Objective To investigate the role and value of pharyngeal tube placement before radiotherapy for nasopharyngeal carcinoma (NPC) on the complications of secretory otitis media (SOM) before and after radiotherapy for NPC. Methods Fifty-three patients with NPC were randomly divided into two groups: 28 patients in the tube placement group, who underwent nasal endoscopic pharyngodural tube placement before radiotherapy; 25 patients in the control group, who did not undergo pharyngodural tube placement, were followed up from 3 months to 12 months, and the incidence of SOM after radiotherapy was compared between the two groups. The incidence of SOM was significantly different between the two groups at 3 months, 6 months and 12 months after radiotherapy. Conclusion Eustachian tube placement before radiotherapy for NPC is an effective method to prevent and treat SOM complicating NPC.
【Key words】Endoscopy; nasopharyngeal tumor; eustachian tube; secretory otitis media; surgery
NPC is a common malignant tumor in the southern coast of China, and its incidence is the most common malignant tumor in otolaryngology, and radiotherapy is the first choice of treatment [1]. However, SOM is often complicated before and after radiotherapy, and symptoms such as tinnitus, tinnitus and deafness occur, which make patients’ quality of life significantly reduced. In order to investigate the role and value of pharyngotube placement before radiotherapy for NPC on the complication of SOM in NPC, 53 patients diagnosed with NPC were treated with pharyngotube placement before radiotherapy from 2000 to 2005, and the occurrence of SOM before and after radiotherapy was observed in our hospital.
1.Data and methods
1.1. Clinical data
From March 2004 to October 2005, 53 cases of nasopharyngeal hypofractionated squamous carcinoma were diagnosed, 41 males and 12 females; age ranged from 24 to 68 years, average 40.5 years, and medical history ranged from 1 month to 1.5 years. The 53 patients with NPC were randomly divided into two groups according to the principle of randomization: 28 patients in the tube placement group, who underwent pharyngeal tube placement before radiotherapy; and 25 patients in the control group, who did not undergo pharyngeal tube placement before and after radiotherapy. There was no statistical difference in age, gender and clinical stage (SOM removal before radiotherapy) between the two groups. The mean hearing loss of speech frequency air conduction ranged from 25 to 45 dB, with a mean of 37.5 dB. In the control group, there were 20 cases with type A conduction curves, 5 cases with type B (5 ears), and 4 cases with pure tone hearing loss. In the control group, there were 20 cases with A-shaped conductance curves and 5 cases with B-shaped conductance curves (5 ears), 4 cases with conductive deafness (4 ears) and 1 case with mixed deafness (1 ear), and the average hearing loss of speech frequency air conduction ranged from 25 to 45 dB, with an average of 36.0 dB. All patients with abnormal hearing test results could see tympanic membrane invagination, turbidity or tympanic fluid, and it was not difficult to diagnose SOM.
1.2, Methods
1.2.1, Tube placement method.
Tube placement group: All patients received eustachian tube placement 1 to 2 days before radiotherapy, and all of them completed the whole radiotherapy.
Under 300 nasal endoscopy, the pharyngo-pharyngeal opening on the affected side was identified, the pharyngo-pharyngeal opening was cleaned with antibiotic solution, and the discharge from the pharyngo-pharyngeal opening was aspirated, and a metal Euclidean tube with a preplaced epidural catheter was introduced (before placing the epidural catheter, the scale of the pharyngo-pharyngeal tube to be inserted was marked with silk thread or gentian violet, usually 2.5 cm), Under the bright view of the nasal endoscope, the metal Euclidean tube is inserted and the epidural catheter is guided to insert about 2.5 cm, and when it passes through the isthmus of the eustachian tube, there is a feeling of falling, and then it is inserted about 0.1 cm to reach the tympanic cavity, and the metal Euclidean tube is withdrawn and the outer end of the epidural catheter is sutured to the lateral wall of the ipsilateral nasal cavity. If SOM is complicated, after removing the tympanic ventricular fluid with a 1 ml syringe, repeatedly inject and retract 0.5 to 1 ml of air 3 to 6 times to loosen the tympanic ventricular adhesions, then inject 0.5 ml of the prepared mixture (usually prepared with 2 ml of ichthyocyte injection + a-chymotrypsin 5 mg), and treat every 1 to 2 days, usually requiring 3 to 10 times of treatment, retracting the stale fluid and secretions, the injected solution can be reduced one by one. During the retention period, oral Genoton, topical nasal dalfamprin spray as well as nasopharyngeal irrigation can be used. The tube was usually removed 2 weeks after radiotherapy, and the follow-up period was 3-12 months. The efficacy of the treatment was evaluated by electro-otolaryngoscopic examination of the tympanic membrane and tympanic chamber fluid, pure tone audiometry and acoustic impedance examination.
In the control group, all patients did not need to undergo eustachian tube placement before and after radiotherapy, and they also completed the whole radiotherapy. From the time of radiotherapy to the following 3 months, the same oral ginotron, topical nasal spray and nasopharyngeal irrigation were used. The same method was followed up from 3 to 12 months after radiotherapy, and the efficacy was evaluated.
