Study of frequency, distribution and diagnostic performance in synchronic neoplastic lesions of colorectal carcinoma

AIM: To analyse the frequency, characteristics and diagnosis of synchronic neoplastic lesions in colorectal cancer. METHODS: A review was carried out of 384 colorectal cancers, diagnosed through complete colonoscopy and resected. The synchronic cancers and the characteristics of the adenomas were determined: number, size, histological type, dysplasia, as well as their localisation in the colon and with respect to the carcinoma. RESULTS: Twenty-eight synchronic cancers were found (7.3% of the total); 8 developed tumours and 20 malignant polyps. In 54.4% of the cases there was a synchronic adenoma. In patients with synchronic lesions, 43% showed an advanced adenoma. Twenty percent of the synchronic polyps found were proximal to the splenic flexure; 41% were distal and 38% had both localisations. Fifty-nine point one percent of the patients had some adenoma proximal to the cancer, with criteria of advanced adenoma in 13.9%. The distribution of the adenomas was more uniformly spread in the cancers with a proximal localisation (p = 0.038). Seventeen percent of the distal cancers presented synchronic lesions with a proximal colon localisation exclusively. Partial endoscopies would diagnose the distal cancers, but would omit a synchronic adenoma in 42.3% of the sigmoidoscopies and 40% of the short colonoscopies. CONCLUSIONS: High rates of carcinoma and synchronic adenomas were registered. We underline the high index of advanced adenomas and the frequency of synchronic lesions proximal to the cancer, which is why incomplete colonoscopies, although allowing the diagnosis of the distal cancer, omit a high percentage of synchronic adenomas, including advanced lesions. All of this confirms the need to perform a complete pre-, intra- and post operational colonoscopy in resectable colorectal cancer.     

Flexible sigmoidoscopy in colorectal cancer screening: implications of different colonoscopy referral strategies

Flexible sigmoidoscopy (FS) screening reduces colorectal cancer incidence and mortality. Its potential to detect proximal neoplasms depends on colonoscopy referral. We estimated diagnostic performance of sigmoidoscopy using 12 different referral criteria in detecting colorectal cancer and advanced adenomas. Colonoscopy results from 14,947 participants of screening colonoscopy in Germany were used to derive sensitivity of sigmoidoscopy for colorectal cancer, advanced adenomas (AAs), and any advanced neoplasms in the proximal colon. It was assumed that FS detects the same neoplasms as colonoscopy within its reach and that distal neoplasms would be followed by colonoscopy. In addition, numbers of colonoscopies needed (NCN) to detect one proximal advanced neoplasm were calculated. The most advanced findings during colonoscopy were colorectal cancer in 213 subjects (1.4%), AA in 1539 subjects (10.2%) and non-advanced adenomas in 2988 subjects (19.8%). Without colonoscopy referral, overall sensitivities for any colorectal cancer, advanced adenoma and any advanced neoplasm (proximal or distal) would be 79, 65 and 66%, respectively. These sensitivities could be increased to up to 86, 83 and 84% by the referral strategies investigated. Compared to referral due to advanced adenomas, referral due to non-advanced adenomas would substantially increase the NCN at a modest gain in sensitivity. Sensitivities were higher and NCNs were lower in men than in women for every strategy. In conclusion, colonoscopy referral can substantially increase sensitivity of sigmoidoscopy-based screening, but the gain by referral due to non-advanced adenomas substantially increases NCN compared to referral due to advanced neoplasms only. Major sex differences may call for sex-specific referral strategies.     

