The incidence and Dukes' staging of colorectal cancer over 3 decades

Anatomical distribution of colorectal carcinoma in Iran: a retrospective 15-yr study to evaluate rightward shift

BACKGROUND

Although more than two third of colorectal cancers are localized on the left side, recent studies suggest a right ward shift in anatomical distribution with increase in proximal colon cancers. The aim of the present study was to determine the anatomical distribution of colorectal cancer in a referral center over a 15 year period.

METHOD

Records of patients who underwent colectomy in the Cancer Institute of Iran from 1994 to 2009 were retrieved. Data including anatomical localization, year of diagnosis, patient age and gender, tumor histology and differentiation, and disease stage were extracted. Tumors located from the cecum to the distal transverse colon were classified as right side and those occurring from the splenic flexure to the descending colon as left-sided. Cancer of rectum and recto-sigmoid junction were considered as rectal cancers.

RESULTS

A total of 442 patients including 220 (49/8%) men and 222 (50/2%) women with mean age 53 were included. Most patients were in stages II and III (47.1% and 33% respectively). There were 157 (35.5 %) colon cancers and 285 (64.5%) rectal cancers. 43.3% of the colon cancers were right sided and 56.7% were left sided. There was no statistically significant increase in right sided cancer during the period of the study. There were no significant differences in age at diagnosis, gender, grade and stage of tumor between the right and the left sided cancers.

CONCLUSION

No proximal shift over time was identified in our study.

Anatomical distribution of colorectal cancer over a 10 year period in a district general hospital: is there a true "rightward shift"?

INTRODUCTION

Recent studies of patients with colorectal cancer have suggested a shift towards the proximal colon and an increase in the incidence of right sided colon cancer. This study aimed to determine the anatomical distribution of colorectal cancer over a 10 year period in a district general hospital.

METHODS

Records of patients diagnosed with primary colorectal cancer from 1993 to 2002 were reviewed for demographic data, histology subtype, and anatomical location of the tumour. Tumours located at and proximal to the splenic flexure were defined as right sided cancer and tumours arising distal to the splenic flexure were defined as left sided cancer.

RESULTS

A total of 763 patients were included in the study, of whom all had adenocarcinoma and 99% were white. Sixty nine percent of cancers were left sided and 31% were right sided. Although there was a 4% increase in the proportion of right sided cancers, there was no statistically significant increase using logistic regression analysis. Mann-Whitney U test revealed no significant difference in age at diagnosis between the right and left sided cancers. Although a higher proportion of females were diagnosed with right sided cancer compared with left sided cancer, this was not statistically significant.

CONCLUSION

The anatomical distribution of colorectal cancer has been fairly stable at this hospital with no evidence of a shift towards the proximal colon. No differences were identified in the tumour distribution with respect to gender and age at diagnosis. Our findings support the initial application of flexible sigmoidoscopy for investigating patients with suspected colorectal malignancy and follow up colonoscopy for selected patients to exclude right sided pathology.

Extracolonic findings in patients undergoing abdomino-pelvic CT for suspected colorectal carcinoma in the frail and disabled patient

AIM

The aims of this study were to evaluate the extracolonic findings identified in patients undergoing minimal preparation abdomino-pelvic CT in place of barium enema or colonoscopy for the detection of possible colorectal carcinoma.

MATERIALS AND METHODS

The CT technique involved helical acquisition (10 mm collimation, 1.5 pitch) following 2 days of preparation with oral contrast medium only. Extracolonic findings were evaluated in the light of subsequent follow-up and accuracy. The evaluation included assessment of the potential contribution of the extracolonic finding(s) to staging the cancer in the subset of patients who had colorectal carcinoma, and to account for the patients' presenting symptoms and signs in the remaining patients.

RESULTS

A total of 344 extracolonic findings were detected in 261 CT examinations, from amongst a total of 1077 cases (24%). Extracolonic findings were potentially important in staging in 32 of the 98 (33%) cases subsequently found to have colorectal cancer. There were 284 extracolonic findings amongst the 221 cases who proved not have colorectal cancer. One hundred and twenty-four (44%) of these 284 findings were actively followed up by clinicians, and 33 (12%) ultimately had a surgical intervention. Fifty-six percent (160/284) of the findings were determined to be correct (by further investigation, autopsy, and/or clinical follow-up); the remainder were incorrect or indeterminate (n = 56) or had no follow-up (n = 68). The commonest extracolonic findings were focal liver lesions (found in 42/1077, 4%) and abdominal aortic aneurysms (31/1077, 3%). Twenty-four (24/1077, 2%) previously unknown extracolonic malignancies were detected. Ten percent (106/1077) of the patients had extracolonic findings that could potentially have accounted for their presenting symptoms.

