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1.
Nasal polyps are tumor-like, hyperplastic swellings of the nasal mucous membranes. The histology may vary. The clinical picture shows a great heterogeneity, ranging from single polyps (so-called choanal polyps) to almost complete polypoid transformation of the mucosa in all paranasal sinuses. Nasal polyps may be associated with different inflammatory nasal diseases such as chronic rhino-sinusitis, cystic fibrosis and Kartagener's syndrome. The exact pathogenesis of nasal polyps is unknown. Several theories have been formulated over the past 20 years attributing nasal polyps to a variety of causes including allergy, genetic predisposition and inflammation. Recently, a relationship has been demonstrated between the production of cytokines and the formation and activation of inflammatory cells in the polyps. The diagnosis and surgical treatment of nasal polyposis has been decisively developed over the past decade. Current diagnostic and therapeutic concepts are presented for the treatment of nasal polyposis. Precise indications for medical and surgical treatment of nasal polyposis can be derived from an evaluation of the allergic endoscopic and radiological examinations. Glucocorticoids play a dominant role in conservative therapy. Topical application of steroids is the preferred route. Surgical therapy should not be radical. It should focus on the lateral nasal wall rather than on the healthy mucosa of the sinuses itself.  相似文献   

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3.
Nitric oxide (NO) plays an important regulatory role in airway function and seems to be implicated in the pathophysiology of several airway diseases. We studied the presence of NO synthase activity in human nasal mucosa and nasal polyp tissues obtained from patients undergoing septoplasty or polypectomy, respectively. NO synthase activity was quantified in tissue homogenates using citrulline release assay and was located in tissue sections using NADPH-diaphorase histochemistry. The results indicated that nasal polyps contain higher levels of total NO synthase activity than nasal mucosa tissue. In addition, nasal polyps contained mainly inducible NO synthase activity whereas all NO synthase activity detected in the nasal mucosa was in constitutive form. In both cases, NO synthase activity was localized in epithelial cells. In view of these results, we conclude that NO may be an important inflammatory mediator in the respiratory system and that the epithelium may be a source of NO production.  相似文献   

4.
OBJECTIVES: To investigate the effect of intranasal corticosteroids in the treatment of polyps in patients with severe polyposis listed for surgical treatment and to determine the treatment effect on the progression of the disease. DESIGN: A double-blind, randomized, parallel-group, placebo-controlled, 12-week study at a single center. SETTING: A tertiary referral center in London, England. PATIENTS: Thirty-four patients with severe polyposis listed for endoscopic surgical treatment. INTERVENTION: By random allocation, fluticasone propionate aqueous nasal spray (FPANS), 200 microg twice a day; beclomethasone dipropionate aqueous nasal spray, 200 microg twice a day; or placebo nasal spray twice a day was administered. Patients received 2 actuations to each nostril in the morning and in the evening. MAIN OUTCOME MEASURES: Efficacy end points were the need for polypectomy at the end of treatment, the results of acoustic rhinometry, the polyp score, the peak nasal inspiratory flow rate, and an assessment of symptoms. RESULTS: The polyp score was significantly decreased in the FPANS-treated group (P < or = .01). The nasal cavity volume was significantly increased in both the FPANS-treated group and the group receiving beclomethasone compared with placebo (P < or = .01) at the end of treatment. The percentage change in the mean morning peak nasal inspiratory flow rate was greater in the FPANS-treated group, with a significant effect observed at week 2 (P = .01). Nasal blockage was significantly decreased in both active groups compared with the group receiving placebo. No significant difference was observed between the treatment groups in the number of patients requiring polypectomy. CONCLUSIONS: Fluticasone and beclomethasone aqueous nasal sprays are effective in treating the symptoms of severe nasal polyps. There was some evidence that the group treated with FPANS responded more quickly to intervention and that the magnitude of the response was greater than in the group receiving beclomethasone.  相似文献   

