CT Preoperative Imaging of Esophageal Cancer: Is the Inclusion of Abdomen Necessary?
Martin Ian Kamanda
Radiology Department, M.P. Shah Hospital
Correspondence to: Dr. Martin Kamanda, P.O Box 20685-00200, Nairobi; email:
Background: Esophageal carcinoma is the third commonest tumor in Kenya with one of the highest mortality rates. Locally, the Kenya National Cancer Treatment Protocols 2019, recommends CT chest and abdomen has the basic imaging tool. Objective: The aim of the study is to determine the necessity of including the abdomen in scanning of patients with cancer of the esophagus. Materials and methods: The sample consisted of fifty consecutive patients with esophageal cancer who underwent CT imaging. Results: Out of 50 patients 32 male patients (64%) and 18 (36%) female patients.4 patients (8%) had a CT diagnosis of upper third cancer of the esophagus while 20 patients were diagnosed with middle third cancer of the esophagus. 26 patients (52%) of the total had a CT diagnosis of lower third cancer of the esophagus Patients with middle and lower third esophagus tumours had nodal and distant metastasis to the upper abdomen. Conclusion: Preoperative CT with the inclusion of abdomen is essential for patients with middle and lower third tumours. However, none of the patients with upper third tumours had metastases to the abdomen. Further studies with a larger sample size should be done to assess the necessity of inclusion of abdomen in these patients.
Key words:Esophageal cancer, CT imaging, Diagnostic yield
Ann Afr Surg. 2019; 17(2):***
Conflicts of Interest: None
© 2020 Author. This work is licensed under the Creative Commons Attribution 4.0 International License.
Esophageal cancer is among the 10 most frequent cancers in the world, and is the seventh leading cause of cancer death (1). Globally, according to GLOBACAN 2018 estimates, cancer of the esophagus accounts for 572,034(3.2%) new cases and 508,585 (5.3%) deaths (2). In sub-Saharan Africa, it’s the 3rd commonest cancer with an estimated 17,500 cases and 19400 deaths (3). In Kenya, esophageal cancer is the third commonest cancer with 4380 new cases (2).
The staging of cancer of the esophagus is based on the American Joint Committee on Cancer Tumour-Node-Metastasis (AJCC TNM) and Union for International Cancer Control Tumour-Node-Metastasis (UICC-TNM).Recently, the 8th edition of the AJCC/UICC Cancer Staging Manual for esophagus and esophagogastric junction cancers was developed based on a wide database of patients (4). The AJCC/UICC system, recommends the inclusion of both the chest and abdomen when CT scanning patients with suspected esophageal tumours (4).
Locally, the Kenya National Cancer Treatment Protocols (2019), recommend CT chest and abdomen has the basic diagnostic imaging tool (5). To the best knowledge of the author, there are few or no local studies done to evaluate the role of CT chest and abdomen in the preoperative staging of cancer of the oesophagus. Most studies done locally have focussed their attention on the incidence, prevalence and risk factors of cancer of the esophagus. The aim of the study was to determine the necessity of including the abdomen in scanning of patients with cancer of the esophagus. This is because the inclusion of abdomen carries the burden of added radiation dose and cost to these patients. The study involved determining the location of the primary tumor and the detection of regional lymphadenopathy and secondary metastasis in both the chest and abdomen.
Materials and Methods
This was a retrospective descriptive quantitative study. The sample consisted of fifty consecutive patients with biopsy proven diagnosis of cancer of the esophagus. The exclusion criteria included: patients without biopsy proven cancer of the esophagus; emaciated patients; patients whom intravenous contrast media was not administered and patients with double primary tumours. Four parameters were studied: primary tumour, local/regional lymphadenopathy and distant metastases.
