Indications.
1.Radical radiotherapy.
Radical radiation therapy is feasible for those who are in moderate or above general condition, can eat semi-liquid or smoothly liquid diet, no supraclavicular lymph node metastasis and distant metastasis, no tracheal invasion, no vocal cord paralysis, lesion length <10CM, no preperforation X-ray signs, no significant chest and back pain, no contraindication to internal medicine, as well as those who have local recurrence or mediastinal lymph node metastasis after esophageal cancer surgery, or have tumor residue in the postoperative stump.
2.Palliative radiotherapy.
Those who are in good general condition but have extensive local lesions, length〉10CM, metastasis of paraesophageal or mediastinal lymph nodes or vocal cord paralysis, tracheal invasion or compression but not penetrating trachea; those who have obvious heaviness and pain in chest and back but no preperforation symptoms and signs; those who have metastasis of supraclavicular lymph nodes or metastasis of lymph nodes in the left vascular area of the stomach under the diaphragm, in order to relieve esophageal obstruction, improve feeding difficulties, reduce pain, improve survival To relieve esophageal obstruction, improve feeding difficulties, reduce pain, improve survival and prolong survival, palliative radiotherapy can be performed. There is no absolute boundary between palliative and radical radiotherapy, unless there are distant metastases, severe complications and systemic failure. For those who start to plan palliative radiation therapy, according to the regression of lesions and the patient’s ability to tolerate, those with significant efficacy should promptly adjust the treatment plan and give as much radiation therapy as possible to achieve the purpose of radical treatment. For those who initially plan to perform radical radiation therapy, but have distant metastasis, serious complications and obvious systemic failure during treatment, the treatment can be interrupted or changed to palliative radiation therapy. For those patients with pre-perforation X-ray signs of esophageal cancer, radiation therapy can also be performed after reducing the single radiation dose and extending the treatment course appropriately. Widened mediastinum, blurred margins, low lung field translucency, increased body temperature, increased pulse rate and chest and back pain are signs of esophageal perforation, and in fact, there is already micro perforation. Once confirmed, radiation therapy should be interrupted and appropriate treatment measures should be taken. Most of the esophageal perforation, fistula formation and hemorrhage in radiation therapy are due to tumor invasion and lesion regression after radiation therapy, not due to excessive radiation damage. For obvious invasion, especially for esophageal cancer with deep ulcers, the segmentation speed of radiation therapy should be slowed down appropriately.
Contraindication.
There are few absolute contraindications to radiation therapy for esophageal cancer. If there is obvious cachexia, existing esophageal fistula, existing mediastinitis or mediastinal abscess, or large amount of bleeding in esophagus, it can be considered as a contraindication. [The lymphatic drainage of esophageal cancer lacks obvious segmentality, and its drainage direction is mainly upward and downward. The upper 2/3 of esophagus is mainly upward and the lower 1/3 is downward. For example, for upper thoracic esophageal cancer, the metastasis rate of upper mediastinum and supraclavicular lymph nodes is about 30%; for lower thoracic esophageal cancer, the metastasis rate of lymph nodes in the left vascular area of the stomach under the diaphragm can reach 50%~80%. Esophageal radiation therapy is divided into extracorporeal irradiation and intracavitary irradiation, and extracorporeal irradiation is the main irradiation method for esophageal cancer radiation therapy at present.
1.Extracorporeal irradiation.
(1) Radiation source.
High-energy X-rays or 60COr rays can be chosen, and electron rays of suitable energy can be added to the anterior field of cervical esophageal cancer.
(2) Scope of irradiation.
According to the esophageal imaging performance, the target area should be determined first (usually fluoroscopically positioned under the simulator, if the unit is not yet equipped with simulator, other methods can be used), the upper and lower ends of the field should exceed the lesion by 3~5CM, and the width of the irradiation field should be determined according to the esophageal soft tissue shadow or the degree of esophageal invasion on CT scan, generally the width of the anterior field is 6~8CM, the width of the posterior oblique field is 5~7CM, if the unit has conditions, treatment can be done Plan and fluoroscopic positioning to ensure that the spinal cord is not subjected to more than its spinal cord tolerated dose, while ensuring the necessary dose in the target area.
(3) Number of irradiation fields.
According to the treatment plan, the size and number of irradiation fields and the weight of each field should be set, so that the tumor can be irradiated evenly and the surrounding normal tissues can be preserved to the maximum. Generally, it is appropriate to irradiate in three fields, i.e. one vertical field in front and two oblique fields in the back to avoid the spinal cord.
(4) Conventional segmentation mode and irradiation dose.
Radical radiation therapy tumor dose is 50~70GY/25~38 times/5~7.5 weeks, this is the conventional segmentation mode.
(5) Unconventional segmentation mode.