5.
OBJECTIVE: This paper was undertaken to review the experience at our institution with bilateral sequential lung transplantation for cystic fibrosis. METHODS: Since 1989, 103 bilateral sequential lung transplants for cystic fibrosis have been performed (46 pediatric, 48 adult, 9 redo); the mean age was 21 +/- 10 years. Cardiopulmonary bypass was used in all but one pediatric (age <18) transplant, and in 15% of adults. RESULTS: Hospital mortality was 4.9%, with 80% of early deaths related to infection. Bronchial anastomotic complications occurred with equal frequency in the pediatric and the adult populations (7.3%). One- and 3-year actuarial survival are 84% and 61%, respectively (no significant difference between pediatric and adult age groups; average follow-up 2.1 +/- 1.6 years). Mean forced expiratory volume in 1 second increased from 25% +/- 9% before transplantation to 79% +/- 35% 1 year after transplantation. Acute rejection occurred 1.7 times per patient-year, with most episodes taking place within the first 6 months after transplantation. The need for treatment of lower respiratory tract infections occurred 1.2 times per patient in the first year after transplantation. Actuarial freedom from bronchiolitis obliterans was 63% at 2 years and 43% at 3 years. Redo transplantation was performed only in the pediatric population and was associated with an early mortality of 33%. Eight living donor transplants (four primary transplants, four redo transplants) were performed with an early survival of 87.5%. CONCLUSION: Patients with end-stage cystic fibrosis can undergo bilateral lung transplantation with morbidity and mortality comparable to that seen in pulmonary transplantation for other disease entities.  相似文献   

6.
To increase an awareness of the developmental anatomy of the nasal cavity as it applies to the radiologic work-up of choanal atresia and frontoethmoidal cephaloceles, we report two cases that demonstrate potentially serious imaging pitfalls. Two neonates with nasopharyngeal obstruction were imaged with CT and MR. Both patients had surgically proved bilateral bony choanal atresia. In addition to choanal atresia, CT showed a radiolucent, or nonossified cribriform plate and mucoid secretions within the nasal fossa, adjacent to the cribriform plate, which approximated the attenuation of brain parenchyma. In one of the patients, a preoperative diagnosis of nasopharyngeal encephalocele resulted in surgical exploration. At surgery, however, the cartilaginous cribriform plate was found to be intact.  相似文献   

7.
D Shin  F Gilbert  M Goldstein  PN Schlegel 《Canadian Metallurgical Quarterly》1997,158(5):1794-8; discussion 1798-9
PURPOSE: We evaluated the penetrance of cystic fibrosis gene mutations for the clinical phenotype of congenital bilateral absence of the vas deferens. MATERIALS AND METHODS: We retrospectively reviewed the fertility status of 244 brothers of 105 men with congenital bilateral absence of the vas deferens. Testing for the most common cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations and for haplotype analysis of the intron 8/polythymidine segment was recommended for all men with congenital bilateral absence of the vas deferens. RESULTS: Of 244 brothers of men with congenital bilateral absence of the vas deferens 131 were eligible for assessment of fertility. Of the 131 evaluable brothers only 7 (5%) were found to have congenital bilateral absence of the vas deferens. This prevalence is 5 times lower than that predicted for congenital bilateral absence of the vas deferens (25%) based on the autosomal recessive inheritance pattern seen in classical cystic fibrosis. For couples in which the man has congenital bilateral absence of the vas deferens and the female partner tests negative for standard CFTR gene mutations including 5T analysis, the maximum risk of having a child with congenital bilateral absence of the vas deferens is less than 1.0%. CONCLUSIONS: Our data are consistent with incomplete penetrance for the congenital bilateral absence of the vas deferens phenotype after inheritance of cystic fibrosis gene mutations, even after adjusting for environmental factors and wolffian anomalies. Incomplete penetrance may account for a low prevalence of congenital bilateral absence of the vas deferens in the population and may lower the risk of having a child with congenital bilateral absence of the vas deferens for couples undergoing sperm retrieval and assisted reproductive techniques.  相似文献   

8.
Congenital bilateral absence of vas deferens causes male excretory infertility and represents 1 to 2% of male infertility. Because of a genotypic similarity with cystic fibrosis, the possible in vitro fertilization with epididymal sperm requires careful genetic counselling. We studied genotype, sweat chloride concentration, respiratory function tests, sinus abnormalities, pancreatic and hepatic functions in 22 subjects with congenital bilateral absence of vas deferens. Among them, four were compound heterozygotus, all of them with the R117H mutation. Ten had a positive sweat test, one of them also being compound heterozygotus. Congenital bilateral absence of vas deferens and double mutation or positive sweat test led to high probable cystic fibrosis diagnosis in 13 subjects. Six subjects were heterozygotus for one cystic fibrosis mutation, criterium which is not sufficient for cystic fibrosis diagnosis; five of them had sinus abnormalities, present in 11 of the 22 subjects. Only three patients had no mutation nor sweat chloride abnormalities. This work confirms the high frequency of cystic fibrosis mutations in males with congenital bilateral absence of vas deferens, with a higher frequency of positive sweat test than in other publications, and a high frequency of sinus abnormalities. This monosymptomatic phenotype of cystic fibrosis suggests new hypotheses for a relationship between genotype and phenotype.  相似文献   

