I. Incidence characteristics
The incidence rate of laryngeal cancer is not high, and the high incidence areas in China are heavy industrial areas such as the northeast, and Guangdong Province is not a high incidence area for laryngeal cancer. According to reports, the incidence rate of laryngeal cancer in China is about 0.01-0.03 per thousand. It is generally believed that urban areas are higher than rural areas, and heavy industrial cities are higher than light industrial cities. However, with the development of modern industry and the aggravation of air pollution, the incidence rate of laryngeal cancer is gradually increasing around the world. In addition, the incidence rate of laryngeal cancer is significantly higher in men than in women, and the incidence ratio of men to women in Guangdong Province is about 11,2:1.
Etiology
Like other tumors of the whole body, the causes of laryngeal cancer are multifaceted, which are summarized as follows
Chronic stimulation From the perspective of the original location of laryngeal cancer, it is most likely to occur in the most obvious part of the vocal folds, so it is presumed that the occurrence of laryngeal cancer may be related to long-term friction and chronic inflammatory stimulation. Among various chronic inflammatory irritants, especially tobacco and alcohol are the most important ones. Clinical statistics show that more than 90% of laryngeal cancer patients are long-term smokers and drinkers, and the chance of occurrence is positively correlated with the time and quantity of smoking, and those who smoke and drink alcohol are at greater risk of developing the disease. Experimentally, it is proved that when normal mucosal epithelium is frequently and repeatedly stimulated by inflammation, the cells appear active proliferation and atypical abnormal proliferation, when the cytoplasm contains more RNA, the division and proliferation of cancer cells is actually the active replication of chromosomal DNA and synthesis of cancer protease.
2.Air pollution It is documented in literature that the chance of laryngeal cancer increases among workers who are engaged in long-term wood processing or frequently exposed to dust, and it is believed that asbestos dust has a direct relationship with the occurrence of laryngeal cancer.
3.Malignant transformation of benign laryngeal diseases Benign laryngeal diseases, such as laryngeal keratosis and laryngeal papilloma, can be induced to malignant transformation by untimely treatment or inappropriate repeated surgical stimulation. Sometimes, it is believed in literature that about 5% of laryngeal cancer patients evolve from benign diseases.
4.Physical factors Mainly refers to radiation, which has a carcinogenic effect and has long been noticed clinically as one of the triggering factors of other malignant tumors, and laryngeal cancer is the same. Some data suggest that patients who have received radiation treatment for other neck diseases in the past are more prone to laryngeal cancer than those who have not received radiation, and the latency period of laryngeal cancer after receiving radiation ranges from 5 to 50 years.
5.Other factors Among the causes of laryngeal cancer. In addition to the above-mentioned causes, there are some other factors which are also quite valued by scholars, such as
1. Genetic factors: among the causes of other malignant tumors are more recognized, mainly refers to the fact that those with genetic history are more prone to the disease than others under the effect of the same causative factors. Although laryngeal cancer has not been reported to be hereditary, it has been noticed.
2.Viral infection: Papilloma is a viral infection, which has been confirmed. However, papilloma is closely related to the occurrence of laryngeal cancer, so viral infection is also regarded as one of the causes of laryngeal cancer.
Pathology of laryngeal cancer
Laryngeal cancer is most common in vocal cord cancer, followed by supraglottis cancer and least in subglottis cancer. To the naked eye, the tumor may appear as papillary, wart-like or cauliflower-like elevation, and may also form ulcers locally.
Histologically, squamous cell carcinoma is the most common cancer in larynx, accounting for 95%-98%, while adenocarcinoma is rare, accounting for about 2%. Squamous cell carcinoma of the larynx can be divided into three types: in situ carcinoma, early invasive carcinoma and infiltrative carcinoma, depending on the degree of development. In situ carcinoma is rare and can develop into infiltrating carcinoma after a period of time; early infiltrating carcinoma generally consists of in situ carcinoma breaking through the epithelial basement membrane and infiltrating downward and forming a nest in the lamina propria; most of the infiltrating carcinomas of larynx are highly differentiated squamous carcinomas, with different degrees of keratinization and intercellular bridges, and keratinized beads can be seen in the center of the nest, while low differentiated squamous carcinomas are rare. Sometimes the tumor is mainly spindle cell, which is called spindle cell carcinoma. The arrangement of cancer cells is disorderly and does not form a cancer nest, which is quite similar to sarcoma. Warty carcinoma is a subtype of laryngeal invasive squamous cell carcinoma, which is less common and accounts for 1%-2% of laryngeal carcinoma, and the tumor grows into the laryngeal cavity in the shape of warts, forming cauliflower-like masses. Microscopically, it is a highly differentiated squamous carcinoma with different degrees of local infiltration, slow growth and rare metastasis.
