Incidence of colorectal adenocarcinoma by anatomic subsite. An epidemiologic study of time trends and racial differences in the Detroit, Michigan area

The Clinicopathologic Characteristics of Colorectal Cancer in Patients under 50 years of Age: Experience of an Oncology Center

Background/aim

Colorectal cancer is seen mostly among patients older than 50 years of age. An aggressive behavior is a frequently cited as characteristic of colorectal cancer in young patients. The purpose of the present study was to reveal the clinicopathologic characteristics of colorectal cancer among patients under 50 years of age.

Methods

Two hundred and seventy-one patients with colorectal cancer admitted to our oncology center were evaluated, and clinicopathologic findings of the young and old patients were compared. Patient gender, site distribution, tumor stage classification, lymph node involvement, metastatic site, histologic classification, histologic differentiation, family history of malignant tumors, presenting symptoms and survival rates were compared.

Results

One hundred patients were 50 years of age or under. Clinical, histopathologic characteristics and overall survival of the two groups did not differ. A higher rate of familial cancer syndromes was detected among young patients.

Conclusions

The presentation and outcome of the disease in young patients do not differ from those of older patients. A significant family history of colorectal cancer in the young patients showed the need for screening whereas the outcome of metastatic disease was poor. In order to anticipate long survival, early detection and aggressive treatment is necessary.

Colorectal Cancer: What has Changed in Diagnosis and Treatment over the Last 50 Years?

Aims and background

This overview focuses on what has changed in the diagnosis and treatment of colorectal cancer over the last 50 years.

Methods

The most important international registers (SEER, European and Italian) as well as the literature have been consulted. Furthermore, many prognostic factors are analyzed with the aim to understand the reasons why 5-year survival has improved over the last two decades.

Results

Since the biologic characteristics of the tumor cannot be changed, improved survival must be supported by concomitant multiple factors, such as earlier diagnosis (as given by a more informed educational behavior and the advent of screening) as well as the wide use of colonoscopy and the technical improvement of surgical and medical treatment. However, it seems that the greatest improvement in survival is limited to 5-year controls, whereas long-term survival does not appear to show any significant improvement.

Conclusions

We can hypothesize that our efforts have just delayed the inevitable end: death. Nevertheless, further research should be done to confirm this hypothesis, perhaps in the field of molecular biology, which may also be the right approach to understanding the biologic aggressiveness of each tumor.

Rising incidence of early-onset colorectal cancer in Australia over two decades: report and review

The average age at diagnosis for colorectal cancer (CRC) in Australia is 69, and the age-specific incidence rises rapidly after age 50 years. The incidence has stabilized or is declining in older age groups in Australia during recent decades, possibly related to the increased uptake of screening and high-risk surveillance. In the same time frame, a rising incidence of CRC in younger adults has been well-documented in the United States. This rise in incidence in the young has not been reported from other countries that share long-term exposure to westernised urban lifestyles. Using data from the Australian Institute of Health and Welfare, we examined trends in national incidence rates for CRC under age 50 years and observed that rates in people under age 40 years have been rising for the last two decades. We further performed a review of the literature regarding CRC in young adults to outline the extent of current understanding, explore potential risk factors such as obesity, alcohol, and sedentary lifestyles, and to identify the questions remaining to be addressed. Although absolute numbers might not justify a population screening approach, the dispersal of young adults with CRC across the primary health-care system decreases probability of their recognition. Patient and physician awareness, aided by stool and emerging blood-screening tests and risk profiling tools, have the potential to aid in identification of those young adults who would most benefit from a colonoscopy through early detection of CRCs or by removal of advanced polyps.

[Morbidity, mortality and analysis of prognostic factors for colorectal cancer]

BACKGROUND

This study analyzed morbidity, mortality and prognostic factors for patient survival in a single center collective of patients with colorectal cancer and a high follow-up rate.

MATERIAL AND METHODS

A total of 698 consecutive patients were included in this study. Data were collected prospectively. Descriptive and survival analyses as well as Cox regression analyses were performed to identify factors for morbidity, mortality and prognostic factors for survival.

RESULTS

At presentation 78.8 % of the colon cancer patients and 83.5 % of rectal cancer patients showed symptomatic disease and 6.5 % of patients underwent an emergency procedure. Mortality was 3.6 %, morbidity was 42.7 % and 4.3 % of patients developed an anastomotic leakage with the need of reoperation. In spite of the regular application of a fast-track program, 10 % of patients had a prolonged duration of bowel paralysis. In patients with colon cancer there were no differences between overall survival (OAS) and disease-free survival, whereas there was a significant difference in patients with rectal cancer. The mean survival of all patients was 65.39 ± 1.722 months. The ASA score, cardiovascular disease, number of metastatic lymph nodes, lymph node ratio, residual tumor and general or surgery-associated complications were strongly independent influencing factors on OAS. A Cox analysis revealed age at diagnosis and microscopic residual tumor (TNM R1) as highly significant influencing factors on OAS. Other significant factors of influence on OAS were development of general or surgery-associated complications and the presence of cardiovascular diseases.

CONCLUSION

Cardiovascular disease leads to a higher morbidity rate whereas age, International Union Against Cancer (UICC) stage, R-status, lymphatic spread and occurrence of complications are important prognostic factors for survival.

Trends in colorectal cancer incidence rates in New Zealand, 1981-2004

BACKGROUND

Incidence rates of colorectal cancer (CRC) in New Zealand rank among the highest worldwide. Internationally, there has been evidence of a shift in colon cancer from left- to right-sided. The objective of this study was to determine trends in left- and right-sided colon and rectal cancers incidence by sex, age and ethnicity.

