Prevalence of Esophageal Adenocarcinoma

 

Daniel Ojuka, Keith Dindi, Mark Awori

 

School of Medicine, University of Nairobi

 

Correspondence to: Dr. Daniel Ojuka, P.O. Box 19762 – 00202, Nairobi, Kenya. Email: danielojuka@gmail.com

 

 

Abstract

 

Background: There has been a marked increase of the prevalence of adenocarcinoma of the esophagus across the globe, with the risk factors including gastroesophageal reflux disease (GERD) and Barrett’s esophagus. It is not known whether the trend is similar locally. Objective: To describe the prevalence and clinicopathological characteristics of adenocarcinoma of the esophagus at Kenyatta National Hospital (KNH).Methods: This was a cross sectional descriptive study of patients presenting with dysphagia at the surgical outpatient unit and the Endoscopy Unit by consecutive sampling. The patients’ demographic and clinical data were obtained using a structured questionnaire. The findings at endoscopy including site of tumor and histopathological findings were recorded. The data was analyzed using SPSS version 22.0. The histological subtypes were presented as a proportion.

 

 

Results: A total of 74 patients were recruited. The mean age at diagnosis of esophageal cancer was 57.7 years. The mean duration of symptomatology was 4.5 months, with 66.2% of the patients presenting with

 

wasting at diagnosis. The prevalence of adenocarcinoma amongst esophageal tumors was 18.9%. Conclusion: There is increasing occurrence of adenocarcinoma, demonstrating a higher rate than a decade earlier. Further studies are needed to elucidate the risk factors locally.

 

Key words: Prevalence, clinicopathological features, adenocarcinoma, Esophagus

 

Ann Afr Surg. 2017; 14(2):82-85 DOI:http://dx.doi.org/10.4314/aas.v14i2.6

 

© 2017 Author. This work is licensed under the Creative Commons Attribution 4.0 International License.

 

 

 

Introduction

 

Esophageal cancer is one of the common malignancies worldwide, with clearly defined endemic regions (1). These regions include China, Iran and some parts of France, Southern and eastern Africa (2). Kenya is one of the countries with high prevalence rates, with this cancer being the leading single site of malignancies in men and the third in women (3-5). It is a deadly cancer with very poor overall 5-year survival rates of18% (1).

 

There are two main histological subtypes of carcinoma of the esophagus; squamous cell carcinoma (SCC) and adenocarcinoma. For many years, squamous cell carcinoma has been the commonest subtype across the world. However, in the last four decades there has been a dramatic rise in the incidence of adenocarcinoma of the esophagus, especially in the western countries (6-9). This has been attributed to certain risk factors including obesity, gastroesophageal reflux disease (GERD) and diet (7-9). It is not known whether there have been

 

 

 

 

 

similar changes in the incidence in Kenyan populations, especially given that there has been a steady adoption of western lifestyles with accumulation of similar risk factors. Previous studies done since the sixties have mainly been retrospective in nature. This study sought to evaluate the prevalence and clinicopathological features of adenocarcinoma of the esophagus among patient presenting esophageal cancer at the Kenyatta National Hospital.

 

Methods

 

This was a cross-sectional descriptive study carried out at Kenyatta National Hospital (KNH) Endoscopy Unit and Surgical outpatient clinics from March 2014 to December 2014. The study population constituted patients who are over 18 years with dysphagia sent for upper gastrointestinalendoscopy at the surgical outpatient clinics and Endoscopy unit in KNH who had

 

 

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who had a biopsy results. We excluded patients with prior surgery for cancer of the esophagus. Patients were recruited via consecutive sampling. Informed consent was then obtained, following which the second author reviewed the patient’s history and sought for any significant physical finding. Endoscopic findings were then recorded. Endoscopy and biopsy were performed by the physician endoscopist of KNH and University of Nairobi. Data was obtained using a pre-designed data extraction sheet. Data collected included age, sex, presenting symptoms, smoking or alcohol use, duration of symptomatology, body mass index (BMI) and treatment with antacids. Wasting was defined as BMI less than 20. Endoscopy findings recorded included level of tumor and any evidence of Barrett’s esophagus. Any tumor below 40cm from the incisors was excluded from the study.