Possible symptoms of laryngeal cancer
1. Hoarseness
Hoarseness is the most common symptom of laryngeal cancer and also an early symptom of vocal cord cancer. However, it does not mean that any hoarseness is laryngeal cancer. The most common cause of hoarseness is laryngitis, but the hoarseness caused by laryngitis is usually accompanied by throat pain and cold-like symptoms, and improves after vocal cord rest and symptomatic treatment. Hoarseness due to laryngeal cancer is mostly progressive and aggravated, and treatment is ineffective. Therefore, if hoarseness persists for 3 weeks, especially for men over 50 years old who are addicted to smoking, they should go to hospital to rule out the possibility of laryngeal cancer.
2.Sore throat
It should be distinguished from acute pharyngitis, which has a rapid onset and is accompanied by “cold”. Laryngeal cancer starts slowly and worsens progressively. The pain increases when swallowing and can be radiated to the ipsilateral inner ear, which sometimes hinders eating.
3.Cough and blood sputum
When the tumor is infected or ruptured, it can stimulate the respiratory tract and cause cough and blood sputum.
4.Difficulty in breathing
When the tumor gradually increases, it can block the respiratory tract and cause difficulty in breathing. This kind of breathing is difficult due to inhalation, with prolonged inhalation time, self-conscious effort and short exhalation time.
5.Metastatic symptoms
Lymphatic metastasis: The cervical lymph node metastasis of laryngeal cancer differs according to different anatomical sites. The lymphatic tissue in the supraglottis area is rich and the cancer cells are poorly differentiated, so lymph node metastasis often occurs earlier, and the metastasis rate is about 30% in general, while that of laryngocervical fold cancer is about 50%, and it mostly metastasizes to the lymph nodes under the diastasis. Vocal cord cancer rarely metastasizes in early stage, except when the lesion is beyond the vocal cord, and its metastasis rate is about 10%, mostly to the lymph nodes in the pre-tracheal, paratracheal or middle region of the internal jugular vein. The metastasis rate of subglottic cancer is more than 10% because of late detection, and it mostly metastasizes to the lymph nodes in the middle or lower regions of the paratracheal or internal jugular veins. The lymph nodes in the corresponding areas are enlarged and hard.
2.Distant metastasis: the metastasis rate of the whole body is about 1%-4%, and the metastasis of lung is the most frequent, followed by mediastinal lymph nodes, liver, bone and pleura, etc. The corresponding symptoms such as cough, chest pain, pain in liver area, jaundice and bone pain appear.
4.How to detect laryngeal cancer at an early stage
The key to early detection of laryngeal cancer is to raise the vigilance of laryngeal cancer, master the basic knowledge about laryngeal cancer, and seek early medical treatment when suspicious symptoms of laryngeal cancer appear. In particular, if you have unexplained hoarseness, especially if it lasts for more than 3 weeks, or if you have a foreign body sensation in the throat that does not heal after symptomatic treatment, or if you are a male smoker over 50 years old, you should consult a doctor as early as possible to avoid delaying the disease.
V. Means to diagnose laryngeal cancer
1. Physical examination
Clinicians will generally examine the laryngeal shape and cervical lymph nodes carefully to get a rough idea of the extent of the disease.
2.Laryngoscopy
1.Indirect laryngoscopy
It is painless, but the patient is required to stick out his tongue and make the “yi” sound as required. Using indirect laryngoscopy, the clinician can understand the larynx of most patients, and can observe the epiglottis, aryepiglottic folds, ventricular zone, vocal folds, laryngeal chambers, and subglottic area. A small percentage of patients with uncooperative, sensitive pharyngeal reflexes and poor epiglottis elevation have difficulty in observing the larynx clearly under indirect laryngoscopy.