Diagnostic performance of flexible sigmoidoscopy combined with fecal immunochemical test in colorectal cancer screening: meta-analysis and modeling

Once-only flexible sigmoidoscopy (FS), which reliably detects neoplasms in the distal colon and rectum but not in the proximal colon, has been shown to reduce incidence and mortality of distal colorectal cancer (CRC). Fecal immunochemical tests (FITs) detect the majority of CRCs and some proportion of adenomas also in the proximal colon. We assessed the expected diagnostic performance of combined application of FS and FIT. We systematically reviewed screening studies conducted in an average risk population that reported specificities and site-specific sensitivities of FITs for detection of CRC or advanced adenoma (AA). Only studies that conducted colonoscopy in all subjects were included. PubMed and Web of Science were searched until May 13, 2016. Reference lists of eligible studies were also screened. Sensitivity of FS was derived from colonoscopy results, assuming the same sensitivity as colonoscopy for left-sided neoplasms and follow-up colonoscopy after detection of distal adenomas. Bivariate meta-analyses were used to derive summary estimates of overall sensitivity and specificity of individual and joint application of both tests. Ten eligible studies were identified. Summary estimates (95% confidence intervals) of overall sensitivity for detecting CRC and AA were 65% (56–74%) and 27% (23–31%) for FIT alone, 67% (58–75%) and 67% (59–75%) for FS alone, and 89% (83–92%) and 75% (68–80%), respectively, for the combination of both tests. The pooled specificity (95% CI) of FIT was 92% (90–95%). Adding a FIT to a once-only screening FS would substantially increase sensitivity of CRC screening at a modest loss in specificity.     

Correlation of Barrett's esophagus and colonic adenomas

INTRODUCTION: According to the case-control studies, colon adenomas are not more frequent as usual in patients with Barrett's oesophagus. AIM: Analysis of the relationship of Barrett's oesophagus with colon adenomas through a case presentation. METHOD: The 62-years old male patient has been treated with pantoprazole for reflux oesophagitis and histologically proven short-segment Barrett's oesophagus. Pantoprazole treatment was started and the patient became symptom-free. In 1997 colonoscopy was performed for rectal bleeding and 4 recto-sigmoideal polyps were removed (tubular adenomas). After 4 years of PPI treatment, laparoscopic fundoplication was performed but after one year of symptom-free period, PPI was started again because of relapse. The patient was followed-up for 5 years. The histological examinations included also Ki67 and p53 antibody staining. RESULTS: On control colonoscopies, small rectal and sigmoid polyps were found. The retrospective histologic examination of the polyps revealed the increase of Ki-67-positive cells from 2-5% to 45-55% during the 5 years of follow-up, which is higher than the values found in controls and may express the increasing proliferative activity of the epithelium. CONCLUSION: Although according to the literature, Barrett's oesophagus does not increase the risk of colon adenomas, this may occur in individual cases, warranting close follow-up.     

Long-term sedentary work and the risk of subsite-specific colorectal cancer

Research suggests that sedentary behavior may increase the risk of some chronic diseases. The aims of the study were to examine whether sedentary work is associated with colorectal cancer and to determine whether the association differs by subsite. A total of 918 cases and 1,021 controls participated in a population-based case-control study of colorectal cancer in Western Australia in 2005-2007. Data were collected on lifestyle, physical activity, and lifetime job history. The estimated effects of sedentary work on the risk of cancers of the proximal colon, distal colon, and rectum were analyzed by using multinomial logistic regression. Compared with participants who did not spend any time in sedentary work, participants who spent 10 or more years in sedentary work had almost twice the risk of distal colon cancer (adjusted odds ratio = 1.94, 95% confidence interval: 1.28, 2.93) and a 44% increased risk of rectal cancer (adjusted odds ratio = 1.44, 95% confidence interval: 0.96, 2.18). This association was independent of recreational physical activity and was seen even among the most recreationally active participants. Sedentary work was not associated with the risk of proximal colon cancer. These results suggest that long-term sedentary work may increase the risk of distal colon cancer and rectal cancer.     

