"Could Cancer Recur Along the Armpit?" Robotic Thyroid Cancer Surgery Leaves No Scar—and No Recurrence [Health Check]

[Financial News] Transaxillary robotic thyroid surgery, which leaves no scar on the neck, has also shown stable long-term cancer treatment outcomes. After more than 10,000 patients were followed for over five years, the recurrence rate was less than 1%.
A research team led by Professor Sang-Wook Kang and Clinical Instructor Ryu, Jae Sang, of the Department of Thyroid and Endocrine Surgery at Yonsei Cancer Center announced on the 29th that it had followed 10,504 patients with differentiated thyroid cancer who underwent transaxillary robotic thyroid surgery. Cancer recurred in 97 patients, or 0.9%. The findings were published in the international journal Surgical Endoscopy.
Differentiated thyroid cancer is a type of cancer that retains relatively many characteristics of normal thyroid cells and accounts for most thyroid cancer cases. It tends to progress slowly and has favorable treatment outcomes, but it can recur long after surgery, making continued monitoring necessary.
Thyroid cancer surgery is usually performed through an incision in the front of the neck. By contrast, transaxillary robotic thyroidectomy involves making an incision in the armpit and inserting robotic instruments to remove the thyroid. Its advantages include leaving no noticeable scar on the neck and allowing surgeons to use the robot's precise movements and magnified field of view.
Although the safety and treatment effectiveness of this surgical method have been confirmed worldwide, few studies have followed large numbers of patients over an extended period to analyze when and where the cancer recurs. It has also remained unclear whether the surgical route from the armpit to the thyroid affects the location of recurrence.
The research team analyzed the clinical and pathological data of patients who underwent the procedure at Yonsei Cancer Center between 2007 and 2024. Along with recurrence rates, the team examined the locations and timing of recurrence by anatomical region.
Among the 97 patients with structural recurrence confirmed through imaging or biopsy, 87 patients, or 89.7%, had recurrence at a single site, while 10 patients, or 10.3%, had recurrence at two or more sites. By location, recurrence in the lateral cervical lymph nodes on the operated side was the most common, with 48 cases. This was followed by 38 cases in the remaining contralateral thyroid, 12 in the central neck lymph nodes, and four in the lateral cervical lymph nodes on the opposite side of the surgery.
The recurrence that had raised concerns—recurrence around the surgical route—was extremely rare. Three patients, or approximately 0.03%, experienced recurrence in areas such as muscle or skin outside the cervical lymph node regions. Only two of these cases occurred along the route taken by the robotic instruments. All were detected within five years of surgery.
The factor that determined the location of recurrence was the patient's lymph node metastasis status at the time of surgery. Patients with metastasis to the central neck lymph nodes showed more recurrence in the lateral neck on the operated side, while those with metastasis to the lateral cervical lymph nodes showed more recurrence in the central neck. Eight of the 12 central neck recurrences occurred in patients with lateral neck metastases. Central neck recurrence occurred equally on the side approached by the robot and on the opposite side, with four cases each. This showed that recurrence was influenced more by the extent of lymph node metastasis and the characteristics of the cancer than by the direction of surgery.
The timing of recurrence also differed by location. Recurrence in the lateral cervical lymph nodes was detected relatively early, whereas recurrence in the central neck lymph nodes and the remaining contralateral thyroid continued to occur five years after surgery and, in some cases, as long as nine years later.
The research team explained that the findings provide evidence that transaxillary robotic thyroid surgery can produce stable long-term cancer treatment outcomes when patients are appropriately selected. The team also stressed the need for personalized long-term follow-up, with the areas and duration of monitoring tailored to the patient's initial lymph node metastasis status. In particular, patients with lateral neck metastases require closer monitoring of the central neck.
Professor Sang-Wook Kang said, "Recurrence after transaxillary robotic thyroid surgery is more closely associated with the patient's extent of lymph node metastasis than with the surgical method or the direction of instrument access." He added, "Because this surgery is not a procedure that should be applied uniformly to every thyroid cancer patient, candidates must be selected carefully after comprehensively considering the cancer's size and location, the extent of lymph node metastasis, and other factors."
[email protected] Medical Specialist Reporter Jeong Myeong-jin Reporter