esophageal cancer is the 7th most common cancer in iran   and it also is among the ten most common cancers in the world . iran is a well - known region with a high prevalence for this cancer , mostly from the north and north east of the country . in the national report of the registered cancer cases in iran in 2007 , esophageal cancer with an incidence rate ( asr ) of 6.4% stood for the 7th most common cancer . esophageal cancer is the 7th leading cause of cancer related death in iran and has the 7th highest disability - adjusted life years ( dalys ) among all cancers in iranian population which had been estimated to be about 15920 years in year 2002 . its prevalence is increasing as the population is getting old ; its highest incidence rate is around the age of 60 - 80   .however , according to a report by yavari and et al . iran s highest incidence was between the age of 50 and 70 based on their studied population . its prognosis is usually undesirable and median survival after esophagectomy for patients with localized tumor is 15 - 18 months , and 5-year survival rate is 20 - 25% . the risk of esophageal cancer increases with constant exposure to stimulants , hot beverages , alcohol and smoking . it has a higher incidence rate in society with a low economical state , severe malnutrition , low vitamin , fruit and vegetable intake and also high consumption of alcohol and cigarettes in various studies conducted in china , relative risk of patients with a family history of esophageal cancer was around 2.9% of cases . its prevention is based on early diagnosis , special attention to modifiable risk factors , particularly tobacco , alcohol and fast food consumption . the symptoms of esophageal cancer usually appear 3 to 4 months prior to diagnosis and such symptoms vary depending on initial involved segment of esophagus . dysphagia is seen in more than 90% of cases while a weight loss over 5% of body weight occurs in 5% and its presence is associated with a worse prognosis . less common symptoms such as hoarseness , cough and progressive lesions with invasion to other organs result in symptoms such as hematemesis , hemoptysis , dyspnea and cough secondary to bronchoesophageal and tracheoesophageal fistula . considering most studies on statistic for epidemiologic indexes in esophageal cancer are implemented in other parts of the world , we aim this study which is to determine epidemiologic index of esophageal cancer patients provides better information on epidemiological characteristic of such cases and also a reliable base for future complementary studies . this is a cross - sectional prospective study based on medical history and other collected data from 238 esophageal cancer patients referred to omid hospital between 2001 and 2010 . no distant metastases , 2 . a karnofski score of 70 and over for the performance status . at the beginning of study , informed consent was obtained from patients for neoadjuvant chemoradiation treatment . the collected data included age , sex , race , occupation , residential location , addiction history , alcohol and smoking habits , dysphagia grading ( i , ii , iii , iv , v ) , weight loss , nausea and vomiting , lack of appetite and paraclinic tests : cbc , liver function tests , sonography or ct scan of abdomen , barium swallow and also anatomic location of tumor , lesion type in endoscopy , lesion length and also type and grade of tumor pathology . twenty two point three percent of patients were younger than 50 years and 77.7% were older . 63% were fars , 13% were turkmen and 24% were from other ethnic groups . regarding the occupation , 30% were farmers , 45% were housewives and 25% had other jobs ; they came mostly ( 72.3% ) from the rural areas . twenty percent ( 33.3% of males and 8.5% of females ) had a history of smoking , 22.3% ( 31.5 of males and 14.6% of females ) were addicted and 1.3% of patients had alcohol consumption ( table 1 ) . the most common anatomical site was the middle ( 53.4% ) , lower ( 44.5% ) and upper ( 2.1% ) segment of esophagus ( table 2 ) . considering clinical signs and symptoms , most patients ( 93.7% ) complained about dysphagia over an average duration of 3.4 months . also 24% , 53% and 23% of patients had grade i and ii , iii , iv and v dysphagia , respectively ( table 3 ) . amongst patients whom their clinical symptoms were registered completely , 84% had weight loss i.e. 21% ( 1 - 5 kg ) , 17% ( 5 - 10 kg ) and 16% more than 10 kg . nausea was recorded in 39% and vomiting in 27.7% . before treatment , anemia , leukopenia and thrombocytopenia were detected in 39% , 2.1% and 0.6% of cases , respectively ( table 3 ) . barium swallow results were abnormal in 65.5% and normal in 6.4% ; it was not performed in 28.1% of cases . at the beginning of the study , all patients had an abdominal sonography with no metastases . on endoscopy , 51.3% of lesions were polypoid , vegetative and fungoid while in 48.7% were ulcerative , ulcerovegetative and infiltrative . the mean lesion length according to endoscopy and barium swallow was 5.7 cm ; the tumor length was less than 5 cm in 52.5% and more in 47.5% ( table 2 ) . the most common pathology was squamous cell carcinoma with 99.1% prevalence . according to tumor grading , 34.2% were well differentiated , 51.3% were moderately differentiated and 14.5% were poorly differentiated ( table 3 ) . in this prospective cross sectional study , epidemiologic status of esophageal cancer was evaluated in a specific area i.e. the northeast of iran and cases were selected from patients who were referred to omid hospital for undergoing neoadjuvant chemoradiation treatment . the goal and reason for selecting this study group was to ensure that their data are usually precisely registered in the form of a protocol . the reported data in this study included : age , sex , race , location , smoking and addiction history . prevalent clinical symptoms including dysphagia ( and its grade ) , weight loss , anemia , nausea and vomiting . many esophageal cancer reports belong to regions of the