All the patients were scanned using a Somatom Definition AS, 128 Slice, Siemens, Elargen, Germany. Patient preparation before the procedure involved nil per mouth two hours prior and requisition of creatinine level. All patients signed an informed consent authorising the use of intravenous use of contrast media after screening for previous history of contrast hypersensitivity and other contraindications of iodinated contrast media. The scan area included the chest and upper abdomen (lower poles of the kidneys). A biphasic scan was done at 23 seconds after iv contrast injection (Ultravist 370) for arterial phase and 31 seconds for portovenous phase using a flow rate of 3.5 mls/sec. Volumetric post processing using a slice thickness of 3mm (B20 smooth kernel, abdomen window) and multiplanar reconstructions ( axial, coronal and sagittal) were performed before evaluation of the images.
The patient age ranged between 33 years to 84 years of age with a mean age in the 58.3 years. Out of 50 patients 32 male patients (64%) and 18 (36%) female patients. The ratio between male and women with cancer of the was 1.7:1. This is similar to other local studies done on cancer of the oesophagus.
Out of the 50 patients,4 patients (8%) had a CT diagnosis of upper third cancer of the esophagus. Out of these 4 patients, 3 patients had local regional nodes while 1 patient had no local regional nodes.
A total of 20 patients out of the 50 patients were diagnosed with middle third cancer of the esophagus. This represented 40 % of the sample size. Out of the 20 patients,10 patients had local and distant nodes while 1 patient had a metastasis in the liver. 9 patients out of the 20 patients had no local regional lymph nodes.
A majority of the patients (52%) of the total had a CT diagnosis of lower third cancer of the esophagus. Out of the 26 patients,19 patients had distant nodes to the upper abdomen with 2 patients with metastatic liver deposits. Of the 50 patients sampled, none had metastatic deposits in the lungs.
Esophageal cancer has two main subtypes: squamous-cell carcinoma and adenocarcinoma. Squamous cell carcinoma has a propensity of affecting the upper and middle third esophagus while the adenocarcinoma typically affects the lower third of the esophagus. Although squamous-cell carcinoma accounts for about 90% of cases of esophageal cancer worldwide, the incidence of and mortality rates associated with esophageal adenocarcinoma are rising and have surpassed those of esophageal squamous-cell carcinoma in several regions (6).
Recently, a joint commission of American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC) released the eighth edition of the staging manual for cancer in the esophagus and esophagogastric junction. It emphasized of a multimodality approach towards the staging of cancer of the esophagus. This is because different modalities have inherent strengths and weaknesses in diagnosis and staging of the disease (4). The main goal of the multimodality approach was to counterbalance the inherent strengths and weakness of each modality in order to increase the sensitivity and specificity rates.
In this study, the mean age at diagnosis was 58.3 years. This similar to a recent study done locally by Ojuka et al which had a mean age of 57.7 years at diagnosis (7). Earlier studies by Patel et al in 2013 and White in 2007 and Wakhisi et al in 2002 found a mean of 56 years,56 years and 55 years at diagnosis respectively (8,9,10). This shows a growing trend in the mean age of patients with cancer of the esophagus.
The male to female ratio for this study was 1.7:1. This ratio is similar to previous study done by White (2007) and Wakhisi et al (2002) which found a ratio of 1.4:1 and 1.5:1 respectively (9,10). However, the ratio of male to female in this study is lower than that of Ojuka et al study in 2013 which had a ratio of 3.6:1(7). The commonality in the ratios is that there is a higher preponderance of males probably due to exposure to the known risk factors for cancer of the esophagus.
Majority of the studies done have showed that CT has a lower sensitivity for assessment of T stage compared to endoscopic ultrasound (4). The exclusion of T4 disease is determined by the preservation of fat planes between the primary tumor and adjacent structures (4). Thus, this study did not focus on the preoperative T staging of the esophageal tumour based on CT findings of increased wall thickness and loss of fat planes. However, data on the tumour location was recorded in order to show its relation to the regional lymphadenopathy and distant metastatic lesions.
