Since the discovery of the effect of ionizing radiation on suppressing the growth of tumor tissues, attempts have been made to use it to treat esophageal cancer. In some cases, it was possible to achieve a positive effect in the form of reducing pain, improving the patency of the esophagus, and also increasing life expectancy in some patients. But only with the development of radiobiology, the physics of ionizing radiation, dosimetry, new technical means and radiation sources, it became possible to scientifically substantiate the conduct of radiation treatment.
Currently, radiation treatment is widely used for both radical and palliative treatment of esophageal cancer. The most commonly used is gamma radiation, bremsstrahlung, and fast electrons.
Methods for delivering radiation to a pathological focus depend on the radiation energy and the equipment at the disposal of the radiologist.
Irradiation can be carried out either remotely (through the skin) or by contact method (so-called brachytherapy), when the radiation source is introduced directly into the lumen of the esophagus directly to the tumor.
Various options for remote static or mobile irradiation with radiation sources are used. Cs137 and Co60 sources are also used for intracavity irradiation.
The task of irradiation is to create a dose maximum in a given volume of the mediastinum, which has the shape of a circular cylinder with a diameter of 6-8 cm and a length of 18-20 cm, in cases where the entire esophagus is irradiated. In this case, the dose maximum should include the entire tumor, possible areas of intramural metastasis, as well as the peri-esophageal zones of regional lymph nodes.
In cases where the lower parts of the esophagus are affected, it is advisable to include in the irradiation volume the paracardial zones, the lesser omentum and the zone of the left gastric lymph nodes.
The optimal absorbed dose in the lesion, at which complete resorption of the esophageal tumor is observed, is 60-70 Gy with irradiation 5 times a week and a single focal dose of 1.5-2 Gy with classical dose fractionation. With other fractionation options, the doses given throughout the day may vary, as may the single focal doses.
With static irradiation, the skin fields are located along the perimeter of the chest, the number of fields with gamma irradiation is 34.1-2 - when using high-energy sources. With mobile irradiation, rotation is carried out within 180-360 degrees.
Intracavitary irradiation is carried out by introducing radioactive sources into the lumen of a special probe installed in the lumen of the esophagus in the area where the tumor is located.
The position of the carrier in the esophagus is monitored using x-ray examination. Most often, a combination of intracavitary and external irradiation is used. In this case, a more optimal dose distribution of absorbed radiation is achieved than with each of the irradiation options used.
Combinations of intracavitary and external irradiation can be different. For example, if the lumen of the esophagus is sufficiently wide, intracavitary irradiation can be used first, and then external. With severe stenosis of the esophagus, treatment should begin with external irradiation. The combined use of external and contact radiation therapy is called combined radiation therapy.
It should be noted that with an increase in the focal dose, along with an increase in the effect of treatment, an increase in the frequency and severity of complications is observed.
Sometimes, due to severe dysphagia, a gastrostomy tube must be placed on the patient for nutrition before starting radiation therapy. In addition, during the operation it is possible to conduct a high-quality revision of areas of regional metastasis below the diaphragm and, accordingly, it becomes possible to reasonably choose radical or palliative treatment. Once treatment is effectively completed, the gastrostomy tube can be closed.
In recent years, increasing attention of oncologists has been drawn to the possibility of increasing the effectiveness of radiation treatment by using a combination of cytostatic drugs and drugs that increase the sensitivity of tumor tissue to radiation (radiosensitizers).
The use of cytostatic drugs is aimed mainly at the possibility of mitotic synchronization of tumor cells and delivering a radiation dose at the moment of greatest cell vulnerability. Recently, 5-fluorouracil has been used as a synchronizer, and platinum preparations as a radiosensitizer.
Contraindications to radiation treatment are the presence of tumor perforation and distant metastases to other organs (liver, kidneys, lungs).
The presence of multiple metastases in the cervico-supraclavicular, paracardial, left gastric and lesser omentum makes radiation treatment on its own unpromising.
The presence of active pulmonary tuberculosis also usually serves as a contraindication to radiation therapy, since generalization or a sharp exacerbation of the tuberculosis process quickly occurs against the background of irradiation.
Impaired cardiac activity and renal function, hypertension, acute inflammatory diseases and blood changes (leukopenia, anemia, lymphopenia, etc.) also limit the possibility of radiation treatment.
Palliative radiation treatment is possible in most patients with esophageal cancer; it is especially indicated after an unsuccessful attempt at surgical treatment - a trial thoracotomy.
Dehydrated, depleted and weakened patients must be specially prepared for radiation therapy with intravenous infusions of protein drugs, electrolyte solutions, small amounts of blood or its components. Although treatment of such patients is rarely successful.
