Preoperative Detection of Cervical Lymph Node Metastases in Papillary Thyroid Cancer: A Surgical Perspective

Abstract

Despite its relatively benign biological behavior, papillary thyroid cancer is frequently associated with cervical lymph node metastases at the time of diagnosis. These metastases have a limited impact on overall survival, but are recognized as a significant risk factor for locoregional recurrence of the disease. This may significantly alter quality of life, and may require further therapeutic interventions which may be associated with increased morbidity. Therefore, preoperative identification of cervical lymph node metastases is of particular importance and allows optimal and effective treatment at the time of initial surgery. Clinical examination remains important but lacks sensitivity. Neck ultrasonography is currently the most useful method to detect cervical lymphadenopathy. Fine-needle aspiration (for cytology and thyroglobulin measurement), usually under ultrasonographic guidance, may confirm the diagnosis of lymph node metastases. Other imaging methods (including computed tomography, magnetic resonance imaging, positron emission tomography) should be used selectively. A compartmentoriented cervical lymph node dissection should be performed at the time of thyroidectomy if preoperative evaluation reveals cervical lymphadenopathy.

The relevance of preoperative ultrasound cervical mapping in patients with thyroid cancer

“…Our results confirmed that US mapping is a reliable tool for detecting affected LNs. With an PPV of 83.82% for the LC and CC together with advantages, such as simplicity, ease in terms of performance, wide availability, comparatively low price, noninvasiveness and lack of radiation, 12 US mapping is an excellent tool for surgery guidance. The relatively low rate of detection of metastatic LNs in the CC might be explained by anatomic limitations in that area of the neck, such as the clavicle, sternum and tracheal air shadow.…”

“…3,20 Micrometastases (< 2 mm) in patients undergoing prophylactic LN dissection were found in up to 80% of individuals. 12,25 Nevertheless, such micrometastases are not clincially relevant, as palpable lymphadenopathies do not develop in most patients with PTC. On the contrary, patients presenting with macrometastases (> 2 mm) have 5%-40% persistent/recurrent (P/R) disease after surgery, 26,27 which has a tremendous impact on quality of life, and despite the additional therapeutic interventions, 10% of patients die from the disease.…”

“…9 Central neck dissection is even associated with a higher rate of complications, such as hypocalcemia, recurrent laryngeal nerve palsy, hematoma, chyle leakage and spinal accessory nerve dysfunction. 10,11 Lymph node involvement can be detected by physical examination, which has a sensitivity as low as 15%-30%, 8,12 whereas neck imaging is highly efficient; high-resolution ultrasonography (US) in particular is able to detect nodules as small as 5 mm. In addition, computed tomography (CT) can be used for staging LNs in patients with thyroid carcin oma.…”

Patterns of Lymph Node Metastasis in Differentiated Thyroid Cancer; Clinical Implications with Particular Emphasis on the Emerging Role of Compartment-Oriented Lymph Node Dissection

“…This classification system is composed of 7 major nodal regions (levels or compartments I-VII) and defines a compartment-oriented neck dissection. Sublevel classification is also used when certain zones within the larger levels have independent biologic significance [6,9]. The classification of cervical lymph nodes is schematically described in figure 1.…”

“…Occasionally, skip metastases can occur, but in general lymphatic dissemination occurs in a stepwise fashion [2,3,4,5]. Accurate knowledge of these metastatic patterns, in addition to a detailed and reliable preoperative ultrasonographic lymphatic mapping of the neck, will allow a more selective and rational therapeutic approach in patients with DTC and lymph node metastases, thereby avoiding routine extensive dissections and their associated increased morbidity [6,7]. The aim of this brief report is to summarize currently available data regarding the patterns of cervical lymph node metastasis in patients with DTC; clinical implications for the practicing surgeon will be briefly discussed, with a particular emphasis on the emerging role of compartment-oriented (so-called ‘selective') CLND, based on the findings of preoperative ultrasonographic lymphatic mapping.…”