A Rare Case of Medullary Carcinoma of the Colon Presenting as Intussusception in an Adult with Rectal Bleeding

Medullary carcinoma is a recently recognized rare subtype of colorectal cancer resembling both poorly differentiated adenocarcinoma and neuroendocrine tumors. Medullary carcinoma most commonly presents in the proximal colon and can be differentiated from other right-sided malignant lesions by histology and immunochemical markers. We present here a rare case of an adult patient with rectal bleeding who was found to have an intussusception due to underlying medullary carcinoma of the splenic flexure. A 72-year-old woman presented to our GI clinic with rectal bleeding. Colonoscopy revealed a necrotic mass of the sigmoid colon, later determined by CT to be a colo-colonic intussusception at the level of the splenic flexure. Patient underwent diagnostic laparoscopy with findings of a large splenic flexure mass, which was resected and found to be medullary carcinoma of the colon. The tumor was poorly differentiated and exhibited microsatellite instability but was discovered at an early stage and thus did not require any adjuvant chemotherapy. Unlike most previously reported cases of medullary carcinoma, our patient presented with a left sided tumor. To our knowledge, this is the first report of a medullary colon cancer presenting with intussusception.     

The malignant side of chronic inflammatory bowel disease

Patients with chronic inflammatory bowel disease (IBD) have a higher risk of colorectal carcinoma, and present with this malignancy at a younger age than non-IBD individuals. In three patients, two men aged 20 and 36 years and one woman aged 34 years, colorectal cancer developed at a young age, following a long history of ulcerative colitis. Surveillance for colorectal cancer in IBD patients needs to be performed by regular colonoscopy with extensive biopsy sampling for the detection of dysplasia, regarded by many as predictive for colon carcinoma. Whenever a dysplasia-associated lesion or mass or a highgrade dysplasia is identified, there is a strong indication for colectomy. When low-grade dysplasia is found, the findings should be discussed with the patient and it should be decided whether the patient should resume surveillance or opt for colectomy.     

Frequency of proximal colonic extension of distal ulcerative colitis

AIMS: To evaluate the frequency of colonic extension in patients with rectal or rectosigmoidal forms of ulcerative colitis and to look for factors associated with a higher risk of proximal colonic extension. METHODS: We conduct a retrospective study on cases of ulcerative colitis limited to the rectum and the rectosigmoid followed up at least for 6 months. Colonic extension was defined by apparition of endoscopic features of ulcerative colitis in initially normal segments of the colon. RESULTS: From 1984 to 2004, 70 patients with distal ulcerative colitis were studied. Initial location was the rectum in 25 cases and the rectosigmoid in 45 cases. After a mean follow-up of 49.4 months, proximal colonic extension was observed in 7 cases (10%), with an actuarial frequency of 12% at 5 years, 20% at 10 years and 20% at 20 years. Patients with colonic extension had a higher number of relapses compared to patients without extension (4.28 +/- 1.36 vs. 1,41 +/- 1.22, p = 0.001). Age, sex-ratio, initial location, maintenance therapy and diagnosis of refractory distal colitis were not associated with a higher risk of colonic extension. CONCLUSION: Colonic extension in our population occurs during the first years after the diagnosis of distal ulcerative colitis. Patients with more relapses are at increased risk of proximal colonic extension.     

Dietary Fatty Acids and Recurrence of Colorectal Adenomas in a European Intervention Trial

Epidemiological studies have provided inconsistent data about the role of dietary fatty acids in colorectal cancer, and few studies have addressed their role in colorectal adenoma. The aim of the study was to assess the risk of overall adenoma recurrence associated with dietary consumption of total fat, subtypes of fat, and specific fatty acids (oleic acid, linoleic acid, α-linolenic acid). The study sample was composed of 523 patients with confirmed adenomas at the index colonoscopy, 35 to 75 yr old, who completed the European fiber-calcium intervention trial and had an initial dietary assessment using a qualitative and quantitative food questionnaire. The overall 3-yr recurrence rate was 22.6% (118 out of 523 patients). There were no significant associations between overall adenoma recurrence and either total fat, subtypes of fat, or specific fatty acids. However, polyunsaturated fatty acids and linoleic acid were both moderately but significantly associated with distal and multiple recurrence. No significant associations were observed with recurrence of proximal or advanced adenomas. Our findings do not support the hypothesis of strong associations between dietary fatty acids and recurrence of colorectal adenomas. The hypothesis of a differential role of specific fatty acids according to colorectal subsites deserves further investigation.     

