The prognostic implication and potential role of BRAF mutation in the decision to perform elective neck dissection for thyroid cancer

Response to Treatment is Highly Predictable in cN0 Patients with Papillary Thyroid Carcinoma

BACKGROUND

While involvement of macrometastatic lymph nodes is a recognized independent predictor of an adverse course in papillary thyroid cancer (PTC) patients, the clinicopathological variables associated with disease persistence/recurrence in clinically node-negative (cN0) disease are not well defined. The indications for prophylactic central neck dissection (pCND) in this patient group remain unclear as well. We aim to investigate the risk factors associated with short- and long-term persistence/recurrence of PTC in patients with cN0 disease at presentation compared to patients with PTC and cervical lymph node involvement (N1) and the response to initial treatment in these subgroups of patients.

METHODS

Data were collected retrospectively for 392 consecutive patients with PTC, 223 with cN0 disease and 169 with N1 disease, who were treated and followed at a single tertiary medical center in which pCND is not routinely performed for PTC.

RESULTS

Compared to patients with N1 disease, patients with cN0 disease had significantly smaller tumors, lower rates of multifocality, and less extrathyroidal extension. Persistency rates at 1 year were 6.7 % in the cN0 group and 47 % in the N1 group, and at last follow-up, 3.6 and 33.5 %, respectively (p = 0.001 for both time points). Within the cN0 group, those with persistent disease at 1 year (n = 15) had significantly larger tumors and higher stimulated thyroglobulin. Only six had structural residual disease, four of them lymph node metastases. All patients with persistent disease were initially treated with total thyroidectomy and radioiodine. Recurrence occurred in only three patients. After 8.3 ± 3.8 years of follow-up, eight patients with cN0 had persistent disease, three of them biochemical. Higher American Joint Committee of Cancer stage and extrathyroidal extension were the only factors that predicted disease persistence at the last follow-up in this group.

CONCLUSIONS

Patients with cN0 PTC and no distant metastases are usually disease free after thyroidectomy with/without radioactive iodine and do not need further interventions. The initial staging in these patients is a valid prognostic factor for disease outcomes.

Detection of Circulating BRAF(V600E) in Patients with Papillary Thyroid Carcinoma

BRAF(V600E) is a common mutation in papillary thyroid carcinoma (PTC) correlated with aggressive features. Our objective was to assess the feasibility and accuracy of a novel RNA-based blood assay to identify individuals with a high-risk tumor mutation in patients with PTC. Patients with benign or malignant thyroid disorders were included between September 2013 and July 2014 before either thyroidectomy (n = 62) or treatment of recurrent or metastatic PTC (n = 8). RNA was isolated from peripheral blood lymphocytes and reverse transcribed and followed by two rounds of nested PCR amplification with a restriction digest specific for wild-type BRAF. BRAF(V600E) levels were quantified with standardization curves. Circulating BRAF(V600E) levels were compared with BRAF mutation status from surgical pathologic DNA-based tissue assays. Testing characteristics and receiving-operator curve using tissue results as the gold standard were assessed. Matched blood and tissue assays for BRAF(V600E) were performed on 70 patients with PTC (stages I to IV, n = 48) or other (n = 22) thyroid tumors. Sixty-three percent of PTC patients tested positive for BRAF(V600E) with conventional tissue assays on surgical specimens. The correlation between the RNA-based blood assay and tissue BRAF status was 0.71. PTC patients harbor detectable BRAF(V600E) circulating tumor cells. This blood assay is feasible and has potential as a biomarker for prognosis, surveillance, clinical decision making, and assessment of treatment response to BRAF-targeted therapies.

Central neck compartment dissection in papillary thyroid carcinoma: An update

Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy, accounting for approximatley 90% of thyroid malignancies in areas of the world without deficit of Iodine. It’s universally accepted that total thyroidectomy is the minimal surgical treatment for patients with PTC higher than 1 cm. When a quality surgery is performed, the prognosis for PTC is excellent with 10 and 20-year overall survival rates around 90% and 85%, respectively. Lymph node metastases are very frequent in PTC, occurring in 50%-80% of PTC patients, the most of them being located in the central compartment of the neck (CCN) and with a high rate of occult or clinically undetectable disease. A lot of controversy exists regarding how to treat the central nodal compartment disease of PTC. The first problem is the lack of standardization of the terminology and concepts related to the CCN, which are clearly established and defined in this paper according to the most recent consensus documents of endocrine societies. This uniformity will provide a more consistent and clear communicaction between all the specialist involved in the treatment of PTC. CCN can be performed to treat patients with clinically detectable, radiologically suspected of intraoperative visualized nodal disease (this is defined as therapeutic) or when these findings are absent (also called prophylactic). Indicactions, advantages and disadvantages of both therapeutic and prophylactic CCN dissection are widely discussed and clear recommendations provided.