 

Histopathological data recorded included histological type of tumor and the tumor grade and any special features including any signet ring or adenosquamous types. The histopathology was performed by the KNH and University of Nairobi (UON) pathologist (10 in number) who all have experienced of more than 5 years in the routine manner. Routinely the histopathological slides are read by at least two pathologists before results are released. At the end of data entry, analysis was performed using SPSS version 22. The study population was described by summarizing categorical data including sex, type of tumor and histological grade into proportions while continuous data such as age and duration of symptoms have been summarized into means and medians. The study was approved by the institutional review board of Kenyatta National Hospital and University of Nairobi.

 

 

carcinoma group (43.3%) (Table 1). The p value was 0.02 on Fisher’s Exact test.

 

Table 1: Histopathological type and epigastric pain

 

 

Tumor histopathological type

Total

 

Squamous

Adenocarcinoma

 

 

cell

 

 

 

 

carcinoma

 

 

History of

Yes

26

11

37

epigastric

No

34

3

37

pain

 

 

 

 

Total

60

 

14

74

 

Majority (58.1%) of the patient had no history of antacid use, with 83.9% of the patients with history of epigastric pain having a positive history of antacid use. There was a positive association between antacid use and adenocarcinoma as the tumor subtype (p value 0.05 on Chi-square test). Forty-three respondents had a history of smoking, majority (40) being males. Seventy-three percent of the patients had a history of alcohol use; 82.8%% of the males and 37.5% of the females. Only 2.7% of the subjects had a family history of esophageal cancer. Most of the tumors occurred in the middle and lower thirds of the esophagus. With regard to the tumor levels, all of the adenocarcinomas were demonstrated more distally (below 35cm from the incisors with only one occurring at 30cm). The mean duration of symptoms before diagnosis was 4.53(SD=2.45) months, with a range of 1month to 12months for all the esophageal cancers. There was no significant difference between the means in either gender. Majority (66.2%) presented with (BMI) of less than 20 at diagnosis, with similar distribution in both histological subtypes. Majority of the patients presented with grade III dysphagia (Figure 2)

 

 

 

Results

 

A total of 74 patients were recruited in the study. The majority (78.4%) were male with male female ration of 3.6:1. The youngest patient was 34 years old and the oldest patient was 88 years old. The mean age was

 

57.72 (SD +/- 11.76) years. There were 14 (18.9%) adenocarcinoma and 60 (81.1%) squamous cell carcinoma. Half of the patients had a positive history of epigastric pain. However, the adenocarcinoma subset had a higher percentage (78.6%) of patients presenting with epigastric pain compared to the squamous cell

Figure 2: Degree of dysphagia

 

 

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Moderately differentiated carcinoma was the most common tumor grade; representing 63.5% of all the tumors, while well differentiated was 22.2% and poorly differentiated were 12.5%. Adenocarcinomas had a higher percentage of well differentiated tumors (42.9%) and no poorly differentiated adenocarcinomas were recorded.

 

Discussion

 

The male to female ratio of 3.6:1 in this study is similar to a study done in Ghana, which had a ratio of 4:1(10). However, a study done at the Moi Teaching and Referral Hospital (MTRH) found a male to female ratio of 1.4:1. These wide variations in the ratio have been well documented for tumors of the esophagus in different geographical regions (11). The higher incidence in males could partly be explained by the fact that more males are exposed to the known risk factors like smoking and use of alcohol than the females. In this study, 72.4% of the male patients had a history of smoking, compared to only 6.3% of females and alcohol was seen in 82.8% for males and 32.5% for females. The mean age at diagnosis was 57 years, which correlates closely with mean age found at MTRH of 56 years (12). The study in Ghana had a mean age of 57.8, while a study done in Tanzania got a mean age of 47(10, 13). In the western populations, the age at diagnosis is higher, with statistics from the United Kingdom indicating that more than 42% of the patients are 75 years or older at diagnosis. This could be related to life expectancy that is higher in the western world as compared to the Africa. The mean duration of symptomatology was 4.5 months which could explain the more severe degrees of dysphagia noted in the study. Mabula et al. in their Tanzanian study found a mean duration of symptomatology of 4 months, which is similar to this study (13). Majority (69%) of the patients had grade III or IV dysphagia, which correlates with advanced disease. Th