1.2.2. Radiotherapy methods.
All patients were irradiated by our conventional irradiation method: the irradiation field was preauricular + cervical segmentation + lateral field, irradiation time was 5 consecutive times per week, 1 time per day, 2 Gy/time (2 weeks of rest after 20 times of irradiation for severe radiotherapy reactions), 35 times of radiotherapy, total dose 66～70 Gy, nasopharyngeal lesions could not be eliminated plus nasopharyngeal cavity afterloading treatment, the dose was 10～15 Gy.
The total dose was 66-70Gy. The total dose of nasopharyngeal radiation therapy was 66-70 Gy/6.5-7 weeks with the conventional fractionated irradiation method by 60Co treatment machine.
1.3, efficacy evaluation criteria
Cured: the clinical symptoms such as tinnitus, ear stuffiness and ear blockage disappeared, the hearing range of pure tone speech frequency improved to normal (0-25dB), and the acoustic impedance graph was A-type; Improved: the clinical symptoms such as tinnitus, ear stuffiness and ear blockage reduced, the hearing range of pure tone speech frequency improved, but did not reach the normal range (25 dB~35dB), and the acoustic impedance graph was As-type or C-type; Invalid: the clinical symptoms did not No improvement in clinical symptoms, no improvement in the results of various tests.
2.Results
The pure tone hearing and acoustic impedance were rechecked after 3-12 months of follow-up after radiotherapy. According to the efficacy criteria, the emergence of SOM and treatment in the placement group and the control group after radiotherapy are shown in Table 1.
Table 1 Comparison of SOM in the tube placement group and the control group at 3, 6 and 12 months after radiotherapy.
Group (cases) 3 months (cases, % ) 6 months (cases, % ) 12 months (cases, % )
Tube placement group (28) 3, 10.7% 4, 14.3% 3, 10.7%
Control group (25) 11, 44.0% 8, 32.0% 7, 25%
The difference between the two groups was significant, indicating that pharyngotomy had a significant effect on the prevention of SOM.
3, Discussion
NPC has a high incidence in the southern coastal region of China, and there are obvious regional differences in its distribution, which has been called “Guangdong tumor” in the past and has been a cause of concern. Although radiation therapy is the first choice of treatment for NPC, it is easy to combine with SOM and sinusitis before radiation therapy, and also easy to cause SOM, radiation pharyngitis, external otitis, temporal bone necrosis and many other complications after radiation therapy. Among them, SOM, is the main cause of deafness after radiotherapy for NPC. The incidence of SOM before and after radiotherapy has been reported differently. Jiang Aiyun et al. reported that the incidence of SOM before radiotherapy was 22 4%, and Low et al. found that the incidence of SOM in NPC patients could reach 40%; the incidence of new SOM after radiotherapy has been reported to be 16%-26%, and another Young et al. reported that the incidence of SOM after radiotherapy was more than 50%.
The mechanism of SOM before radiotherapy for NPC may be as follows: 1) the tumor directly presses the pharyngeal orifice of the nasopharynx and the bulge of the eustachian tube, which may cause the obstruction of the eustachian tube; 2) the tumor invades the constrictor muscle, which may cause the obstruction of the opening of the eustachian tube and the negative pressure as the air in the middle ear is absorbed by the blood; 3) the tumor invades the cartilage of the eustachian tube, which causes the obstruction of the closing of the eustachian tube, and at this time, with the vigorous nasal inhalation, the middle ear generates high negative pressure. The tumor invades the cartilage of the eustachian tube and causes the eustachian tube to close, at this time, with the vigorous nasal aspiration, the middle ear produces high negative pressure; 4.
Clinical studies have shown that although the local cancer shrinks and disappears after radiotherapy for NPC and the mechanical compression of the cancer is eliminated, more than 1/3 of the clinical symptoms of SOM are aggravated; in some cases, new SOM appears after radiotherapy, and the high incidence of SOM after radiotherapy is from 3 to 6 months after radiotherapy.
SOM after radiotherapy for NPC is closely related to radiation damage to the eustachian tube and surrounding tissues. Inner ear damage occurs when the radiation dose reaches 60Gy, and the radiation dose for NPC is usually greater than 60Gy. Moreover, during radiation therapy, the eustachian tube, tympanic chamber and surrounding tissues such as the palatine sail tensor and palatine sail levator are almost impossible to escape from the radiation field. After radiotherapy, the mucous membrane of the eustachian tube is edematous and congested, and the narrowing of the eustachian tube caused by tissue fibrosis leads to the dysfunction of the eustachian tube and the occurrence of SOM.
With the increasing survival rate at 5 years after radiotherapy for NPC, more attention has been paid to the prevention and treatment of post-radiotherapy SOM and the improvement of patients’ quality of life.
