What is tracheal cancer
The trachea, composed of rings of fibrous tissue, is the tube that connects the mouth and nose to the lungs. Tracheal cancer occurs when its cells multiply uncontrollably and develop a tumor.
Primary tumors of the trachea, which originate in the organ, are uncommon. When they occur, they are usually malignant in adults and benign in children. They present with symptoms that mimic other conditions, often leading to delays in diagnosis and discovery when the tumor is in an advanced stage.
Tumors that metastasize to the trachea, originating in organs such as the thyroid, esophagus, larynx (voice box), or lung, are called secondary and are more common than primary tracheal tumors.
Regardless of where these tumors originate and whether they are benign or malignant, they typically result in a narrowing of the tracheal opening, restricting the airflow to the lungs.
Subtypes of tracheal cancer
There are three types of carcinomas – malignant tumors – in the trachea:
- Squamous cell carcinoma – develops most frequently in men between 50 and 70 years old and is usually associated with smoking, accounting for more than half of the cases;
- Adenoid cystic carcinoma – unlike squamous, cystic spreads along the lining of the trachea, usually grows slowly, and is not related to smoking. It occurs equally in men and women aged 40 to 60 years. The incidence of this type of cancer is 10% to 15% of cases;
- Carcinoid tumor – an abnormal mass of slow-growing that originates in the cells of the endocrine (hormonal) or nervous system. These tumors can occur anywhere in the body, including the trachea.
As for benign types of tumors in the trachea:
- Chondroma – the most common type of tracheal tumor. It is formed from the cartilage that makes up the trachea and can become cancerous over time;
- Hemangiomas – Tumors in small blood vessels that can affect children and adults. If a child with a birthmark of hemangioma (abnormal buildup of blood vessels in the skin or internal organs) begins to experience respiratory problems, a hemangioma tumor may be the cause.
- Papillomas – Tumors caused by the human papillomavirus (HPV).
Symptoms and signs of tracheal cancer
Respiratory difficulties are often the first sign of a problem in the trachea, whether the tumor is benign or malignant. However, it is important to remember that respiratory difficulties can result from other diseases such as asthma, bronchitis, or chronic obstructive pulmonary disease (COPD), and may not necessarily be a sign of cancer.
Therefore, in addition to shortness of breath, other symptoms should be associated to suggest a tumor in the trachea. The most important ones are:
- Wheezing, shortness of breath, and cough, with or without blood;
- Noisy breathing, including a wheezing sound;
- Frequent upper respiratory tract infections;
- Difficulty swallowing and hoarseness (suggests that a tracheal tumor is pressing on the esophagus).
Diagnosis of tracheal cancer
Tracheal tumors are difficult to diagnose because they are rare and, in most cases, grow slowly. The tumor can also be misdiagnosed as another respiratory problem, such as asthma or COPD.
Tests that should be requested to confirm a diagnosis of tracheal cancer:
- Computed tomography (CT) scan – the exam can form images that can define the size of a tumor, the narrowing of the trachea, and the status of the surrounding lymph nodes;
- Bronchoscopy – an exam performed with a bronchoscope (a tube with a small camera at the end) inserted into the trachea. This allows the doctor to see any abnormalities in the trachea, as well as remove cells for biopsy;
- Virtual bronchoscopy – an “image” of the trachea is made by a CT scan without the need for a bronchoscope. This exam does not allow for the removal of fragments for biopsy;
- Pulmonary function test – measures the functioning capacity of the lungs and can determine if there is a loss of respiratory capacity that suggests a blockage in the trachea.
Treatment for tracheal cancer
Surgery is the primary treatment for tracheal cancer. Whenever possible, it is followed by other therapies, such as radiation or chemotherapy. Understand the commonly adopted procedures.
- Surgery – Surgical resection improves prognosis, symptoms, and patient quality of life. Five-year survival is 50% for patients treated with surgery, compared to only 10% in patients who are not candidates for the procedure. Several factors are considered in the decision for surgical intervention, such as age, comorbidities, neck mobility, cancer extent, and invasion grade.
Surgery is not recommended for patients with tumors involving more than 50% of the length of the trachea, due to the correlation with increased mortality. Other contraindications for surgery include respiratory failure, dependence on oral corticosteroids, invasion of the heart or aorta, distant metastases, and involvement of multiple groups of lymph nodes.
- Radiation therapy – Can be used to treat tumors involving more than 50% of the trachea or that have spread to lymph nodes or other areas of the chest. It should be used in patients who are not good candidates for surgery. In the case of an adenoid cystic tumor, radiation therapy may be used after surgery. There are two types of radiation therapy for tracheal tumors:
External beam radiation: done daily on an outpatient basis, lasts a few minutes, and the patient generally does not feel anything, but side effects such as discomfort can occur; and
- Brachytherapy – involves the insertion of radiation “seeds,” which are temporarily implanted near the tumor to kill it. It is done on an outpatient basis through a bronchoscope that passes a tiny catheter through the tumor. The seeds are implanted in this catheter for a few minutes and then the catheter and seeds are removed.
- Chemotherapy – The literature lacks randomized clinical trials examining chemotherapy in patients with tracheal cell cancer, and the role of chemotherapy remains unclear. However, cisplatin-based chemotherapy is used in combination with radiation therapy in unresectable disease or after surgery, mainly for the squamous subtype, based on its similarity to head and neck tumors, where this combination is already well established.
Prevention of tracheal cancer
It is believed that the most common tracheal tumor – squamous cell carcinoma – is a direct result of smoking. That is, quitting smoking is a measure that reduces the likelihood of developing this type of cancer, as well as many others associated with the habit.
Another risk factor is hemangioma, which can spread from the face to the neck, but it is not a controllable risk.
Any of the symptoms associated with tracheal cancer need to be investigated early, increasing the chances of a cure if the disease is diagnosed.
