Frequently asked questions about vocal cord cancer
Cancer of the larynx (voice box) is relatively rare in the general population, with an estimated 13,360 new cases diagnosed in the United States in 2017.1 About half of those cases arise on the vocal cords 2 (as opposed to other sites of the larynx), and 50% - 65% of these are considered “early stage” vocal cord (glottic) cancer: this translates to approximately 3300 to 4500 new cases of early vocal cord cancer per year in the United States by recent estimates.
Like the majority of head and neck cancers, most vocal cord cancers arise from the surface membrane, with the most common type being squamous cell carcinoma (SCC).
Because they are solid masses that arise on the vocal cord(s), they distort the ability of the vocal cords to close and/or vibrate normally during sound production. Vocal cord cancers usually present with the initial symptom of hoarseness; often the degree of voice change is of a magnitude that others (in addition to the patient) can hear. For early stage vocal cord cancer, there is typically no pain, change in breathing or swallowing, or coughing up of blood.
Like other cancers, vocal fold cancer is staged by the TNM Staging System:
T = original (primary) tumor,
N = regional lymph node status,
M = distant metastasis status.
The T stage ranges from T1 (lowest) to T4 (highest). Overall stage is a combination of T, N, and M status – ranging from I (earliest) – IV (highest). Early stage cancer is considered stage I or stage II.
Glottic cancer T stage depends on geographic cancer distribution along one or both vocal folds, whether the cancer has spread to the laryngeal tissues above the vocal folds (supraglottis) or laryngeal tissues below the vocal folds (subglottis) ,and whether the normal opening / closing capabilities of the vocal folds during breathing and speaking are preserved or absent. Specifically:
T1a = cancer limited to one vocal fold (but not supraglottis or subglottis), with both vocal folds fully mobile
T1b = cancer involves both vocal folds (but not supraglottis or subglottis) with both vocal folds fully mobile
T2 = either cancer extension to other portions of the larynx (supraglottis or subglottis), and/or impaired vocal fold mobility
T3 = cancer limited to the larynx with vocal cord fixation or paraglottic space involvement, or minor thyroid cartilage erosion (eg inner cortex)
T4 = cancer invading beyond the larynx
An early stage vocal fold cancer is one with a T stage including T1a, T1b, or T2 and no lymph node metastases to the neck (N0) and no distant metastases (M0) . Cancers that meet these criteria are stage I if T1a or T1b, and stage II if T2.
Treatment of VOCAL CORD CANCER
Unlike other head and neck cancers, early stage vocal cord carcinoma has a low tendency to metastasize (spread to sites beyond the initial presenting location). As a result, treatments for early vocal cord cancer are typically limited to the vocal cords(s) themselves.
In general, treatment for early stage vocal cord cancer is either surgical excision or radiation therapy. Surgery is usually performed in one or sometimes two operations, and most commonly is done in a minimally invasive way (through the mouth) under general anesthesia using a laser, or less commonly with “cold steel” micro-instruments (eg microflap excision). Radiation therapy is typically administered over 6 weeks, 5 days / week, in small doses. Chemotherapy generally has no role in the treatment of early stage vocal cord cancer.
Fortunately, most early stage vocal cord cancers are highly curable (local control rates between ~75 - 90+% at 5 years, depending on stage and the particular study), irrespective of whether surgery or radiation is used.
Since ~ 2004, a growing number of laryngeal surgeons have started performing endoscopic surgical resection of early stage vocal cord cancers using angiolytic lasers, most recently the KTP laser [link to KTP laser page]. There is emerging data showing that, in experienced hands, the cure rate of the KTP laser for this disease is equivalent to more conventional minimally-invasive surgical techniques (eg CO2 laser surgery) or radiation.
Before Vocal Cord Cancer Surgery
After Vocal Cord Cancer Surgery
KTP Laser Vocal Cord Cancer Surgery - Treatment Examples
Squamous cell carcinoma of the right vocal fold (left side of image), as viewed on office examination
Squamous cell carcinoma of the right vocal fold (same lesion as in previous image), as viewed in the operating room.
High magnification operating room image of vocal fold squamous cell carcinoma with KTP laser fiber aimed at cancer, just prior to firing of the laser, and a split second later, during pulsed firing of the laser. While the KTP laser is green, it appears yellow in this picture due to a protective filter for the surgeon’s eyes. The deep plane has been cleared of cancer in the bottom portion of the left image.
Low power magnification in the operating room showing right vocal fold cancer mid-ablation with the KTP laser. The deep plane of the tumor is being methodically mapped with ultra-narrow margins so as to maximally preserve non-cancerous tissue and voice.
