Lymph node dissection during thyroidectomy linked to reduced re-operation risk
Patients with medullary thyroid carcinoma (MTC) who underwent lateral and central neck dissection during the initial thyroidectomy procedure were less likely to require re-operation, a recent study found.
“This result supports the recommendation for routine central neck dissection in MTC and the consideration of lateral neck dissection in high-risk patients,” the researchers said.
Researchers analysed data from the California Cancer Registry and the Office of Statewide Health Planning and Development of individuals with MTC who underwent thyroid surgery between 1999 and 2012 and had two or more years of postoperative follow-up (n=609, mean age at diagnosis 52.6 years, 60.8 percent female). Of these, 35.5 percent (n=216) underwent central lymph node (neck) dissection and 25.5 percent (n=155) underwent central and lateral lymph node dissection during the initial thyroidectomy.
About 16 percent of patients required re-operation (n=99) with a median 6.4 months between procedures, 45.5 percent of whom (n=45) remained disease-free after a median 7.7 years follow-up. Of patients who did not undergo re-operation, 69.4 percent (n=354) were disease-free at a median 5.7 years of follow-up.
Patients with lymph node metastasis were more likely to require re-operation (hazard ratio [HR], 3.43, 95 percent confidence interval [CI], 2.00–5.90; p<0.001). Conversely, patients who underwent lateral and central neck dissection during the initial thyroidectomy had a lower risk of re-operation (HR, 0.53, 95 percent CI, 0.30–0.93; p=0.03). [JAMA Surg 2017;doi:10.1001/jamasurg.2017.3555]
Patients who underwent central neck dissection alone did not have a lower risk of re-operation, though the researchers put this finding down to limitations in coding in the Registry database, or that the impact of central neck dissection may differ by disease stage, for example, patients with distant disease being less likely to undergo re-operation.
Re-operation was not a risk factor for disease-specific mortality, though disease-specific mortality risk was elevated in patients of older age (HR, 1.36 per decade; p<0.001), patients with a larger tumour size (HR, 2.83 and 2.89 for tumour size >2 to 4 cm and >4 cm, respectively; p=0.03 for each compared with tumour size of 0–1 cm), patients who received external beam radiotherapy (HR, 2.14; p=0.007), and those with advanced stage disease (HR, 4.77 and 21.08 for regional and metastatic disease, respectively; p<0.001 for each compared with localized disease).
“Prophylactic central neck dissection has been part of the standard treatment of MTC for decades based on the high frequency of lymph node metastasis and increased cure rates after compartment-oriented neck dissection. This recommendation is reflected in current [American Thyroid Association] guidelines. However, adherence to these practice standards is poor,” said the researchers.
Based on the small proportion of patients in this study who underwent central neck dissection during the initial procedure, it appears that many patients with MTC are undergoing treatment that conflicts with recommendations, they said.
While MTC has been associated with an elevated risk of persistent and recurrent disease, the short median time frame between the initial procedure and re-operation in this study suggests that re-operation was mostly done for persistent disease, they added. However, gaps in data limited, among others, the ability to identify size and location of metastasis or whether the lack of surgery was due to issues with diagnosis.