For patients with oropharyngeal cancers, the days of morbid surgical outcomes, often leading to facial disfigurement, are gone after the switch nearly 20 to 30 years ago from early generation open surgery to high-dose radiation (RT) and chemotherapy (CT) as the dominant first-line treatment approach.
Explore This IssueSeptember 2021
Now, for select patients, surgery once again plays a major role as a first-line treatment. Transoral robotic surgery (TORS), a minimally invasive surgery using optics that now allow surgeons to see far into the oropharynx to target and excise cancerous tissue with flexible robotic arms, offers an efficacious and safe way to treat throat cancer and, importantly, reduce the long-term side effects of high-dose radiation that can drastically curtail quality of life for many patients.
“Transoral robotic surgery has brought surgery back into the armamentarium for treatment of oropharynx cancer,” said Eric Moore, MD, a head and neck surgeon in the department of otolaryngology–head and neck surgery at the Mayo Clinic in Rochester, Minn., who explained that robotic surgery allows for faster and easier removal of tumors through the mouth compared to other transoral approaches. It also allows surgeons to perform transoral surgery on tumors that otherwise would need to be excised using more extensive surgical techniques.
Benefits for HPV-Related Cancers
The benefits of this approach are expanding as the population of patients who would benefit from TORS grows and changes. (See the sidebar on page 17 for contraindications to TORS.) Unlike the majority of oropharyngeal cancers, which were once seen primarily in older men who were heavy smokers and drinkers, many oropharyngeal cancers diagnosed today are appearing in younger adults and are associated with the human papilloma virus (HPV).
“The epidemic of HPV-related throat cancers is forcing us to innovate and rethink how we used to do things,” said F. Chris Holsinger, MD, professor and chief of head and neck surgery at Stanford University, Palo Alto, Calif., noting that this group may account for as many as 20,000 patients with oropharyngeal cancers each year. “Diagnosis-and-radiate is really now a thing of the past,” he added.
It’s the younger age of these patients that’s driving the need to reduce the late effects of radiation-induced side effects, according to Dr. Holsinger. For these patients, the benefits of robotic surgery are unquestioned.
Greg Weinstein, MD, professor and vice chair of the department of otorhinolaryngology–head and neck surgery and co-chair of the Center for Head and Neck Cancer at the University of Pennsylvania Perelman School of Medicine in Philadelphia, who with his colleagues at the University of Pennsylvania in 2004 developed and later refined TORS, said that the development of TORS coincided with the rise in HPV-related oropharyngeal cancer. “It became evident in the early 2000s that high-dose chemoradiation, a technique developed for smoking-related squamous cell carcinoma, was leading to far too much toxicity in terms of damage to normal tissues and associated problems with radiation soft tissue damage and swallowing dysfunction for the healthy, younger population suffering from HPV-related cancer,” he said.
In 2009, the U.S. Food and Drug Administration (FDA) approved the use of the da Vinci Surgical System for TORS in patients with T1/T2 oropharyngeal cancer tumors as well as benign oropharyngeal lesions. Since then, evidence has shown that both oncologic and functional outcomes associated with TORS are positive, the latter due in part to the lower doses or the elimination of radiation therapy through TORS as the first-line treatment (Cancer Manag Res. 2018;10:839-846).
“Transoral robotic surgery results have shown good oncologic tumor control for selected oropharyngeal cancers, but the functional (swallowing) results, length of hospital stay, complication rates, and patient satisfaction for transoral robotic surgery have been shown to be superior to open surgical techniques for the same tumors, and often superior to chemotherapy and radiation therapy alone,” said Dr. Moore.
Nearly 12 years after its approval, use of TORS for oropharyngeal cancer still varies among institutions, according to Dr. Holsinger. Part of the reason may be the difficulty of comparing outcomes between treatment regimens—that is, between frontline surgery and frontline radiation. Oftentimes, with TORS, a lower dose of radiation therapy can be given postoperatively; sometimes radiation therapy is omitted completely. Dr. Holsinger explained that the postoperative dose of radiation after TORS might be reduced by 15% from the traditional dose of 70 Gray used when radiation is administered as a definitive treatment with chemotherapy. Lowering or eliminating radiation therapy has been shown to prevent or drastically reduce late radiation-associated dysphagia (RAD) and other complications, but the data are largely retrospective.
According to Dr. Holsinger, however, more evidence is coming soon. He believes compelling evidence from prospective trials funded by the National Institutes of Health will be available in the next couple of years. “We’re going to have level A evidence-based medicine to justify the use of TORS, and that will really transform the conversation among all otolaryngologists—even ones who don’t frequently see patients with oropharyngeal cancer,” he said. He noted that this higher level of evidence will be discussed at tumor boards just as Phase II/III clinical trials are now discussed when talking about chemoradiation. “We’ll have the same high-level evidence advocating the use of robotic surgery in appropriate patients,” he said.
