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Outcomes for patients with papillary thyroid cancer who do not undergo prophylactic central neck dissection. BJS 2016; 103: 218-225.

Published: 29th October 2015

Authors: I. J. Nixon, L. Y. Wang, I. Ganly, S. G. Patel, L. G. Morris, J. C. Migliacci et al.

Background

The role of prophylactic central neck dissection (CND) in the management of papillary thyroid cancer (PTC) is controversial. This report describes outcomes of an observational approach in patients without clinical evidence of nodal disease in PTC.

Method

All patients who had surgery between 1986 and 2010 without CND for PTC were identified. All patients had careful clinical assessment of the central neck during preoperative and perioperative evaluation, with any suspicious nodal tissue excised for analysis. The cohort included patients in whom lymph nodes had been removed, but no patient had undergone a formal neck dissection. Recurrence‐free survival (RFS), central neck RFS and disease‐specific survival (DSS) were calculated using the Kaplan–Meier method.

Results

Of 1798 patients, 397 (22·1 per cent) were men, 1088 (60·5 per cent) were aged 45 years or more, and 539 (30·0 per cent) had pT3 or pT4 disease. Some 742 patients (41·3 per cent) received adjuvant treatment with radioactive iodine. At a median follow‐up of 46 months the 5‐year DSS rate was 100 per cent. Five‐year RFS and central neck RFS rates were 96·6 and 99·1 per cent respectively.

Conclusion

Observation of the central neck is safe and should be recommended for all patients with PTC considered before and during surgery to be free of central neck metastasis.

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2 Comments

Kirsty McFarlane

3 years ago

We were interested to read Nixon et al.’s retrospective cohort study, concluding that in all patients with PTC and no evidence of central neck metastasis, observation of the central compartment is safe. However there are a number of issues with this paper that makes this statement hard to justify from the data presented.

The flow chart demonstrating the number of eligible patients and their nodal status raises some queries. Of 3665 patients with thyroid cancer, 419 and 378 patients were excluded as they underwent central neck dissection (CND) alone and central and lateral lymph node dissection respectively. Further along the flow chart, another group of 338 patients are excluded for a CND. It is unclear how this second group of excluded patients were different from the first.

The final cohort of 1798 patients are then categorized into pN0 (n=864), pN1 (n=260) and pNx (n=674) according to their lymph node status. Does this imply that some lymph nodes were (inadvertently or otherwise) retrieved as part of the thyroidectomy? If this is the case, how do the authors account for patients having up to 27 lymph nodes excised with a thyroidectomy alone? Do the authors routinely ‘sample’ the central compartment? In our understanding, a standard ‘total thyroidectomy without central neck dissection’ would usually contain none but occasionally 1-2 lymph nodes.

In addition, a number of patients were classified as having N1b disease (despite not having a LND). This suggests involvement of nodes in the lateral compartment of the neck (levels II – V). How is this compatible with the premise of the paper?

Patients were only followed up for a median of 46 months with a range of 1-320 months. In our opinion, this is a very short period of time to exclude the benefit of any intervention (i.e. prophylactic neck dissection) in differentiated thyroid cancer. One study has reported recurrence rates of up to 21% between 10-20 years after diagnosis1 and another of 23% after five years2.

We were surprised to note that of nearly 1800 patients none had evidence of either permanent hypocalcaemia or recurrent laryngeal nerve palsy, and would be interested to hear how these were defined by the unit and what special techniques were employed to prevent these complications.

Emma Collins
Beverly Lim
Saba Balasubramanian

Department of Endocrine Surgery
Sheffield Teaching Hospitals NHS Trust
Royal Hallamshire Hospital
Glossop Road
Sheffield, S10 2JF
UK
emmacollins100@hotmail.com

References:
1. Grogan RH, Kaplan SP, Cao H, et al. A study of recurrence and death from papillary thyroid cancer with 27 years of median follow-up. Surgery 2013; 154: 1436–46; discussion, 1446–7.
2. Durante C, Montesano T, Torlontano M, et al. Papillary thyroid cancer. Time course of recurrences during post surgery surveillance. JCEM 2013; 98: 636-42.

Kirsty McFarlane

3 years ago

We thank Collins et al. for their interest in the controversial subject of elective central neck dissection (CND) for papillary thyroid cancer.

Our first group of exclusions were based upon clinico-pathological characteristics. The remaining group were filtered to exclude anyone coded surgically as having a CND leaving 1798 patients. The complication rate for salvage neck surgery, not the group as a whole, was reported in the results.

In current practice, a compartment orientated CND of levels 6 and 7 would be performed for proven metastatic disease. However, particularly in early years prior to the introduction of routine ultrasound and FNA, generous nodal sampling of the neck was performed. Positive level 7 disease would confer N1b status and our results confirm such patients to be at higher risk of recurrent disease. Excluding such patients would have reduced overall recurrence rates further, strengthening the argument that observation of the central neck in the absence of metastatic disease is safe. Recurrence in this low-risk group is extremely rare. Although longer follow-up is always desirable, the reference they cite highlights the fact that the around 70% of recurrences occur in the first 5 years and more importantly that overall recurrence rates of <2% confirm that large numbers of recurrences are not being overlooked (1).

Surgeons managing this low-risk group of patients must balance the very low rate of central neck recurrence against the additional morbidity of elective CND when advising patients on the most appropriate treatment for cT1/2,N0,M0 papillary thyroid cancer.

IJ Nixon
LY Wang
I Ganly
SG Patel
LG Morris
JC Migliacci
RM Tuttle
JP Shah
AR Shaha

Head and Neck Surgery
Memorial Sloan Kettering Cancer Center
1275 York Avenue
New York NY10021
USA
iainjnixon@gmail.com

References:
1. Durante C, Montesano T, Torlontano M, Attard M, Monzani F, Tumino S, et al. Papillary thyroid cancer: time course of recurrences during postsurgery surveillance. J Clin Endocrinol Metab 2013; 98(2): 636-42.