9.
OBJECTIVES: We studied the clinical spectrum, histology, and malignant potential of colonic polyps in Indian children (< or =12 yr). METHODS: Two hundred thirty-six children with colonic polyps were studied from January 1991 to October 1996. They were evaluated clinically and colonoscopic polypectomy was done. Children with five or more juvenile polyps were labeled as having juvenile polyposis and serial colonoscopic polypectomies were done every 3 wk. Colectomy was performed when there were intractable symptoms or clearing of the polyps by colonoscopy was not possible. Histological examination of the polyps was done. Follow-up colonoscopy was done in children with juvenile polyposis only. RESULTS: The mean age of these children was 6.12 +/- 2.7 yr, with a male preponderance (3.5:1). Rectal bleeding of a mean duration of 14 +/- 16 months was the presenting symptom in 98.7%. Solitary polyps were seen in 76%, multiple polyps in 16.5%, and juvenile polyposis in 7% (n = 17) of the children. A majority (93%) of the polyps were juvenile and 85% were rectosigmoid in location. Adenomatous changes, seen in 11%, were more common in juvenile polyposis (59%) than in juvenile polyps (5%). Among those with juvenile polyposis, colon clearance was achieved in eight, six required colectomy for intractable symptoms, and three were still on the polypectomy program. Polyps recurred in 5% of children with juvenile polyps and 37.5% of those with juvenile polyposis. CONCLUSIONS: Juvenile polyps remain the most common colonic polyps in children. A significant number of cases of polyps are multiple and proximally located, which emphasizes the need for total colonoscopy in all. Juvenile polyps should be removed even if asymptomatic because of their neoplastic potential. Colonoscopic polypectomy is effective even in juvenile polyposis. Surveillance colonoscopy is required in juvenile polyposis only.  相似文献   

10.
BACKGROUND: Adenomatous colonic polyps are accepted as premalignant lesions. There is controversy regarding the significance of the hyperplastic polyp. The aim of this study was to determine the incidence of further polyps in patients with only hyperplastic polyps on a first colonoscopy in comparison with patients without polyps and with adenomatous polyps. METHODS: Ninety patients had only hyperplastic polyps (group I). These patients were paired according to age and sex with subjects having no polyps (group II) and with patients having adenomas (group III). RESULTS: Fifty-six patients in group I had at least one follow-up examination. New polyps were found in 46.4% in group I versus 15.5% in group II (p < 0.001) and 50% in group III (NS). In group I, 30.7% of new polyps were hyperplastic and 69.3% were adenomas. In fact, 32.2% of group I patients developed further adenomas (mean 1.5 +/- 0.8 adenomas). These adenomas occurred 1 to 4 years after the first polypectomy (mean 2.4 +/- 0.8 years). Most of these adenomas were small and tubular, but 16.6% were villous or had severe dysplasia. CONCLUSION: Patients with hyperplastic polyps were 2.4 times more likely to have further adenomas than were those without polyps.  相似文献   

11.
The clinical, microscopic, and gross pathologic features of 23 cases of intranasal hemangiopericytoma-like tumors are reviewed and studied. When in the nasal cavity, these lesions often originated in a paranasal sinus and extended into the nasal cavity secondarily. They occurred most commonly in adults in the sixth and seventh decades of life; there was no significant sex predilection. Twenty-two of the 23 patients were Caucasian. These patients most commonly had symptoms of nasal obstruction and epistaxis. Clinically the lesions were generally thought to represent allergic polyps. Although appearing microscopically as non-differentiated spindle-cell neoplasms, these lesions showed little nuclear or cytoplasmic pleomorphism, minimal mitotic activity, and no necrosis or hemorrhage or other evidence of anaplasia found in malignant tumors. Follow-up data showed no evidence to suggest a malignant or biologically unpredictable lesion. Nineteen of 22 cases followed showed no recurrence regardless of the treatment; those that recurred did so locally. No metastasis or other form of aggressive behavior attributed to hemangiopericytomas in other anatomic locations was seen in this series. Another case, diagnosed as a malignant hemangiopericytoma of the nasal cavity, showed dissimilar and anaplastic histologic features. This case metastasized and is discussed, though not included in this study.  相似文献   