METHODS

Using datasets created by linking data from the New Zealand Cancer Registry to the census data, we analysed a total of 47,694 CRCs from 1981 to 2004. Cancers were divided into right-sided colon (cecum to the splenic flexure); left-sided colon (descending and sigmoid colon); and rectal (rectosigmoid junction and rectum).

RESULTS

Left- and right-sided colon, and rectal cancer incidence rates increased by 13-20% among men. In women, colon cancer rates increased by 25% for right-sided cancers, decreased by 8% for left-sided cancers and remained unchanged for rectal cancers. This corresponds with an increase in right-sided cancers from 57% to 65% of total colon cancers in women. The incidence of all CRCs increased at a faster rate among Māori than non-Māori.

CONCLUSION

We identified a left- to right-sided shift in colon cancer limited to women over the age of 65. While Māori trends in site distribution parallel those of their non-Māori counterparts, the rapid increase in Māori incidence rates is noteworthy. It is unclear why such shifts in CRC site distribution are occurring.

Incidence of colorectal cancer in Kashmir valley, India

BACKGROUND

There is wide variation in the incidence of colorectal cancer globally and also within the same country among different racial or ethnic groups. The present population-based study was undertaken to determine the incidence of colorectal cancer in Kashmiri population which is non-migratory and ethnically homogeneous having stable food habits.

METHODS

Over a period of one year, all newly diagnosed and histological proved cases of colorectal cancer in all possible areas, where such patients are diagnosed and treated were prospectively registered.

RESULTS

A total of 212 cases of colorectal cancers were registered; of them 113 (53.3%) originated in the colon and other 99 (46.7%) in rectum. Male to female ratio was 1.2:1. The crude incidence rate of colorectal cancer was 3.65/100,000; it was 3.78 in males, and 3.50/100,000 in females. The incidence rates for colorectal cancer in Muslims and Hindus were different. The crude incidence rate for colorectal carcinoma was highest for district Srinagar 6.19/100,000 (urban area) and lowest for district Kupwara (rural area) 1.59/100,000. The highest numbers of cases were detected in the age group 55-59 years (n = 34). The age-specific rate for colorectal carcinoma was highest in the age group 55-59 years (17.21/100,000), followed by 65-69 years (14.86/100,000). The age standardized incidence rate was 4.52/100,000 per year. The truncated age adjusted incidence rates in age group 35-64 years was 8.31/100,000; while that for colorectal carcinoma was 8.77/100,000 in males and 7.66/100,000 in females.

CONCLUSION

We conclude that the incidence of colorectal cancer in Kashmir valley is similar to that reported in the rest of India.

Use of nonsteroidal antiinflammatory drugs and distal large bowel cancer in whites and African Americans

Despite the belief that the etiology of and risk factors for rectal cancer might differ from those for colon cancer, relatively few studies have examined rectal cancer in relation to use of nonsteroidal antiinflammatory drugs (NSAIDs). The authors evaluated the association between NSAIDs and distal large bowel cancer in African Americans and whites, using data from a population-based case-control study of 1,057 incident cases of adenocarcinoma of the sigmoid colon, rectosigmoid junction, and rectum and 1,019 controls from North Carolina (2001-2006). NSAID use was inversely associated with distal large bowel cancer in whites (odds ratio (OR) = 0.60, 95% confidence interval (CI): 0.46, 0.79). The inverse association was evident for all types of NSAIDs but was slightly stronger with prescription NSAIDs, particularly selective cyclooxygenase 2 inhibitors (OR = 0.38, 95% CI: 0.25, 0.56). Compared with whites, a relatively weak inverse association was found in African Americans (OR = 0.87, 95% CI: 0.55, 1.40), although odds ratio heterogeneity by race could not be confirmed (P = 0.21). In addition, the strength of the association with NSAIDs varied by tumor location, suggesting more potent effects for rectal and rectosigmoid cancers than for sigmoid cancer. The chemopreventive potential of NSAIDs might differ by population and by tumor characteristics.

Proximalisation of colorectal carcinoma: a 10-year study in Italy

INTRODUCTION

Proximalisation of colon carcinoma has been reported over the course of the last 60 years. Changes in site distribution are receiving increasing attention on account of their implications for screening programmes.

OBJECTIVE

A retrospective observational study to determine whether the site distribution of colorectal carcinoma in Italy has varied in the last years and whether changes have been influenced by age and sex.

METHODS

Findings of colonscopies conducted at Turin University from 1992 to 2001 were examined. Inclusion criteria were: outpatients, screening, presence of anaemia or gastrointestinal bleeding, weight loss, constipation or changes in evacuation frequency. Exclusion criteria were: uncompleted, surgical endoscopies or conducted for positive flexible sigmoidoscopy, with doubtful findings. Carcinomas and benign polyps were diagnosed histologically. Age, sex, date of examination, nature and location of lesions were recorded. Lesions were classed as carcinoma, and polyps <1 and >/=1 cm. Data were grouped into different year periods and compared with the chi square test. We compared 1992-1993 vs. 2000-2001 and 1992-1996 vs. 1997-2001.

RESULTS

Of the 8,132 colonoscopies performed, 7,342 were included in the study. Proximal carcinomas moved from 12.2% in 1992-1993 to 14.9% in 2000-2001 (P = 0.57), proximal polyps rose from 16.6% to 22.1% (P < 0.0001). Furthermore proximal carcinomas moved from 16.5% in 1992-1996 to 14.4% in 1997-2001 (P = 0.48); proximal polyps rose from 18.4% to 27.8% (P < 0.005). In the period 1996-2001 there was higher female prevalence (P = 0.0011) and older age (P = 0.0191).

