Transoral robotic surgery (TORS) is an option for treatment of small cancers arising at the palatine tonsil (side of the throat) or the lingual tonsil (base of the tongue). This surgical treatment includes removing the cancer from the throat via the mouth, as well as removal of lymph nodes from the neck via a typical incision in the external neck skin. The multidisciplinary H&N oncology team is typically weighing this as the alternative option to standard non-surgical treatment with combined radiation and chemotherapy for oropharynx cancer.
The TORS approach utilizes a retractor to open the mouth, and then the DaVinci SP surgical robotic device is positioned with flexible endoscope, two bipolar forceps, and one monopolar curved scissors through the mouth to the back of the throat. An assistant at the head also utilizes two sets of instruments through the mouth, while the surgeon operates the robotic instruments from a console in the room, which provides 3-D high-definition magnified view of the back of the throat. Incisions are made on the surface of the throat and the tumor completely excised with a margin of normal tissue completely surrounding the tumor. Pathologists evaluate this tumor resection, and deliver a report which assesses the histologic features in addition to confirming whether the margins are entirely clear of the invasive cancer. Confirmation of clear margins is a very good sign that the tumor in the throat will be completely controlled with this surgical approach.
The wound in the throat can typically be left alone, as a superficial wound, which heals by 'secondary intention' -- meaning the body will be able to seal the wound with new tissue and skin growth, just as happens on other parts of the external skin following an injury. This process of secondary intention healing can take approximately 6 weeks. During this period of time, there is pain and a sore throat especially with swallowing, which is altered initially after surgery, and then does normalize as the healing proceeds. There is a risk of bleeding from this tonsillectomy wound in the throat. Patient's usually take a liquid diet during the early weeks of recovery, and gradually transition to soft foods and then minced foods, and eventually return to normal swallowing. A feeding tube is not necessary, and neither is a tracheostomy tube.
A neck dissection removing lymph nodes from the at-risk lymphatic drainage levels of the neck is performed in conjunction with the TORS throat procedure. Though this does involve an incision in the neck skin and resulting scar, the cosmesis is good and there are typically well-tolerated side effects, including numbness of the skin and lower ear. It is possible to develop some weakness of the trapezius muscle, which is involved with lifting of the upper arm past 90 degrees at the shoulder; if this weakness develops, it is usually transitory though will typically be treated with engaging in physical therapy strengthening and range of motion exercises. During the neck dissection, we ligate the branches of the external carotid artery which feed the area of the throat undergoing TORS excision, to mitigate the risk of substantial arterial bleeding from the throat site during the post-operative period.
The lymph nodes from the neck are evaluated by pathologists, along with the tumor resection from the throat. This pathology information is used by the H&N tumor board to estimate risk of cancer recurrence following this surgical treatment. If the risk is elevated, further adjuvant treatments of radiation or chemotherapy are considered. This version of radiation is at a reduced dose compared to that given to the primary tumors if no surgery was done, which typically translates to reduced toxicity to the normal tissues of the head and neck and better tolerance of the treatment.
If no further radiation treatment is chosen following surgery, then followup period begins, which continues for several years. Recurrences of this cancer are usually seen within the first two years, and periodic imaging will be performed as a method of reassessing. A typical examination in the office at 3 to 4 month intervals with examination of the oropharynx surfaces and neck is also reassuring.
TORS treatment of oropharynx cancer is ideal when the size and number of involved lymph nodes is small, the primary tumor in the throat is relatively small (stage T1 or T2), there is no deep muscle involvement, and the anatomy of the tongue and jaw is conducive to a transoral exposure of the throat tumor. When the lymph nodes in the neck are matted, large, or numerous, or the primary throat tumor is large, endophytic or diffusely invasive with deep extension, TORS is not preferred, and treatment with combined radiation and chemotherapy is typically offered. The alternative surgical approach in these more advanced cases is with a mandibulotomy, along with a reconstructive flap procedure and necessitates a tracheostomy and feeding tube, and has higher degree of side effects.
For well-selected oropharynx cancer, the TORS approach offers substantial advantages over the alternatives, including shorter surgical procedure time and shorter hospitalization, no tracheostomy or feeding tube, possibility of avoiding radiation or lower dose radiation, and very good control of the cancer long-term.