2.Direct laryngoscopy
It should be used when the indirect laryngoscopy is unsatisfactory or it is not easy to obtain pathological specimens, but it has been replaced by fiberoptic laryngoscopy because of the pain of the patient undergoing the examination.
3.Fiber laryngoscopy
The advantages of fiberoptic laryngoscopy are obvious: it can accurately understand the appearance, location, scope and organ activity of the lesion; it can see the parts that are difficult to see clearly by indirect laryngoscopy, such as the anterior union, subglottis, laryngeal ventricle and epiglottis surface; it can take biopsy and smear for cytological examination; it can reduce the patient’s pain; and it can preserve the data.
Based on the above, fiberoptic laryngoscopy can be performed for those who are unsatisfied with indirect laryngoscopy, proposed biopsy, before radiation therapy, before surgery, and during radiation therapy to understand the efficacy of treatment.
3.X-ray examination
X-rays for direct examination of laryngeal lesions have become a thing of the past. Nowadays, they are mainly used to examine the lungs and trachea to exclude lung lesions and contraindications to surgery.
4.CT examination or MRI examination
It can better indicate the existence of tumor, the margin of the mass, the extension of the site, the soft tissue or cartilage and lymph node invasion and other information, which is helpful to guide the correct treatment strategy.
5.Pathological examination
It is the only way to confirm the diagnosis of laryngeal cancer, and clear pathological diagnosis is necessary before radiotherapy and surgery. In some cases, laryngeal lysis can be performed if the diagnosis cannot be confirmed by multiple biopsies before surgery, and the scope and mode of surgery can be determined after the pathological nature is clarified by intraoperative rapid frozen section pathological examination.
Differential diagnosis of laryngeal cancer
1.Vocal cord nodules The manifestation is mild interstitial hoarseness, which is aggravated in the evening and lighter and faster in the morning, dryness, slight pain and increased laryngeal secretion in the larynx, usually at the junction of the anterior and middle 1/3 of the vocal cord, symmetrical mucosal nodules at the free edge, edema-like, smooth surface, rice-like in size, and wide congestion at the base. Rest to reduce vocalization, nebulized inhalation, ultrashort wave physiotherapy, and moderate antibiotic treatment are effective. Larger ones must be removed under laryngoscope.
2, laryngeal nodules Patients with laryngeal nodules have varying degrees of laryngeal pain, and most of the lungs have coexisting tuberculosis lesions. The lesions are granular, pink or pale edema, often accompanied by shallow ulcers covered with purulent secretions, and the posterior union is the preferred site for laryngeal tuberculosis, while laryngeal cancer is rare. Anti-TB treatment is effective, and biopsy cytology and smear of secretion to find antacid bacilli are helpful to confirm the diagnosis.
3.Laryngeal keratosis and laryngeal white spots The manifestation is hoarseness and discomfort in the larynx, which is more common in middle-aged men and above. Pathological biopsy can confirm the diagnosis.
4, laryngeal papilloma This disease is more frequent in young children, adults can be seen, is currently believed to be caused by viral infection, often complicated by skin warts, no difference between men and women. The main manifestation is hoarseness, laryngoscopy can be seen in young children in the larynx of the various parts of the onset, with the tip, the base is more extensive, showing cauliflower-shaped. In adults, a single tipped, often in the vocal cords, activity is not limited to men, the lesion is limited, pathological examination shows severe atypical hyperplasia, should be completely removed to prevent malignant transformation.
5, laryngeal amyloidosis The clinical manifestations of mild hoarseness, sometimes wheezing-like dyspnea, the lesions are usually found in the anterior part of the subglottis, but also in the ventricular zone, the vocal cords, single or multiple nodules, or diffuse thickening of the mucosa, the vocal cords are rarely fixed, the course of the disease is long, the disease examination amyloid Congo red positive, diffuse lesions are sensitive to corticosteroids.
