Laryngeal cancer is a malignant tumor that can affect the vocal cords and adjacent structures. Ninety-nine percent of laryngeal cancers originate in the laryngeal mucosa. The etiology of laryngeal cancer is unknown, although several factors have been clearly and evidently associated: tobacco and alcohol.
In the upper airway, tobacco acts as a carcinogenic substance and, by itself, is capable of inducing the transformation of normal mucosa into cancer. In fact, laryngeal cancers occur almost exclusively in smokers, and are exceptional in non-smokers. The risk of developing cancer in smokers is 60% – 160% higher compared to non-smokers.
Although alcohol is not carcinogenic per se, the effect of both is synergistic, facilitating the action of tobacco, especially in cancers of the supraglottis (above the vocal cords). There is also some genetic predisposition and viral infections (herpes simplex virus, human papilloma virus).
On the other hand, the consumption of fruits, vegetables and foods containing carotenes could reduce the risk. Gastroesophageal reflux and chronic vocal trauma are classically proposed hypotheses, but there are no convincing data on their responsibility in oncogenesis.
Frequency of laryngeal cancer
The incidence of laryngeal cancer ranges in central Europe between 9 and 10 new cases per 100,000 inhabitants. In Spain, this incidence – variable according to provinces or regions – ranges between 15 and 25 new cases per 100,000 inhabitants per year. Specifically, between 1997 and 2005, it is estimated that the annual incidence of laryngeal cancer in our country was 4,557 new cases. As we can deduce, Spain is among the countries with the highest frequency of laryngeal cancer. The average age at presentation is 60 years, with an interval from the fourth to the eighth decade of life. One woman is affected for every eight to nine men, although in other countries, such as the United States, the ratio is four to one.
Symptoms of laryngeal cancer
Dysphonia typically appears in a laryngeal form, progressively worsening. Fortunately, voice change allows early diagnosis. The involvement of the supraglottis (false bands or cords, epiglottis) may present with a clinical presentation of swallowing and/or voice alteration depending on the exact location of the tumor. Swallowing discomfort such as pain, foreign body sensation on swallowing or continued throat clearing are usually mild at first. Although the vocal cords are not affected at first, occupancy of the space above them may produce a more throaty voice. Later, a persistent irritative cough or cough with bloody sputum may occur, as well as more severe swallowing and breathing disorders, difficulty in feeding and consequent weight loss. Occasionally, referred pain to the ear on the same side may occur.
Diagnosis
Palpation of the neck allows evaluation of the presence of any deformity or painful spot in the thyroid cartilage, together with the presence (or not) of neck lymph nodes. The most commonly used radiological analysis in laryngeal cancer is computed tomography (CT), which allows delimitation of the size and extent, as well as the depth of growth. Magnetic resonance imaging (MRI) is a supplementary method of investigation in cases of early extralaryngeal growth or to evaluate the cartilage. Cartilage in general is very resistant to tumor invasion due to its low vascularization.
The use of positron emission tomography (PET) is still very limited but many investigations have already highlighted its high sensitivity and specificity for the early detection of lymph node metastases. Another of its main indications is the early detection of recurrences after radio and/or chemotherapy treatment, with better performance than classic imaging techniques. Ultrasound or ultrasound are innocuous and allow to delimit lymph nodes in the neck with high precision.
The so-called puncture-aspiration of lymph nodes in the neck, under ultrasound control, consisting of puncturing the lymph node and aspirating cells that can then be analyzed under the microscope, makes it possible to determine whether the lymph nodes are metastatic in the neck. This examination is especially indicated in nodes of uncertain origin: for example, when no primary tumor is observed but there is suspicion that the node is a metastasis.