool single samples were analysed. Forty-seven patients had CRC and 85 patients had one or more advanced adenoma(s) at colonoscopy/histology. CRCs were associated with a highly significant increase (P<0.001) in faecal tumour M2-PK (mean 24.2 kU/l), which correlated with Dukes' staging. For CRC detection, i-FOBT was the test with the highest specificity and positive predictive value (0.89 and 0.53), whereas M2-PK had the highest sensitivity and negative predictive value (0.87 and 0.96). Calprotectin showed performance similar to M2-PK in terms of sensitivity and negative predictive value (0.93), but had lower specificity (0.39). The best combination of tests to predict the risk of CRC in this series was i-FOBT+M2-PK, as in patients showing positivity to both markers, the risk of cancer was as high as 79%.

CONCLUSION

The combination of i-FOBT and M2-PK is a sensitive tool in clinical practice for the appropriate management of waiting lists for colonoscopy, as it allows the classification of patients into different degrees of priority for investigation, according to their foreseeable risk of CRC.

Impact of a population-based colorectal cancer screening program on local health services demand in Italy: a 7-year survey in a northern province

OBJECTIVES

In 2005, the National Health Service recommended a population-based colorectal cancer (CRC) screening program using biennial fecal occult blood testing (FOBT), followed by total colonoscopy in positive patients. So far, no studies have been performed to evaluate the impact of a mass-screening CRC campaign on the health system services at the community level in Italy. We have therefore assessed the workload generated by the first two biennial rounds of screening program on the activity of hospital services involved in CRC diagnosis in the Lecco province.

METHODS

Routine data from all hospital services of our province were collected on activity levels related to CRC diagnosis from January 2003 to December 2009. This time span covered the 2 years prior to, as well as the two biennial rounds of the CRC screening program. In particular, we focused on the volume of outpatient FOBTs and colonoscopies (both diagnostic and interventional) performed among subjects outside the screening program. Joinpoint models were used to test whether an apparent change in trend of examination over time was statistically significant in different age cohorts of the population (<50 years, 50-69 years, and ≥70 years).

RESULTS

The volume of "extra-screening" per-patient/FOBTs and colonoscopies increased significantly over the evaluated periods in all ages, until year 2008, when a steady trend was beginning; the AAPCs (average of the annual percent changes) values were 5.7, 3.1, and 8.4 for FOBT and 14.6, 13.4, and 16.7 for colonoscopy in the three age cohorts, respectively. However, the increase in both FOBT and colonoscopy demand was maximal in the cohort ≥70 years, where three statistically significant annual percent changes (APCs) were identified (in 2003-2005, 2005-2006, and 2006-2007 APCs were 12.3, 14.9, and 15.9 for FOBT, and 18.7, 36.8, and 25.4 for colonoscopy, respectively).

CONCLUSIONS

After the implementation of a FOBT-based mass-screening program for CRC, careful consideration must be given to the significant increase in the workload of hospital services involved in CRC diagnosis, outside the screening campaign. The extra-work mainly involves gastroenterologists performing colonoscopy, whose activity increased over the 5-year period by 118%, as well as laboratory services, where the demand of FOBTs rose by 40%. This phenomenon, mainly attributable to a profound change in the attitude toward CRC screening by those age cohorts outside the program, covers a time span of two full rounds of screening, whereupon a steady trend for colonoscopy is apparent.

Cancer incidence and mortality in Spain: estimates and projections for the period 1981-2012

BACKGROUND

National indicators of cancer burden are essential information for cancer surveillance and health planning, so that in countries with partial registration coverage and geographically variable risk patterns, such as Spain, this is even more relevant. This article provides estimates of cancer incidence in Spain for all cancers combined, with the single exception of non-melanoma skin cancer, and for major cancer sites over the period 1981-2006, with projections up to 2012.

PATIENTS AND METHODS

Estimates were obtained by applying the MIAMOD method, a statistical back-calculation approach, to derive incidence from mortality and relative survival data.

RESULTS

During the period 1981-2012, age-standardised incidence rates for all cancers rose from the beginning of the period and started to decline from 2000 onwards among men, and increased across the whole period among women. Differences in incidence trends between men and women might be attributable to the gender-specific case-mix of sites for all cancers, and to differences in risk factors specific to certain cancer sites in men and women, with smoking being the main factor accounting for these differences between the sexes.