DISCUSSION

We can suppose that proximalisation of carcinoma has not yet appeared in Italy.

Relationship between meat and cereal consumption and colorectal cancer in Korea and Japan

BACKGROUND AND AIM

The incidence of colorectal cancer in Asian countries is increasing. The change to a more westernized diet is known to be related to these increases, and there are reports on the relationship between meat consumption and colorectal cancer in Japan. The aim of this study was to investigate the relationship between dietary change and colorectal cancer in Korea and Japan.

METHODS

The data of meat and cereal consumption in Japan (1950-2002) and Korea (1970-2003), and the data of colorectal cancer incidence in Japan (1975-1998) and Korea (1992-2002) were investigated with a 20-year difference between the two countries.

RESULT

We found that the changes in meat and cereal consumption, as well as the increases in the incidence of colon and rectal cancer, were similar between those two countries with a 20-year difference.

CONCLUSION

These similarities between Korea and Japan could be helpful for predicting future colorectal cancer incidences for Korea and other Asian countries.

The anatomical distribution of colorectal cancer in Korea: evaluation of the incidence of proximal and distal lesions and synchronous adenomas

OBJECTIVE

The incidence of colorectal cancer throughout the Republic of Korea has been rising over the last 25 years. The change in incidence is supposed to be due to the westernized life style. We evaluated the anatomical distribution of colorectal cancer and the properties of synchronous adenomatous polyps in the Korean population which were known to be different from those in Western countries.

MATERIALS AND METHODS

From January 1997 to December 2006, 896 cases of colorectal cancer were reviewed retrospectively.

RESULTS

A total of 25.1% were proximally located cancer with a modest female predominance (odds ratio 1.5). Synchronous adenomatous lesions were accompanied in 31.9% of all colorectal cancer cases. In the distal colorectal cancer patients, 18.8% had proximally located synchronous adenomas. In those with proximal colon cancer, only 20.5% of patients had distally located adenomas. The likelihood of a proximal colon cancer without distal sentinel lesions was higher in females (odds ratio 3.0).

CONCLUSION

There has been a steep rise in the incidence of colorectal cancer in Korea and distal colon cancer is more prevalent than in Western countries. However, as over 20% of proximal colon cancers can exist without distal colonic synchronous or sentinel lesions, a total colonoscopic examination should be considered first in surveillance.

Changing sites of colorectal cancer in the Israeli Jewish ethnic populations and its clinical implications

Countries at risk for colorectal cancer noted an increase in right-sided colorectal cancer. We examined this in the Israeli Jewish populations. Israel Cancer Registry data, 1982-2001, were computed by sex, age, ethnic group and colorectal cancer site: 'rectal cancer' included the recto-sigmoid junction, 'right-sided' colorectal cancer included proximal colon up to and including the splenic flexure. In both sexes, colorectal cancer trends increased significantly owing to colonic cancer (P<0.01) whereas rectal cancer decreased (P<0.01). Left and right colorectal cancer trends decreased in Israel born people (P<0.01), but in Asia-Africa born people increases were seen at both sites in the male (P=0.02 and 0.06, respectively) and female (P=0.03 and 0.01, respectively) population. In those > or =65 years old, right colorectal cancer trends increased in all men (P=0.05) and women (P=0.01). On comparing data from 1982-1986 with that from 1997-2001 right colorectal cancer showed an increase in both sexes (P<0.01): to 32.7% of male colorectal cancer and 57.6% of female colorectal cancer. In the period 1997-2001, the total male population > or =65 years had increased relatively by 7.5% (P<0.01), and women by 22.6% (P<0.01) and the proportion of right colorectal cancer in > or =65 years olds increased relatively by 10.9% in the male population, and 18.2% in the female population, with one-third of this increase occurring in Russian immigrants arriving after 1990. In conclusion, there is a trend for right colorectal cancer in Jews aged > or =65 years. The proportion and amount of colorectal cancer increased most significantly in older women, which was partially explained by their increasing numbers and by colorectal cancer occurring in recent immigrants from Russia, who were at high-risk for colorectal cancer. These results should influence colorectal cancer screening and diagnostic methodologies used.

Colon pathology detected after a positive screening flexible sigmoidoscopy: a prospective study in an ethnically diverse cohort

OBJECTIVES

Although the association between distal neoplasia on sigmoidoscopy and proximal colonic pathology on follow-up colonoscopy has been well-described, it is not known if these findings are consistent across ethnic groups. The aim of this study was to evaluate ethnic variations in the prevalence of proximal neoplasia on follow-up colonoscopy after a neoplastic lesion is found on sigmoidoscopy.

METHODS

Consecutive asymptomatic patients at average-risk for colorectal cancer who were referred for screening flexible sigmoidoscopy were prospectively enrolled. Colonoscopy was recommended for all patients with a polyp on flexible sigmoidoscopy, regardless of size. Advanced neoplasms were defined as adenomas > or = 10 mm in diameter or any adenoma, regardless of size, with villous histology, high-grade dysplasia, or cancer.

RESULTS

Among the 2,207 patients who had sigmoidoscopy, 970 were Caucasian, 765 were African American, 395 were Hispanic, and 77 were Asian. The prevalence of neoplasia in the distal colon was 12.6% in Caucasians, 11.2% in African Americans, 15.9% in Hispanics, and 24.7% in Asians (p = 0.002). Of the 290 patients with neoplastic lesions on sigmoidoscopy, follow-up colonoscopy identified neoplasms in the proximal colon in 63.9% of Caucasians, 59.3% of African Americans, 66.7% of Hispanics, and 26.3% of Asians (p = 0.01). Advanced neoplasms in the proximal colon were highest in African Americans (34.9%) and lowest in Asians (10.5%).