world where this type of cancer is considered prevalent . the incidence rate in the northern china , iran , and russia and around the caspian sea is 100 per 100,000 populations . the mean age of the patients was 59 years in our study . in recent report from cdc in iran the mean age at the time of diagnosis in u.s . is 69 years , whereas in our study the mean age was 10 years lower . considering that these patients were candidates for preoperative chemoradiation protocol ; this difference is partially related to bias in patient selection . in another study the mean age of 190 esophageal cancer patients chosen for chemoradiation protocol , was 65 years . the effect of race on the incidence rate has been investigated in several studies . in cumings study which was performed on 1801 esophageal cancer ( scc ) patients in u.s , the incidence rate was 5 and 1.3 in 100,000 in both white and black population respectively . however , adenocarcinoma had a higher incidence rate amongst the whites ( 8 vs. 3.3 in 100,000 ) . despite considerable distance between our center and golestan province , various studies have revealed that residents who are living around the caspian sea are at a greater risk for developing this type of cancer . possible reasons include a diet deficient in fruits , vegetables and animal proteins as well as dry and thick bread which consists of silica fibers ; hot tea , smoking , drugs and burnt opium . smoking , drug and alcohol consumption are the main factors causing this type of cancer in western countries . however , few studies have shown no significant correlation between such factors and esophageal cancer . in the current study 19.7% of affected cases were smokers and 22.3% were drug abuser . study in babolsar , a northern city of iran , 19.3% had a positive smoking history but only 7.9% were addicts . smoking tobacco and drinking of alcohol fortunately in iran due to religious beliefs alcohol consumption is not popular , but smoking and drug abuse are most probably important factors . as reported by heeying kimm and et al . in korean men , alcohol and smoking are indecency associated with increased risk of esophageal cancer but they do not interact synergistically . considering the characteristics of developed tumors , it should be noted that adenocarcinoma has a very small portion in comparison to scc in esophageal tumors in our country . the incidence rate of adenocarcinoma has increased over the past two decades in western countries and at the moment it is more common than scc , for example only 40% of esophageal cancers in u.s . are scc . however in some regions of the world with a high incidence rate for this type of cancer , scc is more prevalent than adenocarcinoma . in developed countries where adenocarcinoma has drastically increased , this cancer is associated with reflux and obesity [ 13 , 14 ] . amongst our 238 cases , other studies in iran have also confirmed the predominance of scc over adenocarcinoma . according to a study reported by farhoudi et al . 86.3 % and 7.3% of cases showed scc and adenocarcinoma respectively . also considering that the current study was performed on patients who had undergone surgery after chemoradiotherapy , only cases with mediastinal esophagus involvement were investigated . in 53.4% of patients , tumors were localized in the middle third of esophagus and 43.3% in the lower third as described by hajian studies . in farhoudi study in mashhad the lower third was also considered as the most common site . in the current study , the lesion types considered as effective factors of prognosis and they were polipoid , vegetative and fungoid in 51.3% as well as ulcerative , ulcerovegetative and infiltrative in 48.7% of cases . in summary , scc comprised more than 99% of all esophageal cancers in our patients and this was also the prominent type in northeast of iran . in our patients ,
backgroundesophageal cancer is the 7th most common cancer in iran . 
 the northern part of the country shows the highest incidence for this malignancy . in this study 
 we present some epidemiological and clinicopathological characteristics of patients with esophageal carcinoma in this region.methodsin a cross sectional study , 238 esophageal cancer patients were enrolled in a prospective study of neoadjuvant chemo - radiation treatment in a 4-year period ( 2006- 2009 ) . in an oncology clinic their epidemiologic characteristics and clinicopathological findings were registered in a preplanned file . 
 data consisted of age , sex , race , occupation , residential location , smoking , addiction history , signs and symptoms , blood biochemistry profile , imaging and endoscopic findings . 
 the data were analyzed with the spss software.resultsthe mean age of the patients was ( 55% female ) 59 years . 
 they were mostly fars ( 63% ) and turkmen ( 13% ) . 
 seventy two percent were residents of rural area , 20% were smokers and 22.3% were opium addict and its analogues . 
 only 1.3% of patients consumed alcohol . 
 the most common presenting symptom was dysphagia ( 93.7% ) , mainly grade iii dysphagia ( 53% ) . 
 location of tumor in esophagus was in the middle third in 53.4% and lower segment in 44.5%.sixty five percent of the patients had an abnormal esophagogram . 
 on endoscopic evaluation the most common types of tumors were polypoid , vegetative and fungoid , respectively . 
 mean tumor length was 5.7 cm . 
 the most common histology type was squamus cell carcinoma ( 99.1% ) which was moderately differentiated in 51.3% of these patients . 
 no significant relationship was found between the grade of dysphagia with the macroscopic type and the pathologic grade of the tumor in this study.conclusionsquamous cell carcinoma comprised more than 99% of all esophageal cancers in our patients and this histological type is the prominent type in the northeast of iran . 
 middle esophageal segment is the major site for this type of cancer which unfortunately most patients present with grade iii . 
 dysphasia reflects the advanced stage of the disease .