In this study, majority of the patients (92%) were diagnosed with middle third and lower third cancer of the oesophagus. This is a slightly higher percentage compared to a study by Ndonga et al in 2008 in which majority of patients (83%) had middle and lower third esophageal tumours (11). In Ojuka et al study, most of the tumours occurred in the middle and lower esophagus. However, no percentages were provided in that study (7). A recent study was done by Hsu et al in 2017 with a larger sample of 3,399 patients. Out of the 3,399 patients,1263(37%) patients had middle third cancer of the esophagus while 969(28.5%) patients had lower third cancer of the esophagus (12). This shows cancer of the esophagus is predominant in the middle and lower third portions of the esophagus. However, these studies did not address the role of inclusion of abdomen in CT in staging of cancer of the esophagus.
The N classification involves mapping of the regional lymph nodes. Patients with no regional lymphadenopathy have a better prognosis than those with neoplastic lymphadenopathy (4). Lymphatic spread is bimodal, transversally penetrating the esophageal wall and longitudinally spreading either cranially to the cervical lymph glands or caudally to the abdominal lymph glands. However, the longitudinal lymphatic flow is much more abundant than the transverse flow (13). For upper third cancer of the esophagus, lymphatic spread is to the upper mediastinal and cervical nodes. Patients with middle third and lower third cancer of the esophagus, the lymphatic flow drains superiorly and inferiorly into the cervical, upper mediastinal, periesophageal and perigastric nodes (13).
Although CT has been used for preoperative evaluation of esophageal cancer, the major role of CT has been the depiction of lymph nodes, distant metastases, or both rather than the evaluation of the local status of esophageal cancer (14). In this study, most of the patients with middle third and lower third had local/regional lymphadenopathy. However, to the best knowledge of the author, no local studies have been done to show the pattern of lymph node invasion by oesophageal cancer. Most of the local studies are on the prevalence of esophageal cancer and the associated risk factors.
Despite its limitations in assessing T and N stages, CT has become the most commonly used modality in the initial staging of newly diagnosed esophageal cancer (15). Liver metastases typically appear at CT as hypoattenuating ill-defined lesions that are best visualized during the portal venous phase of liver enhancement (16,17). Pulmonary metastases usually are well marginated non calcified lesions. However, radionuclide bones scans and PET/CT have a higher sensitivity in the detection of osseous metastatic lesions (18).
Hematogenous spread of cancer of the esophagus is usually to the liver, followed by lung, bone and brain (19). In a study of 3218 patients with esophageal cancer, the most common site of distance metastasis was the liver, followed by distant lymph nodes, lung, bone and brain. In that study, the liver was the commonest site of metastatic lesions (1678, 33.4%), followed by distant (non-regional) lymph nodes (1334, 26.6%), lung (1028, 20.5%), bone (791, 15.7%), and brain (193, 3.8%) (20).Another systematic review by Osama et al in 2017 on 10049 articles, showed the most common pattern of oesophageal cancer metastases is to the lymph nodes, lung, liver, bones, adrenal glands, and brain (21).
The liver and lung are the most common sites for metastases in cancer of the esophagus. In this study, patients with middle third and lower third cancer of the esophagus had distant metastases and local lymphadenopathy to the abdomen. In patients with distant metastases, surgical intervention may be of limited beneficial value compared to other therapeutic modalities. Therefore, detection of distant metastasis is not only useful for staging but for also for prognosis as well.
The study employed a non-probabilistic consecutive sampling method to obtain a sample. Therefore, the study findings should not be considered representative of the entire population or generalised to the entire population.
In the preoperative CT imaging, CT chest with the inclusion of abdomen is essential for patients with middle and lower third oesophageal tumours. However, as this study shows, the inclusion of abdomen in patients with upper third tumours may not be essential. Further local studies with a larger representative sample size should be done to assess the necessity of inclusion of abdomen for patients with upper third oesophageal tumours. This is with regard to added unnecessary radiation dose and cost among these patients.
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