CONCLUSIONS

In our study population, Asians demonstrated a higher prevalence of distal colonic neoplasia and a lower prevalence of proximal colonic neoplasia compared to non-Asians. Future studies should explore ethnic variation in colonic neoplasia prevalence and location since ethnic variation could lead to tailored colorectal cancer screening strategies.

Colonoscopy issues related to women

Colonoscopy is the preferred method of screening for colorectal cancer in women. The longer, more redundant female colon is frequently more difficult for the endoscopist to navigate and most studies show longer insertion times, lower completion rates, and more discomfort associated with the procedure in women, all of which may be exacerbated by hysterectomy. To improve female patients' compliance with colorectal cancer screening we need to understand the barriers to participation prevalent among women. This article reviews the findings of several studies and discusses some steps to improve cancer screening for women.

Prognostic impact of race and ethnicity in the treatment of colorectal cancer

Numerous advances in the treatment of patients who have metastatic disease have improved colorectal cancer management, including new chemotherapeutic agents and combinations and targeted agents that modulate the efficacy of chemotherapy. Recent advances in the administration of irinotecan and oxaliplatin, in combination with 5-FU/LV, plus the addition of targeted agents bevacizumab and cetuximab have afforded steady increases in response rates and survival. Ongoing studies are evaluating the optimal sequencing and combinations of the agents described and the efficacy of new combinations in metastatic and adjuvant settings. Because the number of African-American patients in most clinical trials in colorectal cancer has been low, it is imperative that method increase participation so that new research developments reach all segments of the population.

Changing patterns of colorectal cancer in China over a period of 20 years

AIM: To determine whether any changes have occurred on the patterns of colorectal cancer in China.

METHODS: Data from 21 Chinese articles published from 1980 to 1999, were used to analyze the time trend of colorectal cancer according to the patients’ age at diagnosis, sex, the site of the tumor, stage, and the pathology.

RESULTS: From 1980s to 1990s, the mean age of the colorectal cancer patients has increased. The percentage of the female patients rose. The distribution of colorectal carcinoma shows a predominance of rectal cancer. However, the proportion of proximal colon cancer (including transverse and ascending colon) increased significantly accompanied by a decline in the percentage of rectal cancer. Similarity in the percentage of distal colon cancer between two decades was revealed. In the 1990s, statistically more Stage B patients were found than those in 1980s. In addition, databases show a significant decrease in the Stage D cases. The proportion of adenocarcinoma increased, but the mucinous adenocarcinoma decreased during two decades.

CONCLUSION: These findings indicate that the pattern of colorectal cancer in China has been changing. Especially, a proximal shift due to the increasing proportion of ascending and transverse colon cancer has occurred in China.

The changing distribution and survival of colorectal carcinoma: an epidemiological study in an area of northern Italy

OBJECTIVE

This study analyses the inter-relations of anatomical tumour location, gender, age and incidence rates for colorectal cancer from 1978 to 1999 in an area of northern Italy: the Parma district.

METHODS

Data were obtained from the Parma Cancer Registry. Age-adjusted incidence rates were analysed by gender, age and colorectal cancer subsites. In addition, 5 year observed survival rates were determined.

RESULTS

In the Parma area, the incidence of colorectal cancer is rising. We have observed a true increase in the rate of the age standardized incidence of right colon cancer, linked to an increased incidence of left colon cancer, while the incidence of rectal cancer has remained constant. The frequency of right-sided colon cancer was higher in aged patients, and in women. Age-standardized relative survival of patients after diagnosis of colorectal cancer between 1992 and 1996 was found to be significantly higher than age-standardized relative survival after diagnosis between 1978 and 1982.

CONCLUSIONS

In the Parma area there has been an increased incidence of right colon cancer, linked to an increased incidence of left colon cancer, while the incidence of rectal cancer has remained constant. We feel that this shift, whatever the reason for it, has important implications for the choice of screening techniques.

Colorectal cancer in African Americans

Colorectal cancer in African Americans has an increased incidence and mortality relative to Whites. The mean age of CRC development in African Americans is younger than that of Whites. There is also evidence for a more proximal colonic distribution of cancers and adenomas in African Americans. African Americans are less likely to have undergone diagnostic testing and screening for colorectal cancer. Special efforts are needed to improve colorectal cancer screening participation rates in African Americans. Clinical gastroenterologists should play an active role in educating the public and primary care physicians about special issues surrounding colorectal cancer in African Americans. Community healthcare groups and gastrointestinal specialists should develop culturally sensitive health education programs for African Americans regarding colorectal cancer. The high incidence and younger age at presentation of colorectal cancer in African Americans warrant initiation of colorectal cancer screening at the age 45 yr rather than 50 yr.

Postsurgical disparity in survival between African Americans and Caucasians with colonic adenocarcinoma

BACKGROUND

Studies of colorectal adenocarcinoma (CRC) indicate a higher mortality rate for African Americans compared with Caucasians in the United States. In the current study, the authors evaluated the racial differences in survival based on tumor location and pathologic stage between African-American patients and Caucasian patients who underwent surgery alone for CRC.

METHODS

All 199 African American patients and 292 randomly selected, non-Hispanic Caucasian patients who underwent surgery between 1981 and 1993 for first primary sporadic CRC at the University of Alabama-Birmingham (Birmingham, AL) or an affiliated Veterans Affairs hospital were assessed for differences in survival. None of these patients received preoperative or postoperative neoadjuvant or adjuvant therapy. Survival curves were generated using the Kaplan-Meier method, and hazard ratios with 95% confidence intervals (95% CI) were estimated from Cox proportional hazards models, adjusting for demographic and tumor characteristics.

