Abstract
Objective: To evaluate the incidence and nature of thyroid gland invasion (TGI) in laryngeal carcinoma at the head and neck centres at McGill University.
Method: A retrospective case series was undertaken of 74 total laryngectomies performed at both McGill head and neck centres from 2001 to 2006. Thirteen specimens were excluded because thyroidectomies were not performed or laryngectomies were performed for nonprimary laryngeal carcinoma. Tumour stage, subsite, anatomic characteristics, and thyroid gland involvement were analyzed based on pathologic specimens. Pre- and postoperative radiation therapy treatment and thyroid function were also noted.
Results: Twenty supraglottic, 21 glottic, 15 transglottic, and 5 subglottic tumours were analyzed. Subglottic extension. 10 mm was noted in 22 specimens (36%). Cartilaginous invasion was noted in 37 of our specimens (61%), and lymph node metastasis was noted in 12 specimens (20%). One subglottic tumour demonstrated bilateral invasion of the thyroid gland and lymph node metastasis. Forty patients (54%) received preoperative radiation therapy and 34 patients (46%) received postoperative radiation therapy, with pre- and postoperative rates of hypothyroidism of 38.9% and 91%, respectively.
Conclusion: TGI is rare for laryngeal cancer. Tumours with subglottic involvement or very advanced tumours may show a greater tendency for TGI over other tumours.