12.
BACKGROUND/AIMS: There are genetic, endoengenous, and exogenous factors responsible for colorectal cancer. Calcium may play a chemopreventive role in high risk groups. Binding fatty and biliary acids and their reduced absorbtion, with a consequent decrease of proliferative stimulation and reduction of secondary carcinogenic compounds, may explain this role. MATERIAL AND METHODS: 175 patients with adenomatous polyps after polypectomy and with calcium chemoprevention were evaluated for polyps recurrence. Another three groups of patients with colorectal cancer without chemoprevention (A,B) and with chemoprevention (group C) were followed concerning survival after surgery. RESULTS: The cumulative survival rate of patients after surgery due to colorectal carcinoma is significantly higher in a calcium chemopreventive group. Adenomatous polyps recurrences after polypectomy are lower (12.9%) in the chemoprevention group than in the group without prevention (55%) with a mean time of follow-up 3.1 yrs. CONCLUSIONS: Calcium is an important chemopreventive agent in adenomatous polyps after polypectomy and after colorectal surgery for colorectal cancer.  相似文献   

13.
A colonic adenomatous polyp registry (PR) has been organized at the Roger Williams Medical Center whose main functions are to prevent the occurrence of colorectal cancer (CRC) in the enrollees, to provide a population of subjects for epidemiological and interventional studies, and to provide educational, including dietary, information to subjects and physicians. One hundred four and 202 patients with polyps, originally retrieved from the hospital pathology files, were enrolled in the 1984 and 1987 cohorts, respectively, of whom about 90% were followed for at least three years after polypectomy. Three carcinomas, all Dukes A, were found in the right colon in the follow-up period. New polyps identified in the first three years after polypectomy were generally small tubular adenomas with a greater predilection for the right colon than was found for the index polyps. Risk factors for new polyps included history of previous polyps and, probably, multiple index polyps. The use of colonoscopy for postpolypectomy surveillance increased between 1984 and 1987. About 25% of the subjects in each cohort were either lost to follow-up or received no endoscopic surveillance. On the other hand, some of those who were followed were probably subjected to excessive numbers of procedures. Defects in the PR include inadequacy of personal and family history data, and steady loss of patients during the three to six years after polypectomy. Despite the small size and limited resources of our hospital, its colonic polyp registry has already provided information that may help in the management of patients with this premalignant condition. The more widespread use of securely funded polyp registries would probably reduce the incidence of metachronous CRC in that population and would have significant epidemiological and educational functions.  相似文献   

14.
INTRODUCTION: Cystic fibrosis is a recessive genetic systemic exocrinopathy caused by a variety of mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR). The disease is characterized by alterations of the secretions, which become thickened and viscous. Both the paranasal sinuses and the lung parenchyma are involved in all cases. The aim of this study was to assess a correlation between the rhinosinusal and lung parenchyma changes in cystic fibrosis patients. MATERIAL AND METHODS: Eighteen patients (11 men and 7 women, age range: 8 to 22 years) were examined with chest HRCT and sinonasal low dose CT. Lung symptoms were found in all patients; 13 of them, also affected with rhinosinusal symptoms, had been examined with ENT and nasal endoscopy. The other 5 patients, without rhinosinusal symptoms and previously examined with ENT, were evaluated as control group. Chest CT was performed with the high-resolution technique, 2 mm slice thickness and 10 mm table feed. Rhinosinusal CT was performed with the low dose technique, acquiring contiguous 2-4 mm thickness coronal sections. The CT patterns were analyzed by two radiologists and scored as slight, medium and diffuse involvement of both districts. RESULTS: No statistically significant correlation between lung and sinonasal damage was found in our study. Parenchymal lung involvement appeared more severe than sinonasal involvement in 14/18 patients. The retention of secretions in the paranasal sinuses, even if limited, was demonstrated in all symptomatic and asymptomatic patients. CONCLUSIONS: The absence of correlation between pulmonary and sinonasal damage and more generally, the different severity of cystic fibrosis can be caused by different allele mutations of the cystic fibrosis transmembrane conductance regulator gene, the most frequent of which is Delta F-508.  相似文献   

