Efficacy of nodal dissection for treatment of persistent/recurrent papillary thyroid cancer

Prognostic utility of BRAF mutation in papillary thyroid cancer

Papillary thyroid cancer (PTC) is a common endocrine malignancy that frequently harbors the oncogenic T1799A BRAF mutation. As a novel prognostic molecular marker, this mutation has received considerable attention in recent years for its potential utility in the risk stratification and management of PTC. In PTC, BRAF mutation is closely associated with extrathyroidal extension, lymph node metastasis, advanced tumor stages, disease recurrence, and even patient mortality. Many of the responsible molecular derangements promoted by, or associated with, BRAF mutation have been identified, including over-expression of tumor-promoting genes, suppression of tumor-suppressor genes, and silencing of thyroid iodide-handling genes, resulting in impairment or loss of radioiodine avidity and hence the failure of radioiodine treatment of PTC. BRAF mutation can be readily tested on thyroid fine needle aspiration biopsy specimens, with high preoperative predictive probabilities for clinicopathological outcomes of PTC. As such, the knowledge of BRAF mutation status can facilitate more accurate risk stratification and better decision making at various steps in the management of PTC, from preoperative planning of initial surgical scale to postoperative decisions about appropriate radioiodine treatment and thyroid-stimulating hormone suppression, and to selections of appropriate surveillance modalities for PTC recurrence. The greatest utility of BRAF mutation status is in those cases where traditional clinicopathological criteria alone would otherwise be unreliable in the risk stratification and management of PTC. Use of this unique molecular marker, in conjunction with conventional clinicopathological risk factors, to assist the prognostication of PTC is likely to improve the efficiency of contemporary management of thyroid cancer.

Long-term efficacy of lymph node reoperation for persistent papillary thyroid cancer

OBJECTIVE

The objective of the study was to determine the outcome of surgical resection of metastatic papillary thyroid cancer (PTC) in cervical lymph nodes after failure of initial surgery and I(131) therapy.

DESIGN

This was a retrospective clinical study.

SETTING

The study was conducted at a university-based tertiary cancer hospital.

PATIENTS

A cohort of 95 consecutive patients with recurrent/persistent PTC in the neck underwent initial reoperation during 1999-2005. All had previous thyroidectomy (+/-nodal dissection) and I(131) therapy. Twenty-five patients with antithyroglobulin (Tg) antibodies were subsequently excluded.

MAIN OUTCOME MEASURES

Biochemical complete remission (BCR) was stringently defined as undetectable TSH-stimulated serum Tg.

RESULTS

A total of 107 lymphadenectomies were undertaken in these 70 patients through January 2010. BCR was initially achieved in 12 patients (17%). Of the 58 patients with detectable postoperative Tg, 28 had a second reoperation and BCR was achieved in five (18%), seven had a third reoperation, and none achieved BCR. No patient achieving BCR had a subsequent recurrence after a mean follow-up of 60 months (range 4-116 months). In addition, two more patients achieved BCR during long-term follow-up without further intervention. In total, 19 patients (27%) achieved BCR and 32 patients (46%) achieved a TSH-stimulated Tg less than 2.0 ng/ml. Patients who did not achieve BCR had significant reduction in Tg after the first (P < 0.001) and second (P = 0.008) operations. No patient developed detectable distant metastases or died from PTC.

CONCLUSIONS

Surgical resection of persistent PTC in cervical lymph nodes achieves BCR, when most stringently defined, in 27% of patients, sometimes requiring several surgeries. No biochemical or clinical recurrences occurred during follow-up. In patients who do not achieve BCR, Tg levels were significantly reduced. The long-term durability and impact of this intervention will require further investigation.

Controversies in the surgical management of newly diagnosed and recurrent/residual thyroid cancer

BACKGROUND

Thyroid surgery is the mainstay of treatment for thyroid cancer, but there are options for the surgical approach. There is a general agreement that the goal of thyroid cancer surgery is to remove evident disease, minimize treatment and disease-related morbidity, minimize the risk of recurrence and metastatic spread, and facilitate long-term follow-up. Within these parameters, however, there are a number of controversies regarding the extent of surgery.

SUMMARY

To minimize the risk of recurrence and to optimize the treatment of patients with thyroid cancer, a total thyroidectomy should be performed as the initial operation if the preoperative diagnosis is consistent with thyroid cancer. Macroscopic lymph node involvement does impact recurrence and may influence survival. Therefore, a preoperative ultrasound evaluation of the neck is essential before operative intervention. If pathologic nodes are identified in either the central or lateral neck they should be removed at the initial operation. The role of prophylactic central neck dissection remains controversial, and the risks of this procedure may outweigh the benefits. Therefore, we do not recommend the routine performance of a central neck dissection. Similar to the recent American Thyroid Association guidelines, we agree that their may be a subset of high-risk patients who may benefit from a prophylactic central neck dissection, but that population has yet to be defined. The extent of lateral dissection that is required is also debated as levels 1 and 5 lymph node involvement is uncommon with thyroid cancer. Recurrent disease can be challenging to remove, but several adjuncts are available to maximize the safety and efficacy of reoperation, making it the best option for patients with localized recurrences.

CONCLUSIONS

Total thyroidectomy and neck dissection are very safe procedures when performed by experienced surgeons and can play an essential role in the management of patients with thyroid cancer.

Approach and safety of comprehensive central compartment dissection in patients with recurrent papillary thyroid carcinoma

BACKGROUND

Despite the generally favorable prognosis of patients with papillary thyroid cancers, 10-year recurrence rates for patients with stage I to III disease is greater than 20%, with central compartment recurrences common among these recurrent sites.

METHODS

This study is a retrospective analysis of consecutive patients treated by a single surgeon over an 18-month period of time terminating in 2003.

RESULTS

Sixty-three patients underwent a comprehensive dissection of levels VI and VII for papillary thyroid carcinoma during this period. There was a female predominance of 2:1, with 48% of patients being greater than 45 years of age. The median number of lymph nodes identified was 16 (range, 3-52), with 7 (1-20) lymph nodes pathologically involved. Permanent hypoparathyroidism was present on presentation in 13% of patients and developed in an additional 5% following surgery. Although recurrent laryngeal paralysis was present on presentation among 8 (13%) of patients, no patients experienced paralysis of documented functioning recurrent laryngeal nerves or necessitated tracheotomy. Postoperative thyroglobulin levels were reduced to nondetectable in 71% of the informative cases. Over 60% of patients were discharged on their first postoperative day.

CONCLUSION

Bilateral paratracheal and superior mediastinal dissection is an oncologically safe procedure exhibiting minimal morbidity when performed among experienced individuals despite multiple prior surgical procedures or existing vocal cord paralysis.