End point of treatment in the operating room after KTP laser assisted excision of the right vocal fold cancer.
Disclaimer: It is to be emphasized, that there is a limit to what can be achieved with the KTP laser photoablation method for treating glottic cancer. In particular, this technique is applicable to mainly to early stage glottic cancers that arise from the surface (eg squamous cell carcinomas), not to advanced stage ones (stage III or IV). Moreover, this KTP laser photoablation technique is not generally successful in treating cancers originating in other parts of the larynx (supraglottis or subglottis) or head and neck, which act biologically different, even though they are still commonly the same cancer type (squamous cell carcinoma).
How is the KTP laser different from other surgical treatments?
On its own, the KTP laser is simply a tool, and optimal oncologic and voice outcomes in treating glottic cancer still require meticulous operative laryngoscopy, high-powered magnification at all times, and prudent surgical judgment. Nevertheless, with these pre-requisites in place, the KTP laser can be used to methodically vaporize (photoablate) early stage glottic squamous cell carcinoma (SCC), as opposed to the traditional method of cutting around it with a margin of normal tissue, as is typically been done with the carbon dioxide (CO2) laser or sometimes “cold” microinstruments (for smaller cancers). The physics of the KTP laser allow it to preferentially target tissues that have an increased blood vessel content, like cancer.
The KTP laser photoablation technique capitalizes on the fact that most early stage glottic SCC’s are not a uniform depth over the entire surface area of their disease. Provided that they have not been previously treated, glottic SCC’s are essentially contiguous masses that are deepest at their epicenter but become increasingly superficial as they approach the peripheral boundary with normal, healthy vocal fold tissue. There is commonly avisually identifiable, variable length zone of pre-cancer (dysplasia) at the surface perimeter; but treatment in these areas need not be over-aggressive if voice is to be maximally preserved.
The KTP laser photoablation technique precisely “maps” a vocal fold cancer (in a relatively bloodless field) along its entire deep surface and periphery, with ultra-narrow margins. The end result is that the maximum amount of normal, non-cancerous tissue on the affected vocal fold(s) is saved, without sacrificing oncologic effectiveness. It is not uncommon for patients with shallow but bulky early vocal fold cancers to actually have vocal improvement (and not degradation) after healing from KTP laser treatment.
What Are the Voice Outcomes of the KTP Laser?
Because early glottic cancer is relatively curable by any treatment modality, a key treatment outcome is the quality of the voice. As opposed to radiation therapy (or even CO2 laser resections, which are typically done with small margins of normal vocal fold tissue), KTP laser treatment of early glottic cancer focuses on removing only the portions of the vocal fold(s) that are affected by cancer, leaving the non-diseased areas undamaged, so as to maximally preserve voice quality. This is a result of both the surgical technique used (photoablation) and the physics of the KTP laser itself, which cause it to be preferentially absorbed by tissues that have a dense blood supply (like cancers). Contrast this to the physics of the CO2 laser, which has an affinity for water, not blood.
The end result is that KTP laser treatment of early glottic cancer may translate into superior voice outcomes compared to traditional endoscopic surgical techniques (CO2 laser or cold instrument microflap excision). In fact, one study on voice outcomes of the KTP laser treatment of early glottic cancer found that the need for surgical reconstruction of the voice following use of the KTP laser was approximately 25% of the need in a similar historical cohort of different patients who were previously treated with the CO2 laser or microflap excision, presumably as a result of removal of less normal, non-cancerous vocal fold tissue.
Before Vocal Cord Cancer Surgery
After Vocal Cord Cancer Surgery
Examples of Early Glottic Cancer – Before and After KTP Laser Surgery
Before and after KTP laser surgery for squamous cell carcinoma of both vocal cords. The patient is more than 3 years beyond treatment without evidence of cancer recurrence.
Before and after KTP laser surgery for squamous cell carcinoma of the left vocal fold (right side of image). The patient is more than 3 years beyond treatment without evidence of cancer recurrence.
Before and after KTP laser surgery for squamous cell carcinoma of the right vocal fold (left side of image). The patient is more than 2 years beyond treatment without evidence of recurrence.
Before and after KTP laser surgery for squamous cell carcinoma of the left vocal fold (right side of image). The patient is more than 1 year beyond treatment without evidence of recurrence.
Before and after KTP laser surgery for squamous cell carcinoma of the right vocal fold (left side of image). The patient is more than 1 year beyond treatment without evidence of recurrence.