RESULTS

African Americans were 1.67 (95% CI, 1.21-2.33) and 1.52 (95% CI, 1.12-2.07) times more likely to die of colonic adenocarcinoma (CAC) within 5 years and 10 years of surgery, respectively, compared with Caucasians. Racial differences in survival were observed among patients with Stage II, III, and IV CAC; however, the strongest and statistically significant association was observed among patients with Stage II CAC. There were no significant racial differences in survival in patients with rectal adenocarcinomas.

CONCLUSIONS

The current findings suggest that the decreased overall survival at 5 years and 10 years postsurgery observed in African-American patients with CAC may not be attributable to tumor stage at diagnosis or treatment but may be due to differences in other biologic or genetic characteristics between African-American patients and Caucasian patients.

Colorectal cancer screening in patients presenting with an inguinal hernia: is it necessary?

BACKGROUND

It has been suggested that patients presenting with an inguinal hernia have an increased risk for colorectal cancer. Therefore, surgeons frequently request screening for colorectal cancer before surgery. The aim of this study was to assess the frequency of premalignant and malignant colonic lesions in a group of patients with an inguinal hernia, and to compare this with a control group of subjects undergoing screening colonoscopy.

METHODS

In a case-control study, 243 patients with an inguinal hernia and no history of colonic neoplasia or symptoms suggestive of colorectal cancer underwent perioperative colonoscopy. The patients were stratified into two age groups: less than 50 years old (Group I) and more than 50 years old (Group II). The colonoscopic findings were compared with findings in 534 asymptomatic control patients who underwent screening colonoscopy.

RESULTS

The mean age of patients (n=64) and control subjects (n=200) in Group I was similar, at 44 (3) years. The mean age of the patients (n=179) and control subjects (n=334) in Group II was, respectively, 70 (9) years and 64 (7) years (p<0.001). In Group I, no colorectal cancer was found in patients with inguinal hernia, and only one colorectal cancer was found among control subjects (p=0.571). In Group II, a diagnosis of colorectal cancer was made in 7 patients (4%) with inguinal hernia as compared with 10 patients (3%) among the control subjects (p=0.769). In both groups, the size and the histopathologic type of the polyps were not significantly different.

CONCLUSIONS

In otherwise asymptomatic patients, the presence of inguinal hernia is not associated with an increased risk for colorectal cancer. Therefore, the presence of an inguinal hernia alone does not justify screening colonoscopy before herniorrhaphy.

Advanced presentation of melanoma in African Americans

BACKGROUND

Melanoma in African Americans is rare, and the diagnosis is often delayed, leading to advanced presentation and poor prognosis.

OBJECTIVE

The purpose of this retrospective study is to determine whether African American patients diagnosed with melanoma at the Washington Hospital Center were initially seen with more advanced disease than white patients.

METHODS

A retrospective chart review was performed on 36 African American patients who were diagnosed and/or treated for melanoma at the Washington Hospital Center between 1981 and 2000. Data obtained included patient age at presentation, sex, Breslow's depth and histologic subtype, stage at presentation, and tumor location. These data were compared with information obtained from white patients with melanoma during this period.

RESULTS

A total of 649 African American and white patients were treated for melanoma at the Washington Hospital Center between 1981 and 2000. Of these, 36 (6.1%) patients were African American. African American patients were more likely to initially be seen with stage III/IV disease (32.1%) compared with (12.7%) the white patients initially seen with these disease stages. Of the white patients 60.4% were initially seen with melanoma in situ/stage I disease compared with 39.3% of the African American patients. The 5-year survival rate was 58.8% in African Americans compared with 84.8% in whites.

CONCLUSIONS

In our series, African Americans are more likely than whites to be initially seen with advanced disease and have a subsequent worse prognosis. Physician training and patient education campaigns are crucial to improving the poor prognosis associated with melanoma in the African American community.

Environmental factors affect colon carcinoma and rectal carcinoma in men and women differently

BACKGROUND AND AIMS

Colon cancer is thought to be more closely associated with environmental factors than rectal cancer, but evidence is currently insufficient. We examined whether there are differences in the degree of environmental effect on colon cancer and rectal cancer in Japan.

METHODS

We performed a birth cohort analysis for colon and rectal cancers using Japanese vital statistics from 1950 to 1998 and analyzed time trends by cancer site and gender.

RESULTS

The mean annual increase in age-adjusted mortality rate from colon cancer was greater than that from rectal cancer and was greater in men than in women. In men left colon cancer showed the greatest rate of increase whereas cancer of the right colon showed only a slight change. Although left colon cancer rapidly increased until the middle 1980s and thereafter showed no change, right colon cancer showed no change until the middle 1980s and thereafter rapidly increased in men. However, the rates of increase in left colon cancer were greater than those in right colon cancer until the middle 1980s, after which a reversal in trend was seen in women. Birth cohort analysis indicates that for all cohorts the mortality rates at the same age were higher in the recent cohorts than in the previous ones. This trend was more marked for colon cancer than for rectal cancer and was stronger among men than among women.

CONCLUSION

Colon cancer is more closely associated than rectal cancer with environmental factors, and this association is more pronounced in men than in women. Consequently cancers at these two sites should not be combined in studies of the role of lifestyle factors in causing these neoplasms. Furthermore, the causes of these diseases may differ in men and women.

