Diagnostics
Initially, diagnostics aims to achieve two goals: Exclusion or confirmation of a tumor of the esophagus:If an esophageal tumor is suspected, the patient must first be thoroughly questioned (anamnesis), especially about previous illnesses, their alcohol consumption (alcohol addiction) and nicotine consumption (smoking) and family history of certain diseases. Then the patient is thoroughly examined. During the analysis of the blood (laboratory), certain blood values (laboratory values), in combination with the patient’s symptoms and physical examination findings, may indicate the presence of esophageal cancer, even though they may ultimately not be considered conclusive.
For example, a low blood pigment level (haemoglobin) in the blood may indicate chronic blood loss. However, this also applies to many other diseases. So-called tumor markers are substances in the blood that are found in high concentrations in some types of cancer and can therefore indicate a disease.
They do not play a significant role in the initial diagnosis of esophageal cancer, as there are no reliable tumor markers for this disease. However, if a certain tumor marker value is found to be elevated before surgery, which disappears after surgery, this marker can be used particularly well to quickly diagnose a recurrence of the tumor (tumor recurrence) by means of a blood test. In squamous cell carcinoma (a form of esophageal cancer that originates from the ovarian cells), the tumor marker SCC is sometimes found to be elevated in the blood, and in adenocarcinoma (a form of esophageal cancer that originates from the glandular cells), CA 19-9 may be elevated.
If the signs of the disease are appropriate, an oesophago-gastroscopy should be performed as soon as possible. In some cases, the x-ray pap smear can also indicate a tumor. X-ray gulp swallow: In this non-invasive, imaging examination, the esophagus is X-rayed while the patient swallows an X-ray contrast medium.
The contrast medium is applied to the wall of the esophagus, whereupon it becomes accessible for evaluation. The typical finding in a tumor is a frayed and irregular, also called “corroded” mucous membrane wall. It is also possible to assess the degree of esophageal stenosis caused by a tumor.
However, the x-ray swallow is not a diagnostic procedure by which every oesophageal tumor can be reliably detected. For this purpose, the direct assessment of the esophageal wall by means of an oesophagoscopy is necessary. Nevertheless, it is often used for tumors that cannot be seen with an endoscope (esophagoscopy camera).
Thus, despite this handicap, it is possible to determine the longitudinal extension of a tumor and the degree of esophageal narrowing. Furthermore, this examination is the method of choice for diagnosing an esophago-tracheal fistula. In this case, the x-ray swallow reveals a small, duct-like structure as a connection between the esophagus and the trachea.
Endoscopy (esophago-gastroscopy=esophageal-stomach endoscopy) The “endoscopy” (endoscopy) of the esophagus and stomach is the method of choice for direct assessment and classification of mucous membrane damage and should be performed as soon as possible if an esophageal tumor is suspected. During this examination, images are transmitted to a monitor via a tube camera (endoscope). During the endoscopy, the examiner also pays attention to very discrete changes in the mucous membrane and local flat color changes, so that no small carcinoma is overlooked.
During the endoscopy, tissue samples (biopsy) can also be taken from suspicious mucosal areas. Tissue assessment under the microscope (histological findings) is far more meaningful than the (macroscopic) findings seen with the naked eye. Only in the histological examination can the suspected tumor be proven and the type of tumor be determined, as well as its spread in the wall layers of the esophagus.
X-ray thorax A chest X-ray (X-ray thorax) can sometimes indicate a tumor in the middle chest area. Particularly in the late stages, a widened middle chest area (mediastinum), affected lymph nodes, perhaps even lungs and skeletal metastases or pneumonia can be seen as a result of fistula formation between the trachea and esophagus. Such indications should further intensify the search for a tumor.Once the diagnosis of esophageal cancer is confirmed, the tumor stage is determined in order to plan further therapeutic measures.
In this process, patients who are in an early stage of the disease must be selected so that they can undergo curative surgery as soon as possible. Endosonography (endoluminal ultrasound) In endosonography, as in endoscopy, the patient must swallow a tube during a light anaesthetic. However, during this examination, an ultrasound probe is attached to the end of the tube instead of the camera.
With this method, by placing the ultrasound probe on the tumor, its spread into the depths (infiltration) can be made visible and local (regional) lymph nodes can be assessed. This method is superior to computer tomography (CT = X-ray sectional imaging) for tumor staging of esophageal cancer. Computed tomography Spiral computed tomography (spiral CT) can provide information about the extent of the tumor, lymph node involvement and also about distant metastases.
A CT scan of the chest (thorax), abdomen and possibly also the neck is required. Depending on the location of the tumor, it is thus possible to diagnose lymph node metastases in the neck area and metastases in the lungs in the case of tumors located in the neck, for example, and metastases in the liver in the case of tumors located further down. Magnetic resonance imaging (MRI) provides similar results.
Sonography Using sonography (ultrasound) as a non-invasive and fast procedure, metastases and affected lymph nodes can be identified. For example, sonography of the abdomen can reveal metastases in the liver or affected lymph nodes. With sonography of the neck, the neck lymph nodes can be well visualized and evaluated for tumor infestation.
Skeletal scintigraphy and F-18 fluorine PET Skeletal scintigraphy and F-18 fluorine PET are nuclear medical examinations and are used in tumor staging to detect distant metastases. For this purpose, the patient is intravenously administered a radioactively labeled substance, such as phosphonates or fluorodeoxyglucose, and then the distribution of the radioactive substance, e.g. in the bone, is visualized with a special camera. The radioactive substances accumulate in the tissue of the metastasis.
Bone metastases thus appear in the image as an accumulation of the radioactive substance (more rarely due to reduced storage). In skeletal scintigraphy, the reasons for the increased radioactive accumulation are the increased blood supply to the tumor, increased permeability of the vessels and the surface condition of the metastasis. The F-18-PET makes good use of the fact that the tumor has an increased metabolism.
This allows the tumor to absorb more of the radioactively labelled substance than the neighbouring tissue. In this way, the metabolically overactive skeletal metastases are made visible. PETCT The informative value of the normally performed diagnostic examinations (computer tomography and endosonography) is not sufficient for very small metastases.
PETCT is a so-called fusion imaging technique because it combines the advantages of PET (see above) and CT (see above). The disadvantage of PET is that it is difficult to establish the anatomical relationship of the metastasis to normal tissue. If the good spatial resolution of the CT is combined with the “staining” of the metastasis in the PET, a better statement about the anatomical positional relationship of the tumor or metastasis can be made. During or after chemotherapy or radiotherapy, this method can be used to control the response of the tumor and the metastases.