Body mass and colorectal cancer risk in the NIH-AARP cohort

In most studies, body mass index (BMI) has been associated with increased risk of colorectal or colon cancer in men, but the relation is weaker and less consistent for women, possibly because of interactions with age or hormone replacement therapy. The authors examined the relation between BMI and colorectal cancer incidence in a large, prospective US cohort of 307,708 men and 209,436 women from the NIH-AARP Diet and Health Study. During follow-up of the cohort from 1995 to 2000, 2,314 cases of colorectal cancer were observed in men and 1,029 in women. BMI was related to increased risk of incident colon cancer, but not rectal cancer, for both men and women. For men, relative risks of colon cancer for a BMI of 18.5-<23, 23-<25, 25-<27.5, 27.5-<30, 30-<32.5, 32.5-<35, 35-<40, and > or = 40 kg/m(2) were 1.0 (referent), 1.11, 1.22, 1.44, 1.53, 1.57, 1.71, and 2.39, respectively (95% confidence interval: 1.59, 3.58; p-trend < 0.0005). Corresponding relative risks for women were 1.0, 1.20, 1.29, 1.31, 1.28, 1.13, 1.46, and 1.49 (95% confidence interval: 0.98, 2.25; p-trend = 0.02). BMI was related to colon cancer risk for younger (aged 50-66 years) but not older (aged 67-71 years) women. The association was not modified by hormone replacement therapy in women or physical activity in men or women.     

Tea,Coffee, and Milk Consumption and Colorectal Cancer Risk

Background

Data regarding the effects of tea, coffee, and milk on the risk of colorectal cancer are inconsistent. We investigated associations of tea, coffee, and milk consumption with colorectal cancer risk and attempted to determine if these exposures were differentially associated with the risks of proximal colon, distal colon, and rectal cancers.

Methods

Data from 854 incident cases and 948 controls were analyzed in a case-control study of colorectal cancer in Western Australia during 2005–07. Multivariable logistic regression was used to analyze the associations of black tea (with and without milk), green tea, herbal tea, hot coffee, iced coffee, and milk with colorectal cancer.

Results

Consumption of 1 or more cups of herbal tea per week was associated with a significantly decreased risk of distal colon cancer (adjusted odds ratio, 0.37; 95% CI, 0.16–0.82; P_Trend = 0.044), and consumption of 1 or more cups of iced coffee per week was associated with increased risk of rectal cancer (adjusted odds ratio, 1.52; 95% CI, 0.91–2.54; P_Trend = 0.004). Neither herbal tea nor iced coffee was associated with the risk of proximal colon cancer. Hot coffee was associated with a possible increased risk of distal colon cancer. Black tea (with or without milk), green tea, decaffeinated coffee, and milk were not significantly associated with colorectal cancer risk.

Conclusions

Consumption of herbal tea was associated with reduced risk of distal colon cancer, and consumption of iced coffee was associated with increased rectal cancer risk.Key words: epidemiological, tea, coffee, milk, colorectal cancer, risk factors     

缺血性结肠炎32例临床分析

目的 探讨缺血性结肠炎的临床特征及早期诊断方法,以减少临床误诊.方法 对笔者所在医院收治的32例缺血性结肠炎患者的临床资料进行分析、总结.结果 32例患者入院初步诊断正确率为50%;结肠镜诊断率100%,90.6%的患者病变部位于左半结肠.镜下表现的共同特征是黏膜充血、水肿、糜烂及脆性增加,病变肠段与正常肠段黏膜分界清晰.结论 提高对缺血性结肠炎的认识,及早应用结肠镜检查可以提高缺血性结肠炎的确诊率.     