Recruiting older African American men to a cancer screening trial (the AAMEN Project)

PURPOSE

This article describes the demographic characteristics of participants in a randomized trial (the AAMEN Project) designed to recruit older (aged 55+ years) African American men to a cancer screening trial.

DESIGN AND METHODS

The AAMEN Project is a recruitment trial developed for African American men aged 55+ years living in southeastern Michigan.

RESULTS

Of the 34,376 African American men in the study, 37.6% had low incomes and 62.4% had moderate-to-high incomes. The average age of the men was 63.3 years (SD = 5.9 years). Among men who were eligible and interested in participating, the proportion of men with low incomes was significantly greater than the proportion of men with moderate-to-high incomes (p <.001).

IMPLICATIONS

The AAMEN Project demonstrated success in recruiting a substantial proportion of men with low incomes as well as men with moderate-to-high incomes. These findings may facilitate the development of future recruitment efforts involving older African American men.

Effect of age, period of diagnosis and birth cohort on large bowel cancer incidence in a well-defined French population, 1976-1995

The objective of this study was to present trends in colorectal cancer incidence by sex and subsite in a well-defined French population. All of the 4486 large bowel cancer cases registered between 1976 and 1995 in the Burgundy registry of digestive tract cancers was included in this study. Time trends in colorectal cancer incidence were analysed over the 1976-95 period. The effects of age, period and cohort were evaluated using a log-linear Poisson model. The incidence rates for right colon cancer increased over time: + 21.6% (95% CI: + 13.5; + 29.7) per 5-year period in males and +10.4% (95% CI: + 3.4; + 17.3) in females. Left colon cancer rates increased in males (+ 10.6% 95% CI: + 4.6; + 16.6). Left colon cancer in females and rectal cancer incidence rates did not significantly change. Between the 1901 cohort to the 1941 cohort, estimated cumulative risks for right colon cancer increased sharply. The increase was less marked for left colon and the cumulative risk for rectal cancer remained almost stable. Temporal trends were different by subsites and sexes. In conclusion, our results confirm the existence of different trends in colorectal cancer incidence between subsites and sexes. These differences probably reflect aetiological distinctions.

Epidemiology and prevention of colorectal cancer

CRC, the second-leading cause of cancer death in the United States, is a highly preventable disease. Ironically, available and effective screening technologies are not consistently applied, even as new ones are developed. This discordance between preventive opportunity and practice conveys a sobering message regarding nontechnologic issues that must be addressed if the promise of CRC prevention is to be realized. Our response to this message will determine the public health impact of cancer prevention. In the 1980s, cancer chemoprevention was regarded as scientific speculation. Within the last decade, however, cancer has been recognized as a late, nonobligate stage of carcinogenesis, a chronic process that provides time and targets for preventive intervention. Further advances are emerging out of rigorous clinical testing, which remains the limiting factor in transforming ingenious concepts into useful tools for the prevention of CRC. The challenges and rewards of participation in chemoprevention research--both as patients and health care providers-have never been greater.

The Topography of Colorectal Cancer Varies by Race/Ethnicity and Affects the Utility of Flexible Sigmoidoscopy

Colorectal cancer screening beginning at age 50 is recommended for all Americans considered at “average” risk for the development of colorectal cancer either with flexible sigmoidoscopy and fecal occult blood testing (FOBT) or with colonoscopy. Patients who elect flexible sigmoidoscopy and FOBT undergo full colonoscopy only if left-sided neoplasia is detected or if the FOBT is positive. Unfortunately in blacks and whites most right-sided colorectal lesions are unaccompanied by left-sided sentinel lesions, which leads some to prefer colonoscopic screening in these patients. The topography of colorectal cancer in Asians and Latinos is unavailable. We used 1988–1995 California Cancer Registry data to determine the topography of 105,906 consecutive colorectal cancers among Asian, black, Latino, and white patients. We found that the proportion of colorectal cancer distal to the splenic flexure and therefore detectable by flexible sigmoidoscopy varied by ethnicity: Asian (71%) > Latino (63%) > white (57%) > black (55%); P < 0.001. These differences were significant after adjusting for age and sex. The risk of distal disease relative to whites was 1.61 in Asians, 1.15 in Latinos, and 0.82 in blacks ( P < 0.001). Flexible sigmoidoscopy detects a higher proportion of colorectal cancers in Asians and Latinos than in whites or blacks. Further study is needed to assess whether the topography of benign colorectal neoplasia parallels that of malignant disease. Colorectal screening recommendations may need to incorporate racial and ethnic differences in colorectal neoplasia topography.

Subsite-specific incidence rate and stage of disease in colorectal cancer by race, gender, and age group in the United States, 1992-1997

BACKGROUND

Subsite specific incidence rates of colorectal cancer vary considerably by age, gender, and race. This variation may be related not only to distinctions in exposure to genetic and environment factors but also to current strategies of early detection screening. Patterns of stage of disease in anatomic subsite may reflect the effect of screening. This study used the largest aggregation of cancer incidence data in the U.S. to examine subsite specific incidence rates of colorectal cancer and the relation of stage of disease to anatomic subsites by race, gender, and age group.

METHODS

Data on the incidence of invasive colorectal cancer were obtained from 28 population-based central cancer registries. Age-specific and age-adjusted rates and stage distributions were analyzed by subsite, race, and gender.

RESULTS

The impact of screening can be observed in the percentage of localized disease, which increased from 31.9% among cancers in the proximal colon to 37.0% in the descending colon to 41.5% in the distal colorectum. Within the same subsite, blacks were less likely than whites to receive a diagnosis of localized disease and more likely to receive a diagnosis of distant disease whereas stage distributions were approximately the same for males and females. Blacks were more likely than whites to receive a diagnosis of proximal colon cancer than distal colorectal cancer. The male-to-female rate ratios progressively increased from the proximal colon to the distal colorectum. The ratios of proximal-to-distal colorectal cancer gradually increased with advancing age.

