Analysis of Pattern of Laryngotracheal Invasion by Papillary Thyroid Carcinoma and Their Management: Our Experience.

To analyse the pattern of laryngotracheal invasion (LTI) by papillary-thyroid-carcinoma (PTC) and outcomes of their management. We undertook a retrospective chart review to study patterns of LTI by PTC and to evaluate outcomes of surgical modalities used to treat PTC with LTI. Out of 246cases of PTC, 26-cases had LTI (male-12, female-14, mean-age-55.6 years, range 42-73 years). Common clinical presentation were neck swelling, respiratory distress/stridor and vocal cord paralysis in 100%, 8 (30.8%) and 10 (38.5%) cases respectively. PTC was staged according to AJCC-TNM staging system (T4a-24, T4b-02, N1a-12, N1b-14, M0-25, and M1-01). CT-scan showed obvious LTI and tracheal narrowing in 11(42.3%) and 18(69.2%) cases respectively. All cases underwent total thyroidectomy with central-compartment-clearance. Unilateral and bilateral lateral-neck-dissection was performed in 08 and 06cases respectively. Pattern of Intra-operative LTI were as follows: trachea-13cases, trachea and cricoid-05cases, thyroid cartilage-6cases, trachea, cricoid and thyroid cartilage-2 cases and intra-luminal involvement in 4cases. Modified Shin's staging was used to stage LTI. LTI were superficial, deep-extra-luminal and intra-luminal in 13, 09 and 04cases respectively. LTI was managed by shave-excision, window-resection of trachea, sleeve-resection of trachea and anastomosis, partial laryngectomy and total-laryngectomy in 13,02,04,05 and 2 cases respectively. All patients received radio-active-iodine (RAI) and TSH-suppression-therapy post-operatively. Mean follow-up period was two-years (range 18-30 months). One-case had radio-iodine non-avid local recurrence with lung metastases one-year post-operatively. Shave-excision is adequate for tumours not infiltrating into outer perichondrium. Tracheal-resection and total/partial laryngectomy may be required in cases with laryngo-tracheal cartilage or intra-luminal involvement. Adequate surgical excision along with postoperative RAI and TSH-suppression-therapy gives good loco-regional disease control in PTC with LTI.