Ask the Experts - Neck Dissection After Total Thyroidectomy and Ablation?
Ask the Experts - Neck Dissection After Total Thyroidectomy and Ablation?
Total thyroidectomy in a 24-year-old female with histologically confirmed papillary thyroid carcinoma of the right lobe without neck dissection found adherence of the right thyroid lobe to the strap muscles and slightly to the esophagus with no obvious lymph nodes. Preoperative assessment revealed no vocal cord palsy. Postoperatively, she developed right recurrent laryngeal nerve palsy, which has not resolved. Grossly, the encapsulated tumor was 4.0 x 2.0 x 3.5 cm, with some tumor vesicles noted at one edge of the specimen very close to the surface. Histologically, surgical margins were clear, with capsular invasion present in some areas.
Empirical ablation with 80 mCi 131-I was given after 2 months. D4 post-ablation scan showed uptake at the thyroid bed and one physiological "hotspot" at the bowel region. One month after ablation, clinically palpable cervical nodes are noted: 0.5 x 0.5-cm nodes in the right superior deep cervical chain, 1 x 1-cm nodes in the left posterior triangle superiorly, and 0.5 x 0.5-cm nodes in the left anterior triangle. Magnetic resonance imaging (MRI) showed 2 small lymph nodes, 5-7 mm, at the level of the right mandibular angle around the right carotid sheath and an incidental finding of a solitary antral left maxillary polyp.
My questions are as follows: (1) Do the operative findings satisfy the Mayo Clinic's poor prognostic factor of extrathyroid invasion of local tissue, despite the histologically disease-free surgical margins? (2) How should the clinically palpable nodes be managed if they are not increasing in size? (3) If neck dissection is indicated, when should it be done? Should regions II to VI bilaterally be dissected? (4) Is there a need for consolidation of treatment with radiotherapy to the thyroid bed in view of the operative findings for presumed residual microscopic disease?
This is a young female with papillary thyroid cancer who underwent total thyroidectomy followed with iodine ablation. The tumor was encapsulated, and the surgical margins were clear. These findings would normally indicate a better prognosis. However, it is not clear whether the adjacent soft tissue was involved, a finding that would be considered an adverse prognostic factor. This is in addition to the tumor size of 4 cm, which is borderline between better and worse risks of local recurrence. Nevertheless, even though neck dissection was not performed, only small neck nodes are palpable. In addition, iodine scan after the ablation iodine dose showed uptake in the thyroid bed but not in neck lymph nodes.
In my opinion, the neck does not require dissection because it is not indicated in well-differentiated thyroid cancer. If the tumor invaded adjacent muscle, her highest risk is local recurrence. This can be verified with the pathologist: the small lymph nodes would either be normal or contain microscopic disease that should have been ablated with the iodine therapy. A good method to monitor her progress would be to check the thyroglobulin blood levels, which should be less than 23 ng/mL in this patient; elevated levels indicate a higher risk of recurrence. If a lymph node is suspicious, ultrasound-guided, fine-needle aspiration would be sensitive to potential residual disease.
Total thyroidectomy in a 24-year-old female with histologically confirmed papillary thyroid carcinoma of the right lobe without neck dissection found adherence of the right thyroid lobe to the strap muscles and slightly to the esophagus with no obvious lymph nodes. Preoperative assessment revealed no vocal cord palsy. Postoperatively, she developed right recurrent laryngeal nerve palsy, which has not resolved. Grossly, the encapsulated tumor was 4.0 x 2.0 x 3.5 cm, with some tumor vesicles noted at one edge of the specimen very close to the surface. Histologically, surgical margins were clear, with capsular invasion present in some areas.
Empirical ablation with 80 mCi 131-I was given after 2 months. D4 post-ablation scan showed uptake at the thyroid bed and one physiological "hotspot" at the bowel region. One month after ablation, clinically palpable cervical nodes are noted: 0.5 x 0.5-cm nodes in the right superior deep cervical chain, 1 x 1-cm nodes in the left posterior triangle superiorly, and 0.5 x 0.5-cm nodes in the left anterior triangle. Magnetic resonance imaging (MRI) showed 2 small lymph nodes, 5-7 mm, at the level of the right mandibular angle around the right carotid sheath and an incidental finding of a solitary antral left maxillary polyp.
My questions are as follows: (1) Do the operative findings satisfy the Mayo Clinic's poor prognostic factor of extrathyroid invasion of local tissue, despite the histologically disease-free surgical margins? (2) How should the clinically palpable nodes be managed if they are not increasing in size? (3) If neck dissection is indicated, when should it be done? Should regions II to VI bilaterally be dissected? (4) Is there a need for consolidation of treatment with radiotherapy to the thyroid bed in view of the operative findings for presumed residual microscopic disease?
This is a young female with papillary thyroid cancer who underwent total thyroidectomy followed with iodine ablation. The tumor was encapsulated, and the surgical margins were clear. These findings would normally indicate a better prognosis. However, it is not clear whether the adjacent soft tissue was involved, a finding that would be considered an adverse prognostic factor. This is in addition to the tumor size of 4 cm, which is borderline between better and worse risks of local recurrence. Nevertheless, even though neck dissection was not performed, only small neck nodes are palpable. In addition, iodine scan after the ablation iodine dose showed uptake in the thyroid bed but not in neck lymph nodes.
In my opinion, the neck does not require dissection because it is not indicated in well-differentiated thyroid cancer. If the tumor invaded adjacent muscle, her highest risk is local recurrence. This can be verified with the pathologist: the small lymph nodes would either be normal or contain microscopic disease that should have been ablated with the iodine therapy. A good method to monitor her progress would be to check the thyroglobulin blood levels, which should be less than 23 ng/mL in this patient; elevated levels indicate a higher risk of recurrence. If a lymph node is suspicious, ultrasound-guided, fine-needle aspiration would be sensitive to potential residual disease.