Many recent reports in the North American literature have documented an increase in the ratio of proximal to distal colorectal cancers with an increase in right-sided lesions. In order to assess trends in the distribution of large bowel carcinoma at our hospital we reviewed the files of 1553 patients who presented with primary colorectal carcinoma over a 30-year period. Thirty-nine percent of patients were over 70 years old and 51% were in the 50-69 year age group. Seventy five percent of the carcinomas were left-sided, 22% right-sided and caecal carcinomas accounted for 18%. This distribution varied only slightly over the study period. Left-sided lesions were more common in males (55%: p less than 0.005), and right-sided lesions were more common in females (57%: p less than 0.005). Caecal carcinoma was more common in patients over 69 years old than in younger patients (p less than 0.001). In elderly females (greater than 69 years) 30% of colorectal carcinomas occurred in the caecum. These findings may have important implications for the investigation of patients with suspected colorectal disease or for screening programmes.
Background and purpose: The prevalence of ex vivo 'high on-treatment platelet reactivity' (HTPR) to antiplatelet regimens in patients with ischaemic cerebrovascular disease (CVD) is uncertain. Methods: HTPR was assessed with PFA-100 collagen-epinephrine (C-EPI) and collagen-ADP (C-ADP) cartridges. Platelet activation (CD62P, CD63 and leucocyte -platelet complex formation) was assessed with whole-blood flow cytometry. Patients were assessed at baseline [4 weeks of transient ischaemic attack (TIA) or ischaemic stroke], and at 14 days and 90 days after changing treatment from (i) no medication to aspirin monotherapy (N = 26) or (ii) aspirin to clopidogrel monotherapy (N = 22). HTPR was defined in a novel, 'longitudinal fashion' as failure to prolong relevant closure times compared with the patient's 'baseline value' before he/she underwent an antiplatelet change by more than twice the coefficient of variation of the assay. Results: (i) C-EPI closure times increased at 14 days and 90 days after commencing aspirin (P = 0.002); 24% at 14 days and 18% at 90 days demonstrated HTPR on aspirin. (ii) C-ADP closure times increased at 14 days (P = 0.001) but not 90 days (P = 0.09) after changing from aspirin to clopidogrel; 41% at 14 days, and 35% at 90 days demonstrated HTPR on clopidogrel. Platelet activation was unaffected by aspirin (P = 0.09). The percentage neutrophil-platelet complexes decreased at 14 days (P = 0.02), but this reduction was not maintained 90 days after changing to clopidogrel (P = 0.3). No patient had a recurrent vascular event during prospective follow-up. Conclusions: Longitudinal definitions of HTPR in patients with ischaemic CVD who are undergoing a change in antiplatelet therapy have the potential to provide more clinically meaningful information than traditional 'cross-sectional definitions' of HTPR which are usually based on the comparison of patients' values with those in healthy controls. Using our novel, longitudinal definition of HTPR, the PFA-100 could be used to monitor ex vivo responsiveness to aspirin, and larger, prospective studies are warranted to assess the clinical predictive value of this and other platelet function tests in patients with ischaemic CVD.
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