Unexplained inversion of the incidence ratio of colon and rectal cancer among men in East Germany. A time trend analysis including 147,790 cases

Introduction The incidence rate ratio of colon to rectal cancer is usually about 2:1. It has been observed for a while that the incidence of colon cancer among men (as opposed to women) in the Former German Democratic Republic (GDR) is lower than the rate of rectal cancer. Detailed analyses of this phenomenon have not been done so far. The aim was to give insights in this observation by detailed incidence and mortality analyses and to explore the worldwide ratio of colon and rectal cancers based on population-based cancer registry data. Methods We analyzed age-standardized incidence and mortality data of colorectal cancers in East Germany (1961–1989 and 1996–2002; mortality 1980–2002), West Germany, Saarland (1970–2002) and all over the world (1978–82 up to 1993–97). Results With the incidence increase of colorectal cancers in the GDR, the ratio of colon to rectal cancer incidence became larger and surpassed the reference value (ratio = 1) during the time of the reunification. Also the mortality data revealed a similar pattern. Estimated annual percentage increases of colon subsite incidences tended to be higher within the distal colon as compared to the proximal colon Conclusions Our analyses of international cancer registries over a period of 20 years show that the colon–rectum cancer ratio is positively associated with the overall incidence of colorectal cancer with a stronger association among women than men. Non-causal factors such as underdetection or registration artefacts are unlikely to explain the unusual colon/rectal rate ratio among men. A gradual decrease of the job-related physical activity among men may have contributed to the findings.     

Nitrogen-nitrate exposure from drinking water and colorectal cancer risk for rural women in Wisconsin, USA

One unintentional result of widespread adoption of nitrogen application to croplands over the past 50 years has been nitrate contamination of drinking water with few studies evaluating the risk of colorectal cancer. In our population-based case-control study of 475 women age 20–74 years with colorectal cancer and 1447 community controls living in rural Wisconsin, drinking water nitrate exposure were interpolated to subjects residences based on measurements which had been taken as part of a separate water quality survey in 1994. Individual level risk factor data was gathered in 1990–1992 and 1999–2001. Logistic regression models estimated the risk of colorectal cancer for the study period, separately and pooled. In the pooled analyses, an overall colorectal cancer risk was not observed for exposure to nitrate-nitrogen in the highest category (10 ppm) compared to the lowest category (<0.5 ppm). However, a 2.9 fold increase risk was observed for proximal colon cancer cases in the highest compared to the lowest category. Statistically significant increased distal colon or rectal cancer risk was not observed. These results suggest that if an association exists with nitrate-nitrogen exposure from residential drinking water consumption, it may be limited to proximal colon cancer.     

Risk and surveillance of individuals with colorectal polyps. Who Collaborating Centre for the Prevention of Colorectal Cancer

Since colorectal adenomas are very probably the precursors of colorectal cancer, their detection and removal should result in a decrease in the incidence and mortality from colorectal cancer. Individuals who harbour an adenoma have a 30-50% probability of having additional adenomas at that time, and a 30% probability of having additional adenomas later. Adenomas are prevalent in countries where colorectal cancer is prevalent, about two-thirds of them being tubular and the rest tubulovillous or villous. The initial management of patients with an adenoma consists in searching by colonoscopy the entire colon and removing all additional polyps. Surgical resection is required wherever there is invasive cancer with adverse histological factors. Follow-up in most patients can be after 2-4 years, earlier follow-up being reserved for patients with numerous polyps or with a polyp that had been removed piecemeal. The results of ongoing trials should provide firm guidelines for follow-up and could also be used in mathematical modelling to examine alternative strategies and to help understand the evolving patterns of appearance of new polyps. Finally, a deeper understanding of the biology and inherited and acquired genetics will help identify individuals at risk for adenomas initially and at follow-up. Nutritional factors may also provide a basis for prevention of adenomas in high-risk countries. Many of these issues are being addressed in current research.     

Interest in genetic testing among first-degree relatives of colorectal cancer patients

