CO2 laser minimally invasive treatment of hypopharyngeal carcinoma

[Abstract]　With the improvement of people's quality of life requirements，minimally invasive surgery has become a new trend in the 21st century. Laser technology combined with endoscopic technology realized the minimally invasive treatment in hypopharyngeal cancer，as a result，fruitful research and application results have been achieved. With the emergence of emerging assistive technologies，the use of CO2 laser in the treatment of hypopharyngeal cancer would got a broader range，CO2 laser in hypopharynx cancer treatment there will be more prospects.

1. CO2 laser microsurgery for the development of laryngeal squamous cell carcinoma.

Laryngeal cancer is one of the common tumors in the head and neck. The treatment includes surgery, radiotherapy, and concurrent chemoradiotherapy. In 1972, Strong and Jako [1] applied CO2 laser to laryngeal microsurgery for glottic laryngeal cancer. Since then, laser surgery has developed rapidly. In some developed countries, it has accounted for 30% to 50% of all laryngeal cancer operations. growth trend. The advantages of laryngeal laser surgery are small damage, good functional preservation, quick recovery, short operation time, low cost, etc. It has also been reported that laser surgery can maintain hemoglobin levels and is beneficial for postoperative radiotherapy. There are many reports on its clinical efficacy, and the survival rate and local control rate have reached similar effects as radiotherapy and partial laryngectomy. The 5-year survival rate is 85%-100%, and the local control rate for early laryngeal cancer can reach 90%. %[2~5].
With the development of CO2 laser laryngeal microsurgery, its application is not limited to early glottic laryngeal cancer. In 1978, Vaughan [6,7] first used laser for the treatment of supraglottic cancer. In 1987, Düring et al [8] tried palliative treatment of 120 patients with stage III and IV laryngeal cancer. The laser and postoperative radiotherapy program was initially explored. In 1994, Zeitels et al [9] also began to use laser alone to treat laryngeal cancer and laryngeal and pharyngeal cancer. Later, some doctors in Europe began to apply laser surgery to supraglottic laryngeal cancer, laryngeal squamous cell carcinoma and advanced tumors. A more satisfactory result. In the past decade, laser surgery has developed rapidly. In some developed countries, laser surgery has become the only treatment for laryngeal cancer, while the development of laser treatment in the United States and other regions is relatively slow. For example, in the Netherlands, laryngeal function preservation is placed in the first place, so laser and partial laryngeal surgery are only an alternative and adjuvant treatment for laryngeal cancer preferred radiotherapy [10]. With the promotion of laser application in the treatment of laryngeal squamous cell carcinoma, CO2 laser has also begun to be used in the treatment of recurrent laryngeal cancer. It has been reported in the literature that recurrence after radiotherapy or recurrence after laser surgery can be re-selected with laser therapy [11-13]. Obtaining similar effects to open surgery, with lower complications and less trauma.

2. CO2 laser treatment of laryngeal and pharyngeal cancer in China

In 1991, our hospital first used CO2 laser for laryngeal microsurgery and published a literature on CO2 laser treatment of T1 glottic laryngeal cancer [14], which opened the door for domestic CO2 laser treatment of laryngeal and pharyngeal cancer. With the maturity of technology and accumulated experience in treatment, CO2 laser is not only applied to the treatment of early glottic laryngeal cancer, but also for the treatment of supraglottic laryngeal cancer and laryngeal carcinoma [15,16]. The effect is remarkable, and the throat function preservation effect is good (Fig. 1, Fig. 2). The treatment of CO2 laser in laryngeal and pharyngeal cancer is becoming more and more mature and has been promoted. Various reports on the treatment of early hypopharyngeal carcinoma have been reported all over the world. At present, CO2 laser is applied to primary laryngeal cancer, and it is also used for recurrence after radiotherapy or recurrent salvage treatment after laser surgery. When the effect is similar to open surgery, the complications are lower and the trauma is smaller. Most of the viewpoints suggest that most of the early recurrence (rT1, rT2) lesions, especially those without pre-invasion, are suitable for laser treatment. For the former combined recurrent lesions, careful evaluation of the degree of thyroid cartilage invasion and exclusion of the laryngeal frame structure may be cautious. The salvage treatment method was chosen [11,12,17]; the clinical trial of CO2 laser treatment of T3 supraglottic laryngeal cancer and T3 hypopharyngeal carcinoma was also carried out with our hospital as the lead unit.

3. CO2 laser treatment of laryngeal carcinoma progression

With the continuous improvement of technology and equipment, there have been treatment devices that can make up for the patients who have not been exposed to laryngeal microsurgery. The fiber CO2 laser has solved the problem that the laser output from the light guide arm has been linearly transmitted and cannot enter the throat. Problems with exposed areas [18]. The emergence of narrow band imaging (NBI) technology has promoted the early treatment of laryngeal cancer by CO2 laser. NBI endoscopy is also called "electronic staining endoscope", which will pass the red, green and blue in the ordinary white endoscope. The longest wavelength of red light in the light is filtered out, releasing only blue light with a center wavelength of 415 nm and green light of 540 nm. This optical adjustment can limit the depth of penetration of the illuminating light to the surface of the tissue, highlighting the observation of the fine structure of the mucosal surface, especially the microscopic vascular structure and morphology of the mucosal surface. When the surface of the mucosa is diseased, IPCL (intraepithelial papillary capillary vasospasm) morphological abnormal changes, such as expansion, prolongation or distortion, NBI mode can display abnormal IPCL morphology is very clear, not only can clearly show the microscopic lesions on the mucosal surface, but also identify The accuracy of neoplastic and non-neoplastic lesions is significantly improved, and the detection rate and diagnostic accuracy of endoscopic lesions are significantly improved [19, 20] (Fig. 3). In the literature, NBI is combined with traditional CO2 laser to better and more accurately determine the boundary of the tumor and reduce the possibility of positive margin [21]. There have been reports of malignant tumors that can be combined with robotic surgery and CO2 laser [22].

4. Future development direction.

At present, the development of tumor surgery is becoming more and more individualized, and the requirements for functional preservation are gradually improving. In the future, it is necessary to explore the treatment of CO2 laser in advanced laryngeal squamous cell carcinoma, and combine the prior art with CO2 laser. In microsurgical treatment, the patient's quality of life is further improved, and the recurrence rate and mortality of the disease are reduced.

References
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Huang Zhigang
Department of Otolaryngology Head and Neck Surgery, Key Laboratory of Otorhinolaryngology Head and Neck Surgery, Capital Medical University, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
Anhui, chief physician, professor, doctoral tutor, mainly engaged in the basic and clinical research work of head and neck surgery.