CONCLUSIONS

Differentials in stage of disease by subsites indicate a need for a targeted effort at early detection of cancer in the proximal colon. Risk factors and higher risk populations for colorectal cancers in each subsite need to be studied further to guide actions for improving the efficacy of screening.

Anatomical site-specific response to DNA damage is related to later tumor development in the rat azoxymethane colon carcinogenesis model

There is now general agreement that the etiology of proximal and distal colon cancers may differ, thus prompting renewed interest in understanding anatomical site-specific molecular mechanisms of tumor development. Using a 2x2x2 factorial design with male Sprague-Dawley rats (corn oil, fish oil; pectin, cellulose; plus or minus azoxymethane injection) we found a greater than 2-fold difference (P < 0.001) in tumor incidence proximally versus distally (prox/dist ratio: corn oil, 2.25; fish oil, 2.61). The purpose of the present study was to determine if the higher degree of proximal versus distal tumors in our model system could be accounted for by differences between these two sites in initial DNA damage, response to that damage or an effect of diet at one site but not the other. DNA damage was assessed by quantitative immunohistochemistry of O(6)-methylguanine adducts; repair by measurement of O(6)-methylguanine-DNA alkyltransferase and removal was determined by measurement of targeted apoptosis. Although overall initial DNA damage was similar at both sites, in the distal colon there was a greater expression of repair protein (P < 0.001) and a greater degree of targeted apoptosis (P < 0.0001). There was also a reduction in DNA damage in the distal colon of rats consuming fish oil. Together, these results suggest that the lower tumor incidence in the distal colon may be a result of the capacity to deal with initial DNA damage by the distal colon, as compared with the proximal colon. Therefore, the determination of site-specific mechanisms in tumor development is important because distinct strategies may be required to protect against cancer at different sites.

Methylation and colorectal cancer

Statistics rate colorectal adenocarcinoma as the most common cause of cancer death on exclusion of smoking-related neoplasia. However, the reported accumulation of genetic lesions over the adenoma to adenocarcinoma sequence cannot wholly account for the neoplastic phenotype. Recently, heritable, epigenetic changes in DNA methylation, in association with a repressive chromatin structure, have been identified as critical determinants of tumour progression. Indeed, the transcriptional silencing of both established and novel tumour suppressor genes has been attributed to the aberrant cytosine methylation of promoter-region CpG islands. This review aims to set these epigenetic changes within the context of the colorectal adenoma to adenocarcinoma sequence. The role of cytosine methylation in physiological and pathological gene silencing is discussed and the events behind aberrant cytosine methylation in ageing and cancer are appraised. Emphasis is placed on the interrelationships between epigenetic and genetic lesions and the manner in which they cooperate to define a CpG island methylator phenotype at an early stage in tumourigenesis. Finally, the applications of epigenetics to molecular pathology and patient diagnosis and treatment are reviewed.

Racial differences in colorectal cancer mortality. The importance of stage and socioeconomic status

This investigation studies racial and socioeconomic differences in mortality from colorectal cancer, and how they vary by stage and age at diagnosis. Cox proportional hazards models were used to estimate the hazard ratio of dying from colorectal cancer, controlling for tumor characteristics and sociodemographic factors. Black adults had a greater risk of death from colorectal cancer, especially in early stages. The gender gap in mortality is wider among blacks than whites. Differences in tumor characteristics and socioeconomic factors each accounted for approximately one third of the excess risk of death among blacks. Effects of socioeconomic factors and race varied significantly by age. Higher stage-specific mortality rates and more advanced stage at diagnosis both contribute to the higher case-fatality rates from colorectal cancer among black adults, only some of which is due to socioeconomic differences. Socioeconomic and racial factors have their most significant effects in different age groups.

Screening for colorectal cancer

Colorectal cancer is the third most commonly diagnosed cancer and the second leading cause of cancer deaths in the United States. Fortunately, both the incidence and mortality associated with the disease have declined during the past 2 decades. This is likely due, at least in part, to improved efforts at screening and more aggressive removal of adenomatous polyps. However, colorectal cancer screening is still generally underutilized. This article reviews the current status and future outlook for colorectal cancer screening, including a discussion of risk factors for the disease, its anatomic distribution, proposed mechanisms of development from adenomatous polyps, rationale for screening, and screening options. Published literature concerning the cost-effectiveness of colorectal cancer screening is also summarized. The article concludes with a discussion of the emerging consensus regarding the importance of and approaches to screening.

Screening colonoscopy in asymptomatic average-risk African Americans

BACKGROUND

Recent data indicate that colorectal cancer incidence and mortality in white Americans have been declining since 1985 at a rate of 2% to 3% per year. In African Americans, however, mortality from colorectal cancer appears to be increasing. We sought to evaluate the prevalence of colonic neoplasia in asymptomatic African Americans.

METHODS

We performed a cross-sectional colonoscopy screening study to determine the prevalence of colonic neoplasia in asymptomatic African Americans older than 50 years of age.

RESULTS

One hundred sixty-six subjects were evaluated for the study of whom 121 (69 women) were deemed to be asymptomatic average-risk persons and completed colonoscopy. Forty-two individuals (35%) had a total of 72 adenomas (67 tubular and 5 tubulovillous); 47 (65.3%) of these were proximal to the splenic flexure. Three subjects had an adenoma 1 cm or greater in diameter and none had severe dysplasia.