During radiation treatment, patients are prescribed a high-calorie diet rich in proteins and vitamins. Food should be warm, semi-liquid or liquid in consistency and taken often, in small portions.
Long-term results of radiation treatment of patients with esophageal cancer are very far from optimal and cannot in any way be considered satisfactory.
The overall 5-year survival rate ranges from 3.5 to 8.5%. Even the use of different dose fractionation options made it possible to increase the five-year survival rate for stage II only to 12.5 ± 2.7%. Using only bremsstrahlung with B-protons made it possible to obtain a three-year survival rate of 15.5 ± 5.4%.
+7 495 66 44 315 - where and how to cure cancer
Treatment of breast cancer in Israel
Today in Israel, breast cancer is completely curable. According to the Israeli Ministry of Health, Israel has currently achieved a 95% survival rate for this disease. This is the highest figure in the world. For comparison: according to the National Cancer Register, the incidence in Russia in 2000 compared to 1980 increased by 72%, and survival rate was 50%.
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- INCIDENCE AND RISK FACTORS
In approximately 50% of cases, esophageal cancer is localized in the middle third, and 25% of cases each occur in the upper and lower thirds. The incidence and mortality of this tumor varies in different regions of the world, being lowest (2.2/100,000) in Canada and highest (109/100,000) in northern China. Other regions with high incidence include South Africa, Iran and western France. According to national statistics, the death rate from esophageal cancer in China ranks second among deaths from other cancers in men and third among women. Mortality rates from esophageal cancer are higher in rural areas than in urban areas. Alcoholism in combination with cigarette smoking and eating disorders (diet low in animal proteins, fats, vegetables and fruits) are the main etiological factors.
- CLINICAL PICTURE AND COURSE
The leading symptom of esophageal cancer is dysphagia, but, unfortunately, it manifests itself late. In the early stages of esophageal cancer, the main symptoms are stenosis and chest pain when swallowing. In advanced esophageal cancer, dysphagia occurs in 98% of cases, weight loss in 51%, chest pain in 33%, belching and vomiting in 23%, cough in 7% and hoarseness in 3% of cases.
Depending on the growth pattern of esophageal cancer
can be mushroom-shaped, infiltrative and ulcerative. The mushroom type is found in approximately 55% of cases. Its main feature is the presence of pronounced intraluminal growth, forming tumors with areas of ulceration or multiple polypoid growths. Infiltrative cancer accounts for 25% of all cases and is primarily manifested by intramural tumor growth, which is usually extensive, and the mucous membrane along the periphery remains intact. The ulcerative form of cancer accounts for about 20% of cases. The ulcer has different depths. It always penetrates through the wall into the mediastinum or neighboring organs, primarily the trachea and bronchi.
Metastases to the lymph nodes are detected in 50% of cases. Metastases to distant organs are detected only in the presence of metastases to regional lymph nodes. The liver and lungs are most often affected.
- PATHOHISTOLOGY
The most common type of esophageal cancer is squamous cell carcinoma (>90%). Less commonly observed is adenocarcinoma, which is usually localized in the distal esophagus, being in close connection with the epithelium of the gastric mucosa.
- SURVEY
Necessary examinations include:
- X-ray examination of the upper digestive tract (with barium);
- endoscopy with biopsy;
- computed tomography of the mediastinum and abdominal cavity to assess the condition of the lymph nodes, the condition of the paraesophageal space and identify metastases in the liver;
- postoperative pathohistological examination with assessment of the extent of the tumor, the degree of its spread to neighboring structures, the degree of radicalism of the resection and the condition of the lymph nodes (number, location);
- Before surgery or radiation therapy, a thorough examination of the lymph nodes of the neck, especially the supraclavicular ones.
- STAGING AND PROGNOSIS
The clinical oncological classification of TNM-UICC is identical to the histological (postoperative) one, however, it is always easy to give an accurate preoperative assessment of the condition of the mediastinal lymph nodes and the condition of the peri-esophageal structures (Table 4.1).
The prognosis is very poor due to rapid spread beyond the esophageal wall to adjacent structures. Therefore, radical resection of the esophagus is difficult to perform. In recent years, radiation therapy has changed the situation by reducing the symptoms of the disease, but the pessimistic outcome has not significantly improved. Table 4.2 contains predicted survival rates by treatment and stage.