At present, conventional irradiation is generally used, the tumor dose is 30~42GY/15~23 times/3~5 weeks, the specific operation is 1.8~2GY per time, once a day, 5 times a week, and then the post-process accelerated hyper-segmentation radiation therapy is given, the specific operation is 1.5GY per time, twice a day, at least 6 hours between the two times, 10 times a week, the dose is 30GY. the total dose is 60~70GY. The total dose is 60~70 GY. This method can also be used in advanced age, poor general condition and advanced cases. In addition, continuous hyper-segmentation, continuous accelerated hyper-segmentation and other unconventional segmentation methods can also be used.
2.Intraluminal irradiation for esophageal cancer.
Intracavitary irradiation is characterized by high surface dose of radiation source, and the dose decreases sharply with increasing depth, and the dose distribution is very uneven. This treatment method is mainly used for those who have residual lesions after sufficient external irradiation, or those who have local recurrence and difficulty in eating in the near future after external irradiation, and palliative radiotherapy is performed to relieve eating obstruction. Intraluminal irradiation cannot replace external irradiation as the standard conventional treatment for esophageal cancer, it can only be an adjunct and supplement to external irradiation. The reference point is usually located at 10MM from the center of the source (8~12MM), and the total dose of intracavitary irradiation is no more than 15GY at the reference point, which can be divided into 2~3 times. 3 Three-dimensional conformal radiotherapy and IMRT for esophageal cancer is a promising method that can improve the local control rate and survival rate of esophageal cancer, and is being tried both at home and abroad. Based on the CT scan, the tumor target area is outlined, 3D image reconstruction is performed, and precise plan design is given, and co-planar multifield or non-co-planar multifield irradiation is used. The segmentation dose and total dose, total irradiation course time, spinal cord tolerance, and the protection value of both lungs of this irradiation method are currently under study. With this technique, the outline of the tumor target area is more important, and it is better to use the conventional segmentation, commonly used super-segmentation, and less to use the large segmentation with a single extra large dose. This technique can also be used as a late supplemental irradiation to conventional radiation therapy techniques.
Precautions.
1.Esophageal cancer radiation therapy efficacy.
There are many factors to image the efficacy of esophageal radiation therapy, the depth of tumor invasion to the esophageal wall and lymph node metastasis are the most important. Other factors may include the general condition of the patient, age, primary site, X-ray pathological classification, presence of anemia, X-ray performance at the end of treatment, sensitivity of the tumor to radiation therapy and total radiation dosage, etc. Most of the patients with esophageal cancer who underwent radiation therapy were estimated the sensitivity of the procedure itself to radiation therapy and the total radiation dose, etc. Most of the patients with esophageal cancer treated with radiation therapy are estimated to be unresectable by surgery, have contraindications to surgery or refuse surgery, and more than 95% of the patients have lesions >5cm at the time of radiation therapy. Even after radical radiation therapy, the 5-year survival rate is generally 5%~10%.
2.Complications and sequelae of radiation reaction.
(1) Radiation esophagitis.
Generally after the radiation treatment dose reaches 20Gy, dysphagia, hypopharyngeal pain and retrosternal pain can occur.
(2) Radiation tracheitis.
After the trachea is irradiated with dose up to 20Gy, inflammatory reaction of trachea can appear, producing cough, mostly dry cough without sputum, trachea is exposed to 70Gy/30~35 times/8 weeks, serious complications may occur, tracheal stenosis, mostly occurs after 4~6 months of treatment.
(3) Esophageal perforation, esophageal fistula and hemorrhage.
It is difficult to avoid serious complications such as perforation, bleeding and esophageal fistula due to tumor invasion, invasion of surrounding organs or blood vessels, and tumor regression during or after radiation therapy.
(4) Radioactive rib injury.
Because of the posterior oblique field irradiation when the field includes the ribs, bone absorption of radiation can cause radioactive rib fractures after treatment, most of them are several heel rib fractures at the same time or not, related to individual sensitivity.
(5) Radiation pneumonia.
With the improvement of the technology under radiation, radiation pneumonia has been significantly reduced, but in recent years radiotherapy simultaneous or sequential application, so that the incidence of radiation pneumonia has increased. With the increasing popularity of CT, the detection rate of asymptomatic radiation pneumonia and late pulmonary fibrosis will increase significantly.
(6) Radiation myelitis.
The incidence of radiation myelitis is 0.8%~3.5%, and the spinal cord should be strictly controlled within the tolerated dose range. Radiation myelitis may also occur in individuals with high radiosensitivity and spinal cord doses lower than the tolerated dose.
(7) Radiation esophageal stenosis.
After radiation therapy, the tumor lesion disappears, but due to local fibrosis and scar formation, the esophageal lumen is narrowed and the wall is stiffened in the original lesion and in the irradiated field, which affects eating.