When cancer patients experience voice changes, such as hoarseness, a weakened or breathy quality, or even a complete loss of sound, it can be distressing. These alterations, medically termed dysphonia or aphonia, are a common concern during cancer diagnosis and treatment. The underlying reasons are varied, stemming from the tumor’s direct presence, cancer treatment side effects, or broader systemic health issues.
Direct Cancer Involvement
A tumor can directly impair voice production by physically interacting with structures involved in speech. Cancers in or near the larynx (voice box) frequently cause voice changes. Laryngeal cancer, particularly affecting the vocal cords, often causes persistent hoarseness or changes in voice quality. Tumors here interfere with vocal cord vibration, leading to noticeable alterations in sound.
Beyond the larynx, cancers in other parts of the body can also affect vocal function by impacting the nerves that control the vocal cords. The recurrent laryngeal nerve, a branch of the vagus nerve, is crucial for vocal cord movement. If a tumor presses on or invades this nerve, it can lead to vocal cord paralysis, resulting in a hoarse, weak, or breathy voice. This is relevant in thyroid cancer, where the nerve runs close to the gland and can be invaded. It also occurs in lung cancer, when chest tumors or enlarged lymph nodes compress the left recurrent laryngeal nerve.
Treatment-Related Side Effects
Cancer treatments can significantly impact vocal quality. Radiation therapy to the head and neck, especially involving the larynx, commonly causes voice changes. Radiation can lead to inflammation (mucositis or laryngitis), scarring, and fibrosis of vocal cords and surrounding tissues. This damages the delicate vocal cord surface, impairing vibration and causing hoarseness that may persist or become permanent.
Chemotherapy can also contribute to voice changes. Some drugs cause mucositis, an inflammation of the mouth and throat lining, making speaking painful and altering vocal resonance. Certain agents, like platinum-based drugs or vinca alkaloids, can cause neuropathy (nerve damage) affecting the recurrent laryngeal nerve, leading to vocal cord palsy. General weakness and fatigue induced by chemotherapy can also reduce the muscular support needed for strong voice production.
Surgical interventions, especially those in the head, neck, or chest, pose a direct risk to the vocal cords or the recurrent laryngeal nerve. Procedures like thyroidectomy or head and neck cancer surgeries can damage or require cutting this nerve to remove tissue. Such damage can result in vocal cord paralysis and persistent hoarseness or voice loss, with effects ranging from temporary to permanent depending on injury extent and nerve regeneration potential.
General Health and Systemic Factors
Beyond the direct effects of cancer and its treatments, the overall health of a patient can also contribute to voice changes. Cancer and its therapies often lead to general weakness and fatigue. This widespread weakness can reduce the muscular strength and coordination required for effective voice production, making it difficult to sustain vocalization or project the voice.
Immunosuppression, common with cancer and its treatments, increases infection susceptibility. Opportunistic infections, like oral thrush, can inflame and irritate vocal cords, causing hoarseness. Dehydration, common due to nausea, vomiting, or reduced fluid intake, also affects vocal quality. Insufficient hydration can dry out the vocal cords, making them less pliable and more prone to irritation and impaired vibration.
Systemic issues like anemia or nutritional deficiencies, common in cancer patients, can contribute to weakness and muscle wasting, impacting voice production. Gastroesophageal reflux disease (GERD), where stomach acid flows back into the esophagus, can also exacerbate voice problems. GERD is often worsened by cancer treatments or medications; the acid can irritate and inflame the larynx and vocal cords, leading to chronic hoarseness.