Value of oral effervescent powder administration for multidetector CT evaluation of esophageal cancer

https://doi.org/10.1016/j.ejrad.2014.11.008Get rights and content

Highlights

  • Oral effervescent powder improves esophageal distension and wall assessment at CT.

  • This technique improves detection and T staging of esophageal cancer at CT.

  • It can be easily adopted in clinical routine in patients with esophageal pathology.

Abstract

Purpose

To assess the value of oral effervescent powder (EP) for evaluation of esophageal distension, and for detection and staging of esophageal cancer with contrast-enhanced CT.

Materials and methods

84 patients without esophageal pathology and 52 patients with histological confirmed diagnosis of esophageal cancer were included in this prospective IRB-approved study. Half of the patients in both groups received EP prior to CT. Esophageal distension was assessed by planimetry of the inner (IA) and outer area (OA). Two blinded readers evaluated the datasets separately with regard to diagnosis of esophageal cancer (yes/no) and staging (T0-T4), if applicable. Distension results were compared (t-Test). In patients with cancer sensitivity, specificity, NPV and PPV were calculated. CT staging results were compared to histopathology (Cohen-k).

Results

IA and IA/OA were significantly larger after EP as compared to the group without EP (p < 0.05). Sensitivity, specificity, NPV and PPV for cancer detection cancer were as follows: 78%/78%, 98%/98%, 95%/95%, 87%/87% with EP; 60%/68%, 98%/98%, 94%/94%, 80%/83% without EP. Staging with EP was good (k = 0.84/0.67) and moderate without EP (k = 0.58/0.59).

Conclusions

Administration of EP prior to CT results in good distension of the esophagus, and improves detection and staging of esophageal cancer, as compared to control studies without EP.

Introduction

Esophageal cancer is the eighth most common malignancy in the world and the sixth most common cause of death from cancer [1]. Prognosis is poor with overall five-year survival rates of 17% [2]. Histologically, most tumors are squamous cell and adenocarcinomas. Over the last years a significant increase of the latter arising in the lower third of the esophagus and at the gastro-esophageal junction has been observed [3].

Staging of esophageal cancer is performed using the TNM system as developed by the American Joint Committee on Cancer (AJCC) [4] and is crucial for both, selection of treatment and prediction of patient prognosis [5]. Because each technique has its specific advantages and disadvantages, different modalities (ultrasound, endosonography, CT, PET/CT) are often used complementary for staging and therapeutic monitoring of patients with esophageal cancer. Currently most patients undergo CT for evaluation of tumor invasion into adjacent structures (T4) and for assessment of metastatic tumor spread.

For evaluation of local tumor extent (T-stage), endoscopic ultrasound (EUS) is considered the most accurate imaging modality. Sensitivity and specificity of EUS tend to improve as T-stage increases [6], with an overall accuracy of approximately 80% [7]. Using miniprobes, differentiation of T1 and T2 tumors is possible in up to 92% [6]. However, EUS is an operator-dependent invasive technique and may be limited by severe stenosis preventing passage of the esophagus and by its finite depth of penetration that may be insufficient for staging of T4 tumors [8].

In most comparative studies, the accuracy of CT for assessment of T-stage is lower than that of EUS [9], [10], [11]. CT evaluation of the esophagus is difficult. Luminal distension is an important factor since the collapsed lumen may obscure lesions or can even produce pseudolesions [12]. Further, reliable delineation of wall layers at CT is not possible. Therefore early tumor stages (T1 and T2 lesions) cannot be reliably differentiated [5] resulting in detection rates of T1 tumors as poor as 30% [13].

In order to overcome these limitations of CT, different techniques for evaluation of the esophagus and esophageal cancer have been described. Scan acquisition in the prone position [14] or the arterial phase [15] have been performed for better assessment of local tumor extent. The insufflation of air [16] or carbon dioxide [17] as negative contrast agents were shown to be feasible and effective. The use of effervescent granules for distension of the esophageal lumen has been suggested before [18], [19], [20]. In these studies, however, only patients with esophageal cancer were included with no control group present. Further, readers were aware of the diagnosis, constituting a potential bias to the radiologists interpreting the CT scans.

The purpose of our present study was twofold: First, to validate the technique of effervescent powder administration at CT for quantitative and qualitative evaluation of the esophagus. Secondly, to assess the added value of this technique for detection and T-staging of esophageal cancer in a blinded manner.

Section snippets

Materials and methods

This prospective IRB-approved and HIPAA-compliant study had two parts. The first part was a validation study in patients without esophageal pathology in order to assess the value and reliability of the applied distension technique itself. In the second part, patients with esophageal cancer were included in order to evaluate the added value of effervescent powder administration with regards to tumor detection and T-staging (cancer study).

Results

CT was completed successfully in all patients. None of the patients receiving effervescent powder complained of any discomfort, especially no aspiration or urge to cough was observed.

Discussion

Accurate staging of local tumor extent and metastatic spread in patients with esophageal cancer are crucial factors for determining the appropriate treatment. It is well known that T-staging by means of CT is somewhat limited. In the present study, we demonstrated that effervescent powder swallowed just before image acquisition results in good distension of the esophagus. This allows for better assessment of the esophageal wall with contrast-enhanced CT, resulting in an increase in diagnostic

Conflict of interest

None declared.

References (26)

  • R.B. Iyer et al.

    Diagnosis, staging, and follow-up of esophageal cancer

    AJR Am J Roentgenol

    (2003)
  • C.J. Lightdale et al.

    Role of endoscopic ultrasonography in the staging and follow-up of esophageal cancer

    J Clin Oncol

    (2005)
  • D.G. Richards et al.

    Endoscopic ultrasound in the staging of tumours of the oesophagus and gastro-oesophageal junction

    Ann R Coll Surg Engl

    (2000)
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