Although there are many traditional treatment methods, the efficacy of these methods varies, and they may lead to many complications. Some scholars have adopted the method of tympanic intubation for prevention and treatment, but the efficacy is poor. Although tympanic tube placement for SOM is beneficial to the recovery of pharyngeal tube function, the incidence of ear leakage after tube placement is 25.5% and the incidence of tympanic membrane perforation is 9.8%. Some scholars used floating catheters into the eustachian tube to dilate the eustachian tube to treat SOM after radiotherapy for NPC, and the efficiency was only 43.2-56.25%.
Before radiotherapy for NPC, the key to treating SOM complicated by NPC is to release the obstruction of the eustachian tube and balance the air pressure inside and outside the middle ear drum. For SOM after NPC radiotherapy, the treatment is more complicated due to the presence of neuromuscular paralysis, eustachian tube compliance changes, eustachian tube mucosal edema and congestion, and tissue fibrosis. It has been reported that the pharyngo-drum dysfunction after radiotherapy for NPC is mostly of the obstructive type. It has also been suggested that organic obstruction of the eustachian tube at the end of radiotherapy is the root cause of high negative pressure in the tympanic chamber, and high negative pressure in the tympanic chamber is an important indicator of eustachian tube dysfunction. Therefore, it is important to unblock the obstructed eustachian tube and keep it in a good open state while enhancing local care.
In the case of the tube placement group in this study, the catheter of the eustachian tube can be accurately placed under the direct view of nasal endoscopy, avoiding the blindness of the operation; the catheter is inserted into the tympanic chamber through the natural channel of the eustachian tube, and the tympanic chamber and the eustachian tube are directly affected by blowing the tympanic membrane and injecting medicine through the catheter, achieving anti-inflammatory and anti-swelling, reducing exudation, thinning and eliminating mucus, and restoring the normal pressure balance of the middle ear without damaging the tympanic membrane, etc. The epidural anesthesia silicone catheter has no stimulating effect on tissues, and the smooth and medium quality of the head end makes it easier to be placed and less likely to damage the mucosa, so there is no case of damage or adhesion of the eustachian tube in this group. Among the injected drugs, ichthyocyte liquid had an antibacterial effect, and а-chymotrypsin had the effect of diluting middle ear secretions and promoting the elimination of effusion. From the results, the incidence rates of SOM in the two groups from 3 to 12 months after radiotherapy were significantly different, in which the incidence rates in both groups at 12 months after radiotherapy were maintained to a relatively stable level, indicating that pharyngodural tube placement has a significant effect on the prevention of SOM.
Although this method has good efficacy in preventing and treating NPC complicated by SOM, there are still several issues that need to be clarified.
1. It has been reported that SOM has a tendency to heal spontaneously and gradually become an open pharyngeal tube after 5 and 10 years of follow-up after radiotherapy. From the present study, we can also see that the incidence of SOM in the control group was highest within six months after the end of radiotherapy. In contrast, the incidence of SOM was relatively stable from 3 to 12 months after extubation in the tube placement group. The incidence rate of SOM in both groups remained relatively stable at 12 months after radiotherapy, but the difference was still significant.
The ciliated cells are more abundant in the bottom wall of the eustachian tube, and the cup cells, glands and mucosal folds are also more abundant in the bottom wall of the eustachian tube, indicating that the active function of clearing secretions mainly occurs in the bottom wall of the eustachian tube; the mucosal folds increase the area of the eustachian tube, and at the same time, the mucosal surface of the eustachian tube is not directly exposed to airflow, which is conducive to the discharge of secretions; therefore, the eustachian tube insertion body currently used in our clinic needs to be improved. Therefore, we hope that some manufacturers can make more reasonable pharyngeal tube inserts according to the special physiological structure, physiological characteristics and functional characteristics of the pharyngeal tube.
3. It should be noted that the prognosis of SOM is also related to the regulation function of the eustachian tube, which is the basic defect of the function of the eustachian tube and an important reason for the persistence and recurrence of the disease. Therefore, how to improve and restore the regulatory function of the eustachian tube after radiotherapy for NPC is an important issue that we need to solve, which will directly relate to the long-term efficacy of SOM.
4, For SOM complicated before radiotherapy, as all of them have mechanical compression by tumor, the MRI or CT of the patient must be carefully studied before tube placement to understand the compression of the eustachian tube, and it is not appropriate to force through the eustachian tube invaded by tumor, and whether a better time period should be chosen for tube placement is to be further studied.
5. From this study, it can be seen that there is no significant difference in the morbidity rate between 3 and 12 months of follow-up when the tube was removed two weeks after radiotherapy in the tube placement group, therefore, it is meaningless to increase the time of tube retention after radiotherapy.
Compared with many traditional methods, this method avoids many disadvantages such as damage to the tympanic membrane, can be repeatedly administered to the middle ear cavity, is simple, accurate, non-invasive, safe, efficacious, easily accepted by patients, and can be left in the tube for a long time, and is a good method for clinical prevention and treatment of NPC complicated by SOM, which is worthy of further clinical study due to the small number of observed cases in this group.