CONCLUSIONS

The overall prevalence of adenomas in asymptomatic average-risk African Americans was comparable to that of previously described populations. The predominance of right-sided adenomas in this study confirms previous findings and is an area requiring further study. Until this issue is resolved, we suggest the use of colonoscopy rather than sigmoidoscopy for screening for colorectal neoplasia in asymptomatic, average-risk African Americans.

Proximal shift of colorectal cancer in the Australian Capital Territory over 20 years

BACKGROUND

Several studies in other countries have demonstrated a change in subsite distribution of colorectal cancer, with increasing proximal cancers. Confirmation of such a change in Australia would have implications for screening and diagnosis of colorectal cancer.

AIMS

To determine whether there has been an increase in the proportion of proximal colorectal cancers in Australia, and whether there have been changes in other clinical and pathological aspects of colorectal cancer.

METHODS

A study of the hospital files of patients with colorectal cancer diagnosed and treated at all hospitals in the Australian Capital Territory (ACT) between 1989 and 1995 was compared with data from a published study of patients diagnosed between 1969 and 1976.

RESULTS

There was a proximal shift of cancers with a significant increase in the proportion of tumours in the hepatic flexure, ascending colon and caecum, more marked for females than males. There was a corresponding reduction in distal colorectal cancers. Time from onset of symptoms to diagnosis decreased, risk factors for colorectal cancer were noted more frequently, and endoscopy replaced barium enema X-ray as the main diagnostic modality. The resectability of cancers increased, stay in hospital and 30 day mortality declined. Despite apparent earlier presentation and improved surgical resectability, the proportion of patients with localised disease (Dukes' stage A and B) had not changed significantly.

CONCLUSIONS

We have detected a number of changes in clinical and pathological aspects of colorectal cancer over a 20 year period in the ACT, including a proximal shift in the subsite distribution of colorectal cancer. These changes suggest that proximal and distal colorectal cancers may have a different aetio-pathogenesis, and have implications for the investigation of patients with suspected colorectal cancer and in screening high-risk groups.

Colorectal carcinoma among ethnic Chinese in Singapore: trends in incidence rate by anatomic subsite from 1968 to 1992

BACKGROUND

Recent epidemiologic studies have suggested that the anatomic distribution of colorectal carcinoma may have undergone a distal to proximal shift over several decades, which has been attributed variously to environmental and genetic factors as well as preventive intervention.

METHODS

Trends in subsite distribution and the incidence rate of colorectal carcinoma among Chinese in Singapore between 1968 and 1992 were explored using data from the Singapore Cancer Registry (n = 10,489). Age-standardized incidence rates were computed and compared further using age-period-cohort models by subsite and gender.

RESULTS

The proportion of lesions in the distal colon was found to have increased from 23.2% to 24.4% whereas that for the proximal colon and rectum were fairly consistent over the past 25 years. Our results also showed that age-standardized rates have doubled in proximal lesions (2-3% annually) and more than doubled in distal lesions (3-4% annually) whereas rates in rectal carcinoma have shown a slight increase or stability over time. The patterns of change in all subsite tumors could be attributed to a significant birth cohort effect.

CONCLUSIONS

The results of the current study suggest that incidence rates have increased rapidly with no distal to proximal shift observed among ethnic Chinese in Singapore over the past 25 years. The pattern of change differs from findings reported in high incidence countries such as the U. S. and parts of Europe, suggesting that the preventive intervention and early diagnostic capabilities that may have played an important role in these countries have had less effect in Asia. The rapid overall increase in the incidence rate of colon carcinoma supports the role of dietary and other environmental factors as possible risk factors.

Nuclear accumulation of p53 in colorectal adenocarcinoma: prognostic importance differs with race and location of the tumor

BACKGROUND

Although several studies have been conducted to examine the role of p53 genetic abnormalities and their prognostic value in colorectal carcinoma, the incidence of nuclear accumulation of p53 and the prognostic importance of nuclear accumulation of p53 in African-American and white patients have not been investigated separately. Therefore, the authors evaluated the prognostic significance of p53 nuclear accumulation in these two racial groups.

METHODS

Nuclear accumulation of p53 was evaluated immunohistochemically in archival tissue specimens from 204 African-American and 300 white patients with primary colorectal adenocarcinomas who had undergone surgery. Survival times from colorectal adenocarcinoma were analyzed using Kaplan-Meier survival estimates and the Cox proportional hazards model for nuclear accumulation of p53 with adjustments for other confounding demographic and clinical variables.

RESULTS

Approximately equivalent proportions of distal (54%) and proximal adenocarcinomas (47%) were positive for nuclear accumulation of p53 in African-American patients. In contrast, distal colorectal adenocarcinomas from white patients more frequently were positive for nuclear accumulation of p53 than adenocarcinomas of the proximal colon (63% vs. 38%, respectively). Nuclear accumulation of p53 was found to be a strong predictor of poor survival in white patients (hazard ratio = 6.77; P = 0.0001) but not in African-American patients with primary adenocarcinomas of the proximal colon. Nuclear accumulation of p53 was not of prognostic value in patients of either race with primary adenocarcinomas of the distal colorectum.

CONCLUSIONS

Nuclear accumulation of p53 is a valuable indicator of poor prognosis only for white patients with adenocarcinomas of the proximal colon. The current study also suggests that the role of p53 dysregulation in colorectal adenocarcinomas may vary with the anatomic location of the tumor and the race of the patient. These findings suggest that the demographic characteristics of patients should be considered in the evaluation of prognostic markers of colorectal neoplasia.