Distribution of cancer and adenomatous polyps in the colorectum: study in an Iranian population.

OBJECTIVE: There is consensus that the majority of colorectal carcinomas (CRCs) arise from adenomatous polyps. Therefore, for management of colorectal cancer, diagnosis and endoscopic resection of adenomas is advised. If the same etiologic factors are operating for polyps and cancers their anatomical distributions should be the same. The present study was conducted to determine whether the distribution of adenomas is consistent with that of CRCs and for comparison with other studies, especially in Western populations. MATERIALS AND METHODS: We reviewed, retrospectively , endoscopically reported anatomic sites of all adenomatous polyps and CRCs which were histologically confirmed from Jan 1992 to Dec 2005 in Tabriz, the North-west of Iran. One hundred and forty-three CRC's and 180 adenomatous polyps (in 145 patients) were found. Patients with polyposis syndromes were excluded the analysis. Age and sex of patients, size and anatomic sites of polyps and cancers were studied. RESULTS: The average ages of patients with adenomas and cancers were 46.3(SD 14.7) and 53.9(SD 13.3)years, with 55.5% and 62.2% in males, respectively. In both cancer and adenoma cases the most common presenting symptoms were rectal bleeding and bloody diarrhea ( 52.4% , 16.9% and 39.2% , 15.8% for cancers and adenomas, respectively) without any significant difference(0>05). The vast majority of adenomas (85%) and cancers (81.7%) were left sided (p>0.05). The propensity for polyps to be found in the descending colon was of borderline significance (p=0.07). The cecal segment uniquely demonstrated cancers(p=0.01) without any polyps. CONCLUSION: A similar anatomic distribution pattern and left shift of colorectal adenomas and cancers in this Iranian population is compatible with most other Asian countries. However, because of the occurrence of the neoplasms in the right colon total colonoscopy should still be considered for screening purposes.

Demographic and anatomical survey of colorectal polyps in an Iranian population.

OBJECTIVE: Asian countries generally have low incidences of colorectal cancers (CRCs). One approach to prevention is based on recognition and removal of polyps. The aim of this study was to determine basic demographic features, anatomic distribution and characteristics of colorectal polyps in a local Asian population for comparison with western data. METHODS: We here performed a retrospective chart review of 194 patients with colorectal polyps detected by endoscopy [total colonoscopy in 136 cases (73.1%), and flexible sigmoidoscopy in the remainder] during 1992-2005, focusing on descriptive statistics for categorical variables, including distribution pattern and histology. Cold biopsy in 14 cases, piecemeal endoscopic resection in 5 patients, and usual snare polypectomy in the remainder were performed. Patients with polyposis syndromes were excluded from the analysis. RESULTS: The average age of patients was 43.2 yr (range 2-80) with 71% being males. Most of the polyps were presented in 5th decade (p=0.029). A total of 32 (17.2%) had synchronous proximal polyps (15% adenomas), and 154 cases had solitary polyps. The vast majority of the polyps were left sided and the most frequent type was adenoma (63%), with a villous component in 37.1%. Coexistent cancer was seen in 10.9% of cases. CONCLUSION: In this Iranian population, the majority of polyps are left sided. The incidence of adenomas and their histology appear comparable to data for western patients, but with a significantly lower rate for synchronous neoplastic lesions.