CONCLUSIONS

Estimates and projections of cancer incidence and mortality show divergent trends in Spain by sex and tumour type. This information is basic for planning and enhancing public health strategies and resources.

Small bowel capsule endoscopy performance in octogenarians: a case-control study

BACKGROUND AND STUDY AIMS

Capsule endoscopy is a high-sensitive tool for the investigation of suspected small bowel disorders, but its effectiveness in elderly patients is unknown. We sought to determine capsule endoscopy feasibility and diagnostic yield in octogenarians.

PATIENTS AND METHODS

Records of patients ≥ 80 years old (Group A) were retrieved from a database of 827 consecutive capsule endoscopy performed on as many patients. Capsule endoscopy failures, complications, diagnostic yield, and findings were recorded and compared with those of patients younger than 80 (Group B), randomly extracted from the same database in a > 2:1 ratio.

RESULTS

Group A consisted of 79 patients, 84 ± 6 years old and Group B of 188, 44 ± 11 years old (p < .0001). We visualized the entire small bowel in 59 (74.6%) patients of Group A and in 169 (89%) of Group B (odds ratio = 0.33, 95% confidence interval: 0.16-0.66, p = .0025), mainly for capsule failures in reaching the duodenum; this event occurred in 10 patients of Group A and in 3 of Group B (odds ratio = 9, 95% confidence interval: 2.4-33.4, p = .0004). The rate of adverse events and diagnostic yield did not differ between the two groups. Inflammatory and neoplastic lesions were more common in Group A (odds ratio = 2.60, 95% confidence interval: 1.07-6.28, p = .03 and odds ratio = 2.01, 95% confidence interval: 1.02-3.97, p = .04, respectively).

CONCLUSIONS

In octogenarians, small bowel capsule endoscopy may be troublesome for capsule failure in reaching the duodenum. However, the diagnostic yield of small bowel capsule endoscopy and the rate of clinically significant lesions are high.

Participation in colorectal cancer screening with FOBT and colonoscopy: an Italian, multicentre, randomized population study

BACKGROUND

Data on the adherence rate to screening colonoscopy (OC) in the average-risk general population are limited and variable. Aim of this study was to compare the uptake of OC screening with that of fecal occult blood (FOBT).

METHODS

A nationwide, population-based, multicentre, randomized trial comparing attendance to OC with that to FOBT was performed. Sixty-four general practitioners (GPs), overall including in their lists 9889 average-risk subjects aged 55-64 years, were randomized between OC and FOBT screening programs. Eligible subjects were mailed a personal invitation letter co-signed by their GP and the coordinator of the area-reference GI centre. Attendance rate and detection rate for advanced neoplasia (colorectal cancer, adenoma >10mm or with villous histology or high-grade dysplasia) for each arm of the study were assessed.

RESULTS

The overall attendance rate was 18.7% (1563/8378 eligible subjects). It was markedly lower in the OC than in the FOBT strategy (10% vs. 27.1%; OR 0.28, 95% CI: 0.25-0.32; P<0.0001). In particular, participation in OC screening arm was extremely low in South Italy (2.8%), whilst it was higher in North-Central Italy (12.4%; P<0.0001). Compliance to colonoscopy in those with a positive FOBT was only 58%. Advanced neoplasia was detected in 28 (6.8%) patients in the OC arm and in 6 (18%) in those with a positive FOBT submitted to OC.

CONCLUSIONS

The results of our study underline the difficulties and barriers to implement a OC population screening in Italy, at least through primary care. Although attendance to FOBT was higher, it was disappointingly less than 30%. Significant actions to improve awareness amongst GPs and the population are a high priority.

Colorectal cancer in Italy: a review of current national and regional practice on screening and treatment

Colorectal cancer (CRC) is one of the most prevalent and deadly cancers in Italy. Its burden is expected to remain significant in the coming years, although it is mostly a preventable disease. Prevention and screening programmes will play an important role in the fight against CRC. A national formal screening programme was introduced in the 2003-2005 and 2005-2007 national health programmes, leaving the planning and implementation, respectively, to each region and local health unit. In 2007, screening programmes covered 46.6% of the eligible population, with a higher coverage in the North (71.6%) and in the Centre (52.1%) than in the South (7%). The majority of programmes used the guaiac faecal occult blood test (FOBT) as first-line test. Only few programmes used the flexible sigmoidoscopy, or a combination of both tests. The quality and efficacy of the screening programmes are evaluated using ad hoc indicators with acceptable and desirable targets. In Italy, there are formal guidelines for population-based and opportunistic screening, diagnosis, surgery, adjuvant and neoadjuvant treatments and surveillance, differentiating colon cancer from rectal cancer and advanced CRC. Guidelines are updated yearly. Overall, Italy is well positioned in the fight against CRC. Although many regions lag behind in the uptake of screening programmes, they are in the process of introducing them.

