Joshua D. Waltonen, MD
Assistant Professor of Otolaryngology
Comprehensive Cancer Center
Wake Forest Baptist Medical Center
Christopher A. Sullivan, MD
Associate Professor of Otolaryngology
Wake Forest Baptist Medical Center –
Comprehensive Cancer Center
The incidence of oropharyngeal squamous cell carcinoma (OPSCC) has been steadily increasing over the last few decades, mostly due to HPV, which is now associated with the majority of newly diagnosed cases of OPSCC. If current trends continue, projections indicate that HPV-related OPSCC may constitute the majority of all head and neck cancers by the year 2025. These patients are likely to be nonsmokers and are typically younger, with higher education levels and socioeconomic status than tobacco-related OPSCC patients.
Long-term data indicate that HPV-related OPSCC has better survival rates than tobacco-related OPSCC, especially in advanced stages (III and IV).
Historical Management of OPSCC
In previous decades, therapy for advanced OPSCC involved a composite surgical resection, followed by adjuvant radiotherapy (RT) or chemoradiotherapy (CRT). This surgery was quite morbid, involving facial incisions, division or removal of the mandible, and disarticulation of the tongue and pharyngeal muscles. Reconstruction utilized insensate pedicled or microvascular flaps. Long hospitalizations, need for tracheotomy and gastrostomy tubes, and poor speech and swallowing outcomes were typical and expected following these surgeries. Poor functional outcomes were only intensified by side effects of adjuvant therapy.
In the early 1990s, concurrent chemotherapy and radiotherapy for definitive treatment of laryngeal cancers proved successful and was adapted to treat advanced-stage OPSCC. This strategy allowed high cure rates and retained organ function in many patients, without the disfigurement and disability of traditional open surgical procedures. With the onset of the HPV-related OPSCC epidemic, survival rates exceeded 75%. However, long-term toxicities of definitive CRT, including xerostomia, tissue fibrosis, osteoradionecrosis, dysphagia, and g-tube dependence rates of 10% to 40%, reduced overall long-term quality of life.
Emergence of Transoral Surgery
The rise in popularity of definitive CRT for OPSCC carried with it recognition of long-term associated swallowing dysfunction and encouraged the development of several minimally invasive surgical approaches, in which exposure was achieved transorally using a headlight or microscope, and tumors were resected using endoscopic instrumentation and CO2 lasers. Drawbacks of these approaches included difficult exposure, poor lighting, and inability in some cases to adequately remove the posterior or inferior extent of tumors. The learning curve for these techniques was steep and expertise was limited to a few centers nationwide.
To address some of the shortfalls of existing minimally invasive techniques, a new transoral approach to the oropharynx was developed at the University of Pennsylvania beginning in 2006, using the daVinci surgical robot (Intuitive Surgical, Sunnyvale, California). Traditional transoral approaches lacked adequate lighting and exposure of distal oropharyngeal locations; thus, the robot, with its stereoscopic, high-definition display and articulating arms, provided the perfect tool to approach oropharyngeal cancers.
Transoral robotic surgery (TORS) involves inserting a camera into the mouth to provide illumination and visualization, with two miniature arms on either side of the camera that manipulate and divide tissue. These arms are controlled by the surgeon at a remote console, translating the surgeon’s large arm and hand movements at the console into fine, precise actions in the mouth. TORS eliminated some of the difficulties presented by the earlier minimally invasive approaches and quickly gained momentum nationwide as the ease of use became recognized and favorable initial results were published.