PURPOSE: The present study examined colorectal cancer screening behaviors, risk perceptions, and willingness to receive genetic testing to determine colorectal cancer susceptibility. METHODS: We recruited 95 first-degree relatives of colorectal cancer patients, then conducted a brief telephone interview using a structured questionnaire that elicited information on sociodemographics, cancer screening behaviors, risk perceptions, and interest in genetic testing. RESULTS: Among these high-risk individuals who were aged 40 years or older, only 31% reported fecal occult blood testing within the past year and 59% reported undergoing sigmoidoscopy or colonoscopy within the past 5 years. The majority of participants believed their relative risk of colorectal cancer was increased (68%). Eighty-four percent of the participants indicated that they would have a genetic test if one were available. Participants who believed that <50% of colorectal cancers were caused by heredity were more likely to be interested in genetic testing than were participants who believed that 50% or more of colorectal cancers were caused by heredity. Referral source, sociodemographic factors, clinical factors, and perceived personal risk were not significantly associated with interest in genetic testing. CONCLUSION: Our results suggest that the demand for colorectal cancer susceptibility testing may be high among individuals with a family history of colorectal cancer. We also observed that a substantial number of first-degree relatives were not adhering to colorectal cancer screening guidelines. Accurate information on the genetic aspects of colorectal cancer and the benefits and limitations of genetic testing may help relatives of colorectal cancer patients make informed decisions about whether to undergo enhanced screening and genetic testing.     

Flexible sigmoidoscopy in asymptomatic patients with negative fecal occult blood tests.

BACKGROUND. Although the American Cancer Society and others have established guidelines for colorectal cancer screening, questions of who and how to screen still exist. METHODS. A 60-cm flexible sigmoidoscopy was performed on 1000 asymptomatic patients, 45 years of age or older, with negative fecal occult blood tests, who presented for routine physical examinations. Patients with clinically significant lesions were referred for colonoscopy. The proportion of lesions that would not have been found if the 24-cm rigid or the 30-cm flexible sigmoidoscope had been used was identified. RESULTS. Using the 60-cm flexible sigmoidoscope, lesions were found in 3.6% of the patients. Eighty percent of the significant lesions were beyond the reach of the 24-cm rigid sigmoidoscope and 37% were beyond the reach of the 30-cm sigmoidoscope. Thirty-six patients with lesions were referred for colonoscopy; additional lesions were found in 14%. A total of 62 lesions were discovered, including tubular adenomas, villous adenomas, tubular villous adenomas (23 of the adenomas with atypia), and one adenocarcinoma. The highest percentage of lesions discovered were in the sigmoid colon and the second highest percentage were in the ascending colon. CONCLUSIONS. The 60-cm flexible sigmoidoscope was able to detect more lesions than either the 24-cm or 30-cm sigmoidoscope when used in asymptomatic patients, 45 years of age and over, with negative fecal occult blood tests. When significant lesions are discovered by sigmoidoscopy, colonoscopy should be performed.     

Change in location of colorectal cancer in Hungarian patients between 1993-2004

The incidence of proximal tumours in Western countries has steadily increased while that of distal tumours has shown a corresponding decrease. Our aim was to investigate the prevalence, location and histology of colorectal cancers in the last twelve years in Hungarian patients. PATIENTS AND METHODS: Clinical data of 1738 patients diagnosed with colorectal tumors (M/F: 940/798, mean age at diagnosis: 65.2 +/- 12.5 years) between 1st of January 1993 and 31st of December 2004 at the 1st Internal Medicine and 1st Surgery Department of Semmelweis University were enrolled. Pathology and clinical data were analysed retrospectively. The observed periods were the following 1993-1998 and 1999-2004. RESULTS: 1694 (97.5%) of the patients had adenocarcinoma (CRC), 15 anaplastic cancers, 9 carcinoid, 6 planocellular, 5 GIST, 3 leiomyoma and 2-2 melanoma, lymphoma and shigillocellular cancers were diagnosed. 75.7% (943/1246) of the CRCs were diagnosed at locally advanced stage (T3-T4), and 47.7% (521/1093) of CRC patients had lymph node metastasis at the time of diagnosis. 11.0% of the CRCs were diagnosed in <50 year-olds (<40 years: 2.5%, <30 years: 0.5%). The location of the CRC was distal in 1186 (rectum: 53.9%, sigmoid/descending: 46.1) and proximal in 508 cases. Synchronous cancers were detected in 12 patients (age: 68.8 +/- 11.6 years, gender: 11 male/1 female, location: rectum and transverse in 6, rectum and ascending/caecum in 5 patients). Age at diagnosis was not different according to gender (M/F: 64.8 +/- 12.0 years vs. 65.8 +/- 12.9 years), but it was lower in patients with rectal cancer compared to left or right sided cancers (64.1 years vs. left: 66.1 years, right: 66.0 years, p = 0.02). Rectal CRC was more common in males, while the proportion of proximal cancers was lower (rectum, M/F: 41.2% vs. 33.5%, proximal M/F: 26.8% vs. 33.8%, p = 0.003). The proportion of rectal cancers increased over the observed period (1993-1998: rectal: 31.6% vs. 1999-2004: 42.1%, p = 0.002). CONCLUSIONS: In contrast to Western countries, the proportion of proximal CRC did not become higher in Hungary. Still more than two-third of the patients were diagnosed to have distal cancers. The proportion of male patients was higher in this subset of CRC. The high percentage of locally advanced and metastatic cancers supports the need for colorectal screening program in Hungary.     

