{'fraction_non_alphanumeric': 0.0399400898652022, 'fraction_numerical': 0.028457314028956564, 'mean_word_length': 4.911504424778761, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
[Prevalence of metastatic lymph nodes in the central compartment of the neck following prophylactic clearance for papillary thyroid cancer].

INTRODUCTION
Clinical suspicion of regional lymph nodes' involvement is present in approximately 10% of patients with papillary thyroid cancer (PTC). Nevertheless, among the remaining 90% of individuals staged pre-, or intraoperatively as node negative, some cases of metastatic lymph nodes from PTC are found on final pathological report. Both quality of life and survival can be influence by eventual nodal recurrence in this group of patients.


AIMS
To evaluate the prevalence of metastatic lymph nodes in patients with PTC in stage cT1-3NxMx undergoing prophylactic central compartment lymph nodes' clearance, and to assess associated morbidity.


METHODS
Clinical database of patients with thyroid cancer undergoing surgery in 2009 and 2010 was retrospectively analyzed. 116 (78.9%) patients with PTC, with pre-, or intraoperatively not suspected lymph nodes were identified. Total extracapsular thyroidectomy with one-stage prophylactic bilateral level VI lymph nodes clearance was performed in all patients. The numbers of excised and metastatic lymph nodes within the surgical specimen were analyzed. In addition, surgical morbidity was evaluated.


RESULTS
Metastatic level VI lymph nodes' involvement was found in 22 of 116 (19%) patients. Mean number of lymph nodes within the surgical specimen was 4.5 +/- 3.3 (1-17, median 4). Mean number of 1 +/- 2 metastatic lymph nodes were identified (0-7, median 1). Transient vs. permanent hypoparathyroidism was found in 31 (26.7%) vs. 2 (1.7%) and temporary vs. permanent recurrent laryngeal nerve injury was found in 7 (3.0%) vs. 2 (0.9%) of 232 nerves at risk.


CONCLUSIONS
One fifth of PTC patients with clinically and intraoperatively non-suspected lymph nodes within the central compartment are positive for metastatic nodal de- posits in surgical specimen following prophylactic level VI clearance.