Further data on the use of TORS in more advanced oropharyngeal cancers may expand the candidates for this surgery (Cancer Manag Res. 2018;10:839-846). Dr. Weinstein and his colleagues at the University of Pennsylvania are starting to publish excellent results, he said, using TORS for treating larger T3 and T4 oropharyngeal tumors while simultaneously reconstructing the oropharyngeal defect with free flap reconstruction (J Clin Oncol. 2020;38:15_suppl:6500-6500).
Critical for Dr. Weinstein and his colleagues is sharing their techniques with other surgeons through publications, online videos, and other forms of education to expand TORS use to institutions worldwide. Since its FDA clearance in 2009, Dr. Weinstein pointed out, the Robotic Surgery Laboratory in the department of otorhinolaryngology–head and neck surgery at the University of Pennsylvania has hosted over 500 international and national trainees for two-day didactic, hands-on cadaver and case observation courses. Prerequisites for participating in the courses include online training and participating in a full-day live porcine robotics lab. This training course for postgraduate trainees, he believes, is one of the important reasons behind the rapid adoption of TORS.
Other Current and Future Otolaryngology Uses
To date, TORS is most widely used in otolaryngology for select oropharyngeal cancers—largely management of throat and oropharynx cancers. But it’s also used for benign lesions, such as excising parapharyngeal space tumors to avoid neck incision, as well as in sleep surgery for base and tongue reduction for patients with sleep apnea.
Dr. Weinstein also said that TORS has become a standard of care option for the management of patients in whom a squamous carcinoma is found in a head and neck node without an obvious primary noted on clinical or radiologic exam. For these patients, including robotics in the workup of the palatine and tongue base tonsillectomy has allowed for identification of the primary in about 90% of patients, compared to 50% when robotics is not included. “This has resulted in a marked reduction of the use of radiation with or without chemotherapy to the primary site and or neck,” he said.
Where TORS doesn’t offer significant improvement, Dr. Weinstein said, is for the management of laryngeal cancer. “In my opinion, TORS does not offer significant improvement over either surgical or nonsurgical treatment modalities, and so, at least for the technology in its present form, does not offer significant benefit,” he said.
Dr. Weinstein emphasized that, to date and for the foreseeable future, the main role of TORS is in the treatment of HPV-related oropharyngeal cancer, parapharyngeal space tumors, and sleep apnea. For him, a drawback of robotic surgery in its present technology is the paucity of indications for general otolaryngology as well as other otolaryngologic subspecialties outside head and neck cancer.
When looking further down the road, advancements in technology may offer even greater tools to surgeons working in difficult-to-reach areas of the head and neck. Dr. Holsinger is excited by the possibilities of expanding the current technologies in robotics: the single-port (SP) system with 6-mm instruments on double-wristed joints that allows for greater flexibility of movement, and high-definition vision that allows the surgeon to view the inside of the mouth unlike anything in the past. “Beyond the single-port and its mechanical advantages, I’m excited about how advances in computer vision and artificial intelligence can transform and augment the surgeon’s judgement in real time,” he said.
Also highlighting the benefits of the SP system now available, Andrés Bur, MD, director of robotics and minimally invasive head and neck surgery and an associate professor in the division of head and neck surgery within the department of otolaryngology–head and neck surgery at the University of Kansas Medical Center in Kansas City, noted that the instruments used to operate within the oropharynx are still fairly large, making it challenging to get all the instruments into the mouth despite the benefits of the single-port system. “Our hope is that as the technology improves, it will expand our ability to use the robot in different areas,” he said.
One area of expansion would be endoscopic skull base surgeries. “A robot with flexible arms like our current robot could potentially improve surgeries of the skull base by allowing surgeons to go through the nose to operate on tumors in the skull base,” he said.
General Otolaryngologists and TORS
Noting that general otolaryngologists are the gatekeepers for triaging patients, Dr. Weinstein underscored their importance in recognizing the value of TORS for their patients and referring appropriate patients to a surgeon for consultation. “The most important development in my opinion will be for the triaging general otolaryngologist to recognize the value of the TORS for their patients with both HPV-positive and negative oropharyngeal cancer and create a partnership with TORS surgeons in their communities so we can offer more patients the benefits of this important technology,” he said.
Dr. Bur underscored the important role of general otolaryngologists in ensuring that the appropriate patients are given the opportunity to consider TORS, adding that, traditionally, general otolaryngologists have referred their patients to radiation and medical oncologists, so many patients have not been given the option of surgery. “I think TORS has expanded the options for patients. Otolaryngologists who see a patient with a suspected cancer should send those patients to a surgeon who has experience in robotic surgery to discuss if that patient is a good candidate for it.”
Mary Beth Nierengarten is a freelance medical writer based in Minnesota.