6, Wegener’s granuloma The clinical manifestations of this disease are not hoarse, laryngeal ulceration, secondary infection, often accompanied by dyspnea, pathological tissue is necrotic granulation, vasculitis and scattered giant cells and inflammatory cell infiltration. There are often pulmonary and renal lesions. Pathological examination is required to confirm the diagnosis.
7, benign mixed laryngeal tumor This disease is rare, from the small salivary gland, in the aryepiglottic fold or supraglottic area. The surface mucosa is smooth, the boundary is clear, and the tumor is solid. A lateral X-ray of the neck shows a smoothly bordered mass shadow, and pathological examination is of great significance in confirming the diagnosis.
8.Laryngeal endotracheal thyroid gland Rarely, the embryonic thyroid gland grows into the trachea through the cartilage, usually in the posterior wall of the trachea in the subglottic region, and the mass is partially outside the trachea.
9, benign granulosa cell tumor of the larynx This tumor occurs in 29-42 years of age, the lesion is located in the vocal folds, mostly with symptoms of hoarseness, mucosal smooth nodules less than 1 cm in diameter, the boundary is unclear, the vocal folds are not restricted, pathological examination is required to confirm the diagnosis.
10, laryngeal plasmacytoma This disease is rare, mostly in middle-aged and elderly males, and occurs in various parts of the larynx, with the epiglottis, vocal cord, ventricular cord and laryngeal chambers being more frequent. Laryngoscopy shows diffuse infiltration of submucosal tumor tissue in the larynx, and the lesion often extends beyond the larynx and involves the pharynx.
Treatment methods of laryngeal cancer
Since larynx is an articulatory organ, the treatment of laryngeal cancer must take the following two factors into consideration: one is to eradicate the tumor and the other is to preserve the articulation. Clinicians usually choose the treatment method according to the following factors: tumor site, stage, pathology, patient’s gender, age and general condition. The available options are: surgery, radiotherapy, and combined treatment of radiation and surgery.
1.Radiation therapy
Radiotherapy is an effective treatment for laryngeal cancer and can treat some cases. For early cases of T1, which can both eradicate tumor and not affect vocalization, it is generally considered that radiation therapy can be given in the following cases: 1, T1 lesion of laryngeal cancer; 2, pathology of low-differentiated squamous carcinoma; 3, comprehensive treatment cases; 4, post-operative recurrence or residual tumor; 5, palliative treatment for advanced cases.
Anyone with severe necrosis, infection and respiratory distress should not be treated with radiotherapy. Adenocarcinoma is not sensitive to radiotherapy. In addition, radiotherapy for laryngeal cancer with cervical lymph node metastases is poor.
2. Surgical treatment
Since Billroth successfully performed the first total laryngectomy in 1874, surgical treatment of laryngeal cancer has experienced more than 100 years of history, and its specific methods have been greatly improved. Surgery for laryngeal cancer has the advantages of short course and high cure rate, so it is still the main means of treatment for laryngeal cancer. However, after surgery, patients have to lose some or all laryngeal tissues, causing different degrees of articulation difficulties. After total laryngectomy, which causes complete loss of voice and changes the normal breathing passage, methods such as electronic larynx can be used to replace laryngeal vocalization in a more satisfactory way. In recent decades, many scholars advocate irregular partial laryngectomy to achieve both eradication of tumor and preservation of vocal and respiratory functions, and practice shows that research in this area has made great progress.
There are various surgical methods, including vocal cord resection, horizontal hemilaryngectomy, vertical hemilaryngectomy, irregular partial laryngectomy, total laryngectomy, and combined radical laryngectomy for laryngeal cancer. Each method has different indications. Strictly grasping the indications can achieve good treatment effect and preserve laryngeal function as much as possible.
It is generally believed that for stage I cases, radiation therapy is similar to surgery, but the former does not affect pronunciation and is therefore the preferred treatment method, while surgery is preferred for stage II, III and some stage IV cases, supplemented by radiation therapy when necessary.
Of course, any kind of treatment method has its advantages and disadvantages, and the fundamental starting point of the so-called comprehensive treatment is to take advantage of the strengths and weaknesses, with the ultimate goal of improving the cure rate and reducing side effects.