Faecal occult blood test-based screening programme with high compliance for colonoscopy has a strong clinical impact on colorectal cancer

Background

The results of a pilot colorectal cancer screening programme by biennial immunochemical faecal occult blood test (FOBT) are reported.

Methods

All residents aged between 50 and 69 years in the Italian province of Lecco were invited to have a FOBT. Those with a positive result were offered colonoscopy. FOBT uptake and compliance with colonoscopy were assessed. Detection rate and positive predictive value (PPV) for cancer and adenoma were calculated. Tumour stages were compared between screen-detected cancers and other colorectal cancers diagnosed within the target age group.

Results

Some 38 693 (49·6 per cent) of 78 083 individuals had a FOBT and 2392 (6·2 per cent) had a positive result. Colorectal cancer was diagnosed in 4·6 per cent and advanced adenoma in 32·7 per cent. PPVs were 4·0 per cent for cancer, 28·1 per cent for advanced adenoma and 36·6 per cent for any adenoma. There was a significant difference in incidence of stage III/IV disease between screened and non-screened cohorts. Compliance for colonoscopy was 92·0 per cent. Major determinants of compliance were age less than 59 years, female sex, high education level and non-manual work.

Conclusion

These results justify extension of colorectal cancer screening to other regions of Italy.

Rectal cancer

Rectal cancer is an important tumour from an epidemiological point of view and represents the benchmark for an optimal use of integrated treatments (surgery, radiotherapy and chemotherapy) in the oncological practice. The conventional use of total mesorectal excision and the integration with radiochemotherapy, better if preoperatively, are now able to increase survival, to decrease the occurrence of pelvic recurrence and to ameliorate the quality of life of patients. Updated recommendations for the management of these patients are here reported.

No effects of olive oils with different phenolic content compared to corn oil on 1,2-dimethylhydrazine-induced colon carcinogenesis in rats

BACKGROUND

Some epidemiological and experimental studies suggest that olive oil, despite its elevated caloric content, may have protective activity against colon cancer, partially due to its phenolic content. However, little experimental evidence exists to support this claim in vivo.

AIM OF THE STUDY

To test the effect of olive oils with different phenolic content in a well-characterized model of colon carcinogenesis, comparing them with corn oil (CO).

METHODS

F344 rats were fed AIN-76 based diets for the entire experimental period; the diets contained 23% (w/w) of lipids from three different sources: extra-virgin olive oil rich in phenolic compounds (EV), rectified olive oil (ROO) with the same fatty acid composition but devoid of phenolic compounds and CO as a control diet. One week later, rats were induced with 1,2-dimethylhydrazine (DMH) (150 mg/kg b.w. x 2 times) to measure preneoplastic lesions (aberrant crypt foci (ACF) and mucin depleted foci (MDF)) and tumours in the intestine.

RESULTS

Thirteen weeks after DMH, the numbers of ACF and MDF were similar in the different groups (ACF/colon were 344.9 +/- 27.0, 288.6 +/- 28.5 and 289.8 +/- 21.4 in CO, EV and ROO groups, respectively, means +/- SE; MDF/colon were 8.83 +/- 1.2, 8.41 +/- 1.5 and 8.75 +/- 1.6 in CO, EV and ROO groups, respectively, means +/- SE). Thirty-two weeks after DMH, the incidence of tumours (rats with tumours/rats in the group) did not differ among the different groups (20/21, 18/19 and 20/20 in the CO, EV, and ROO groups, respectively). Similarly, the number of tumours/ rat in the colorectum (both adenomas and cancers) was not different in the three different groups (2.33 +/- 0.26, 2.42 +/- 0.41 and 2.25 +/- 0.40 in CO, EV and ROO groups, respectively, means +/- SE).

CONCLUSIONS

Olive oil, irrespective of its phenolic content, does not affect DMH-induced colon carcinogenesis in F344 rats compared with CO.