15.
Because of rapid technological advances in endoscopic instrumentation, electrosurgical polypectomy and electrocoagulation has become a reality in the upper gastrointestinal tract. Twenty gastric polyps and three duodenal polyps have been removed. Six additional hyperplastic gastric polyps were electrodesiccated. Nine gastric ulcers, four duodenal ulcers, one hemorrhagic gastritis, one gastric varix and three Mallory-Weiss tears were successfully electrocoagulated. One duodenal ulcer and one Mallory-Weiss tear was unsuccessfully electrocoagulated. No morbidity nor mortality occurred as a result of electrosurgical polypectomy or electrocoagulation.  相似文献   

16.
Nasosinusal polyposis in the pediatric population is uncommon and its etiology is unclear. In this eleven-year retrospective study, we describe the etiologic features and evaluate the effectiveness of endoscopic sinus surgery in 49 children. Patients were divided into three groups according to whether nasosinusal polyposis was either isolated (n = 14), or associated with either asthma (n = 5) or cystic fibrosis (n = 30). An allergy was present in 10% of patients with isolated polyposis, 80% of patients with polyposis associated with asthma, and 19% of patients with polyposis associated with cystic fibrosis. The indications for surgery were disabling symptoms, specially chronic nasal obstruction, rhinorrhea and mouth breathing, and failure to respond to medical treatment. No surgical complications were encountered. Most patients reported improvement in quality of life with reduction of nasal obstruction in 83% of cases and rhinorrhea in 61%. Minor asymptomatic recurrence (i.e. a few micropolyp localized on the roof of the ethmoid cavity) was observed in 22.7% of the cases in this series, and major recurrence with the same functional symptoms as before surgery in 13.6%. However, recurrences were higher in patients with cystic fibrosis, since minor recurrence with no clinical manifestation was observed in 28.6% of cases and major recurrence in 17.8%. Endoscopic sinus surgery must be decided in collaboration with the pediatric and pulmonary physicians, and must be performed skillfully. With a mean follow-up of 4 years, results in this series are encouraging.  相似文献   

17.
BACKGROUND: The surgical closure of a nasal septal perforation is considered to be one of the most difficult procedures in nasal surgery with a relatively poor success rate. After a new surgical concept ("bipedicled-flap technique") was developed, a follow-up study was done in order to find out whether surgical results can be improved by means of this new method. PATIENTS AND METHOD: From 1988-1995 the bipedicled-flap technique was applied in 126 patients with nasal septal perforations (82 males, 44 females). In all patients the closure of the septal perforation was performed with an endonasal bilateral bipedicled-flap plasty and reconstruction of the cartilaginous defect with an autogenous cartilage graft from either the rib, the auricle, or from remnants of the septal cartilage. Postoperative results were evaluated in all patients. The follow-up period varied from a minimum of six months to a maximum of over seven years. RESULTS: The age peak was found in the third decade of life (females) and fifth decade (males), respectively. Most frequent preoperative symptoms were difficult nasal breathing, crusting and recurrent epistaxis. 65.8% of septal perforations were of iatrogenic origin. In 32 patients, the aetlology remained unknown. Six patients used silicone obturators preoperatively without getting any relief from complaints. In nine patients, surgical repair of the septal perforation had been attempted previously at another hospital. With the bipedicled-flap technique, primary closure was achieved in 118 patients (= 93.6%); revision surgery (same technique) was successfully performed in 2 patients, increasing the final success rate to 95.2%. Complications were rare and could always be managed easily. CONCLUSIONS: At present, the bipedicled-flap technique appears to be the most successful method for surgical repair of nasal septal perforations. The underlying principles responsible for the good success rate are: (1) the bilateral closure of the mucosal defects; and (2) the additional reconstruction of the cartilaginous septal defect with an autogenous cartilage graft only.  相似文献   

