True statement about Infraglottic carcinoma larynx

SUBGLOTTIC CANCER (1-2%) Subglottic region extends from glottic area to lower border of cricoid cailage. Lesions of this region are rare. Spread:- Growth stas on one side of subglottis and may spread around the anterior wall to the opposite side or downwards to the trachea. Upward spread to the vocal cords is late and that is why hoarseness is not an early symptom. Subglottic growths can invade cricothyroid membrane, thyroid gland and ribbon muscles of neck. Lymphatic metastases go to prelaryngeal, pretracheal, paratracheal and lower jugular nodes(mediastinal lymph nodes). Symptoms:- The earliest presentation of subglottic cancer may be stridor or laryngeal obstruction but this is often late and by this time disease has already spread sufficiently to encroach the airway. Hoarseness in subglottic cancer indicates spread of disease to the undersurface of vocal cords, infiltration of thyroarytenoid muscle or the involvement of recurrent laryngeal nerve at the cricoarytenoid joint. Hoarseness is a late feature of subglottic growth. Ref:-Dhingra; pg num:-309