CLINICAL UNDERESTIMATION OF LARYNGEAL-CANCER - PREDICTIVE INDICATORS

Objective: To evaluate the accuracy of clinical staging of advanced la ryngeal cancer and to morphologically analyze the underestimated cases . Design: We conducted a retrospective histopathologic study of laryng es from patients who had had total laryngectomy and were seen over a 2 1-year period. Settings: Academic tertiary referral medical center. Pa rticipants: Forty-one patients had clinically staged T3 laryngeal canc er and 16 patients had T4 cancer. Intervention: Patients all underwent wide-field total laryngectomy. All larynges were processed as whole-o rgan serial sections in the coronal plane. Outcome Measure: The incide nce of clinically underestimated laryngeal cancer. During this investi gation, it became obvious that predictive indicators of thyroid cartil age involvement could be established. Results: Clinical underestimatio n had been made in approximately 50% of all T3 laryngeal cancer cases. The, extent of the cartilage involvement in the underestimated group was characterized by microinvasion without penetration; approximately 90% of the cartilage involvement affected the thyroid notch and adjace nt area. We established five objective indicators of thyroid cartilage involvement: (1) extensive cartilage ossification (risk for cartilage involvement, 73%); (2) glottic fixation (54%); (3) transglottic cance r (74%); (4) tumor length longer than the entire vocal fold length or longer than 2 cm (66%); and (5) extensive involvement of the anterior commissure (67%). Conclusions: Clinical underestimation of T4 laryngea l cancer was high because thyroid cartilage involvement was not accura tely diagnosed. We believe our indicators of thyroid cartilage involve ment will provide objective guidelines for laryngeal cancer staging an d will contribute to more reliable clinical cancer-staging decisions.