18.
BACKGROUND: We compared the efficacy and tolerability of the intranasal corticosteroid fluticasone propionate with that of the antihistamine terfenadine in patients with seasonal allergic rhinitis. METHODS: Two hundred thirty-two adults and adolescents with seasonal allergic rhinitis received intranasal fluticasone propionate (200 micrograms once daily), terfenadine tablets (60 mg twice daily), or placebo for 2 weeks in a double-blind, randomized, parallel-group study. Main outcome measures were clinician- and patient-rated individual and total nasal symptom scores (based on ratings of nasal obstruction, sneezing, nasal itching, and rhinorrhea); clinician-rated overall response to therapy; changes in nasal inflammatory cell counts; adverse events; and morning plasma cortisol concentrations. RESULTS: Both clinician- and patient-rated total and individual nasal symptom scores were significantly lower in the fluticasone group than in either the terfenadine group or the placebo group at nearly every measured time point throughout the treatment period. After 2 weeks of therapy, clinician-rated total nasal symptom scores decreased by 49% in the fluticasone group compared with 27% in the terfenadine group and 19% in the placebo group. In general, therapy with terfenadine was not statistically distinguishable from that with placebo based on patient-rated total or individual nasal symptom scores. According to clinician ratings, 64% of fluticasone-treated patients compared with 49% and 44% of patients treated with terfenadine and placebo, respectively, experienced significant or moderate improvement. A greater percentage of fluticasone-treated patients compared with either terfenadine- or placebo-treated patients experienced reductions in intranasal eosinophil and basophil counts after 2 weeks of therapy. No unusual or serious drug-related adverse events were reported. Morning plasma cortisol concentrations after 2 weeks of therapy did not differ among groups. CONCLUSION: Fluticasone aqueous nasal spray, a well-tolerated corticosteroid preparation that can be administered once daily, is more effective than terfenadine tablets or placebo in controlling symptoms of seasonal allergic rhinitis.  相似文献   

19.
BACKGROUND: The neutrophil elastase inhibitor, secretory leucocyte protease inhibitor (SLPI), is a potential therapeutic tool in inflammatory lung diseases such as cystic fibrosis and pulmonary emphysema. The distribution and disappearance in the lung of aerosolised recombinant SLPI (rSLPI) was investigated in healthy humans and in patients with cystic fibrosis or alpha 1-antitrypsin-associated emphysema. METHODS: To distinguish aerosolised rSLPI from endogenous SLPI the recombinant inhibitor was radiolabelled with 99m-technetium (99mTc) pertechnetate. Distribution and disappearance of aerosolised 99mTc-rSLPI in the lungs were studied by gamma radiation imaging. RESULTS: The deposition of 99mTc-rSLPI in normal volunteers was homogeneous in all lung lobes, while in patients with cystic fibrosis or emphysema only well ventilated areas showed deposition of the aerosol. The disappearance rate of 99mTc-rSLPI was biexponential. The half life of the rapid phase was 0.2-2.8 hours, while that of the slow phase was more than 24 hours. CONCLUSIONS: Future aerosol therapy with rSLPI will be most beneficial for well ventilated lung tissue that needs protection against neutrophil derived elastase. It may be more difficult to neutralise the burden of elastase in poorly ventilated, highly inflamed areas as are seen in cystic fibrosis.  相似文献   

20.
The study's objective was to examine whether there is evidence that colonoscopic polypectomy reduces the incidence of colorectal cancer. The records of all patients who underwent colonoscopic polypectomy by a single surgeon between 1974 and 1991 were reviewed. Patients with colorectal cancer diagnosed at the initial colonoscopy, with a history of colorectal cancer, inflammatory bowel disease or familial adenomatous polyposis or with only hyperplastic polyps were excluded. There were 1008 remaining patients, of whom 645 have attended at least one follow-up colonoscopic examination, and these 645 patients from the basis of the study, because the incidence of cancer is known exactly in this group. The mean period of follow up was 4.4 years and the mean number of follow-up colonoscopic examinations was 2.2. There was a total of 2847 person-years of colonoscopic follow up. The expected incidence of cancer, age and sex adjusted, is calculated using Australian epidemiological figures. The observed incidence of cancer was 3 cases (all asymptomatic) per 2847 person-years, which is indistinguishable from the general population's risk of 3.75 cases per 2847 person-years. Analysis of previous publications suggests that patients with adenomas are at an increased risk of developing colorectal cancer of about 2.5 times the general population's risk. If correct, then the observed incidence of 3 cases per 2847 person-years is less than the expected incidence of 9.4 cases per 2847 person-years. This analysis suggests colonoscopic polypectomy does reduce the incidence of colorectal cancer.  相似文献   

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