Red meat intake may increase the risk of colon cancer in Japanese, a population with relatively low red meat consumption

Asian populations have changed from traditional to Westernized diets, with increased red meat intake. They are suggested to be particularly susceptible to the adverse effects of red meat on the development of colorectal cancers, however, few prospective studies of this putative link have been conducted. We examined associations between the consumption of red and processed meat and the risk of subsite-specific colorectal cancer by gender in a large Japanese cohort. During 1995-1998, a validated food frequency questionnaire was administered to 80,658 men and women aged 45-74 years. During 758,116 person-years of follow-up until the end of 2006, 1,145 cases of colorectal cancer were identified. Higher consumption of red meat was significantly associated with a higher risk of colon cancer among women [multivariate hazard ratios (95%CIs) for the highest versus lowest quintiles (HR): 1.48 (1.01, 2.17; trend p=0.03)], as was higher consumption of total meat among men [HR=1.44 (1.06, 1.98; trend p=0.07)]. By site, these positive associations were found for the risk of proximal colon cancer among women and for distal colon cancer among men. No association was found between the consumption of processed meat and risk of either colon or rectal cancer. In conclusion, red meat intake may modestly increase the risk of colon cancer in middle-aged Japanese, although the highest quintile of red meat consumption could be considered moderate by Western standards.     

Colon cancer screening in the ambulatory setting

BACKGROUND: Despite evidence of decreased mortality, recommendations for colon cancer screening have not been widely implemented by physicians. The objective of this study was to determine patient and clinician factors associated with screening for colon cancer. METHODS: A retrospective review of computerized medical records from primary care practices in an academic medical center was performed. Patients comprised men and women aged 50-74 with at least one visit between July 1, 1995 and June 30, 1997. Measurements included Fecal occult blood testing in the past 1 or 2 years, sigmoidoscopy in the previous 5 or 10 years, or colonoscopy in the past 10 years. RESULTS: A total of 6,039 patients were included in the analysis. Fecal occult blood testing had been performed in 44% of patients and sigmoidoscopy in 26%. Fifty-three percent of patients had undergone some type of colon cancer screening. In multivariate analysis, patient factors predictive of fecal occult blood testing included age (odds ratio (OR) per 5 years 1.05; 95% confidence interval 1.04, 1.06), Asian ethnicity (OR 1.23; 1.08, 1.41), number of visits during the study period (OR 1.05; 1.04, 1.06), recency of the last visit (OR 1.03; 1.02, 1.04), and having private insurance (OR 1.65; 1.04, 2.62). Predictors of sigmoidoscopy were similar except that patients with a family history of colon cancer and those with managed care insurance were also more likely to undergo sigmoidoscopy. Patients of nurse practitioners were less likely to receive fecal occult blood testing than were patients of physicians (OR 0.78; 0.65, 0.93). Patients of residents were less likely to undergo sigmoidoscopy than were patients of faculty (OR 0.79; 0.66, 0.94). CONCLUSIONS: Among patients seen in primary care practices, rates of colon cancer screening remain low, especially in patients who are younger, who have been seen less frequently, who are uninsured, or who do not have managed care insurance. Future research should explore these differences and should focus on increasing screening in all patient groups, especially in those who are underscreened.