Potential Role for Carbon Nanoparticles to Guide Central Neck Dissection in Patients With Papillary Thyroid Cancer
Potential Role for Carbon Nanoparticles to Guide Central Neck Dissection in Patients With Papillary Thyroid Cancer
Papillary thyroid cancer (PTC) is the most common subtype of thyroid cancer.

 The most common site of PTC nodal metastases is the central neck, which has a reported rate
 of lymph node metastases as high as 50%~70%.

 Central neck dissection has important value to ensure accurate clinical staging and surgical
 planning.

 As a novel lymphatic tracer, carbon nanoparticles (CN) have been applied successfully in the
 detection of sentinel lymph nodes in breast and gastric cancers, while not been used as a
 lymphatic tracer for PTC. The goal of this study was to evaluate whether the use of CN
 facilitates the detection of lymph nodes, increases the number of metastatic lymph nodes
 removed, accurately reflects the metastatic condition of the central neck, and has the
 potential to protect the parathyroid glands.
Thyroid cancer is the most common endocrine malignancy. It is estimated that 96% of all new
 endocrine organ cancers will originate from the thyroid gland, resulting in approximately
 63,000 new cases in 2014 in the US1. Among them, papillary thyroid cancer (PTC) is the most
 common subtype of thyroid cancer, accounting for more than 90% of all thyroid cancers. The
 incidence of PTC has been increasing in recent years, largely because of advances in early
 detection with ultrasonography and fine-needle aspiration biopsy1-4. The most effective
 treatment for PTC is the complete removal of the primary tumor and the metastatic regional
 lymph nodes, which is a prerequisite for other adjuvant therapies. Cervical lymph node
 metastases are quite common in PTC and have been reported to occur in 12-81% of patients with
 PTC5. The most common site of PTC nodal metastases is the central neck, which has a reported
 rate of lymph node metastases as high as 50%~70%5. Lymph node metastases in this area are
 difficult to identify preoperatively because the lymph nodes typically do not appear abnormal
 on preoperative imaging6,7.

 Routine dissection of the central neck compartment is still controversial due to uncertain
 prognostic value of preserving clinically non-apparent lymph node metastasis1,8, central neck
 dissection has important value to ensure accurate clinical staging and surgical planning.
 According to previously published data, prophylactic central dissection has been suggested to
 improve disease-specific survival and to decrease local recurrence9,10 as well as
 post-treatment thyroglobulin levels9,11. Neck dissection also informs postoperative
 treatment, follow-up programs, assessment of recurrence risk, and prognosis12. However,
 routine neck dissection is controversial because of the uncertain effect on prognosis of
 clinically non-apparent lymph node metastases and because of complications, such as damage to
 the parathyroid glands, hypoparathyroidism, temporary/permanent recurrent laryngeal nerve
 injury, and tracheal or esophageal injury, that may profoundly influence a patient's qual¬ity
 of life.

 Methylene blue has been used in the detection of sentinel lymph nodes in thyroid cancer, but
 methylene blue can also stain parathyroid glands, thyroid tissue, and fat, which can make the
 anatomic boundaries unclear and thereby restrict the use of methylene blue in PTC. As a novel
 lymphatic tracer13,14, carbon nanoparticles (CN) have been applied successfully in the
 detection of sentinel lymph nodes in breast and gastric cancers, while not been used as a
 lymphatic tracer for PTC. Thus, investigators hypothesized that CN may have clinical value in
 thyroid cancer as a novel lymph node tracer to guide central neck dissection. The goal of
 this study was to evaluate whether the use of CN facilitates the detection of lymph nodes,
 increases the number of metastatic lymph nodes removed, accurately reflects the metastatic
 condition of the central neck, and has the potential to protect the parathyroid glands. In
 this study, investigators evaluated the clinical value of CN in acquiring a more accurate
 reflection of the central neck lymph node status and in guiding central neck dissection.
Inclusion Criteria:

 -  All patients were diagnosed with PTC by preoperative fine needle aspiration cytology,

 -  Underwent the initial operation in our department, and had all tumors located in one
 lobe.

 -  PTC with a tumor between 1 and 4 cm

 Exclusion Criteria:

 -  Nonthyroid cancer,

 -  Previous thyroid or parathyroid surgery

 -  Preoperative hypoparathyroidism or hypocalcemia

 -  Pregnancy or lactation

 -  Presence or suspicion of lateral neck lymph node metastasis,

 -  Age under 18 years

 -  Noncompliance with the follow-up protocol