Table 4.1 Classification of esophageal cancer (UICC, 1987) |
|
Description |
|
The primary tumor is not assessable |
|
The primary tumor is not detected |
|
The tumor grows into its own membrane or submucosa |
|
The tumor grows into the muscle layer |
|
The tumor grows into the adventitia |
|
The tumor grows into neighboring structures |
|
The status of regional lymph nodes cannot be assessed |
|
There are no metastases to regional lymph nodes |
|
There are metastases to regional lymph nodes |
|
The presence of distant metastases cannot be assessed |
|
No distant metastases |
|
Distant metastases are present |
|
Table 4.2 Results of treatment for esophageal cancer
- CHOOSING A TREATMENT METHOD
- Radical treatment
Surgery is the main method of choice for early stages of esophageal cancer (T1-T2N0). There is real hope for a cure only after tumor resection. However, less than 50% of patients are candidates for surgery, since by the time of detection the tumor is already widespread in most patients.
As we know, there is no evidence to support postoperative radiotherapy in terms of improving long-term survival rates for esophageal cancer. When the patient is curable but inoperable, radiation therapy, sometimes in combination with chemotherapy, becomes the treatment of choice. The most promising option is the combination with cisplatin.
- Palliative care
For cancer in stages T3 and T4 or, regardless of the stage of the primary tumor, in the presence of lymphogenous or distant metastases, radical treatment is useless. For severe dysphagia, bypass anastomoses are indicated in these cases. Additional palliative methods may include endoscopic laser coagulation, esophageal intubation through the site of narrowing, and intracavitary radiation therapy.
In cases of esophageal stenosis with severe malnutrition due to prolonged fasting and dehydration, the condition may improve with total parenteral nutrition and/or gastrostomy prior to a full program of palliative radiotherapy.
- RADIATION THERAPY TECHNIQUE
- Radical radiation therapy as an independent method
It is used in patients with tumors in stages TI and T2 without signs of metastasis and in the presence of contraindications to surgical treatment. The volume of irradiation includes a tumor involving healthy tissue 4 cm above and below, as well as mediastinal lymph nodes at the level of the tumor. The recommended dose is 54 Gy to the mediastinum and 64 Gy to the esophagus. Methodology - four fields on a telecobalt installation.
- Position: on the back.
- Field boundaries (Fig. 4.1 and 4.2).
Front and back margins (15 x 7 - 20 x 9 cm):
lateral borders: 2 cm around the esophagus.
Side margins (15 x 6 - 20 x 8 cm):
upper and lower borders: 4 cm above and below the tumor,
lateral borders: 2 cm around the esophagus, anterior border: 2 cm anterior to the esophagus, posterior border: 1 cm posterior to the anterior surface of the vertebral bodies.
- Beam formation: shielding blocks on the side fields to protect the spinal cord if it enters the irradiation zone.
- Recommended dose (Figs. 4.3 and 4.4): mediastinal dose 54 Gy in 27 fractions over 5.5 weeks. After a three-week break, an additional dose of 10 Gy is administered to the tumor in 5 fractions over 1 week. rotational method and with reduced field sizes.
- Note: As an alternative, a three-field technique (one anterior and two posterior oblique fields) can be used.
Rice. 4.1. Radical irradiation. Markings on the skin: (a) anterior field; (b) side field. 
Rice. 4.2. Radical irradiation. Designation of field boundaries on a radiograph: (a) anterior field; (b) side field.
- Palliative radiotherapy
It is used to relieve dysphagia. Only the esophageal tumor is included in the radiation zone. A simple technique with two opposing anteroposterior fields and moderate doses are recommended.
- Position: on the back.
- Marking: using barium contrast of the esophagus.
- Field boundaries.
Rice. 4.3. Radical irradiation. Isodose distribution for cobalt at RIC = 80 cm. [N] 100% isodose normalization point (ICRU); (■) maximum dose 103%. Laying: (1) front 80 cGy/fr; (2) rear: 80 cGy/fr; (3) right lateral: 20 cGy/fr; (4) left lateral: 20 cGy/fr.
Front and back margins (15 x 7 - 20 x 9 cm):
upper and lower borders at a distance of 4 cm from the tumor,
lateral borders: 2 cm around the esophagus.
- Recommended dose (Fig. 4.5): 30 Gy in 10 fractions, at 5 fractions per week.
- COMPLICATIONS
Most patients experience radiation esophagitis after about 3 weeks. after the start of radiation therapy. By- 
Rice. 4.4. Radical irradiation. Distribution of isodoses for bremsstrahlung radiation with an energy of 18 MB at RIC = 100 cm. IN]100% isodose normalization point (ICRU); (■) maximum dose 100%. Laying: (1) front: 80 cGy/fr; (2) rear: 80 cGy/fr; (3) right lateral: 20 cGy/fr; (4) left lateral: 20 cGy/fr. 
Rice. 4.5. Radical irradiation. Distribution of isodoses for cobalt at RIC = 80 cm.)