Is routine dissection of level II-B and V-A necessary in patients with papillary thyroid cancer undergoing lateral neck dissection for FNA-confirmed metastases in other levels.

BACKGROUND: The purpose of the present study was to determine the utility of routine dissection of level II-B and level V-A in patients with papillary thyroid cancer (PTC) undergoing lateral neck dissection for ultrasound-guided fine-needle aspiration (FNA)-confirmed lateral nodal metastasis in at least one neck nodal level.
METHODS: In a retrospective review, we studied the charts of 53 consecutive patients (February 2002-December 2007) with PTC who had undergone therapeutic lateral neck dissection that included at least level II-(A and B) and/or level V-(A and B). The levels were designated as such in situ prior to surgical pathology specimen processing. Reports of the preoperative FNA cytopathologic findings, the extent of lateral neck dissection by levels, and the postoperative final histopathologic examination were reviewed.
RESULTS: A total of 53 patients underwent therapeutic lateral neck dissection for FNA-confirmed nodal metastasis of PTC at a minimum of one lateral neck level. All 53 patients had preoperative ultrasonography and FNA confirmation of lateral neck disease: 46 patients had PTC, 5 had the tall cell variant of PTC, and 2 had the follicular variant of PTC on final surgical pathology. Ten patients underwent neck dissection at the time of thyroidectomy, and 43 patients underwent neck dissection for lateral neck recurrence/persistence of PTC following a previous thyroidectomy and radioactive iodine +/- previous neck dissection. A total of 46 patients underwent unilateral neck dissection and 7 patients underwent bilateral neck dissection; thus 60 neck dissection specimens were evaluated. Level II (A and B) was excised in 59/60 neck dissections, with 33 of 59 specimens (33/59 = 60%) positive for metastasis. Level II-B was positive 5 times (5/59; 8.5-95% CI: 2.4, 20.4), and each time level II-B was positive, level II-A was also grossly (and histopathologically--seen at the time of surgery) positive for metastasis. Level III was excised 58 times and was positive in 38 specimens (38/58 = 66%). Level IV was excised 58 times and was positive in 29 specimens (29/58 = 50%). Level V (A and B) was excised 40 times and was positive in 16 specimens (16-40 = 40%). Level V-A did not account for any of the positive level V results (0%).
CONCLUSIONS: Cervical lateral neck metastases in PTC occur in a predictable pattern, with levels III, II-A, and IV most commonly involved. Patients with PTC who undergo lateral neck dissection for FNA-confirmed nodal metastases might harbor disease in level II-B, especially if level II-A is involved. We recommend elective dissection of level II-B only when level II-A is involved, based on FNA confirmation, or when it is grossly involved on intraoperative evaluation. Routine dissection of level V-B is recommended in this patient population, while elective dissection of level V-A is not necessary.