CONCLUSIONS

CT has the added benefit, compared with colonoscopy and barium enema, of not just evaluating the colon but also of detecting extracolonic abnormalities. Such findings may be useful in staging the cancer, may explain the patient's presenting symptoms, and may detect other potentially serious disorders.

Colorectal cancer, screening and survival: the influence of socio-economic deprivation

OBJECTIVES

To determine the extent to which socio-economic deprivation explains colorectal cancer prevalence, subject participation in screening, and postoperative survival and life expectancy.

METHODS

Regression analyses of clinical data from a large randomized controlled trial, augmented by geographical-based indices of deprivation.

RESULTS

Deprivation appears to exert no significant impact on colorectal cancer prevalence but is a major factor explaining subject participation in screening. Cancer detection at later stages reduces life expectancy at time of treatment. Females from more-deprived areas have poorer post-treatment life expectancies and survival prospects, independently of their screening behaviour.

CONCLUSIONS

Screening increases the chances of having a cancer treated at an earlier stage, and treatment at an earlier stage is associated with longer subsequent life expectancy. However, those from more-deprived areas are less likely to accept an invitation to be screened.

A prospective, controlled assessment of factors influencing acceptance of screening colonoscopy

OBJECTIVES

Medicare beneficiaries now have access to screening colonoscopy (SC). For colon cancer screening to be fruitful, SC must become more acceptable to a broad segment of this population. However, we currently lack knowledge of which aspects of SC have an impact on patient acceptance. The aims of this study were: 1) to identify the features of SC that are most important in deterring participation, and 2) to prioritize and to compare the perceptions of never-screened individuals with those of individuals previously screened for colon cancer.

METHODS

Questionnaires were distributed to 300 outpatients at Mayo Clinic, Rochester (150 never-screened patients; 150 previously screened patients). The survey instrument addressed domains of the Health Belief Model and colon cancer risk perception. Patients ranked the three most important barriers to SC and answered general knowledge questions on colon cancer.

RESULTS

Response rates of never-screened (84%) and screened (88%) patients were similar. Never-screened patients were less likely to have a regular primary physician (80% vs 95%, p = 0.0003) and were less likely to have undergone a prior screening mammography (87% vs 96% of women, p = 0.02) compared with screened patients. The four most reported deterrents to SC ("volume of bowel preparation," "adequate analgesia," "no recommendation from primary physician," and "embarrassment") were ranked similarly by both groups. Never-screened patients had less understanding of the incidence and treatment outcomes of colon cancer.

CONCLUSION

Colon cancer screening behavior seems to be associated with having a regular primary physician, as well as other cancer screening behaviors. Knowledge of colon cancer is the most reliable discriminator of prior screening status. There does not seem to be any difference in the preferences expressed by never-screened and screened patients with respect to the aspects of colonoscopy that they find objectionable.

Current trends in colorectal cancer: site, incidence, mortality and survival in England and Wales

The objective was to examine trends in colorectal cancer (CRC) incidence and mortality in England and Wales over the last 30 years. Age-standardized incidence, mortality and survival rates for CRC, based on data from the National Cancer Intelligence Centre at the Office for National Statistics, were calculated and trends assessed. Between 1971 and 1997 the total number of cases of CRC increased by 42%, from 20,400 to 28,900. The site distribution of CRC between 1971 and 1994 was: rectum 38%, sigmoid 29%, caecum 15%, transverse colon and flexures 10%, ascending colon 5%, and descending colon 3%. Between 1971 and 1997 the direct age-standardized incidence increased by 20% in males and by 5% in females. The direct age-standardized mortality fell by 24% in males and by 37% in females. Age-standardized relative 5-year survival in adults improved from 22%-27% for patients diagnosed during 1971-1975 to over 40% for those diagnosed during the period 1991-1993. In conclusion, the incidence of CRC in England and Wales has been steadily rising. It is more common in males and has increased more rapidly in males than in females. The reasons for these trends remain unclear. Five-year survival has improved substantially, but rates are still below those in comparable countries elsewhere in Europe and in the USA.

Antioxidants enhance the susceptibility of colon carcinoma cells to 5-fluorouracil by augmenting the induction of the bax protein

5 Fluorouracil (5 FU), the most effective systemic chemotherapeutic agent in the management of advanced colorectal carcinoma acts by inducing apoptosis. Response rates, approximately 20% is improved by folinic acid. This study investigates similar modulation of 5 FU-induced apoptosis by oxidant quenching. A five-fold reduction of intracellular oxidant levels by antioxidants N-acetylcysteine and vitamin E did not induce apoptosis, it however augmented pro-apoptotic bax protein expression, and apoptotic response to a non-toxic dose of 5 FU in the colorectal cancer cell lines colo 201 and colo 205. This suggests that reduction of intracellular levels of reactive oxygen species enhance susceptibility to 5 FU (apoptotic stimuli) by augmentation of bax expression.